Small passenger car transmission test; Chevrolet LUV transmission

NASA Technical Reports Server (NTRS)

Bujold, M. P.

1980-01-01

A 1978 Chevrolet LUV manual transmission tested per the applicable portions of a passenger car automatic transmission test code (SAE J65lb) which required drive performance, coast performance, and no load test conditions. Under these test conditions, the transmission attained maximum efficiencies in the upper ninety percent range for both drive performance tests and coast performance tests. The major results of this test (torque, speed, and efficiency curves) are presented. Graphs map the complete performance characteristics for the Chevrolet LUV transmission.

Small passenger car transmission test; Ford C4 transmission

NASA Technical Reports Server (NTRS)

Bujold, M. P.

1980-01-01

A 1979 Ford C4 automatic transmission was tested per a passenger car automatic transmission test code (SAE J651b) which required drive performance, coast performance, and no load test conditions. Under these test conditions, the transmission attained maximum efficiencies in the mid-eighty percent range for both drive performance tests and coast performance tests. The major results of this test (torque, speed, and efficiency curves) are presented. Graphs map the complete performance characteristics for the Ford C4 transmission.

A multimodal assessment of driving performance in HIV infection.

PubMed

Marcotte, T D; Wolfson, T; Rosenthal, T J; Heaton, R K; Gonzalez, R; Ellis, R J; Grant, I

2004-10-26

To examine if HIV-seropositive (HIV+) individuals are at risk for impaired driving. Sixty licensed drivers (40 HIV+, 20 HIV-) completed a neuropsychological (NP) test battery and driving assessments. Eleven HIV+ subjects were NP-impaired. Driving-related skills were assessed using 1) two driving simulations (examining accident avoidance and navigational abilities), 2) the Useful Field of View (UFOV) test, and 3) an on-road evaluation. HIV+ NP-impaired subjects had greater difficulty than cognitively intact subjects on all driving measures, whereas the HIV- and HIV+ NP-normal groups performed similarly. On the UFOV, the HIV+ NP-impaired group had worse performance on Visual Processing and Divided Attention tasks but not in overall risk classification. They also had a higher number of simulator accidents (1.3 vs 2.0; p = 0.03), were less efficient at completing the navigation task (3.2 vs 9.2 blocks; p = 0.001), and were more likely to fail the on-road evaluation (6 vs 36%; p = 0.02). Impairment in Executive Functioning was the strongest NP predictor of failing the on-road drive test. NP performance and both simulations independently contributed to a model predicting 48% of the variance in on-road performance. HIV+ NP-impaired individuals are at increased risk for on-road driving impairments, whereas HIV+ individuals with normal cognition are not at a significantly higher risk than HIV- subjects. Executive Functioning is most strongly associated with impaired on-road performance. Cognitive and simulator testing may each provide data in identifying driving-impaired individuals.

Standard operation procedures for conducting the on-the-road driving test, and measurement of the standard deviation of lateral position (SDLP).

PubMed

Verster, Joris C; Roth, Thomas

2011-01-01

This review discusses the methodology of the standardized on-the-road driving test and standard operation procedures to conduct the test and analyze the data. The on-the-road driving test has proven to be a sensitive and reliable method to examine driving ability after administration of central nervous system (CNS) drugs. The test is performed on a public highway in normal traffic. Subjects are instructed to drive with a steady lateral position and constant speed. Its primary parameter, the standard deviation of lateral position (SDLP), ie, an index of 'weaving', is a stable measure of driving performance with high test-retest reliability. SDLP differences from placebo are dose-dependent, and do not depend on the subject's baseline driving skills (placebo SDLP). It is important that standard operation procedures are applied to conduct the test and analyze the data in order to allow comparisons between studies from different sites.

Small passenger car transmission test: Mercury Lynx ATX transmission

NASA Technical Reports Server (NTRS)

Bujold, M. P.

1981-01-01

The testing of a Mercury Lynx automatic transmission is reported. The transmission was tested in accordance with a passenger car automatic transmission test code (SAE J65lb) which required drive performance, coast performance, and no load test conditions. Under these conditions, the transmission attained maximum efficiencies in the mid-ninety percent range both for drive performance test and coast performance tests. The torque, speed, and efficiency curves are presented, which provide the complete performance characteristics for the Mercury Lynx automatic transmission.

Neuropsychological assessment of driving ability and self-evaluation: a comparison between driving offenders and a control group.

PubMed

Zingg, Christina; Puelschen, Dietrich; Soyka, Michael

2009-12-01

The relationship between performance in neuropsychological tests and actual driving performance is unclear and results of studies on this topic differ. This makes it difficult to use neuropsychological tests to assess driving ability. The ability to compensate cognitive deficits plays a crucial role in this context. We compared neuropsychological test results and self-evaluation ratings between three groups: driving offenders with a psychiatric diagnosis relevant for driving ability (mainly alcohol dependence), driving offenders without such a diagnosis and a control group of non-offending drivers. Subjects were divided into two age categories (19-39 and 40-66 years). It was assumed that drivers with a psychiatric diagnosis relevant for driving ability and younger driving offenders without a psychiatric diagnosis would be less able to adequately assess their own capabilities than the control group. The driving offenders with a psychiatric diagnosis showed poorer concentration, reactivity, cognitive flexibility and problem solving, and tended to overassess their abilities in intelligence and attentional functions, compared to the other two groups. Conversely, younger drivers rather underassessed their performance.

Neurocognitive Correlates of Young Drivers' Performance in a Driving Simulator.

PubMed

Guinosso, Stephanie A; Johnson, Sara B; Schultheis, Maria T; Graefe, Anna C; Bishai, David M

2016-04-01

Differences in neurocognitive functioning may contribute to driving performance among young drivers. However, few studies have examined this relation. This pilot study investigated whether common neurocognitive measures were associated with driving performance among young drivers in a driving simulator. Young drivers (19.8 years (standard deviation [SD] = 1.9; N = 74)) participated in a battery of neurocognitive assessments measuring general intellectual capacity (Full-Scale Intelligence Quotient, FSIQ) and executive functioning, including the Stroop Color-Word Test (cognitive inhibition), Wisconsin Card Sort Test-64 (cognitive flexibility), and Attention Network Task (alerting, orienting, and executive attention). Participants then drove in a simulated vehicle under two conditions-a baseline and driving challenge. During the driving challenge, participants completed a verbal working memory task to increase demand on executive attention. Multiple regression models were used to evaluate the relations between the neurocognitive measures and driving performance under the two conditions. FSIQ, cognitive inhibition, and alerting were associated with better driving performance at baseline. FSIQ and cognitive inhibition were also associated with better driving performance during the verbal challenge. Measures of cognitive flexibility, orienting, and conflict executive control were not associated with driving performance under either condition. FSIQ and, to some extent, measures of executive function are associated with driving performance in a driving simulator. Further research is needed to determine if executive function is associated with more advanced driving performance under conditions that demand greater cognitive load. Copyright © 2016 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Standard operation procedures for conducting the on-the-road driving test, and measurement of the standard deviation of lateral position (SDLP)

PubMed Central

Verster, Joris C; Roth, Thomas

2011-01-01

This review discusses the methodology of the standardized on-the-road driving test and standard operation procedures to conduct the test and analyze the data. The on-the-road driving test has proven to be a sensitive and reliable method to examine driving ability after administration of central nervous system (CNS) drugs. The test is performed on a public highway in normal traffic. Subjects are instructed to drive with a steady lateral position and constant speed. Its primary parameter, the standard deviation of lateral position (SDLP), ie, an index of ‘weaving’, is a stable measure of driving performance with high test–retest reliability. SDLP differences from placebo are dose-dependent, and do not depend on the subject’s baseline driving skills (placebo SDLP). It is important that standard operation procedures are applied to conduct the test and analyze the data in order to allow comparisons between studies from different sites. PMID:21625472

Cognitive deficits are associated with poorer simulated driving in older adults with heart failure

PubMed Central

2013-01-01

Background Cognitive impairment is prevalent in older adults with heart failure (HF) and associated with reduced functional independence. HF patients appear at risk for reduced driving ability, as past work in other medical samples has shown cognitive dysfunction to be an important contributor to driving performance. The current study examined whether cognitive dysfunction was independently associated with reduced driving simulation performance in a sample of HF patients. Methods 18 persons with HF (67.72; SD = 8.56 year) completed echocardiogram and a brief neuropsychological test battery assessing global cognitive function, attention/executive function, memory and motor function. All participants then completed the Kent Multidimensional Assessment Driving Simulation (K-MADS), a driving simulator scenario with good psychometric properties. Results The sample exhibited an average Mini Mental State Examination (MMSE) score of 27.83 (SD = 2.09). Independent sample t-tests showed that HF patients performed worse than healthy adults on the driving simulation scenario. Finally, partial correlations showed worse attention/executive and motor function were independently associated with poorer driving simulation performance across several indices reflective of driving ability (i.e., centerline crossings, number of collisions, % of time over the speed limit, among others). Conclusion The current findings showed that reduced cognitive function was associated with poor simulated driving performance in older adults with HF. If replicated using behind-the-wheel testing, HF patients may be at elevated risk for unsafe driving and routine driving evaluations in this population may be warranted. PMID:24499466

Driving performance in adults with ADHD: results from a randomized, waiting list controlled trial with atomoxetine.

PubMed

Sobanski, E; Sabljic, D; Alm, B; Dittmann, R W; Wehmeier, P M; Skopp, G; Strohbeck-Kühner, P

2013-08-01

To investigate effects of a 12-week treatment with atomoxetine (ATX) on driving performance in real traffic, driving-related neuropsychological performance tests and self-evaluation of driving in adult patients with ADHD compared to an untreated control group with ADHD. Parallel group design with an ATX and a waiting list group. At baseline and endpoint patients were evaluated with a standardized on-road driving test (SDBO), a driving-related neuropsychological test battery (Act and React Test System [ART2020]), and subjective measures of driving performance (one-week driving diary, Driver Coping Questionnaire). Forty-three of the 64 included patients completed the study (n=22 ATX, n=21 controls). Mean intervention period was 11.9±3.0 weeks, mean daily ATX dosage was 71.6±14.9mg. At endpoint, 60.1% of patients treated with ATX and 0% of waiting list group had reduced ADHD symptoms by greater or equal to 30%. In SDBO, ATX group reduced driving errors in three of four driving performance categories (attention, P<0.05; risk-related self-control, P<0.005; driver skills, P<0.001), number of driving errors remained stable in control group. At endpoint, 47.6% of control group and 18.2% of ATX group (P<0.05) did not fulfil the driving fitness criteria according to German Guidelines (percentile rank less or equal to 16 in one or more subtests in ART2020). Total number of self-reported critical traffic situations decreased from 12.0 to 6.8 per week in ATX group (P<0.05) and remained stable in controls by 9.3 and 9.9 at baseline and endpoint (ns). Coping strategies with stressful traffic situations did not change within both groups. Our study provides first evidence that treatment with ATX improves driving performance in real traffic in adults with ADHD. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Neuropsychological Assessment of Driving Safety Risk in Older Adults With and Without Neurologic Disease

PubMed Central

Anderson, Steven W.; Aksan, Nazan; Dawson, Jeffrey D.; Uc, Ergun Y.; Johnson, Amy M.; Rizzo, Matthew

2013-01-01

Decline in cognitive abilities can be an important contributor to the driving problems encountered by older adults, and neuropsychological assessment may provide a practical approach to evaluating this aspect of driving safety risk. The purpose of the present study was to evaluate several commonly used neuropsychological tests in the assessment of driving safety risk in older adults with and without neurological disease. A further goal of this study was to identify brief combinations of neuropsychological tests that sample performances in key functional domains and thus could be used to efficiently assess driving safety risk. 345 legally licensed and active drivers over the age of 50, with either no neurologic disease (N=185), probable Alzheimer's disease (N=40), Parkinson's disease (N=91), or stroke (N=29), completed vision testing, a battery of 10 neuropsychological tests, and an 18 mile drive on urban and rural roads in an instrumented vehicle. Performances on all neuropsychological tests were significantly correlated with driving safety errors. Confirmatory factor analysis was used to identify 3 key cognitive domains assessed by the tests (speed of processing, visuospatial abilities, and memory), and several brief batteries consisting of one test from each domain showed moderate corrected correlations with driving performance. These findings are consistent with the notion that driving places demands on multiple cognitive abilities that can be affected by aging and age-related neurological disease, and that neuropsychological assessment may provide a practical off-road window into the functional status of these cognitive systems. PMID:22943767

Neuropsychological assessment of driving safety risk in older adults with and without neurologic disease.

PubMed

Anderson, Steven W; Aksan, Nazan; Dawson, Jeffrey D; Uc, Ergun Y; Johnson, Amy M; Rizzo, Matthew

2012-01-01

Decline in cognitive abilities can be an important contributor to the driving problems encountered by older adults, and neuropsychological assessment may provide a practical approach to evaluating this aspect of driving safety risk. The purpose of the present study was to evaluate several commonly used neuropsychological tests in the assessment of driving safety risk in older adults with and without neurological disease. A further goal of this study was to identify brief combinations of neuropsychological tests that sample performances in key functional domains and thus could be used to efficiently assess driving safety risk. A total of 345 legally licensed and active drivers over the age of 50, with no neurologic disease (N = 185), probable Alzheimer's disease (N = 40), Parkinson's disease (N = 91), or stroke (N = 29), completed vision testing, a battery of 10 neuropsychological tests, and an 18-mile drive on urban and rural roads in an instrumented vehicle. Performances on all neuropsychological tests were significantly correlated with driving safety errors. Confirmatory factor analysis was used to identify 3 key cognitive domains assessed by the tests (speed of processing, visuospatial abilities, and memory), and several brief batteries consisting of one test from each domain showed moderate corrected correlations with driving performance. These findings are consistent with the notion that driving places demands on multiple cognitive abilities that can be affected by aging and age-related neurological disease, and that neuropsychological assessment may provide a practical off-road window into the functional status of these cognitive systems.

Next-day effects of ramelteon (8 mg), zopiclone (7.5 mg), and placebo on highway driving performance, memory functioning, psychomotor performance, and mood in healthy adult subjects.

PubMed

Mets, Monique A J; de Vries, Juna M; de Senerpont Domis, Lieke M; Volkerts, Edmund R; Olivier, Berend; Verster, Joris C

2011-10-01

To evaluate the next-morning residual effects of ramelteon (8 mg), zopiclone (7.5 mg), and placebo on driving performance, memory functioning, psychomotor performance, and mood in healthy adult subjects following bedtime dosing and a middle of the night awakening. Single-center, randomized, double-blind, double-dummy, placebo-controlled, crossover study. Utrecht University, The Netherlands. 30 healthy volunteers (15 males and 15 females). a single dose of ramelteon (8 mg), zopiclone (7.5 mg), and placebo, administered at bedtime. A balance test was performed at night. Other tests were performed the following morning, 8.5 h after administration. Subjects performed a 100-km highway driving test in normal traffic. Primary outcome measure was the standard deviation of the lateral position (SDLP), i.e., the weaving of the car. After driving, cognitive, memory, and psychomotor tests were performed and mood was assessed. SDLP was significantly increased after the intake of ramelteon (+2.2 cm) and zopiclone (+2.9 cm). Ramelteon and zopiclone produced significant impairment on reaction time (P<0.024) in the Sternberg Memory Scanning Test, slow (P<0.007) and fast (P<0.010) tracking, reaction speed (P<0.015) and tracking (P<0.001) in the Divided Attention Test, and delayed recall (P<0.032) in the Word Learning Test. In contrast to ramelteon, zopiclone additionally impaired performance on the Digit Symbol Substitution Test (P<0.001) and the balance test (P<0.001). Ramelteon (8 mg) and zopiclone (7.5 mg) significantly impaired driving performance, cognitive, memory, and psychomotor performance the morning following bedtime administration. In contrast to zopiclone, ramelteon produced no balance impairments. CLINICAL TRIAL IDENTIFIER: NCT00319215 (www.clinicaltrials.gov).

Performance testing of EVs in the EPRI/TVA EV program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Driggans, R.L.

1983-01-01

Performance testing has been completed on four electric vehicles: the Grumman-Olson Kubvan, SCT Electric (VW) Pickup, Jet Industries Electrica, and VW Electrotransporter Bus. The tests performed included vehicle dc energy consumption and driving range at constant speeds and on the SAE J227a C cycle, on-road driving range, hill climbing, maximum acceleration, top speed, and braking performance. Descriptions of the vehicles tested and comparisons of major performance parameters on all four vehicles are presented. This testing was performed at the TVA Electric Vehicle Test Facility.

Saccadic eye movement performance as an indicator of driving ability in elderly drivers.

PubMed

Schmitt, Kai-Uwe; Seeger, Rolf; Fischer, Hartmut; Lanz, Christian; Muser, Markus; Walz, Felix; Schwarz, Urs

2015-01-01

Regular checking of the fitness to drive of elderly car-license holders is required in some countries, and this will become increasingly important as more countries face aging populations. The present study investigated whether the analysis of saccadic eye movements could be used as a screening method for the assessment of driving ability. Three different paradigms (prosaccades, antisaccades, and visuovisual interactive (VVI) saccades) were used to test saccadic eye movements in 144 participants split into four groups: elderly drivers who came to the attention of road authorities for suspected lack of fitness to drive, a group of elderly drivers who served as a comparison group, a group of neurology patients with established brain lesion diagnoses, and a young comparison group. The group of elderly drivers with suspected deficits in driving skills also underwent a medical examination and a practical on-road driving test. The results of the saccadic eye tests of the different groups were compared. Antisaccade results indicated a strong link to driving behaviour: elderly drivers who were not fit to drive exhibited a poor performance on the antisaccade task and the performance in the VVI task was also clearly poorer in this group. Testing saccadic eye movements appears to be a promising and efficient method for screening large numbers of people such as elderly drivers. This study indicated a link between antisaccade performance and the ability to drive. Hence, measuring saccadic eye movements should be considered as a tool for screening the fitness to drive.

Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Performance Verification Report: AMSU-A1 Antenna Drive Subsystem, PN 1331720-2, S/N 106

NASA Technical Reports Server (NTRS)

Luu, D.

1999-01-01

This is the Performance Verification Report, AMSU-A1 Antenna Drive Subsystem, P/N 1331720-2, S/N 106, for the Integrated Advanced Microwave Sounding Unit-A (AMSU-A). The antenna drive subsystem of the METSAT AMSU-A1, S/N 106, P/N 1331720-2, completed acceptance testing per A-ES Test Procedure AE-26002/lD. The test included: Scan Motion and Jitter, Pulse Load Bus Peak Current and Rise Time, Resolver Reading and Position Error, Gain/ Phase Margin, and Operational Gain Margin. The drive motors and electronic circuitry were also tested at the component level. The drive motor test includes: Starting Torque Test, Motor Commutation Test, Resolver Operation/ No-Load Speed Test, and Random Vibration. The electronic circuitry was tested at the Circuit Card Assembly (CCA) level of production; each test exercised all circuit functions. The transistor assembly was tested during the W3 cable assembly (1356941-1) test.

Test drives in the Daimler-Benz driving simulator with drivers under diazepam

DOT National Transportation Integrated Search

1990-05-01

The research project investigated the influence of diazepam on the driving performance measured in the Daimler-Benz Driving Simulator. Test subjects were male students; 20 received a medium, and 20 received a high dosage of diazepam. A third group of...

Effects of two doses of methylphenidate on simulator driving performance in adults with attention deficit hyperactivity disorder.

PubMed

Barkley, Russell A; Murphy, Kevin R; O'Connell, Trisha; Connor, Daniel F

2005-01-01

Numerous studies have documented an increased frequency of vehicular crashes, traffic citations, driving performance deficits, and driving-related cognitive impairments in teens and adults with attention deficit hyperactivity disorder. The present study evaluated the effects of two single, acute doses of methylphenidate (10 and 20 mg) and a placebo on the driving performance of 53 adults with ADHD (mean age=37 years, range=18-65) using a virtual reality driving simulator, examiner and self-ratings of simulator performance, and a continuous performance test (CPT) to evaluate attention and inhibition. A double-blind, drug-placebo, within-subjects crossover design was used in which all participants were tested at baseline and then experienced all three drug conditions. A significant beneficial effect for the high dose of medication was observed on impulsiveness on CPT, variability of steering in the standard driving course, and driving speed during the obstacle course. A beneficial effect of the low dose of medication also was evident on turn signal use during the standard driving course. An apparent practice effect was noted on some of the simulator measures between the baseline and subsequent testing sessions that may have interacted with and thereby obscured drug effects on those measures. The results, when placed in the context of prior studies of stimulants on driving performance, continue to recommend their clinical use as one means of reducing the driving risks in ADHD teens and adults. Given the significantly higher risk of adverse driving outcomes associated with ADHD, industry needs to better screen for ADHD among employees who drive as part of employment so as to improve safety and reduce costs. Use of stimulants to treat the adult ADHD driver may reduce safety risks.

Acute tolerance to alcohol impairment of behavioral and cognitive mechanisms related to driving: drinking and driving on the descending limb.

PubMed

Weafer, Jessica; Fillmore, Mark T

2012-04-01

Alcohol effects on behavioral and cognitive mechanisms influence impaired driving performance and decisions to drive after drinking (Barry 1973; Moskowitz and Robinson 1987). To date, research has focused on the ascending limb of the blood alcohol curve, and there is little understanding of how acute tolerance to impairment of these mechanisms might influence driving behavior on the descending limb. To provide an integrated examination of the degree to which alcohol impairment of motor coordination and inhibitory control contributes to driving impairment and decisions to drive on the ascending and descending limbs of the blood alcohol curve. Social-drinking adults (N = 20) performed a testing battery that measured simulated driving performance and willingness to drive, as well as mechanisms related to driving: motor coordination (grooved pegboard), inhibitory control (cued go/no-go task), and subjective intoxication. Performance was tested in response to placebo and a moderate dose of alcohol (0.65 g/kg) twice at comparable blood alcohol concentrations: once on the ascending limb and again on the descending limb. Impaired motor coordination and subjective intoxication showed acute tolerance, whereas driving performance and inhibitory control showed no recovery from impairment. Greater motor impairment was associated with poorer driving performance under alcohol, and poorer inhibitory control was associated with more willingness to drive. Findings suggest that acute tolerance to impairment of motor coordination is insufficient to promote recovery of driving performance and that the persistence of alcohol-induced disinhibition might contribute to risky decisions to drive on the descending limb.

Acute tolerance to alcohol impairment of behavioral and cognitive mechanisms related to driving: drinking and driving on the descending limb

PubMed Central

Weafer, Jessica

2015-01-01

Rationale Alcohol effects on behavioral and cognitive mechanisms influence impaired driving performance and decisions to drive after drinking (Barry 1973; Moskowitz and Robinson 1987). To date, research has focused on the ascending limb of the blood alcohol curve, and there is little understanding of how acute tolerance to impairment of these mechanisms might influence driving behavior on the descending limb. Objectives To provide an integrated examination of the degree to which alcohol impairment of motor coordination and inhibitory control contributes to driving impairment and decisions to drive on the ascending and descending limbs of the blood alcohol curve. Methods Social-drinking adults (N=20) performed a testing battery that measured simulated driving performance and willingness to drive, as well as mechanisms related to driving: motor coordination (grooved pegboard), inhibitory control (cued go/no-go task), and subjective intoxication. Performance was tested in response to placebo and a moderate dose of alcohol (0.65 g/kg) twice at comparable blood alcohol concentrations: once on the ascending limb and again on the descending limb. Results Impaired motor coordination and subjective intoxication showed acute tolerance, whereas driving performance and inhibitory control showed no recovery from impairment. Greater motor impairment was associated with poorer driving performance under alcohol, and poorer inhibitory control was associated with more willingness to drive. Conclusions Findings suggest that acute tolerance to impairment of motor coordination is insufficient to promote recovery of driving performance and that the persistence of alcohol-induced disinhibition might contribute to risky decisions to drive on the descending limb. PMID:21960182

Validation of a short cognitive battery to screen for fitness-to-drive of people with multiple sclerosis.

PubMed

Akinwuntan, A E; Backus, D; Grayson, J; Devos, H

2018-05-26

Some symptoms of multiple sclerosis (MS) affect driving. In a recent study, performance on five cognitive tests predicted the on-road test performance of individuals with relapsing-remitting MS with 91% accuracy, 70% sensitivity and 97% specificity. However, the accuracy with which the battery will predict the driving performance of a different cohort that includes all types of MS is unknown. Participants (n = 118; 48 ± 9 years of age; 97 females) performed a comprehensive off-road evaluation that lasted about 3 h and a standardized on-road test that lasted approximately 45 min over a 2-day period within the same week. Performance on the five cognitive tests was used to predict participants' performance on the standardized on-road test. Performance on the five tests together predicted outcome of the on-road test with 82% accuracy, 42% sensitivity and 90% specificity. The accuracy of predicting the on-road performance of a new MS cohort using performance on the battery of five cognitive tests remained very high (82%). The battery, which was administrable in <45 min and cost ~$150, was better at identifying those who actually passed the on-road test (90% specificity). The sensitivity (42%) of the battery indicated that it should not be used as the sole determinant of poor driving-related cognitive skills. A fail performance on the battery should only imply that more comprehensive testing is warranted. © 2018 EAN.

Driving performance analysis of the ACAS FOT data and recommendations for a driving workload manager.

DOT National Transportation Integrated Search

2006-12-01

This report contains analyses of driving performance data from the Advanced Collision Avoidance System (ACAS) Field Operational Test (FOT), with data from nearly 100 drivers and over 100,000 miles of driving. The analyses compared normal and distract...

Modafinil improves real driving performance in patients with hypersomnia: a randomized double-blind placebo-controlled crossover clinical trial.

PubMed

Philip, Pierre; Chaufton, Cyril; Taillard, Jacques; Capelli, Aurore; Coste, Olivier; Léger, Damien; Moore, Nicholas; Sagaspe, Patricia

2014-03-01

Patients with excessive daytime sleepiness (EDS) are at high risk for driving accidents, and physicians are concerned by the effect of alerting drugs on driving skills of sleepy patients. No study has up to now investigated the effect of modafinil (a reference drug to treat EDS in patients with hypersomnia) on on-road driving performance of patients suffering from central hypersomnia. The objective is to evaluate in patients with central hypersomnia the effect of a wake-promoting drug on real driving performance and to assess the relationship between objective sleepiness and driving performance. Randomized, crossover, double-blind placebo-controlled trial conducted among 13 patients with narcolepsy and 14 patients with idiopathic hypersomnia. Patients were randomly assigned to receive modafinil (400 mg) or placebo for 5 days prior to the driving test. Each condition was separated by at least 3 weeks of washout. Mean number of Inappropriate Line Crossings, Standard Deviation of Lateral Position of the vehicle and mean sleep latency in the Maintenance of Wakefulness Test were assessed. Modafinil reduced the mean number of Inappropriate Line Crossings and Standard Deviation of Lateral Position of the vehicle compared to placebo (F(1,25) = 4.88, P < 0.05 and F(1,25) = 3.87, P = 0.06 tendency). Mean sleep latency at the Maintenance of Wakefulness Test significantly correlated with the mean number of Inappropriate Line Crossings (r = -0.41, P < 0.001). Modafinil improves driving performance in patients with narcolepsy and idiopathic hypersomnia. The Maintenance of Wakefulness Test is a suitable clinical tool to assess fitness to drive in this population.

Maintenance of Wakefulness Test scores and driving performance in sleep disorder patients and controls.

PubMed

Philip, Pierre; Chaufton, Cyril; Taillard, Jacques; Sagaspe, Patricia; Léger, Damien; Raimondi, Monika; Vakulin, Andrew; Capelli, Aurore

2013-08-01

Sleepiness at the wheel is a risk factor for traffic accidents. Past studies have demonstrated the validity of the Maintenance of Wakefulness Test (MWT) scores as a predictor of driving impairment in untreated patients with obstructive sleep apnea syndrome (OSAS), but there is limited information on the validity of the maintenance of wakefulness test by MWT in predicting driving impairment in patients with hypersomnias of central origin (narcolepsy or idiopathic hypersomnia). The aim of this study was to compare the MWT scores with driving performance in sleep disorder patients and controls. 19 patients suffering from hypersomnias of central origin (9 narcoleptics and 10 idiopathic hypersomnia), 17 OSAS patients and 14 healthy controls performed a MWT (4×40-minute trials) and a 40-minute driving session on a real car driving simulator. Participants were divided into 4 groups defined by their MWT sleep latency scores. The groups were pathological (sleep latency 0-19 min), intermediate (20-33 min), alert (34-40 min) and control (>34 min). The main driving performance outcome was the number of inappropriate line crossings (ILCs) during the 40 minute drive test. Patients with pathological MWT sleep latency scores (0-19 min) displayed statistically significantly more ILC than patients from the intermediate, alert and control groups (F (3, 46)=7.47, p<0.001). Pathological sleep latencies on the MWT predicted driving impairment in patients suffering from hypersomnias of central origin as well as in OSAS patients. MWT is an objective measure of daytime sleepiness that appears to be useful in estimating the driving performance in sleepy patients. Copyright © 2013 Elsevier B.V. All rights reserved.

Reduced Physical Fitness in Patients With Heart Failure as a Possible Risk Factor for Impaired Driving Performance

PubMed Central

Alosco, Michael L.; Penn, Marc S.; Spitznagel, Mary Beth; Cleveland, Mary Jo; Ott, Brian R.

2015-01-01

OBJECTIVE. Reduced physical fitness secondary to heart failure (HF) may contribute to poor driving; reduced physical fitness is a known correlate of cognitive impairment and has been associated with decreased independence in driving. No study has examined the associations among physical fitness, cognition, and driving performance in people with HF. METHOD. Eighteen people with HF completed a physical fitness assessment, a cognitive test battery, and a validated driving simulator scenario. RESULTS. Partial correlations showed that poorer physical fitness was correlated with more collisions and stop signs missed and lower scores on a composite score of attention, executive function, and psychomotor speed. Cognitive dysfunction predicted reduced driving simulation performance. CONCLUSION. Reduced physical fitness in participants with HF was associated with worse simulated driving, possibly because of cognitive dysfunction. Larger studies using on-road testing are needed to confirm our findings and identify clinical interventions to maximize safe driving. PMID:26122681

Driving Performance Under Alcohol in Simulated Representative Driving Tasks

PubMed Central

Kenntner-Mabiala, Ramona; Kaussner, Yvonne; Jagiellowicz-Kaufmann, Monika; Hoffmann, Sonja; Krüger, Hans-Peter

2015-01-01

Abstract Comparing drug-induced driving impairments with the effects of benchmark blood alcohol concentrations (BACs) is an approved approach to determine the clinical relevance of findings for traffic safety. The present study aimed to collect alcohol calibration data to validate findings of clinical trials that were derived from a representative test course in a dynamic driving simulator. The driving performance of 24 healthy volunteers under placebo and with 0.05% and 0.08% BACs was measured in a double-blind, randomized, crossover design. Trained investigators assessed the subjects’ driving performance and registered their driving errors. Various driving parameters that were recorded during the simulation were also analyzed. Generally, the participants performed worse on the test course (P < 0.05 for the investigators’ assessment) under the influence of alcohol. Consistent with the relevant literature, lane-keeping performance parameters were sensitive to the investigated BACs. There were significant differences between the alcohol and placebo conditions in most of the parameters analyzed. However, the total number of errors was the only parameter discriminating significantly between all three BAC conditions. In conclusion, data show that the present experimental setup is suitable for future psychopharmacological research. Thereby, for each drug to be investigated, we recommend to assess a profile of various parameters that address different levels of driving. On the basis of this performance profile, the total number of driving errors is recommended as the primary endpoint. However, this overall endpoint should be completed by a specifically sensitive parameter that is chosen depending on the effect known to be induced by the tested drug. PMID:25689289

Sensitivity and validity of psychometric tests for assessing driving impairment: effects of sleep deprivation.

PubMed

Jongen, Stefan; Perrier, Joy; Vuurman, Eric F; Ramaekers, Johannes G; Vermeeren, Annemiek

2015-01-01

To assess drug induced driving impairment, initial screening is needed. However, no consensus has been reached about which initial screening tools have to be used. The present study aims to determine the ability of a battery of psychometric tests to detect performance impairing effects of clinically relevant levels of drowsiness as induced by one night of sleep deprivation. Twenty four healthy volunteers participated in a 2-period crossover study in which the highway driving test was conducted twice: once after normal sleep and once after one night of sleep deprivation. The psychometric tests were conducted on 4 occasions: once after normal sleep (at 11 am) and three times during a single night of sleep deprivation (at 1 am, 5 am, and 11 am). On-the-road driving performance was significantly impaired after sleep deprivation, as measured by an increase in Standard Deviation of Lateral Position (SDLP) of 3.1 cm compared to performance after a normal night of sleep. At 5 am, performance in most psychometric tests showed significant impairment. As expected, largest effect sizes were found on performance in the Psychomotor Vigilance Test (PVT). Large effects sizes were also found in the Divided Attention Test (DAT), the Attention Network Test (ANT), and the test for Useful Field of View (UFOV) at 5 and 11 am during sleep deprivation. Effects of sleep deprivation on SDLP correlated significantly with performance changes in the PVT and the DAT, but not with performance changes in the UFOV. From the psychometric tests used in this study, the PVT and DAT seem most promising for initial evaluation of drug impairment based on sensitivity and correlations with driving impairment. Further studies are needed to assess the sensitivity and validity of these psychometric tests after benchmark sedative drug use.

H1 antihistamines and driving.

PubMed

Popescu, Florin Dan

2008-01-01

Driving performances depend on cognitive, psychomotor and perception functions. The CNS adverse effects of some H1 antihistamines can alter the patient ability to drive. Data from studies using standardized objective cognitive and psychomotor tests (Choice Reaction Time, Critical Flicker Fusion. Digital Symbol Substitution Test), functional brain imaging (Positron Emission Tomography, functional Magnetic Resonance Imaging), neurophysiological studies (Multiple Sleep Latency Test, auditory and visual evoked potentials), experimental simulated driving (driving simulators) and real driving studies (the Highway Driving Test, with the evaluation of the Standard Deviation Lateral Position, and the Car Following Test, with the measurement of the Brake Reaction Time) must be discussed in order to classify a H1 antihistamine as a true non-sedating one.

H1 antihistamines and driving

PubMed Central

Florin-Dan, Popescu

2008-01-01

Driving performances depend on cognitive, psychomotor and perception functions. The CNS adverse effects of some H1 antihistamines can alter the patient ability to drive. Data from studies using standardized objective cognitive and psychomotor tests (Choice Reaction Time, Critical Flicker Fusion, Digital Symbol Substitution Test), functional brain imaging (Positron Emission Tomography, functional Magnetic Resonance Imaging), neurophysiological studies (Multiple Sleep Latency Test, auditory and visual evoked potentials), experimental simulated driving (driving simulators) and real driving studies (the Highway Driving Test, with the evaluation of the Standard Deviation Lateral Position, and the Car Following Test, with the measurement of the Brake Reaction Time) must be discussed in order to classify a H1 antihistamine as a true non-sedating one. PMID:20108503

On-road driving impairments and associated cognitive deficits after stroke.

PubMed

Devos, Hannes; Tant, Mark; Akinwuntan, Abiodun E

2014-01-01

Little is known about the critical on-road driving skills that get affected after a stroke. The purpose of this study was to investigate the key on-road driving impairments and their associated cognitive deficits after a stroke. A second aim was to investigate if lateralization of stroke impacts results of the cognitive and on-road driving tests. In this cross-sectional study, 99 participants with a first-ever stroke who were actively driving prior to stroke underwent a cognitive battery and a standardized road test that evaluated 13 specific on-road driving skills. These on-road driving skills were mapped onto an existing, theoretical framework that categorized the on-road items into hierarchic clusters of operational, tactical, visuo-integrative, and mixed driving skills. The total score on the road test and the on-road decision, made by a certified fitness-to-drive expert, decided the main outcome. The critical on-road driving skills predicting the on-road decision were identified using logistic regression analysis. Linear regression analysis was employed to determine the cognitive impairments leading to poor total on-road scores. Analyses were repeated for right- and left-sided strokes. In all, 37 persons scored poorly on the road test. These participants performed worse in all hierarchic clusters of on-road driving. Performances on the operational cluster and the visuo-integrative cluster best predicted on-road decisions (R(2) = 0.60). 'Lane changing' and 'understanding, insight, and quality of traffic participation' were the critical skill deficits leading to poor performance on the road test (R(2) = 0.65). Divided attention was the main determinant of on-road scores in the total group (R(2) = 0.06). Participants with right-sided stroke performed worse on visual field, visual neglect, visual scanning, visuo-constructive skills, and divided attention compared with those with left-sided stroke. Divided attention was the main determinant of total on-road scores in the right-sided stroke group (R(2) = 0.10). A combination of visual scanning, speed of processing, and executive dysfunction yielded the best model to predict on-road scores in left-sided strokes (R(2) = 0.46). Poor performance in the road test after stroke is determined by critical operational and visuo-integrative driving impairments. Specific and different driving evaluation and training programs are needed for right- and left-sided strokes. © 2014 S. Karger AG, Basel.

Computerized Maze Navigation and On-Road Performance by Drivers With Dementia

PubMed Central

Ott, Brian R.; Festa, Elena K.; Amick, Melissa M.; Grace, Janet; Davis, Jennifer D.; Heindel, William C.

2012-01-01

This study examined the ability of computerized maze test performance to predict the road test performance of cognitively impaired and normal older drivers. The authors examined 133 older drivers, including 65 with probable Alzheimer disease, 23 with possible Alzheimer disease, and 45 control subjects without cognitive impairment. Subjects completed 5 computerized maze tasks employing a touch screen and pointer as well as a battery of standard neuropsychological tests. Parameters measured for mazes included errors, planning time, drawing time, and total time. Within 2 weeks, subjects were examined by a professional driving instructor on a standardized road test modeled after the Washington University Road Test. Road test total score was significantly correlated with total time across the 5 mazes. This maze score was significant for both Alzheimer disease subjects and control subjects. One maze in particular, requiring less than 2 minutes to complete, was highly correlated with driving performance. For the standard neuropsychological tests, highest correlations were seen with Trail Making A (TrailsA) and the Hopkins Verbal Learning Tests Trial 1 (HVLT1). Multiple regression models for road test score using stepwise subtraction of maze and neuropsychological test variables revealed significant independent contributions for total maze time, HVLT1, and TrailsA for the entire group; total maze time and HVLT1 for Alzheimer disease subjects; and TrailsA for normal subjects. As a visual analog of driving, a brief computerized test of maze navigation time compares well to standard neuropsychological tests of psychomotor speed, scanning, attention, and working memory as a predictor of driving performance by persons with early Alzheimer disease and normal elders. Measurement of maze task performance appears to be useful in the assessment of older drivers at risk for hazardous driving. PMID:18287166

40 CFR 86.135-90 - Dynamometer procedure.

Code of Federal Regulations, 2012 CFR

2012-07-01

... startup and operation over the first 505 seconds of the driving schedule complete the hot start test. The... 505 seconds of the driving schedule complete the hot start test. The exhaust emissions are diluted... over the prescribed driving schedule may be performed at test point, provided an emission sample is not...

40 CFR 86.135-90 - Dynamometer procedure.

Code of Federal Regulations, 2013 CFR

2013-07-01

... startup and operation over the first 505 seconds of the driving schedule complete the hot start test. The... 505 seconds of the driving schedule complete the hot start test. The exhaust emissions are diluted... over the prescribed driving schedule may be performed at test point, provided an emission sample is not...

Motion perception and driving: predicting performance through testing and shortening braking reaction times through training.

PubMed

Wilkins, Luke; Gray, Rob; Gaska, James; Winterbottom, Marc

2013-12-30

A driving simulator was used to examine the relationship between motion perception and driving performance. Although motion perception test scores have been shown to be related to driving safety, it is not clear which combination of tests are the best predictors and whether motion perception training can improve driving performance. In experiment 1, 60 younger drivers (22.4 ± 2.5 years) completed three motion perception tests (2-dimensional [2D] motion-defined letter [MDL] identification, 3D motion in depth sensitivity [MID], and dynamic visual acuity [DVA]) followed by two driving tests (emergency braking [EB] and hazard perception [HP]). In experiment 2, 20 drivers (21.6 ± 2.1 years) completed 6 weeks of motion perception training (using the MDL, MID, and DVA tests), while 20 control drivers (22.0 ± 2.7 years) completed an online driving safety course. The EB performance was measured before and after training. In experiment 1, MDL (r = 0.34) and MID (r = 0.46) significantly correlated with EB score. The change in DVA score as a function of target speed (i.e., "velocity susceptibility") was correlated most strongly with HP score (r = -0.61). In experiment 2, the motion perception training group had a significant decrease in brake reaction time on the EB test from pre- to posttreatment, while there was no significant change for the control group: t(38) = 2.24, P = 0.03. Tests of 3D motion perception are the best predictor of EB, while DVA velocity susceptibility is the best predictor of hazard perception. Motion perception training appears to result in faster braking responses.

Modafinil Improves Real Driving Performance in Patients with Hypersomnia: A Randomized Double-Blind Placebo-Controlled Crossover Clinical Trial

PubMed Central

Philip, Pierre; Chaufton, Cyril; Taillard, Jacques; Capelli, Aurore; Coste, Olivier; Léger, Damien; Moore, Nicholas; Sagaspe, Patricia

2014-01-01

Study Objective: Patients with excessive daytime sleepiness (EDS) are at high risk for driving accidents, and physicians are concerned by the effect of alerting drugs on driving skills of sleepy patients. No study has up to now investigated the effect of modafinil (a reference drug to treat EDS in patients with hypersomnia) on on-road driving performance of patients suffering from central hypersomnia. The objective is to evaluate in patients with central hypersomnia the effect of a wake-promoting drug on real driving performance and to assess the relationship between objective sleepiness and driving performance. Design and Participants: Randomized, crossover, double-blind placebo-controlled trial conducted among 13 patients with narcolepsy and 14 patients with idiopathic hypersomnia. Patients were randomly assigned to receive modafinil (400 mg) or placebo for 5 days prior to the driving test. Each condition was separated by at least 3 weeks of washout. Measurements: Mean number of Inappropriate Line Crossings, Standard Deviation of Lateral Position of the vehicle and mean sleep latency in the Maintenance of Wakefulness Test were assessed. Results: Modafinil reduced the mean number of Inappropriate Line Crossings and Standard Deviation of Lateral Position of the vehicle compared to placebo (F(1,25) = 4.88, P < 0.05 and F(1,25) = 3.87, P = 0.06 tendency). Mean sleep latency at the Maintenance of Wakefulness Test significantly correlated with the mean number of Inappropriate Line Crossings (r = -0.41, P < 0.001). Conclusions: Modafinil improves driving performance in patients with narcolepsy and idiopathic hypersomnia. The Maintenance of Wakefulness Test is a suitable clinical tool to assess fitness to drive in this population. Citation: Philip P; Chaufton C; Taillard J; Capelli A; Coste O; Léger D; Moore N; Sagaspe P. Modafinil improves real driving performance in patients with hypersomnia: a randomized double-blind placebo-controlled crossover clinical trial. SLEEP 2014;37(3):483-487. PMID:24587570

Driving performance of stable outpatients with depression undergoing real-world treatment.

PubMed

Miyata, Akemi; Iwamoto, Kunihiro; Kawano, Naoko; Aleksic, Branko; Ando, Masahiko; Ebe, Kazutoshi; Fujita, Kiyoshi; Yokoyama, Motonori; Akiyama, Tsuyoshi; Igarashi, Yoshio; Ozaki, Norio

2018-06-01

Although the effects of psychotropics on driving ability have received much attention, little research is available on driving performance of stable outpatients with depression undergoing real-world treatment. This observational study investigated driving performance, cognitive functions, and depressive symptomatology of partly remitted outpatients with depression under daily-practice psychopharmacologic treatment. Seventy stable outpatients with depression and 67 healthy volunteers were enrolled. Patients' prescriptions were not controlled in order to capture the real-world treatment environment. Participants underwent three driving tasks - road-tracking, car-following, and harsh-braking - using a driving simulator, and three cognitive tasks - Continuous Performance Test, Wisconsin Card Sorting Test, and Trail-Making Test. The Symptom Assessment Scale - Structured Interview Guide for the Hamilton Depression Rating Scale, Beck Depression Inventory-II, Social Adaptation Self-Evaluation Scale, and Stanford Sleepiness Scale were also completed. Although many patients received various pharmacologic treatments, there were no significant differences in the three driving tasks between outpatients with depression and healthy controls. Difficulty of maintaining set in the Wisconsin Card Sorting Test was significantly increased in patients with depression. Results on the Social Adaptation Self-Evaluation Scale were significantly associated with road-tracking and car-following performance, in contrast to results on the Hamilton Depression Rating Scale and the Beck Depression Inventory-II. We conclude that partly remitted depressive patients under steady-state pharmacologic treatment do not differ from healthy controls with respect to driving performance, which seems to be more affected by psychosocial functioning than by pharmacologic agents. This, however, should be investigated systematically in an off/on study. © 2018 The Authors. Psychiatry and Clinical Neurosciences © 2018 Japanese Society of Psychiatry and Neurology.

Visual and cognitive predictors of driving safety in Parkinson's disease patients

PubMed Central

Amick, M.M.; Grace, J.; Ott, B.R.

2012-01-01

This study assessed the clinical utility of contrast sensitivity (CS) relative to attention, executive function, and visuospatial abilities for predicting driving safety in participants with Parkinson's disease (PD). Twenty-five, non-demented PD patients completed measures of contrast sensitivity, visuospatial skills, executive functions, and attention. All PD participants also underwent a formal on-road driving evaluation. Of the 25 participants, 11 received a marginal or unsafe rating on the road test. Poorer driving performance was associated with worse performance on measures of CS, visuospatial constructions, set shifting, and attention. While impaired driving was associated with a range of cognitive and visual abilities, only a composite measure of executive functioning and visuospatial abilities, and not CS or attentional skills, predicted driving performance. These findings suggest that neuropsychological tests, which are multifactorial in nature and require visual perception and visual spatial judgments are the most useful screening measures for hazardous driving in PD patients. PMID:17851032

Visual and cognitive predictors of driving safety in Parkinson's disease patients.

PubMed

Amick, M M; Grace, J; Ott, B R

2007-11-01

This study assessed the clinical utility of contrast sensitivity (CS) relative to attention, executive function, and visuospatial abilities for predicting driving safety in participants with Parkinson's disease (PD). Twenty-five, non-demented PD patients completed measures of contrast sensitivity, visuospatial skills, executive functions, and attention. All PD participants also underwent a formal on-road driving evaluation. Of the 25 participants, 11 received a marginal or unsafe rating on the road test. Poorer driving performance was associated with worse performance on measures of CS, visuospatial constructions, set shifting, and attention. While impaired driving was associated with a range of cognitive and visual abilities, only a composite measure of executive functioning and visuospatial abilities, and not CS or attentional skills, predicted driving performance. These findings suggest that neuropsychological tests, which are multifactorial in nature and require visual perception and visual spatial judgments are the most useful screening measures for hazardous driving in PD patients.

Effects of armodafinil on simulated driving and alertness in shift work disorder.

PubMed

Drake, Christopher; Gumenyuk, Valentina; Roth, Thomas; Howard, Ryan

2014-12-01

Forty-one percent of shift workers report dozing while driving. This study tested whether armodafinil improves driving simulator performance in subjects with shift work disorder (SWD). A primary outcome was performance late in the shift when workers are typically driving home. Randomized, double-blind, crossover. During each 12-h test session (21:30-09:30), subjects were kept awake except for multiple sleep latency testing (MSLT: 01:30, 03:30, 05:30, and 07:30). Subjective sleepiness (Karolinska Sleepiness Scale, KSS), driving performance, and cognitive performance (digit symbol substitution test and creativity on the Remote Associates Test, RAT) were evaluated during the night shift and commute home times. Hospital-based sleep research laboratory. Twenty night workers (age: 42.7 ± 8.7 y, 17 F) with excessive sleepiness (≥ 10 on the Epworth Sleepiness Scale), meeting International Classification of Sleep Disorders, Second Edition (ICSD-2) criteria for SWD, and having no other medical conditions. Armodafinil (150 mg) or placebo at (23:45 h) on counterbalanced nights separated by 7-14 days. Primary endpoints were driving simulator performance (standard deviation of lateral position (SDLP) and off-road deviations) with four sessions starting 3.25 h after drug administration, objective sleepiness (MSLT; 1.75 to 7.75 h post-drug), and creativity (5 h post-drug). Significant effects of drug were observed for each driving measure (P < 0.05). Armodafinil significantly improved SDLP for simulator sessions at 05:30, 07:30, and 09:30, and off-road deviations at 7 h, 15 min and 9 h, 15 min post-drug (P < 0.05). Armodafinil also improved objective sleepiness from 3.7 ± 0.6 min to 9.7 ± 5.2 min (P < 0.001) and RAT score from 8.75 ± 4.9 to 11.25 ± 6.0 (P < 0.005). Armodafinil 150 mg early in the night shift improves driving simulator performance in SWD. Effects on sleepiness, cognition, and driving were found up to 9.5 h post-ingestion, during the critical time when many night workers are driving home. © 2014 Associated Professional Sleep Societies, LLC.

Test drivers in the Daimler-Benz driving simulator with drivers under diphenhydramine

DOT National Transportation Integrated Search

1991-01-01

The research project investigated the influence of diphenhydramine on the driving performance measured in the Daimler-Benz driving simulator. Test subjects were male students; 20 received a medium, and 20 received a high dosage of diphenhydramine. A ...

Visual function and fitness to drive.

PubMed

Kotecha, Aachal; Spratt, Alexander; Viswanathan, Ananth

2008-01-01

Driving is recognized to be a visually intensive task and accordingly there is a legal minimum standard of vision required for all motorists. The purpose of this paper is to review the current United Kingdom (UK) visual requirements for driving and discuss the evidence base behind these legal rules. The role of newer, alternative tests of visual function that may be better indicators of driving safety will also be considered. Finally, the implications of ageing on driving ability are discussed. A search of Medline and PubMed databases was performed using the following keywords: driving, vision, visual function, fitness to drive and ageing. In addition, papers from the Department of Transport website and UK Royal College of Ophthalmologists guidelines were studied. Current UK visual standards for driving are based upon historical concepts, but recent advances in technology have brought about more sophisticated methods for assessing the status of the binocular visual field and examining visual attention. These tests appear to be better predictors of driving performance. Further work is required to establish whether these newer tests should be incorporated in the current UK visual standards when examining an individual's fitness to drive.

The sensitivity of laboratory tests assessing driving related skills to dose-related impairment of alcohol: A literature review.

PubMed

Jongen, S; Vuurman, E F P M; Ramaekers, J G; Vermeeren, A

2016-04-01

Laboratory tests assessing driving related skills can be useful as initial screening tools to assess potential drug induced impairment as part of a standardized behavioural assessment. Unfortunately, consensus about which laboratory tests should be included to reliably assess drug induced impairment has not yet been reached. The aim of the present review was to evaluate the sensitivity of laboratory tests to the dose dependent effects of alcohol, as a benchmark, on performance parameters. In total, 179 experimental studies were included. Results show that a cued go/no-go task and a divided attention test with primary tracking and secondary visual search were consistently sensitive to the impairing effects at medium and high blood alcohol concentrations. Driving performance assessed in a simulator was less sensitive to the effects of alcohol as compared to naturalistic, on-the-road driving. In conclusion, replicating results of several potentially useful tests and their predictive validity of actual driving impairment should deserve further research. In addition, driving simulators should be validated and compared head to head to naturalistic driving in order to increase construct validity. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

The Effects of Dextromethorphan on Driving Performance and the Standardized Field Sobriety Test.

PubMed

Perry, Paul J; Fredriksen, Kristian; Chew, Stephanie; Ip, Eric J; Lopes, Ingrid; Doroudgar, Shadi; Thomas, Kelan

2015-09-01

Dextromethorphan (DXM) is abused most commonly among adolescents as a recreational drug to generate a dissociative experience. The objective of the study was to assess driving with and without DXM ingestion. The effects of one-time maximum daily doses of DXM 120 mg versus a guaifenesin 400 mg dose were compared among 40 healthy subjects using a crossover design. Subjects' ability to drive was assessed by their performance in a driving simulator (STISIM® Drive driving simulator software) and by conducting a standardized field sobriety test (SFST) administered 1-h postdrug administration. The one-time dose of DXM 120 mg did not demonstrate driving impairment on the STISIM® Drive driving simulator or increase SFST failures compared to guaifenesin 400 mg. Doses greater than the currently recommended maximum daily dose of 120 mg are necessary to perturb driving behavior. © 2015 American Academy of Forensic Sciences.

40 CFR 86.235-94 - Dynamometer procedure.

Code of Federal Regulations, 2011 CFR

2011-07-01

... over the prescribed driving schedule may be performed at test point for the purpose of finding the... make a complete cold start test. Engine startup and operation over the first 505 seconds of the driving... preselectable power settings may be set anytime prior to the beginning of the emission test. (g) The driving...

40 CFR 86.235-94 - Dynamometer procedure.

Code of Federal Regulations, 2012 CFR

2012-07-01

... over the prescribed driving schedule may be performed at test point for the purpose of finding the... make a complete cold start test. Engine startup and operation over the first 505 seconds of the driving... preselectable power settings may be set anytime prior to the beginning of the emission test. (g) The driving...

40 CFR 86.235-94 - Dynamometer procedure.

Code of Federal Regulations, 2013 CFR

2013-07-01

... over the prescribed driving schedule may be performed at test point for the purpose of finding the... make a complete cold start test. Engine startup and operation over the first 505 seconds of the driving... preselectable power settings may be set anytime prior to the beginning of the emission test. (g) The driving...

Preclinical Alzheimer's disease and longitudinal driving decline.

PubMed

Roe, Catherine M; Babulal, Ganesh M; Head, Denise M; Stout, Sarah H; Vernon, Elizabeth K; Ghoshal, Nupur; Garland, Brad; Barco, Peggy P; Williams, Monique M; Johnson, Ann; Fierberg, Rebecca; Fague, M Scot; Xiong, Chengjie; Mormino, Elizabeth; Grant, Elizabeth A; Holtzman, David M; Benzinger, Tammie L S; Fagan, Anne M; Ott, Brian R; Carr, David B; Morris, John C

2017-01-01

Links between preclinical AD and driving difficulty onset would support the use of driving performance as an outcome in primary and secondary prevention trials among older adults (OAs). We examined whether AD biomarkers predicted the onset of driving difficulties among OAs. 104 OAs (65+ years) with normal cognition took part in biomarker measurements, a road test, clinical and psychometric batteries and self-reported their driving habits. Higher values of CSF tau/Aβ 42 and ptau 181 /Aβ 42 ratios, but not uptake on PIB amyloid imaging (p=.12), predicted time to a rating of Marginal or Fail on the driving test using Cox proportional hazards models. Hazards ratios (95% confidence interval) were 5.75 (1.70-19.53), p=.005 for CSF tau/Aβ 42 ; 6.19 (1.75-21.88) and p=.005 for CSF ptau 181 /Aβ 42 . Preclinical AD predicted time to receiving a Marginal or Fail rating on an on-road driving test. Driving performance shows promise as a functional outcome in AD prevention trials.

Self-regulation of driving and its relationship to driving ability among older adults.

PubMed

Baldock, M R J; Mathias, J L; McLean, A J; Berndt, A

2006-09-01

Although it is known that older drivers limit their driving, it is not known whether this self-regulation is related to actual driving ability. A sample of 104 older drivers, aged between 60 and 92, completed a questionnaire about driving habits and attitudes. Ninety of these drivers also completed a structured on-road driving test. A measure of self-regulation was derived from drivers' self-reported avoidance of difficult driving situations. The on-road driving test involved a standard assessment used to determine fitness to drive. Driving test scores for the study were based on the number of errors committed in the driving tests, with weightings given according to the seriousness of the errors. The most commonly avoided difficult driving situations, according to responses on the questionnaire, were parallel parking and driving at night in the rain, while the least avoided situation was driving alone. Poorer performance on the driving test was not related to overall avoidance of difficult driving situations. Stronger relationships were found between driving ability and avoidance of specific difficult driving situations. These specific driving situations were the ones in which the drivers had low confidence and that the drivers were most able to avoid if they wished to.

Assessment of Driving Safety in Older Adults with Mild Cognitive Impairment.

PubMed

Anstey, Kaarin J; Eramudugolla, Ranmalee; Chopra, Sidhant; Price, Jasmine; Wood, Joanne M

2017-01-01

With population aging, drivers with mild cognitive impairment (MCI) are increasing; however, there is little evidence available regarding their safety. We aimed to evaluate risk of unsafe on-road driving performance among older adults with MCI. The study was a cross-sectional observational study, set in Canberra, Australia. Participants were non-demented, current drivers (n = 302) aged 65 to 96 years (M = 75.7, SD = 6.18, 40% female) recruited through the community and primary and tertiary care clinics. Measures included a standardized on-road driving test (ORT), a battery of screening measures designed to evaluate older driver safety (UFOV®, DriveSafe, Multi-D), a neurocognitive test battery, and questionnaires on driving history and behavior. Using Winblad criteria, 57 participants were classified as having MCI and 245 as cognitively normal (CN). While the MCI group had a significantly lower overall safety rating on the ORT (5.61 versus 6.05, p = 0.03), there was a wide range of driving safety scores in the CN and MCI groups. The MCI group performed worse than the CN group on the off-road screening tests. The best fitting model of predictors of ORT performance across the combined sample included age, the Multi-D, and DriveSafe, classifying 90.4% of the sample correctly. Adults with MCI exhibit a similar range of driving ability to CN adults, although on average they scored lower on off-road and on-road assessments. Driving specific tests were more strongly associated with safety ratings than traditional neuropsychological tests.

Assessment of Driving Safety in Older Adults with Mild Cognitive Impairment

PubMed Central

Anstey, Kaarin J.; Eramudugolla, Ranmalee; Chopra, Sidhant; Price, Jasmine; Wood, Joanne M.

2017-01-01

Background: With population aging, drivers with mild cognitive impairment (MCI) are increasing; however, there is little evidence available regarding their safety. Objective: We aimed to evaluate risk of unsafe on-road driving performance among older adults with MCI. Method: The study was a cross-sectional observational study, set in Canberra, Australia. Participants were non-demented, current drivers (n = 302) aged 65 to 96 years (M = 75.7, SD = 6.18, 40% female) recruited through the community and primary and tertiary care clinics. Measures included a standardized on-road driving test (ORT), a battery of screening measures designed to evaluate older driver safety (UFOV®, DriveSafe, Multi-D), a neurocognitive test battery, and questionnaires on driving history and behavior. Results: Using Winblad criteria, 57 participants were classified as having MCI and 245 as cognitively normal (CN). While the MCI group had a significantly lower overall safety rating on the ORT (5.61 versus 6.05, p = 0.03), there was a wide range of driving safety scores in the CN and MCI groups. The MCI group performed worse than the CN group on the off-road screening tests. The best fitting model of predictors of ORT performance across the combined sample included age, the Multi-D, and DriveSafe, classifying 90.4% of the sample correctly. Conclusion: Adults with MCI exhibit a similar range of driving ability to CN adults, although on average they scored lower on off-road and on-road assessments. Driving specific tests were more strongly associated with safety ratings than traditional neuropsychological tests. PMID:28372333

Effects of valerian on subjective sedation, field sobriety testing and driving simulator performance.

PubMed

Thomas, Kelan; Canedo, Joanne; Perry, Paul J; Doroudgar, Shadi; Lopes, Ingrid; Chuang, Hannah Mae; Bohnert, Kimberly

2016-07-01

The availability of herbal medicines over-the-counter (OTC) has increased the use of natural products for self-treatment. Valerian has been used to effectively treat generalized anxiety disorder and insomnia. Studies suggest that valerenic acid may increase gamma-aminobutyric acid (GABA) modulation in the brain. Benzodiazepines have a similar mechanism of action and have been linked to an increased risk of hospitalizations due to traffic accidents. Despite the risk of somnolence, the safety of driving while under the influence of valerian remains unknown. The purpose of the study was to determine the effects of a one-time valerian 1600mg dose on subjective sedation effects, standardized field sobriety testing (SFST) and driving simulator performance parameters. The study design was a randomized, placebo-controlled, double-blind, cross-over trial. For each session, participants received either a dose of valerian or placebo. The outcome measures included a simple visual reaction test (SVRT), subjective sleepiness scales, SFST performance scores, and driving simulator performance parameters. There were no significant differences in the SVRT or sleepiness scales between placebo and valerian exposures, but the study may have been underpowered. SFST total and individual test failure rates were not significantly different between the two exposures. The driving simulator performance parameters were equivalent between the two exposure conditions. A one-time valerian 1600mg dose, often used to treat insomnia, does not appear to impair driving simulator performance after acute ingestion. Copyright © 2016 Elsevier Ltd. All rights reserved.

Parametric tests of a traction drive retrofitted to an automotive gas turbine

NASA Technical Reports Server (NTRS)

Rohn, D. A.; Lowenthal, S. H.; Anderson, N. E.

1980-01-01

The results of a test program to retrofit a high performance fixed ratio Nasvytis Multiroller Traction Drive in place of a helical gear set to a gas turbine engine are presented. Parametric tests up to a maximum engine power turbine speed of 45,500 rpm and to a power level of 11 kW were conducted. Comparisons were made to similar drives that were parametrically tested on a back-to-back test stand. The drive showed good compatibility with the gas turbine engine. Specific fuel consumption of the engine with the traction drive speed reducer installed was comparable to the original helical gearset equipped engine.

Sensitivity and Validity of Psychometric Tests for Assessing Driving Impairment: Effects of Sleep Deprivation

PubMed Central

Jongen, Stefan; Perrier, Joy; Vuurman, Eric F.; Ramaekers, Johannes G.; Vermeeren, Annemiek

2015-01-01

Objective To assess drug induced driving impairment, initial screening is needed. However, no consensus has been reached about which initial screening tools have to be used. The present study aims to determine the ability of a battery of psychometric tests to detect performance impairing effects of clinically relevant levels of drowsiness as induced by one night of sleep deprivation. Methods Twenty four healthy volunteers participated in a 2-period crossover study in which the highway driving test was conducted twice: once after normal sleep and once after one night of sleep deprivation. The psychometric tests were conducted on 4 occasions: once after normal sleep (at 11 am) and three times during a single night of sleep deprivation (at 1 am, 5 am, and 11 am). Results On-the-road driving performance was significantly impaired after sleep deprivation, as measured by an increase in Standard Deviation of Lateral Position (SDLP) of 3.1 cm compared to performance after a normal night of sleep. At 5 am, performance in most psychometric tests showed significant impairment. As expected, largest effect sizes were found on performance in the Psychomotor Vigilance Test (PVT). Large effects sizes were also found in the Divided Attention Test (DAT), the Attention Network Test (ANT), and the test for Useful Field of View (UFOV) at 5 and 11 am during sleep deprivation. Effects of sleep deprivation on SDLP correlated significantly with performance changes in the PVT and the DAT, but not with performance changes in the UFOV. Conclusion From the psychometric tests used in this study, the PVT and DAT seem most promising for initial evaluation of drug impairment based on sensitivity and correlations with driving impairment. Further studies are needed to assess the sensitivity and validity of these psychometric tests after benchmark sedative drug use. PMID:25668292

Association between older driver characteristics, on-road driving test performance, and crash liability.

PubMed

Keall, Michael D; Frith, William J

2004-06-01

From May 1999, a new system for licensing older drivers was introduced in New Zealand. It included a practical on-road driving test with expanded scope, to be completed every two years from the time the driver turns 80. The relationship between crashes and test performance needed to be studied to inform the debate regarding the testing system. The population studied was all drivers who entered this licensing system during its first three years of operation. They were defined as crash involved if they were involved in an injury crash during the two years following their first licensure under the new system. Logistic regression was used to describe the risk of crash involvement in terms of driving test performance and other driver characteristics. Each driving test failure was associated with a 33% increase in the odds of crash involvement (95% CI 14% to 55%), controlling for age, gender, minor traffic violations, and whether the older driver lived with another licensed driver or not. Minor traffic violations in the two years following the driving test were associated with twice the odds of crash involvement. These results suggest that the new on-road driving test does identify older driver behaviors or limitations that are related to crash liability. It is anticipated that the results presented here will provide essential information for discussing older driver licensing systems, whose impact will grow in importance as the population of drivers ages.

Predicting driving performance in older adults: we are not there yet!

PubMed

Bédard, Michel; Weaver, Bruce; Darzins, Peteris; Porter, Michelle M

2008-08-01

We set up this study to determine the predictive value of approaches for which a statistical association with driving performance has been documented. We determined the statistical association (magnitude of association and probability of occurrence by chance alone) between four different predictors (the Mini-Mental State Examination, Trails A test, Useful Field of View [UFOV], and a composite measure of past driving incidents) and driving performance. We then explored the predictive value of these measures with receiver operating characteristic (ROC) curves and various cutoff values. We identified associations between the predictors and driving performance well beyond the play of chance (p < .01). Nonetheless, the predictors had limited predictive value with areas under the curve ranging from .51 to .82. Statistical associations are not sufficient to infer adequate predictive value, especially when crucial decisions such as whether one can continue driving are at stake. The predictors we examined have limited predictive value if used as stand-alone screening tests.

A dose-ranging study of the effects of mequitazine on actual driving, memory and psychomotor performance as compared to dexchlorpheniramine, cetirizine and placebo.

PubMed

Theunissen, E L; Vermeeren, A; van Oers, A C M; van Maris, I; Ramaekers, J G

2004-02-01

Mequitazine is a so-called 'non-sedative' second-generation antihistamine even though it has never been firmly established that this drug's sedative potential actually differs from that of the 'sedative' first-generation antihistamines. The present study compares the sedative effects of three doses of mequitazine on actual driving, psychomotor performance and memory with those of a first- and a second-generation antihistamine. Eighteen healthy volunteers received on separate days a single dose of 5, 10 and 15 mg mequitazine, 10 mg cetirizine, 6 mg dexchlorpheniramine and placebo. Drug effects were assessed using two actual driving tests (highway-driving test and car-following test), cognitive and psychometric tests (tracking, divided attention, memory, reasoning and critical flicker fusion), pupil size and questionnaires. Highway-driving data revealed an overall effect of Treatment on the standard deviation of lateral position (SDLP). Dexchlorpheniramine impaired driving performance as indicated by a significant rise in SDLP. Mequitazine significantly increased SDLP in a dose-related manner, but the separate dose effects failed to reach statistical significance. Divided attention performance was also affected by Treatment. Reaction time (RT) during mequitazine treatments increased in a dose-related manner and significantly differed from placebo at the highest dose. Subjects reported to be less alert after treatment with dexchlorpheniramine. Cetirizine did not affect performance in any of the tasks. It was concluded that mequitazine is mildly sedating. The effects of mequitazine are comparable to those of other second-generation antihistamines, in that it causes mild driving impairment, particularly at higher doses.

40 CFR 86.535-90 - Dynamometer procedure.

Code of Federal Regulations, 2014 CFR

2014-07-01

... minutes. Engine startup (with all accessories turned off), operation over the driving schedule, and engine... driving schedule complete the hot start test. The exhaust emissions are diluted with ambient air and a... Administrator. (d) Practice runs over the prescribed driving schedule may be performed at test points, provided...

40 CFR 86.535-90 - Dynamometer procedure.

Code of Federal Regulations, 2011 CFR

2011-07-01

... minutes. Engine startup (with all accessories turned off), operation over the driving schedule, and engine... driving schedule complete the hot start test. The exhaust emissions are diluted with ambient air and a... Administrator. (d) Practice runs over the prescribed driving schedule may be performed at test points, provided...

40 CFR 86.535-90 - Dynamometer procedure.

Code of Federal Regulations, 2012 CFR

2012-07-01

... minutes. Engine startup (with all accessories turned off), operation over the driving schedule, and engine... driving schedule complete the hot start test. The exhaust emissions are diluted with ambient air and a... Administrator. (d) Practice runs over the prescribed driving schedule may be performed at test points, provided...

40 CFR 86.535-90 - Dynamometer procedure.

Code of Federal Regulations, 2013 CFR

2013-07-01

... minutes. Engine startup (with all accessories turned off), operation over the driving schedule, and engine... driving schedule complete the hot start test. The exhaust emissions are diluted with ambient air and a... Administrator. (d) Practice runs over the prescribed driving schedule may be performed at test points, provided...

Driving Competence in Mild Dementia with Lewy Bodies: In Search of Cognitive Predictors Using Driving Simulation

PubMed Central

Yamin, Stephanie; Stinchcombe, Arne; Gagnon, Sylvain

2015-01-01

Driving is a multifactorial behaviour drawing on multiple cognitive, sensory, and physical systems. Dementia is a progressive and degenerative neurological condition that impacts the cognitive processes necessary for safe driving. While a number of studies have examined driving among individuals with Alzheimer's disease, less is known about the impact of Dementia with Lewy Bodies (DLB) on driving safety. The present study compared simulated driving performance of 15 older drivers with mild DLB with that of 21 neurologically healthy control drivers. DLB drivers showed poorer performance on all indicators of simulated driving including an increased number of collisions in the simulator and poorer composite indicators of overall driving performance. A measure of global cognitive function (i.e., the Mini Mental State Exam) was found to be related to the overall driving performance. In addition, measures of attention (i.e., Useful Field of View, UFOV) and space processing (Visual Object and Space Perception, VOSP, Test) correlated significantly with a rater's assessment of driving performance. PMID:26713169

How do distracted and normal driving differ : an analysis of the ACAS naturalistic driving data

DOT National Transportation Integrated Search

2007-05-01

To determine how distracted and normal driving differ, this report re-examines : driving performance data from the advanced collision avoidance system (ACAS) field : operational test (FOT), a naturalistic driving study (96 drivers, 136,792 miles). : ...

Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Performance Verification Report: METSAT AMSU-A2 Antenna Drive Subsystem, P/N 1331200-2, S/N 106

NASA Technical Reports Server (NTRS)

Higgins, T.

1998-01-01

An antenna drive subsystem test was performed on the METSAT AMSU-A2 S/N 106 instrument. The objective of the test was to demonstrate compliance with applicable paragraphs of AMSU-A specifications S480-80. Tests were conducted at both the subassembly and instrument level.

Effects of age and auditory and visual dual tasks on closed-road driving performance.

PubMed

Chaparro, Alex; Wood, Joanne M; Carberry, Trent

2005-08-01

This study investigated how driving performance of young and old participants is affected by visual and auditory secondary tasks on a closed driving course. Twenty-eight participants comprising two age groups (younger, mean age = 27.3 years; older, mean age = 69.2 years) drove around a 5.1-km closed-road circuit under both single and dual task conditions. Measures of driving performance included detection and identification of road signs, detection and avoidance of large low-contrast road hazards, gap judgment, lane keeping, and time to complete the course. The dual task required participants to verbally report the sums of pairs of single-digit numbers presented through either a computer speaker (auditorily) or a dashboard-mounted monitor (visually) while driving. Participants also completed a vision and cognitive screening battery, including LogMAR visual acuity, Pelli-Robson letter contrast sensitivity, the Trails test, and the Digit Symbol Substitution (DSS) test. Drivers reported significantly fewer signs, hit more road hazards, misjudged more gaps, and increased their time to complete the course under the dual task (visual and auditory) conditions compared with the single task condition. The older participants also reported significantly fewer road signs and drove significantly more slowly than the younger participants, and this was exacerbated for the visual dual task condition. The results of the regression analysis revealed that cognitive aging (measured by the DSS and Trails test) rather than chronologic age was a better predictor of the declines seen in driving performance under dual task conditions. An overall z score was calculated, which took into account both driving and the secondary task (summing) performance under the two dual task conditions. Performance was significantly worse for the auditory dual task compared with the visual dual task, and the older participants performed significantly worse than the young subjects. These findings demonstrate that multitasking had a significant detrimental impact on driving performance and that cognitive aging was the best predictor of the declines seen in driving performance under dual task conditions. These results have implications for use of mobile phones or in-vehicle navigational devices while driving, especially for older adults.

Differential Contributions of Selective Attention and Sensory Integration to Driving Performance in Healthy Aging and Alzheimer's Disease.

PubMed

Venkatesan, Umesh M; Festa, Elena K; Ott, Brian R; Heindel, William C

2018-05-01

Patients with Alzheimer's disease (AD) demonstrate deficits in cross-cortical feature binding distinct from age-related changes in selective attention. This may have consequences for driving performance given its demands on multisensory integration. We examined the relationship of visuospatial search and binding to driving in patients with early AD and elderly controls (EC). Participants (42 AD; 37 EC) completed search tasks requiring either luminance-motion (L-M) or color-motion (C-M) binding, analogs of within and across visual processing stream binding, respectively. Standardized road test (RIRT) and naturalistic driving data (CDAS) were collected alongside clinical screening measures. Patients performed worse than controls on most cognitive and driving indices. Visual search and clinical measures were differentially related to driving behavior across groups. L-M search and Trail Making Test (TMT-B) were associated with RIRT performance in controls, while C-M binding, TMT-B errors, and Clock Drawing correlated with CDAS performance in patients. After controlling for demographic and clinical predictors, L-M reaction time significantly predicted RIRT performance in controls. In patients, C-M binding made significant contributions to CDAS above and beyond demographic and clinical predictors. RIRT and C-M binding measures accounted for 51% of variance in CDAS performance in patients. Whereas selective attention is associated with driving behavior in EC, cross-cortical binding appears most sensitive to driving in AD. This latter relationship may emerge only in naturalistic settings, which better reflect patients' driving behavior. Visual integration may offer distinct insights into driving behavior, and thus has important implications for assessing driving competency in early AD. (JINS, 2018, 24, 486-497).

A brief peripheral motion contrast threshold test predicts older drivers' hazardous behaviors in simulated driving.

PubMed

Henderson, Steven; Woods-Fry, Heather; Collin, Charles A; Gagnon, Sylvain; Voloaca, Misha; Grant, John; Rosenthal, Ted; Allen, Wade

2015-05-01

Our research group has previously demonstrated that the peripheral motion contrast threshold (PMCT) test predicts older drivers' self-report accident risk, as well as simulated driving performance. However, the PMCT is too lengthy to be a part of a battery of tests to assess fitness to drive. Therefore, we have developed a new version of this test, which takes under two minutes to administer. We assessed the motion contrast thresholds of 24 younger drivers (19-32) and 25 older drivers (65-83) with both the PMCT-10min and the PMCT-2min test and investigated if thresholds were associated with measures of simulated driving performance. Younger participants had significantly lower motion contrast thresholds than older participants and there were no significant correlations between younger participants' thresholds and any measures of driving performance. The PMCT-10min and the PMCT-2min thresholds of older drivers' predicted simulated crash risk, as well as the minimum distance of approach to all hazards. This suggests that our tests of motion processing can help predict the risk of collision or near collision in older drivers. Thresholds were also correlated with the total lane deviation time, suggesting a deficiency in processing of peripheral flow and delayed detection of adjacent cars. The PMCT-2min is an improved version of a previously validated test, and it has the potential to help assess older drivers' fitness to drive. Copyright © 2015 Elsevier Ltd. All rights reserved.

Positive effects of Red Bull® Energy Drink on driving performance during prolonged driving.

PubMed

Mets, Monique A J; Ketzer, Sander; Blom, Camilla; van Gerven, Maartje H; van Willigenburg, Gitta M; Olivier, Berend; Verster, Joris C

2011-04-01

The purpose of this study was to examine if Red Bull® Energy Drink can counteract sleepiness and driving impairment during prolonged driving. Twenty-four healthy volunteers participated in this double-blind placebo-controlled crossover study. After 2 h of highway driving in the STISIM driving simulator, subjects had a 15-min break and consumed Red Bull® Energy Drink (250 ml) or placebo (Red Bull® Energy Drink without the functional ingredients: caffeine, taurine, glucuronolactone, B vitamins (niacin, pantothenic acid, B6, B12), and inositol) before driving for two additional hours. A third condition comprised 4 h of uninterrupted driving. Primary parameter was the standard deviation of lateral position (SDLP), i.e., the weaving of the car. Secondary parameters included SD speed, subjective driving quality, sleepiness, and mental effort to perform the test. No significant differences were observed during the first 2 h of driving. Red Bull® Energy Drink significantly improved driving relative to placebo: SDLP was significantly reduced during the 3rd (p < 0.046) and 4th hour of driving (p < 0.011). Red Bull® Energy Drink significantly reduced the standard deviation of speed (p < 0.004), improved subjective driving quality (p < 0.0001), and reduced mental effort to perform the test (p < 0.024) during the 3rd hour of driving. Subjective sleepiness was significantly decreased during both the 3rd and 4th hour of driving after Red Bull® Energy Drink (p < 0.001 and p < 0.009, respectively). Relative to uninterrupted driving, Red Bull® Energy Drink significantly improved each parameter. Red Bull® Energy Drink significantly improves driving performance and reduces driver sleepiness during prolonged highway driving.

Alcohol calibration of tests measuring skills related to car driving.

PubMed

Jongen, Stefan; Vuurman, Eric; Ramaekers, Jan; Vermeeren, Annemiek

2014-06-01

Medication and illicit drugs can have detrimental side effects which impair driving performance. A drug's impairing potential should be determined by well-validated, reliable, and sensitive tests and ideally be calibrated by benchmark drugs and doses. To date, no consensus has been reached on the issue of which psychometric tests are best suited for initial screening of a drug's driving impairment potential. The aim of this alcohol calibration study is to determine which performance tests are useful to measure drug-induced impairment. The effects of alcohol are used to compare the psychometric quality between tests and as benchmark to quantify performance changes in each test associated with potentially impairing drug effects. Twenty-four healthy volunteers participated in a double-blind, four-way crossover study. Treatments were placebo and three different doses of alcohol leading to blood alcohol concentrations (BACs) of 0.2, 0.5, and 0.8 g/L. Main effects of alcohol were found in most tests. Compared with placebo, performance in the Divided Attention Test (DAT) was significantly impaired after all alcohol doses and performance in the Psychomotor Vigilance Test (PVT) and the Balance Test was impaired with a BAC of 0.5 and 0.8 g/L. The largest effect sizes were found on postural balance with eyes open and mean reaction time in the divided attention and the psychomotor vigilance test. The preferable tests for initial screening are the DAT and the PVT, as these tests were most sensitive to the impairing effects of alcohol and being considerably valid in assessing potential driving impairment.

Effects of different blood alcohol concentrations and post-alcohol impairment on driving behavior and task performance.

PubMed

Liu, Yung-Ching; Ho, Chin Heng

2010-08-01

A study using simulator methodology was conducted to investigate the effects of (1) different blood alcohol concentrations (BAC) of 0, 0.05, 0.08, and 0.10 percent and (2) post-alcohol impairment (where BAC approximately 0%) on driving behavior and subsidiary cognitive task performance. Two driving sessions were investigated, that is, drunk driving and post-alcohol driving, with each requiring approximately 20 min of driving. In addition to driving safely, participants were instructed to perform the critical flicker fusion (CFF) test and completed the NASA-TLX mental workload questionnaire. Eight licensed drivers (6 males, 2 females) participated in this 2 (road complexities) x 2 (simulated driving sessions) x 4 (levels of BAC) within-subjects experiment. The study revealed that higher BAC levels were associated with lower performing driving behavior. The driver's mental workload reached the highest values in the post-alcohol session. In terms of tasks involving divided attention, the traffic sign distance estimation showed significant deterioration with increased BAC levels. The relationship between drunk-driving behavior and alcohol dosage was supported in this study. Noticeably, no significant difference was found between drunk driving and post-alcohol driving, indicating that even in the post-alcohol situation, the impairment still remained significant enough to jeopardize traffic safety as much as it does in the case of drunk driving. In real-life situations, adopting a rest-time strategy to avoid post-alcohol impairment effects may not be the most appropriate solution by drivers; rather, drivers should be given some tests to verify the probability of post-alcohol effects on driving.

The Maintenance of Wakefulness Test and driving simulator performance.

PubMed

Banks, Siobhan; Catcheside, Peter; Lack, Leon C; Grunstein, Ron R; McEvoy, R Doug

2005-11-01

It has been suggested that the Maintenance of Wakefulness Test (MWT) may be clinically useful to assess fitness to drive, yet little is known about the actual relationship between sleep latency and driving performance. This study examined the ability of 2 MWT trials to predict driving-simulator performance in healthy individuals. Experimental. NA. Twenty healthy volunteers (mean age 22.8 years; 9 men). NA. The MWT and driving-simulator performance were examined under 2 conditions-partial sleep deprivation and a combination of partial sleep deprivation and alcohol consumption. Each subject was studied a week apart, with the order randomly assigned. Subjects completed a nighttime 70-minute AusEd driving simulation task and two 40-minute MWT trials, 1 before (MWT1) and 1 after (MWT2) the driving task. In the sleep-deprived condition, the MWT1 sleep latency was inversely correlated with braking reaction time. During the partial sleep deprivation and alcohol condition, the number of microsleeps during the driving task, steering deviation, braking reaction time, and crashes all negatively correlated with the MWT1 sleep latency. Additionally, construction of a receiver-operator characteristic curve revealed that MWT1 sleep latency in the partial sleep deprivation plus alcohol condition significantly discriminated subjects who had a crash from those who did not. These results indicate that sleep latency on the MWT is a reasonable predictor of driving simulator performance in sleepy, alcohol-impaired, normal subjects. Further research is needed to examine the relationship between daytime MWT results and driving simulator performance in sleepy patients (eg, those with obstructive sleep apnea) and in experimentally sleep-deprived normal subjects.

Acute and subchronic effects of bilastine (20 and 40 mg) and hydroxyzine (50 mg) on actual driving performance in healthy volunteers.

PubMed

Conen, Silke; Theunissen, Eef L; Van Oers, Anita C M; Valiente, Román; Ramaekers, Johannes G

2011-11-01

Bilastine is a new second-generation H1 antagonist. Although bilastine has been demonstrated to produce little or no performance impairment in laboratory tests, it cannot be excluded that it produces impairments in real-life performance such as driving. This study aims to assess the effects of two doses of bilastine (20 and 40 mg) on actual driving after single and repeated administration. Hydroxyzine 50 mg was included as an active control. Twenty-two participants (11 females, 11 males) were tested in a placebo-controlled, randomized, double-blind, four-way cross-over design. Participants were treated with once-daily doses for eight consecutive days. On day 1 and 8 of each treatment period participants performed an actual highway driving test. The primary variable was standard deviation of lateral position (SDLP), a measure of weaving. Results demonstrated that hydroxyzine significantly increased SDLP on days 1 and 8 of treatment. Bilastine did not affect SDLP. It is concluded that hydroxyzine produces severe driving impairment after single doses and that this impairment only partly mitigates over time due to a lack of complete tolerance. Bilastine did not produce any driving impairment after single and repeated doses and can be safely used in traffic in doses up to 40 mg.

Cognitive Functioning and Driving Simulator Performance in Middle-aged and Older Adults with HIV

PubMed Central

Vance, David E.; Fazeli, Pariya L.; Ball, David A.; Slater, Larry Z.; Ross, Lesley A.

2014-01-01

Nearly half of people living with HIV experience cognitive deficits that may impact instrumental activities of daily living. As the number of people aging with HIV increases, concerns mount that disease-related cognitive deficits may be compounded by age-related deficits, which may further compromise everyday functions such as driving. In this cross-sectional pilot study, during a 2.5-hour visit, 26 middle-aged and older adults (40+ years) were administered demographic, health, psychosocial, and driving habits questionnaires; cognitive assessments; and driving simulator tests. Although CD4+T lymphocyte count and viral load were unrelated to driving performance, older age was related to poorer driving. Furthermore, poorer visual speed of processing performance (i.e., Useful Field of View) was related to poorer driving performance (e.g., average gross reaction time). Mixed findings were observed between driving performance and cognitive function on self-reported driving habits of participants. Implications for these findings on nursing practice and research are posited. PMID:24513104

Does correcting astigmatism with toric lenses improve driving performance?

PubMed

Cox, Daniel J; Banton, Thomas; Record, Steven; Grabman, Jesse H; Hawkins, Ronald J

2015-04-01

Driving is a vision-based activity of daily living that impacts safety. Because visual disruption can compromise driving safety, contact lens wearers with astigmatism may pose a driving safety risk if they experience residual blur from spherical lenses that do not correct their astigmatism or if they experience blur from toric lenses that rotate excessively. Given that toric lens stabilization systems are continually improving, this preliminary study tested the hypothesis that astigmats wearing toric contact lenses, compared with spherical lenses, would exhibit better overall driving performance and driving-specific visual abilities. A within-subject, single-blind, crossover, randomized design was used to evaluate driving performance in 11 young adults with astigmatism (-0.75 to -1.75 diopters cylinder). Each participant drove a highly immersive, virtual reality driving simulator (210 degrees field of view) with (1) no correction, (2) spherical contact lens correction (ACUVUE MOIST), and (3) toric contact lens correction (ACUVUE MOIST for Astigmatism). Tactical driving skills such as steering, speed management, and braking, as well as operational driving abilities such as visual acuity, contrast sensitivity, and foot and arm reaction time, were quantified. There was a main effect for type of correction on driving performance (p = 0.05). Correction with toric lenses resulted in significantly safer tactical driving performance than no correction (p < 0.05), whereas correction with spherical lenses did not differ in driving safety from no correction (p = 0.118). Operational tests differentiated corrected from uncorrected performance for both spherical (p = 0.008) and toric (p = 0.011) lenses, but they were not sensitive enough to differentiate toric from spherical lens conditions. Given previous research showing that deficits in these tactical skills are predictive of future real-world collisions, these preliminary data suggest that correcting low to moderate astigmatism with toric lenses may be important to driving safety. Their merits relative to spherical lens correction require further investigation.

Comparison of driving simulator performance and neuropsychological testing in narcolepsy.

PubMed

Kotterba, Sylvia; Mueller, Nicole; Leidag, Markus; Widdig, Walter; Rasche, Kurt; Malin, Jean-Pierre; Schultze-Werninghaus, Gerhard; Orth, Maritta

2004-09-01

Daytime sleepiness and cataplexy can increase automobile accident rates in narcolepsy. Several countries have produced guidelines for issuing a driving license. The aim of the study was to compare driving simulator performance and neuropsychological test results in narcolepsy in order to evaluate their predictive value regarding driving ability. Thirteen patients with narcolepsy (age: 41.5+/-12.9 years) and 10 healthy control patients (age: 55.1+/-7.8 years) were investigated. By computer-assisted neuropsychological testing, vigilance, alertness and divided attention were assessed. In a driving simulator patients and controls had to drive on a highway for 60 min (mean speed of 100 km/h). Different weather and daytime conditions and obstacles were presented. Epworth Sleepiness Scale-Scores were significantly raised (narcolepsy patients: 16.7+/-5.1, controls: 6.6+/-3.6, P < or = 0.001). The accident rate of the control patients increased (3.2+/-1.8 versus 1.3+/-1.5, P < or = 0.01). Significant differences in concentration lapses (e.g. tracking errors and deviation from speed limit) could not be revealed (9.8+/-3.5 versus 7.1+/-3.2, pns). Follow-up investigation in five patients after an optimising therapy could demonstrate the decrease in accidents due to concentration lapses (P < or = 0.05). Neuropsychological testing (expressed as percentage compared to a standardised control population) revealed deficits in alertness (32.3+/-28.6). Mean percentage scores of divided attention (56.9+/-25.4) and vigilance (58.7+/-26.8) were in a normal range. There was, however, a high inter-individual difference. There was no correlation between driving performance and neuropsychological test results or ESS Score. Neuropsychological test results did not significantly change in the follow-up. The difficulties encountered by the narcolepsy patient in remaining alert may account for sleep-related motor vehicle accidents. Driving simulator investigations are closely related to real traffic situations than isolated neuropsychological tests. At the present time the driving simulator seems to be a useful instrument judging driving ability especially in cases with ambiguous neuropsychological results.

Blue-Enriched White Light Enhances Physiological Arousal But Not Behavioral Performance during Simulated Driving at Early Night

PubMed Central

Rodríguez-Morilla, Beatriz; Madrid, Juan A.; Molina, Enrique; Correa, Angel

2017-01-01

Vigilance usually deteriorates over prolonged driving at non-optimal times of day. Exposure to blue-enriched light has shown to enhance arousal, leading to behavioral benefits in some cognitive tasks. However, the cognitive effects of long-wavelength light have been less studied and its effects on driving performance remained to be addressed. We tested the effects of a blue-enriched white light (BWL) and a long-wavelength orange light (OL) vs. a control condition of dim light on subjective, physiological and behavioral measures at 21:45 h. Neurobehavioral tests included the Karolinska Sleepiness Scale and subjective mood scale, recording of distal-proximal temperature gradient (DPG, as index of physiological arousal), accuracy in simulated driving and reaction time in the auditory psychomotor vigilance task. The results showed that BWL decreased the DPG (reflecting enhanced arousal), while it did not improve reaction time or driving performance. Instead, blue light produced larger driving errors than OL, while performance in OL was stable along time on task. These data suggest that physiological arousal induced by light does not necessarily imply cognitive improvement. Indeed, excessive arousal might deteriorate accuracy in complex tasks requiring precision, such as driving. PMID:28690558

Clock Drawing as a Screen for Impaired Driving in Aging and Dementia: Is It Worth the Time?

PubMed Central

Manning, Kevin J.; Davis, Jennifer D.; Papandonatos, George D.; Ott, Brian R.

2014-01-01

Clock drawing is recommended by medical and transportation authorities as a screening test for unsafe drivers. The objective of the present study was to assess the usefulness of different clock drawing systems as screening measures of driving performance in 122 healthy and cognitively impaired older drivers. Clock drawing was measured using four different scoring systems. Driving outcomes included global ratings of safety and the error rate on a standardized on-road test. Findings revealed that clock drawing was significantly correlated with the driving score on the road test for each of the scoring systems. However, receiver operator curve analyses showed limited clinical utility for clock drawing as a screening instrument for impaired on-road driving performance with the area under the curve ranging from 0.53 to 0.61. Results from this study indicate that clock drawing has limited utility as a solitary screening measure of on-road driving, even when considering a variety of scoring approaches. PMID:24296110

Clock drawing as a screen for impaired driving in aging and dementia: is it worth the time?

PubMed

Manning, Kevin J; Davis, Jennifer D; Papandonatos, George D; Ott, Brian R

2014-02-01

Clock drawing is recommended by medical and transportation authorities as a screening test for unsafe drivers. The objective of the present study was to assess the usefulness of different clock drawing systems as screening measures of driving performance in 122 healthy and cognitively impaired older drivers. Clock drawing was measured using four different scoring systems. Driving outcomes included global ratings of safety and the error rate on a standardized on-road test. Findings revealed that clock drawing was significantly correlated with the driving score on the road test for each of the scoring systems. However, receiver operator curve analyses showed limited clinical utility for clock drawing as a screening instrument for impaired on-road driving performance with the area under the curve ranging from 0.53 to 0.61. Results from this study indicate that clock drawing has limited utility as a solitary screening measure of on-road driving, even when considering a variety of scoring approaches.

The effect of feedback on attitudes toward cellular phone use while driving: a comparison between novice and experienced drivers.

PubMed

Wang, Ying; Zhang, Wei; Reimer, Bryan; Lavallière, Martin; Lesch, Mary F; Horrey, William J; Wu, Su

2010-10-01

To assess and compare the effectiveness of a simulation-based approach to change drivers' attitudes toward cellular phone use while driving for younger novice and older experienced drivers. Thirty young novice drivers were tested on a driving simulator in this study. Their performance in dealing with driving tasks was measured for a single task and dual tasks (driving while using a cellular phone) and compared to 30 older experienced drivers tested previously in another study. Half of the younger drivers received video-based feedback regarding their performance in the two conditions, with an emphasis on the contribution of dual-tasking to degraded performance. The other half did not receive any performance feedback. Drivers' perceptions and attitudes toward cellular phone use while driving were investigated by a questionnaire before, immediately after, and again one month following the simulation-based testing for both groups of drivers (feedback; no feedback). All drivers (including the novice and experienced) reported willingness to engage in driving and talking on a cellular phone in some situations. The simulated driving test showed that a secondary cellular phone task significantly degraded driving performance for both the novice and the experienced drivers. The feedback treatment group (both the novice and the experienced) showed significant attitude change toward cellular phone use while driving (toward being less favorable), whereas the control group had no attitude change. At the one-month follow-up, the benefit of feedback was sustained more so in the experienced driver group than the novice driver group, although both groups still benefited relative to the control conditions. Simulation-based feedback training is promising for short-term education in novice drivers but may be more effective in the long-term for drivers with higher levels of experience. Drivers with more experience appear to have a greater, more sustained benefit from the training than novices. Additional research is needed to better tailor this education method toward novice drivers. Simulation-based participative education approach through feedback needs to be better tailored toward novice drivers.

Older drivers: On-road and off-road test results.

PubMed

Selander, Helena; Lee, Hoe C; Johansson, Kurt; Falkmer, Torbjörn

2011-07-01

Eighty-five volunteer drivers, 65-85 years old, without cognitive impairments impacting on their driving were examined, in order to investigate driving errors characteristic for older drivers. In addition, any relationships between cognitive off-road and on-road tests results, the latter being the gold standard, were identified. Performance measurements included Trail Making Test (TMT), Nordic Stroke Driver Screening Assessment (NorSDSA), Useful Field of View (UFOV), self-rating driving performance and the two on-road protocols P-Drive and ROA. Some of the older drivers displayed questionable driving behaviour. In total, 21% of the participants failed the on-road assessment. Some of the specific errors were more serious than others. The most common driving errors embraced speed; exceeding the speed limit or not controlling the speed. Correlations with the P-Drive protocol were established for NorSDSA total score (weak), UFOV subtest 2 (weak), and UFOV subtest 3 (moderate). Correlations with the ROA protocol were established for UFOV subtest 2 (weak) and UFOV subtest 3 (weak). P-Drive and self ratings correlated weakly, whereas no correlation between self ratings and the ROA protocol was found. The results suggest that specific problems or errors seen in an older person's driving can actually be "normal driving behaviours". Copyright © 2011 Elsevier Ltd. All rights reserved.

Differential residual effects of zaleplon and zopiclone on actual driving: a comparison with a low dose of alcohol.

PubMed

Vermeeren, Annemiek; Riedel, Wim J; van Boxtel, Martin P J; Darwish, Mona; Paty, Isabelle; Patat, Alain

2002-03-15

To compare residual effects of zaleplon 10 mg, zopiclone 7.5 mg, and placebo, and a social dose of alcohol on car driving, memory, and psychomotor performance. Two-part placebo controlled, crossover study. Part 1 was single blind, Part 2 double blind. University research institute. Thirty healthy volunteers (15 men and 15 women, mean age 32 +/- 7 years) In Part 1 alcohol and alcohol-placebo drinks were administered around noon. In Part 2 single oral doses of zaleplon 10 mg, zopiclone 7.5 mg and placebo were administered at bedtime. A highway driving test, laboratory tests of word learning, critical tracking and divided attention, and subjective assessments of sleep, mood, and effects of treatments on driving. Driving started 40 minutes after a second alcohol dose in Part 1, and 10 hours after drug intake in Part 2. The results demonstrated that alcohol, at average plasma concentrations of approximately 0.030 g/dl, significantly impaired performance in all tests. Zaleplon's residual effects did not differ significantly from those of placebo in any test. In contrast, zopiclone had significant residual effects on driving, divided attention, and memory. The magnitude of impairment in the driving test observed the morning after zopiclone 7.5 mg was twice that observed with alcohol. Zaleplon 10 mg has no residual effects on driving when taken at bedtime, 10 hours before driving. In contrast, zopiclone 7.5 mg can cause marked residual impairment. Patients should be advised to avoid driving the morning after zopiclone administration.

The role of effort in moderating the anxiety-performance relationship: Testing the prediction of processing efficiency theory in simulated rally driving.

PubMed

Wilson, Mark; Smith, Nickolas C; Chattington, Mark; Ford, Mike; Marple-Horvat, Dilwyn E

2006-11-01

We tested some of the key predictions of processing efficiency theory using a simulated rally driving task. Two groups of participants were classified as either dispositionally high or low anxious based on trait anxiety scores and trained on a simulated driving task. Participants then raced individually on two similar courses under counterbalanced experimental conditions designed to manipulate the level of anxiety experienced. The effort exerted on the driving tasks was assessed though self-report (RSME), psychophysiological measures (pupil dilation) and visual gaze data. Efficiency was measured in terms of efficiency of visual processing (search rate) and driving control (variability of wheel and accelerator pedal) indices. Driving performance was measured as the time taken to complete the course. As predicted, increased anxiety had a negative effect on processing efficiency as indexed by the self-report, pupillary response and variability of gaze data. Predicted differences due to dispositional levels of anxiety were also found in the driving control and effort data. Although both groups of drivers performed worse under the threatening condition, the performance of the high trait anxious individuals was affected to a greater extent by the anxiety manipulation than the performance of the low trait anxious drivers. The findings suggest that processing efficiency theory holds promise as a theoretical framework for examining the relationship between anxiety and performance in sport.

Driving with Binocular Visual Field Loss? A Study on a Supervised On-Road Parcours with Simultaneous Eye and Head Tracking

PubMed Central

Aehling, Kathrin; Heister, Martin; Rosenstiel, Wolfgang; Schiefer, Ulrich; Papageorgiou, Elena

2014-01-01

Post-chiasmal visual pathway lesions and glaucomatous optic neuropathy cause binocular visual field defects (VFDs) that may critically interfere with quality of life and driving licensure. The aims of this study were (i) to assess the on-road driving performance of patients suffering from binocular visual field loss using a dual-brake vehicle, and (ii) to investigate the related compensatory mechanisms. A driving instructor, blinded to the participants' diagnosis, rated the driving performance (passed/failed) of ten patients with homonymous visual field defects (HP), including four patients with right (HR) and six patients with left homonymous visual field defects (HL), ten glaucoma patients (GP), and twenty age and gender-related ophthalmologically healthy control subjects (C) during a 40-minute driving task on a pre-specified public on-road parcours. In order to investigate the subjects' visual exploration ability, eye movements were recorded by means of a mobile eye tracker. Two additional cameras were used to monitor the driving scene and record head and shoulder movements. Thus this study is novel as a quantitative assessment of eye movements and an additional evaluation of head and shoulder was performed. Six out of ten HP and four out of ten GP were rated as fit to drive by the driving instructor, despite their binocular visual field loss. Three out of 20 control subjects failed the on-road assessment. The extent of the visual field defect was of minor importance with regard to the driving performance. The site of the homonymous visual field defect (HVFD) critically interfered with the driving ability: all failed HP subjects suffered from left homonymous visual field loss (HL) due to right hemispheric lesions. Patients who failed the driving assessment had mainly difficulties with lane keeping and gap judgment ability. Patients who passed the test displayed different exploration patterns than those who failed. Patients who passed focused longer on the central area of the visual field than patients who failed the test. In addition, patients who passed the test performed more glances towards the area of their visual field defect. In conclusion, our findings support the hypothesis that the extent of visual field per se cannot predict driving fitness, because some patients with HVFDs and advanced glaucoma can compensate for their deficit by effective visual scanning. Head movements appeared to be superior to eye and shoulder movements in predicting the outcome of the driving test under the present study scenario. PMID:24523869

Cold-air performance of compressor-drive turbine of Department of Energy upgraded automobile gas turbine engine. 2: Stage performance

NASA Technical Reports Server (NTRS)

Roelke, R. J.; Haas, J. E.

1982-01-01

The aerodynamic performance of the compressor-drive turbine of the DOE upgraded gas turbine engine was determined in low temperature air. The as-received cast rotor blading had a significantly thicker profile than design and a fairly rough surface finish. Because of these blading imperfections a series of stage tests with modified rotors were made. These included the as-cast rotor, a reduced-roughness rotor, and a rotor with blades thinned to near design. Significant performance changes were measured. Tests were also made to determine the effect of Reynolds number on the turbine performance. Comparisons are made between this turbine and the compressor-drive turbine of the DOE baseline gas turbine engine.

Characterization, performance, and prediction of a lead-acid battery under simulated electric vehicle driving requirements

NASA Technical Reports Server (NTRS)

Ewashinka, J. G.; Bozek, J. M.

1981-01-01

A state-of-the-art 6-V battery module in current use by the electric vehicle industry was tested at the NASA Lewis Research Center to determine its performance characteristics under the SAE J227a driving schedules B, C, and D. The primary objective of the tests was to determine the effects of periods of recuperation and long and short periods of electrical regeneration in improving the performance of the battery module and hence extendng the vehicle range. A secondary objective was to formulate a computer program that would predict the performance of this battery module for the above driving schedules. The results show excellent correlation between the laboratory tests and predicted results. The predicted performance compared with laboratory tests was within +2.4 to -3.7 percent for the D schedule, +0.5 to -7.1 percent for the C schedule, and better than -11.4 percent for the B schedule.

Characterization, performance, and prediction of a lead-acid battery under simulated electric vehicle driving requirements

NASA Astrophysics Data System (ADS)

Ewashinka, J. G.; Bozek, J. M.

1981-05-01

A state-of-the-art 6-V battery module in current use by the electric vehicle industry was tested at the NASA Lewis Research Center to determine its performance characteristics under the SAE J227a driving schedules B, C, and D. The primary objective of the tests was to determine the effects of periods of recuperation and long and short periods of electrical regeneration in improving the performance of the battery module and hence extendng the vehicle range. A secondary objective was to formulate a computer program that would predict the performance of this battery module for the above driving schedules. The results show excellent correlation between the laboratory tests and predicted results. The predicted performance compared with laboratory tests was within +2.4 to -3.7 percent for the D schedule, +0.5 to -7.1 percent for the C schedule, and better than -11.4 percent for the B schedule.

Driving and off-road impairments underlying failure on road testing in Parkinson's disease.

PubMed

Devos, Hannes; Vandenberghe, Wim; Tant, Mark; Akinwuntan, Abiodun E; De Weerdt, Willy; Nieuwboer, Alice; Uc, Ergun Y

2013-12-01

Parkinson's disease (PD) affects driving ability. We aimed to determine the most critical impairments in specific road skills and in clinical characteristics leading to failure on a road test in PD. In this cross-sectional study, certified driving assessment experts evaluated specific driving skills in 104 active, licensed drivers with PD using a standardized, on-road checklist and issued a global decision of pass/fail. Participants also completed an off-road evaluation assessing demographic features, disease characteristics, motor function, vision, and cognition. The most important driving skills and off-road predictors of the pass/fail outcome were identified using multivariate stepwise regression analyses. Eighty-six (65%) passed and 36 (35%) failed the on-road driving evaluation. Persons who failed performed worse on all on-road items. When adjusted for age and gender, poor performances on lateral positioning at low speed, speed adaptations at high speed, and left turning maneuvers yielded the best model that determined the pass/fail decision (R(2) = 0.56). The fail group performed poorer on all motor, visual, and cognitive tests. Measures of visual scanning, motor severity, PD subtype, visual acuity, executive functions, and divided attention were independent predictors of pass/fail decisions in the multivariate model (R(2) = 0.60). Our study demonstrated that failure on a road test in PD is determined by impairments in specific driving skills and associated with deficits in motor, visual, executive, and visuospatial functions. These findings point to specific driving and off-road impairments that can be targeted in multimodal rehabilitation programs for drivers with PD. © 2013 Movement Disorder Society.

Modeling Heavy/Medium-Duty Fuel Consumption Based on Drive Cycle Properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Lijuan; Duran, Adam; Gonder, Jeffrey

This paper presents multiple methods for predicting heavy/medium-duty vehicle fuel consumption based on driving cycle information. A polynomial model, a black box artificial neural net model, a polynomial neural network model, and a multivariate adaptive regression splines (MARS) model were developed and verified using data collected from chassis testing performed on a parcel delivery diesel truck operating over the Heavy Heavy-Duty Diesel Truck (HHDDT), City Suburban Heavy Vehicle Cycle (CSHVC), New York Composite Cycle (NYCC), and hydraulic hybrid vehicle (HHV) drive cycles. Each model was trained using one of four drive cycles as a training cycle and the other threemore » as testing cycles. By comparing the training and testing results, a representative training cycle was chosen and used to further tune each method. HHDDT as the training cycle gave the best predictive results, because HHDDT contains a variety of drive characteristics, such as high speed, acceleration, idling, and deceleration. Among the four model approaches, MARS gave the best predictive performance, with an average absolute percent error of -1.84% over the four chassis dynamometer drive cycles. To further evaluate the accuracy of the predictive models, the approaches were first applied to real-world data. MARS outperformed the other three approaches, providing an average absolute percent error of -2.2% of four real-world road segments. The MARS model performance was then compared to HHDDT, CSHVC, NYCC, and HHV drive cycles with the performance from Future Automotive System Technology Simulator (FASTSim). The results indicated that the MARS method achieved a comparative predictive performance with FASTSim.« less

Driving competences and neuropsychological factors associated to driving counseling in multiple sclerosis.

PubMed

Badenes, Dolors; Garolera, Maite; Casas, Laura; Cejudo-Bolivar, Juan Carlos; de Francisco, Jorge; Zaragoza, Silvia; Calzado, Noemi; Aguilar, Miquel

2014-05-01

Multiple Sclerosis (MS) significantly impacts daily living activities, including car driving. To investigate driving difficulties experienced with MS, we compared 50 MS patients with minor or moderate disability and 50 healthy controls (HC) using computerized driving tests (the ASDE driver test and the Useful Field of View (UFOV) test) and neuropsychological tests. Inclusion criteria included being active drivers. We evaluated whether cognitive deterioration in MS is associated with the results of driving tests by comparing MS patients without cognitive deterioration with HC. The results indicated that the MS patients performed worse than the HCs in attention, information processing, working memory and visuomotor coordination tasks. Furthermore, MS patients with cognitive impairments experienced more difficulties in the driving tests than did the non-impaired MS patients. Motor dysfunction associated with MS also played an important role in this activity. The results of this study suggest that MS should be assessed carefully and that special emphasis should be placed on visuomotor coordination and executive functions because patients with minor motor disability and subtle cognitive impairments can pass measures predictive of driving safety.

Timeframe for return to driving for patients with minimally invasive knee arthroplasty is associated with knee performance on functional tests

PubMed Central

2014-01-01

Background This study hopes to establish the timeframe for a safe return to driving under different speed conditions for patients after minimally invasive total knee arthroplasty and further explores how well various kinds of functional tests on knee performance can predict the patients’ braking ability. Methods 14 patients with right knee osteoarthritis were included in the present study and instructed to perform three simulated driving tasks at preoperative, 2 weeks postoperative and 4 weeks postoperative. Results The results showed that the total braking time at 4 week postoperative has attained the preoperative level at the driving speed 50 and 70 km/hr but not at the driving speed 90 km/hr. It had significantly improving in knee reaction time and maximum isometric force at 4 weeks postoperative. Besides, there was a moderate to high correlation between the scores of the step counts and the total braking time. Conclusions Summary, it is recommended that driving may be resumed 4 weeks after a right knee replacement but had to drive at low or moderate speed and the best predictor of safety driving is step counts. PMID:24913312

Next-day residual effects of hypnotics in DSM-IV primary insomnia: a driving simulator study with simultaneous electroencephalogram monitoring.

PubMed

Staner, Luc; Ertlé, Stéphane; Boeijinga, Peter; Rinaudo, Gilbert; Arnal, Marie Agnès; Muzet, Alain; Luthringer, Rémy

2005-10-01

Most studies that investigated the next-day residual effects of hypnotic drugs on daytime driving performances were performed on healthy subjects and after a single drug administration. In the present study, we further examine whether the results of these studies could be generalised to insomniac patients and after repeated drug administration. Single and repeated (7 day) doses of zolpidem (10 mg), zopiclone (7.5 mg), lormetazepam (1 mg) or placebo were administered at bedtime in a crossover design to 23 patients (9 men and 14 women aged 38.8+/-2.0 years) with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) primary insomnia. Driving tests were performed 9-11 h post-dose. Results showed that treatment effects were evidenced for subjective sleep, for driving abilities, and for electroencephalogram (EEG) recorded before (resting EEG) and during the driving simulation test (driving EEG). Compared to placebo, zopiclone increased the number of collisions and lormetazepam increased deviation from speed limit and deviation from absolute speed, whereas zolpidem did not differentiate from placebo on these analyses. EEG recordings showed that in contrast to zolpidem, lormetazepam and zopiclone induced typical benzodiazepine-like alterations, suggesting that next-day poor driving performance could relate to a prolonged central nervous system effect of these two hypnotics. The present results corroborate studies on healthy volunteers showing that residual effects of hypnotics increase with their half-lives. The results further suggest that drugs preserving physiological EEG rhythms before and during the driving simulation test 9-11 h post-dose, such as zolpidem, do not influence next-day driving abilities.

The impact of Stereotype Threat on the simulated driving performance of older drivers.

PubMed

Joanisse, Mélanie; Gagnon, Sylvain; Voloaca, Mihnea

2013-01-01

Older drivers are perceived as being dangerous and overly cautious by other drivers. We tested the hypothesis that this negative stereotype has a direct influence on the performance of older drivers. Based on the Stereotype Threat literature, we predicted that older driving performance would be altered after exposure to a Stereotype Threat. Sixty-one older drivers aged 65 and above completed a simulated driving assessment course. Prior to testing, half of the participants were told that the objective of the study was to investigate why older adults aged 65 and above were more implicated in on-road accidents (Stereotype Threat condition) and half were showed a neutral statement. Results confirmed that exposure to the threat significantly altered driving performance. Older adults in the Stereotype Threat condition made more driving mistakes than those in the control group. Interestingly, under a Stereotype Threat condition, older adults tended to commit more speeding infractions. We also observed that domain identification (whether driving is deemed important or not) moderated the impact of the threat. Taken together, these results support recent older drivers' performance models suggesting that the interaction between individual and social factors need to be considered when examining older drivers' performance. Copyright © 2012 Elsevier Ltd. All rights reserved.

Predictors of the On-Road Driving Assessment After Traumatic Brain Injury: Comparing Cognitive Tests, Injury Factors, and Demographics.

PubMed

McKay, Adam; Liew, Carine; Schönberger, Michael; Ross, Pamela; Ponsford, Jennie

(1) To examine the relations between performance on cognitive tests and on-road driving assessment in a sample of persons with traumatic brain injury (TBI). (2) To compare cognitive predictors of the on-road assessment with demographic and injury-related predictors. Ninety-nine people with mild-severe TBI who completed an on-road driving assessment in an Australian rehabilitation setting. Retrospective case series. Wechsler Test of Adult Reading or National Adult Reading Test-Revised; 4 subtests from the Wechsler Adult Intelligence Scale-III; Rey Auditory Verbal Leaning Test; Rey Complex Figure Test; Trail Making Test; demographic factors (age, sex, years licensed); and injury-related factors (duration of posttraumatic amnesia; time postinjury). Participants who failed the driving assessment did worse on measures of attention, visual memory, and executive processing; however, cognitive tests were weak correlates (r values <0.3) and poor predictors of the driving assessment. Posttraumatic amnesia duration mediated by time postinjury was the strongest predictor of the driving assessment-that is, participants with more severe TBIs had later driving assessments and were more likely to fail. Cognitive tests are not reliable predictors of the on-road driving assessment outcome. Traumatic brain injury severity may be a better predictor of on-road driving; however, further research is needed to identify the best predictors of driving behavior after TBI.

40 CFR 86.535-90 - Dynamometer procedure.

Code of Federal Regulations, 2010 CFR

2010-07-01

... run consists of two tests, a “cold” start test and a “hot” start test following the “cold” start by 10... Administrator. (d) Practice runs over the prescribed driving schedule may be performed at test points, provided... the proper speed-time relationship, or to permit sampling system adjustments. (e) The drive wheel...

Excessive daytime sleepiness in adult patients with ADHD as measured by the Maintenance of Wakefulness Test, an electrophysiologic measure.

PubMed

Bioulac, Stéphanie; Chaufton, Cyril; Taillard, Jacques; Claret, Astrid; Sagaspe, Patricia; Fabrigoule, Colette; Bouvard, Manuel P; Philip, Pierre

2015-07-01

To quantify the objective level of sleepiness in adult attention-deficit/hyperactivity disorder (ADHD) patients and to determine the relationship between excessive daytime sleepiness and simulated driving performance. Forty adult ADHD patients (DSM-IV criteria) and 19 matched healthy control subjects were included between June 30, 2010, and June 19, 2013. All participants completed the Epworth Sleepiness Scale and the Manchester Driving Behavior Questionnaire. After nocturnal polysomnography, they performed 2 neuropsychological tests, a 4 × 40-minute Maintenance of Wakefulness Test, and a 1-hour driving session. The primary outcome measure was the mean sleep latency on the Maintenance of Wakefulness Test. ADHD patients were divided into 3 groups defined by their Maintenance of Wakefulness Test scores. Participants (patients and control subjects) were allocated as follows: sleepy ADHD (0-19 min), intermediate ADHD (20-33 min), alert ADHD (34-40 min), and control group (34-40 min). The driving performance outcome was the mean standard deviation of lateral position of the vehicle during the simulated session. The group mean (SD) Epworth Sleepiness Scale score was higher in ADHD patients (12.1 [4.4]) than in controls (6.0 [2.7]) (P < .001). On the basis of the Maintenance of Wakefulness Test scores, 14 patients (35%) were in the sleepy group, 20 (50%) were in the intermediate group, and only 6 (15%) were in the alert group. Sleepy ADHD patients exhibited significantly deteriorated driving performance compared to the other 3 groups (P < .01). Our study shows that a significant proportion of adult ADHD patients exhibit an objective excessive daytime sleepiness, which, in addition, has an impact on simulated driving performance. Excessive daytime sleepiness, therefore, may be a key element needed to better evaluate these ADHD patients. ClinicalTrials.gov identifier: NCT01160874. © Copyright 2015 Physicians Postgraduate Press, Inc.

Hypnotics and driving safety: meta-analyses of randomized controlled trials applying the on-the-road driving test.

PubMed

Verster, Joris C; Veldhuijzen, Dieuwke S; Patat, Alain; Olivier, Berend; Volkerts, Edmund R

2006-01-01

Many people who use hypnotics are outpatients and are likely to drive a car the day after drug intake. The purpose of these meta-analyses was to determine whether or not this is safe. Placebo-controlled, randomized, double-blind trials were selected if using the on-the-road driving test to determine driving ability the day following one or two nights of treatment administration. Primary outcome measure of the driving test was the Standard Deviation of Lateral Position (SDLP); i.e., the weaving of the car. Fixed effects model meta-analyses were performed. Effect size (ES) was computed using mean standardized (weighted) difference scores between treatment and corresponding placebo SDLP values. Ten studies, published from 1984 to 2002 (207 subjects), were included in the meta-analyses. The morning following bedtime administration, i.e. 10-11 hours after dosing, significant driving impairment was found for the recommended dose of various benzodiazepine hypnotics (ES=0.42; 95% Confidence Interval (CI)=0.14 to 0.71). Twice the recommended dose impaired driving both in the morning (ES=0.68; CI=0.39 to 0.97) and afternoon, i.e. 16-17 hours after dosing (ES=0.57; CI=0.26 to 0.88). Zopiclone 7.5 mg also impaired driving in the morning (ES=0.89; CI=0.54 to 1.23). Zaleplon (10 and 20 mg) and zolpidem (10 mg) did not affect driving performance the morning after dosing. Following middle-of-the-night administration, significantly impaired driving performance was found for zopiclone 7.5 mg (ES=1.51, CI=0.85 to 2.17), zolpidem 10 mg (ES=0.66, CI=0.13 to 1.19) and zolpidem 20 mg (ES=1.16, CI=0.60 to 1.72). Zaleplon (10 and 20 mg) did not affect driving performance. The analyses show that driving a car the morning following nocturnal treatment with benzodiazepines and zopiclone is unsafe, whereas the recommended dose of zolpidem (10 mg) and zaleplon (10 mg) do not affect driving ability.

Bilastine safety in drivers who need antihistamines: new evidence from high-speed simulator driving test on allergic patients.

PubMed

Demonte, A; Guanti, M B; Liberati, S; Biffi, A; Fernando, F; Fainello, M; Pepe, P

2018-02-01

Bilastine is a highly selective, non-sedating antihistamine, indicated for the symptomatic treatment of allergic rhinoconjunctivitis and urticaria. Available data suggest that bilastine interferes neither with driving ability nor with flying-related performance. However, no data are available on the effect of bilastine on the driving ability in extreme conditions. Here we analyzed the effect of 7 days treatment with 20 mg bilastine in patients with allergic rhinitis and/or chronic urticaria, on psychophysical performance assessed by the Formula One (F1) high-speed simulator-driving test. This study is a phase IV, interventional, prospective, mono-centric, single arm, open-label trial. Eighteen outpatients affected by allergic rhinitis and/or chronic urticaria, able to perform a preliminary driving test on F1 simulator were considered (V-1). First, the patients had a screening visit to assess their eligibility (V0). Visit 1 (V1), at the end of placebo before bilastine treatment and Visit 2 (V2), at the end of bilastine treatment. The primary variable parameter was the ability to maintain the vehicle in a central position at different speeds (50, 150, and 250 km/h). Bilastine had a good safety profile and was well tolerated in terms of adverse events, laboratory parameters and vital signs. Bilastine did not have any negative effect on the ability to maintain the requested path, a constant speed as well as on attention and reactivity levels, even in extreme driving conditions. This study is the first done in patients with allergic rhinitis and/or chronic urticaria using a F1-high speed simulator-driving test evaluating subjects' performance under bilastine treatment.

Driving with Mild Cognitive Impairment or Dementia: Cognitive Test Performance and Proxy Report of Daily Life Function in Older Women.

PubMed

Vaughan, Leslie; Hogan, Patricia E; Rapp, Stephen R; Dugan, Elizabeth; Marottoli, Richard A; Snively, Beverly M; Shumaker, Sally A; Sink, Kaycee M

2015-09-01

To investigate associations between proxy report of cognitive and functional limitations and cognitive performance and current or former driving status in older women with mild cognitive impairment (MCI) and all-cause dementia. Cross-sectional data analysis of retrospectively identified older women with adjudicated MCI and all-cause dementia in the Women's Health Initiative Memory Study-Epidemiology of Cognitive Health Outcomes (WHIMS-ECHO). Academic medical center. Women (mean age ± standard deviation 83.7 ± 3.5) adjudicated with MCI or dementia during Year 1, 2, 3, or 4 of the WHIMS-ECHO follow-up period (N = 385). The telephone-administered cognitive battery included tests of attention, verbal learning and memory, verbal fluency, executive function, working memory, and global cognitive function plus self-report measures of depressive symptomatology. The Dementia Questionnaire (DQ) was administered to a knowledgeable proxy (family member, friend). Sixty percent of women with MCI and 40% of those with dementia are current drivers. Proxy reports of functional limitations in instrumental activities of daily living (IADLs) are associated with current driving status in women with MCI, whereas performance-based cognitive tests are not. In women with dementia, proxy reports of functional limitations in IADLs and performance-based cognitive tests are associated with current driving status, as expected. These findings have clinical implications for the importance of evaluating driving concurrently with other instrumental functional abilities in MCI and dementia. Additional work is needed to determine whether proxy report of cognitive and functional impairments should help guide referrals for driving assessment and rehabilitation or counseling for driving transition. © 2015, Copyright the Authors Journal compilation © 2015, The American Geriatrics Society.

High performing actuation system for use with a louver array for satellite thermal control. [design and performance tests on prototype Bourdon spiral configuration

NASA Technical Reports Server (NTRS)

Reusser, P. U.; Coebergh, J. A. F.

1973-01-01

A high performing actuation system has been developed to drive one pair or a set of 9 pairs of louver blades. The system uses a Bourdon spiral as the driving member. The response time of the liquid expansion of the spiral system is in the order of three seconds. Besides performance tests, qualification tests have been carried out on a prototype system, demonstrating that the actuation system withstands normal launching conditions; projected operating life of 7 years with more than 7000 cycles can be expected.

Manual transmission enhances attention and driving performance of ADHD adolescent males: pilot study.

PubMed

Cox, Daniel J; Punja, Mohan; Powers, Katie; Merkel, R Lawrence; Burket, Roger; Moore, Melissa; Thorndike, Frances; Kovatchev, Boris

2006-11-01

Inattention is a major contributor to driving mishaps and is especially problematic among adolescent drivers with ADHD, possibly contributing to their 2 to 4 times higher incidence of collisions. Manual transmission has been demonstrated to be associated with greater arousal. This study tests the hypotheses that manual transmission, compared to automatic transmission, would be associated with better attention and performance on a driving simulator. Ten adolescent drivers with ADHD practice driving on the simulator in the manual and automatic mode. Employing a single-blind, cross-over design, participants drive the simulator at 19:30 and 22:30 hr for 30 min in both transmissions and rate their attention to driving. Subjectively, participants report being more attentive while driving in manual transmission mode. Objectively, participants drive safer in the manual transmission mode. Although in need of replication, this pilot study suggests a behavioral intervention to improve driving performance among ADHD adolescents.

Distracted driving due to visual working memory load.

DOT National Transportation Integrated Search

2014-07-01

In an attempt to understand the : specific mechanism by which distractions (such as cell : - : phone use) can interfere with : driving, this work tested the idea that driving performance depends on available space within visual short : - : term memor...

Modeling Simple Driving Tasks with a One-Boundary Diffusion Model

PubMed Central

Ratcliff, Roger; Strayer, David

2014-01-01

A one-boundary diffusion model was applied to the data from two experiments in which subjects were performing a simple simulated driving task. In the first experiment, the same subjects were tested on two driving tasks using a PC-based driving simulator and the psychomotor vigilance test (PVT). The diffusion model fit the response time (RT) distributions for each task and individual subject well. Model parameters were found to correlate across tasks which suggests common component processes were being tapped in the three tasks. The model was also fit to a distracted driving experiment of Cooper and Strayer (2008). Results showed that distraction altered performance by affecting the rate of evidence accumulation (drift rate) and/or increasing the boundary settings. This provides an interpretation of cognitive distraction whereby conversing on a cell phone diverts attention from the normal accumulation of information in the driving environment. PMID:24297620

Insufficient sleep impairs driving performance and cognitive function.

PubMed

Miyata, Seiko; Noda, Akiko; Ozaki, Norio; Hara, Yuki; Minoshima, Makoto; Iwamoto, Kunihiro; Takahashi, Masahiro; Iidaka, Tetsuya; Koike, Yasuo

2010-01-22

Cumulative sleep deprivation may increase the risk of psychiatric disorders, other disorders, and accidents. We examined the effect of insufficient sleep on cognitive function, driving performance, and cerebral blood flow in 19 healthy adults (mean age 29.2 years). All participants were in bed for 8h (sufficient sleep), and for <4h (insufficient sleep). The oxyhaemoglobin (oxyHb) level by a word fluency task was measured with a near-infrared spectroscopy recorder on the morning following sufficient and insufficient sleep periods. Wisconsin card sorting test, continuous performance test, N-back test, and driving performance were evaluated on the same days. The peak oxyHb level was significantly lower, in the left and right frontal lobes after insufficient sleep than after sufficient sleep (left: 0.25+/-0.13 vs. 0.74+/-0.33 mmol, P<0.001; right: 0.25+/-0.09 vs. 0.69+/-0.44 mmol, P<0.01). The percentage of correct responses on CPT after insufficient sleep was significantly lower than that after sufficient sleep (96.1+/-4.5 vs. 86.6+/-9.8%, P<0.05). The brake reaction time in a harsh-braking test was significantly longer after insufficient sleep than after sufficient sleep (546.2+/-23.0 vs. 478.0+/-51.2 ms, P<0.05). Whereas there were no significant correlations between decrease in oxyHb and the changes of cognitive function or driving performance between insufficient sleep and sufficient sleep. One night of insufficient sleep affects daytime cognitive function and driving performance and this was accompanied by the changes of cortical oxygenation response. (c) 2009 Elsevier Ireland Ltd. All rights reserved.

Highway driving performance and cognitive functioning the morning after bedtime and middle-of-the-night use of gaboxadol, zopiclone and zolpidem.

PubMed

Leufkens, Tim R M; Lund, Jesper S; Vermeeren, Annemiek

2009-12-01

Gaboxadol is a selective extrasynaptic GABA(A) receptor agonist previously in development for the treatment of insomnia. Due to its short half-life (1.5-2 h) it is expected to be free from residual effects the next morning. The present study assessed the residual effects of evening and middle-of-the-night administration of 15 mg of gaboxadol on cognitive, psychomotor and driving performance. Twenty-eight healthy volunteers entered the study with 25 (12 women; mean age 31.4 years) completing a double-blind, placebo-controlled, active-referenced five-way cross-over study. Each treatment night subjects ingested one capsule at 23:00 hours and one at 04:00 hours. Treatments were placebo at both times, 15 mg gaboxadol or 7.5 mg zopiclone followed by placebo, and placebo followed by 15 mg gaboxadol or 10 mg zolpidem. Effects on cognition and psychomotor performance were assessed between 07:30 and 08:30 hours and on driving between 09:00 and 10:00 hours. Driving, as measured by standard deviation of lateral position in an on-the-road driving test, was almost significantly (P < 0.07) impaired after evening administration of gaboxadol for the all-subjects-completed set (n = 25) but significantly (P < 0.05) in the full analysis set (n = 28). Effects of all other active treatments on driving were significant. Evening administration of gaboxadol had minor effects on divided attention only, whereas middle-of-the-night administration impaired performance significantly in all tests except memory. Zolpidem and zopiclone impaired performance significantly in every test except tracking after zopiclone; 15 mg of gaboxadol can produce minor residual effects on driving after evening administration. Administration later at night is associated with moderately impairing residual effects on driving and psychomotor performance but not on memory.

On-Road Driving Performance by Persons with Hemianopia and Quadrantanopia

PubMed Central

Wood, Joanne M.; McGwin, Gerald; Elgin, Jennifer; Vaphiades, Michael S.; Braswell, Ronald A.; DeCarlo, Dawn K.; Kline, Lanning B.; Meek, G. Christine; Searcey, Karen; Owsley, Cynthia

2009-01-01

Purpose This study was designed to examine the on-road driving performance of drivers with hemianopia and quadrantanopia compared with age-matched controls. Methods Participants included persons with hemianopia or quadrantanopia and those with normal visual fields. Visual and cognitive function tests were administered, including confirmation of hemianopia and quadrantanopia through visual field testing. Driving performance was assessed using a dual-brake vehicle and monitored by a certified driving rehabilitation specialist. The route was 14.1 miles of city and interstate driving. Two “back-seat” evaluators masked to drivers’ clinical characteristics independently assessed driving performance using a standard scoring system. Results Participants were 22 persons with hemianopia and 8 with quadrantanopia (mean age, 53 ± 20 years) and 30 participants with normal fields (mean age, 52 ± 19 years). Inter-rater agreement for back-seat evaluators was 96%. All drivers with normal fields were rated as safe to drive, while 73% (16/22) of hemianopic and 88% (7/8) of quadrantanopic drivers received safe ratings. Drivers with hemianopia or quadrantanopia who displayed on-road performance problems tended to have difficulty with lane position, steering steadiness, and gap judgment compared to controls. Clinical characteristics associated with unsafe driving were slowed visual processing speed, reduced contrast sensitivity and visual field sensitivity. Conclusions Some drivers with hemianopia or quadrantanopia are fit to drive compared with age-matched control drivers. Results call into question the fairness of governmental policies that categorically deny licensure to persons with hemianopia or quadrantanopia without the opportunity for on-road evaluation. PMID:18936138

Good distractions: Testing the effects of listening to an audiobook on driving performance in simple and complex road environments.

PubMed

Nowosielski, Robert J; Trick, Lana M; Toxopeus, Ryan

2018-02-01

Distracted driving (driving while performing a secondary task) causes many collisions. Most research on distracted driving has focused on operating a cell-phone, but distracted driving can include eating while driving, conversing with passengers or listening to music or audiobooks. Although the research has focused on the deleterious effects of distraction, there may be situations where distraction improves driving performance. Fatigue and boredom are also associated with collision risk and it is possible that secondary tasks can help alleviate the effects of fatigue and boredom. Furthermore, it has been found that individuals with high levels of executive functioning as measured by the OSPAN (Operation Span) task show better driving while multitasking. In this study, licensed drivers were tested in a driving simulator (a car body surrounded by screens) that simulated simple or complex roads. Road complexity was manipulated by increasing traffic, scenery, and the number of curves in the drive. Participants either drove, or drove while listening to an audiobook. Driving performance was measured in terms of braking response time to hazards (HRT): the time required to brake in response to pedestrians or vehicles that suddenly emerged from the periphery into the path of the vehicle, speed, standard deviation of speed, standard deviation of lateral position (SDLP). Overall, braking times to hazards were higher on the complex drive than the simple one, though the effects of secondary tasks such as audiobooks were especially deleterious on the complex drive. In contrast, on the simple drive, driving while listening to an audiobook lead to faster HRT. We found evidence that individuals with high OSPAN scores had faster HRTs when listening to an audiobook. These results suggest that there are environmental and individual factors behind difference in the allocation of attention while listening to audiobooks while driving. Copyright © 2017 Elsevier Ltd. All rights reserved.

Recording and wear characteristics of 4 and 8 mm helical scan tapes

NASA Technical Reports Server (NTRS)

Peter, Klaus J.; Speliotis, Dennis E.

1993-01-01

Performance data of media on helical scan tape systems (4 and 8 mm) is presented and various types of media are compared. All measurements were performed on a standard MediaLogic model ML4500 Tape Evaluator System with a Flash Converter option for time based measurements. The 8 mm tapes are tested on an Exabyte 8200 drive and 4 mm tapes on an Archive Python drive; in both cases, the head transformer is directly connected to a Media Logic Read/Write circuit and test electronics. The drive functions only as a tape transport and its data recover circuits are not used. Signal to Noise, PW 50, Peak Shift and Wear Test data is used to compare the performance of MP (metal particle), BaFe, and metal evaporate (ME). ME tape is the clear winner in magnetic performance but its susceptibility to wear and corrosion, make it less than ideal for data storage.

Residual effects of zopiclone 7.5 mg on highway driving performance in insomnia patients and healthy controls: a placebo controlled crossover study.

PubMed

Leufkens, T R M; Ramaekers, J G; de Weerd, A W; Riedel, W J; Vermeeren, A

2014-07-01

Residual effects of hypnotics on driving performance have been mainly determined in studies using a standardized driving test with healthy good sleepers. Responses to effects may differ, however, between insomniacs and healthy volunteers due to the underlying sleep disorder. In addition, a majority of insomniacs uses hypnotics chronically resulting in the development of tolerance to impairing effects. Impaired driving performance in healthy volunteers may then be an overestimation of the actual effects in insomniacs. The present study aims to compare the residual effects of zopiclone 7.5 mg on on-the-road driving performance of 16 middle-aged insomniacs chronically using hypnotics (chronic users), 16 middle-aged insomniacs not or infrequently using hypnotics (infrequent users), and 16 healthy, age matched, good sleepers (controls). The study was conducted according to a 3 × 2 double-blind, placebo controlled crossover design, with three groups and two treatment conditions. Treatments were single oral doses of zopiclone 7.5 mg and placebo administered at bedtime (2330 hours). Between 10 and 11 h after administration subjects performed a standardized highway driving test. Zopiclone 7.5 mg significantly impaired on-the-road driving performance in both insomnia groups and healthy controls. The magnitude of impairment was significantly less in the chronic users group as compared with the controls. The smaller magnitude of effects suggests that investigating residual effects of hypnotics in healthy volunteers may yield a minor overestimation of the actual effects in insomnia patients.

40 CFR 1066.430 - Performing emission tests.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Performing emission tests. 1066.430... CONTROLS VEHICLE-TESTING PROCEDURES Vehicle Preparation and Running a Test § 1066.430 Performing emission tests. The overall test consists of prescribed sequences of fueling, parking, and driving at specified...

40 CFR 1066.430 - Performing emission tests.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Performing emission tests. 1066.430... CONTROLS VEHICLE-TESTING PROCEDURES Vehicle Preparation and Running a Test § 1066.430 Performing emission tests. The overall test consists of prescribed sequences of fueling, parking, and driving at specified...

The influence of music on mental effort and driving performance.

PubMed

Ünal, Ayça Berfu; Steg, Linda; Epstude, Kai

2012-09-01

The current research examined the influence of loud music on driving performance, and whether mental effort mediated this effect. Participants (N=69) drove in a driving simulator either with or without listening to music. In order to test whether music would have similar effects on driving performance in different situations, we manipulated the simulated traffic environment such that the driving context consisted of both complex and monotonous driving situations. In addition, we systematically kept track of drivers' mental load by making the participants verbally report their mental effort at certain moments while driving. We found that listening to music increased mental effort while driving, irrespective of the driving situation being complex or monotonous, providing support to the general assumption that music can be a distracting auditory stimulus while driving. However, drivers who listened to music performed as well as the drivers who did not listen to music, indicating that music did not impair their driving performance. Importantly, the increases in mental effort while listening to music pointed out that drivers try to regulate their mental effort as a cognitive compensatory strategy to deal with task demands. Interestingly, we observed significant improvements in driving performance in two of the driving situations. It seems like mental effort might mediate the effect of music on driving performance in situations requiring sustained attention. Other process variables, such as arousal and boredom, should also be incorporated to study designs in order to reveal more on the nature of how music affects driving. Copyright © 2012 Elsevier Ltd. All rights reserved.

Acute disinhibiting effects of alcohol as a factor in risky driving behavior

PubMed Central

Fillmore, Mark T.; Blackburn, Jaime S.; Harrison, Emily L. R.

2008-01-01

Automobile crash reports show that up to 40% of fatal crashes in the United States involve alcohol and that younger drivers are over-represented. Alcohol use among young drivers is associated with impulsive and risky driving behaviors, such as speeding, which could contribute to their over-representation in alcohol-related crash statistics. Recent laboratory studies show that alcohol increases impulsive behaviors by impairing the drinker’s ability to inhibit inappropriate actions and that this effect can be exacerbated in conflict situations where the expression and inhibition of behavior are equally motivating. The present study tested the hypothesis that this response conflict might also intensify the disruptive effects of alcohol on driving performance. Fourteen subjects performed a simulated driving and a cued go/no-go task that measured their inhibitory control. Conflict was motivated in these tasks by providing equal monetary incentives for slow, careful behavior (e.g., slow driving, inhibiting impulses) and for quick, abrupt behavior (fast driving, disinhibition). Subjects were tested under two alcohol doses (0.65 g/kg and a placebo) that were administered twice: when conflict was present and when conflict was absent. Alcohol interacted with conflict to impair inhibitory control and to increase risky and impaired driving behavior on the drive task. Also, individuals whose inhibitory control was most impaired by alcohol displayed the poorest driving performance under the drug. The study demonstrates potentially serious disruptions to driving performance as a function of alcohol intoxication and response conflict, and points to inhibitory control as an important underlying mechanism. PMID:18325693

Drive Cycle Analysis Tool - DriveCAT | NREL

Science.gov Websites

tool was created by NREL's fleet test and evaluation team, which conducts in-service performance their needs. Learn more about NREL's fleet test and evaluation research. Contact Us Let us know if you have any questions about the data, need assistance, or would like to contribute test cycles. We also

Focus of NASA's Spaceliner 100 Investment Area

NASA Technical Reports Server (NTRS)

Hueter, Uwe; Lyles, Garry (Technical Monitor)

2000-01-01

This presentation discuss the goals and objectives of the SL100 Technology Focus. Some of the Technology objectives were to: increase system performance margin; drive down operations costs; drive down manufacturing and production costs; and drive down development test and evaluation costs.

Predictors of driving safety in early Alzheimer disease.

PubMed

Dawson, J D; Anderson, S W; Uc, E Y; Dastrup, E; Rizzo, M

2009-02-10

To measure the association of cognition, visual perception, and motor function with driving safety in Alzheimer disease (AD). Forty drivers with probable early AD (mean Mini-Mental State Examination score 26.5) and 115 elderly drivers without neurologic disease underwent a battery of cognitive, visual, and motor tests, and drove a standardized 35-mile route in urban and rural settings in an instrumented vehicle. A composite cognitive score (COGSTAT) was calculated for each subject based on eight neuropsychological tests. Driving safety errors were noted and classified by a driving expert based on video review. Drivers with AD committed an average of 42.0 safety errors/drive (SD = 12.8), compared to an average of 33.2 (SD = 12.2) for drivers without AD (p < 0.0001); the most common errors were lane violations. Increased age was predictive of errors, with a mean of 2.3 more errors per drive observed for each 5-year age increment. After adjustment for age and gender, COGSTAT was a significant predictor of safety errors in subjects with AD, with a 4.1 increase in safety errors observed for a 1 SD decrease in cognitive function. Significant increases in safety errors were also found in subjects with AD with poorer scores on Benton Visual Retention Test, Complex Figure Test-Copy, Trail Making Subtest-A, and the Functional Reach Test. Drivers with Alzheimer disease (AD) exhibit a range of performance on tests of cognition, vision, and motor skills. Since these tests provide additional predictive value of driving performance beyond diagnosis alone, clinicians may use these tests to help predict whether a patient with AD can safely operate a motor vehicle.

Exploring the Black Box: An Analysis of Work Group Diversity, Conflict, and Performance.

ERIC Educational Resources Information Center

Pelled, Lisa Hope; Eisenhardt, Kathleen M.; Xin, Katherine R.

1999-01-01

Tests an integrative model of the relationships among diversity, conflict, and performance, using a sample of 45 electronics-industry worker teams. Functional background diversity drives task conflict; multiple types of diversity drive emotional conflict. Task conflict affects task performance more favorably than does emotional conflict. (102…

'I didn't see that coming': simulated visual fields and driving hazard perception test performance.

PubMed

Glen, Fiona C; Smith, Nicholas D; Jones, Lee; Crabb, David P

2016-09-01

Evidence is limited regarding specific types of visual field loss associated with unsafe driving. We use novel gaze-contingent software to examine the effect of simulated visual field loss on computer-based driving hazard detection with the specific aim of testing the impact of scotomata located to the right and left of fixation. The 'hazard perception test' is a component of the UK driving licence examination, which measures speed of detecting 15 different hazards in a series of real-life driving films. We have developed a novel eye-tracking and computer set up capable of generating a realistic gaze-contingent scotoma simulation (GazeSS) overlaid on film content. Thirty drivers with healthy vision completed three versions of the hazard perception test in a repeated measures experiment. In two versions, GazeSS simulated a scotoma in the binocular field of view to the left or right of fixation. A third version was unmodified to establish baseline performance. Participants' mean baseline hazard perception test score was 51 ± 7 (out of 75). This reduced to 46 ± 9 and 46 ± 11 when completing the task with a binocular visual field defect located to the left and right of fixation, respectively. While the main effect of simulated visual field loss on performance was statistically significant (p = 0.007), there were no average differences in the experimental conditions where a scotoma was located in the binocular visual field to the right or left of fixation. Simulated visual field loss impairs driving hazard detection on a computer-based test. There was no statistically significant difference in average performance when the simulated scotoma was located to the right or left of fixation of the binocular visual field, but certain types of hazard caused more difficulties than others. © 2016 Optometry Australia.

Performance in normal subjects on a novel battery of driving-related sensory-motor and cognitive tests.

PubMed

Innes, Carrie R H; Jones, Richard D; Anderson, Tim J; Hollobon, Susan G; Dalrymple-Alford, John C

2009-05-01

Currently, there is no international standard for the assessment of fitness to drive for cognitively or physically impaired persons. A computerized battery of driving-related sensory-motor and cognitive tests (SMCTests) has been developed, comprising tests of visuoperception, visuomotor ability, complex attention, visual search, decision making, impulse control, planning, and divided attention. Construct validity analysis was conducted in 60 normal, healthy subjects and showed that, overall, the novel cognitive tests assessed cognitive functions similar to a set of standard neuropsychological tests. The novel tests were found to have greater perceived face validity for predicting on-road driving ability than was found in the equivalent standard tests. Test-retest stability and reliability of SMCTests measures, as well as correlations between SMCTests and on-road driving, were determined in a subset of 12 subjects. The majority of test measures were stable and reliable across two sessions, and significant correlations were found between on-road driving scores and measures from ballistic movement, footbrake reaction, hand-control reaction, and complex attention. The substantial face validity, construct validity, stability, and reliability of SMCTests, together with the battery's level of correlation with on-road driving in normal subjects, strengthen our confidence in the ability of SMCTests to detect and identify sensory-motor and cognitive deficits related to unsafe driving and increased risk of accidents.

Chasing the silver bullet: measuring driver fatigue using simple and complex tasks.

PubMed

Baulk, S D; Biggs, S N; Reid, K J; van den Heuvel, C J; Dawson, D

2008-01-01

Driver fatigue remains a significant cause of motor-vehicle accidents worldwide. New technologies are increasingly utilised to improve road safety, but there are no effective on-road measures for fatigue. While simulated driving tasks are sensitive, and simple performance tasks have been used in industrial fatigue management systems (FMS) to quantify risk, little is known about the relationship between such measures. Establishing a simple, on-road measure of fatigue, as a fitness-to-drive tool, is an important issue for road safety and accident prevention, particularly as many fatigue related accidents are preventable. This study aimed to measure fatigue-related performance decrements using a simple task (reaction time - RT) and a complex task (driving simulation), and to determine the potential for a link between such measures, thus improving FMS success. Fifteen volunteer participants (7 m, 8 f) aged 22-56 years (mean 33.6 years), underwent 26 h of supervised wakefulness before an 8h recovery sleep opportunity. Participants were tested using a 30-min interactive driving simulation test, bracketed by a 10-min psychomotor vigilance task (PVT) at 4, 8, 18 and 24h of wakefulness, and following recovery sleep. Extended wakefulness caused significant decrements in PVT and driving performance. Although these measures are clearly linked, our analyses suggest that driving simulation cannot be replaced by a simple PVT. Further research is needed to closely examine links between performance measures, and to facilitate accurate management of fitness to drive, which requires more complex assessments of performance than RT alone.

Assessment of driving after stroke--a pluridisciplinary task.

PubMed

Ponsford, A-S; Viitanen, M; Lundberg, C; Johansson, K

2008-03-01

The aim of the study was to analyze the assessment procedure and identify predictors for the team decision when assessing fitness to drive a car after stroke. The material used was a retrospective data set with 200 stroke clients from Queen Elisabeth's Foundation Mobility Centre at Banstead UK. Fifty-four percent of clients were considered fit to continue driving where 9% could resume driving after car adaptation and training. Important factors for the outcome were vision (acuity and field), neuropsychological functions (divided attention), and track and/or on road test (reaction time, anticipation, speed, and positioning). Cognitive impairment was the main problem in those who failed the driving test and judged not fit for continued driving. Car adaptation, mainly comprising infrared transmitted secondary controls together with automatic transmission was recommended in 35% of the cases. The contribution of different specialist groups appears to be necessary for an effective evaluation, but the assessment procedure can be done more cost-effectively by dividing it into two separate parts and removing certain subtests. The in-car track test is an important part of the assessment procedure with a high face validity and could in many cases make it unnecessary to perform in-traffic tests with unsafe drivers. Car adaptation is often necessary for a client with pronounced hemi-paresis and a full road test can for those only be performed after training the use of car controls.

Drive-train dynamics technology - State-of-the-art and design of a test facility for advanced development

NASA Technical Reports Server (NTRS)

Badgley, R. H.; Fleming, D. P.; Smalley, A. J.

1975-01-01

A program for the development and verification of drive-train dynamic technology is described along with its basis and the results expected from it. A central feature of this program is a drive-train test facility designed for the testing and development of advanced drive-train components, including shaft systems, dampers, and couplings. Previous efforts in designing flexible dynamic drive-train systems are reviewed, and the present state of the art is briefly summarized. The design of the test facility is discussed with major attention given to the formulation of the test-rig concept, dynamic scaling of model shafts, and the specification of design parameters. Specific efforts envisioned for the test facility are briefly noted, including evaluations of supercritical test shafts, stability thresholds for various sources and types of instabilities that can exist in shaft systems, effects of structural flexibility on the dynamic performance of dampers, and methods for vibration control in two-level and three-level flexible shaft systems.

INTERACTIONS BETWEEN AGE AND MODERATE ALCOHOL EFFECTS ON SIMULATED DRIVING PERFORMANCE

PubMed Central

Sklar, Alfredo L.; Boissoneault, Jeff; Fillmore, Mark T.; Nixon, Sara Jo

2013-01-01

Rationale There is a substantial body of literature documenting the deleterious effects of both alcohol consumption and age on driving performance. There is, however, limited work examining the interaction of age and acute alcohol consumption. Objectives The current study was conducted to determine if moderate alcohol doses differentially affect the driving performance of older and younger adults. Methods Healthy older (55 – 70) and younger (25 – 35) adults were tested during a baseline session and again following consumption of one of three beverages (0.0% (placebo), 0.04% or 0.065% target breath alcohol concentration). Measures of driving precision and average speed were recorded. Results Older adults performed more poorly on precision driving measures and drove more slowly than younger adults at baseline. After controlling for baseline performance, interactions between alcohol and age were observed following beverage consumption on two measures of driving precision with older adults exhibiting greater impairment as a result of alcohol consumption. Conclusions These data provide evidence that older adults may be more susceptible to the effects of alcohol on certain measures of driving performance. An investigation of mechanisms accounting for alcohol’s effects on driving in older and younger adults is required. Further evaluation using more complex driving environments is needed to assess the real-world implication of this interaction. PMID:24030469

Neuropsychological Correlates of Hazard Perception in Older Adults.

PubMed

McInerney, Katalina; Suhr, Julie

2016-03-01

Hazard perception, the ability to identify and react to hazards while driving, is of growing importance in driving research, given its strong relationship to real word driving variables. Furthermore, although poor hazard perception is associated with novice drivers, recent research suggests that it declines with advanced age. In the present study, we examined the neuropsychological correlates of hazard perception in a healthy older adult sample. A total of 68 adults age 60 and older who showed no signs of dementia and were active drivers completed a battery of neuropsychological tests as well as a hazard perception task. Tests included the Repeatable Battery for the Assessment of Neuropsychological Status, Wechsler Test of Adult Reading, Trail Making Test, Block Design, Useful Field of View, and the Delis-Kaplan Executive Function System Color Word Interference Test. Hazard perception errors were related to visuospatial/constructional skills, processing speed, memory, and executive functioning skills, with a battery of tests across these domains accounting for 36.7% of the variance in hazard perception errors. Executive functioning, particularly Trail Making Test part B, emerged as a strong predictor of hazard perception ability. Consistent with prior work showing the relationship of neuropsychological performance to other measures of driving ability, neuropsychological performance was associated with hazard perception skill. Future studies should examine the relationship of neuropsychological changes in adults who are showing driving impairment and/or cognitive changes associated with Mild Cognitive Impairment or dementia.

A simulation study of the effects of alcohol on driving performance in a Chinese population.

PubMed

Li, Y C; Sze, N N; Wong, S C; Yan, Wei; Tsui, K L; So, F L

2016-10-01

Driving under the influence of alcohol (DUIA) is a significant factor contributing to road traffic crashes, injuries, and fatalities. Although the effects of alcohol on driving performance are widely acknowledged, studies of the effects of alcohol impairment on driving performance and particularly on the control system of Chinese adults are rare. This study attempts to evaluate the effects of alcohol on the driving performance of Chinese adults using a driving simulator. A double-blind experimental study was conducted to evaluate the effects of alcohol impairment on the driving performance of 52 Chinese participants using a driving simulator. A series of simulated driving tests covering two driving modules, including emergency braking (EB) and following braking (FB), at 50km/h and 80km/h were performed. Linear mixed models were established to evaluate driving performance in terms of braking reaction time (BRT), the standard deviation of lateral position (SD-LANE), and the standard deviation of speed (SD-SPEED). Driving performance in terms of BRT and SD-LANE was highly correlated with the level of alcohol consumption, with a one-unit increase in breath alcohol concentration (BrAC) degrading BRT and SD-LANE by 0.3% and 0.2%, respectively. Frequent drinkers generally reacted faster in their BRT than less-frequent drinkers and non-drinkers by 10.2% and 30.6%, respectively. Moreover, alcohol impairment had varying effects on certain aspects of the human control system, and automatic action was less likely to be affected than voluntary action from a psychological viewpoint. The findings should be useful for planning and developing effective measures to combat drink driving in Chinese communities. Copyright © 2016 Elsevier Ltd. All rights reserved.

Alcohol effects on simulated driving performance and self-perceptions of impairment in DUI offenders

PubMed Central

Van Dyke, Nicholas; Fillmore, Mark T.

2014-01-01

Drivers with a history of driving under the influence (DUI) of alcohol self-report heightened impulsivity and display reckless driving behaviors as indicated by increased rates of vehicle crashes, moving violations, and traffic tickets. Such poor behavioral self-regulation could also increase sensitivity to the disruptive effects of alcohol on driving performance. The present study examined the degree to which DUI drivers display an increased sensitivity to the acute impairing effects of alcohol on simulated driving performance and overestimate their driving fitness following alcohol consumption. Adult drivers with a history of DUI and a demographically-matched group of drivers with no history of DUI (controls) were tested following a 0.65 g/kg alcohol and a placebo. Results indicated that alcohol impaired several measures of driving performance and there was no difference between DUI offenders and controls in these impairments. However, following alcohol DUI drivers self-reported a greater ability and willingness to drive compared with controls. These findings indicate that drivers with a history of DUI might perceive themselves as more fit to drive after drinking which could play an important role in their decisions to drink and drive. PMID:25347077

Driver fatigue and highway driving: a simulator study.

PubMed

Ting, Ping-Huang; Hwang, Jiun-Ren; Doong, Ji-Liang; Jeng, Ming-Chang

2008-06-09

Long duration of driving is a significant cause of fatigue-related accidents on motorways or major roadways. The fatigue caused by driving for extended periods acutely impairs driver alertness and performance and can compromise transportation safety. This study quantitatively measured the progression of driver fatigue and identified the conservative safe duration of continuous highway driving. Thirty young male subjects were analyzed during 90 min of laboratory-simulated highway driving. Sleepiness ratings (SSS) and reaction time (RT) tests were used to assess impairment of driver alertness and vigilance. Additionally, various measures of driving performance recorded throughout the experiment were used to measure temporal deterioration of driver performance from alert to fatigued using principal component analysis (PCA). The analytical results revealed that SSS scores, reaction times (RTs) and unstable driving performance significantly increased over time, indicating that excessive driving time is a significant fatigue factor and potential cause of fatigue-related accidents. Moreover, the analytical results indicated that 80 min was the safe limit for monotonous highway driving. Based on the experimental findings of this study, public awareness of the adverse affects of driver fatigue during long-distance driving should be enhanced. This study provides explicit information of fatigue development that can be used to prevent fatigue-related accidents.

Alcohol effects on simulated driving performance and self-perceptions of impairment in DUI offenders.

PubMed

Van Dyke, Nicholas; Fillmore, Mark T

2014-12-01

Drivers with a history of driving under the influence (DUI) of alcohol self-report heightened impulsivity and display reckless driving behaviors as indicated by increased rates of vehicle crashes, moving violations, and traffic tickets. Such poor behavioral self-regulation could also increase sensitivity to the disruptive effects of alcohol on driving performance. The present study examined the degree to which DUI drivers display an increased sensitivity to the acute impairing effects of alcohol on simulated driving performance and overestimate their driving fitness following alcohol consumption. Adult drivers with a history of DUI and a demographically matched group of drivers with no history of DUI (controls) were tested following a 0.65 g/kg alcohol and a placebo. Results indicated that alcohol impaired several measures of driving performance, and there was no difference between DUI offenders and controls in these impairments. However, following alcohol, DUI drivers self-reported a greater ability and willingness to drive compared with controls. These findings indicate that drivers with a history of DUI might perceive themselves as more fit to drive after drinking, which could play an important role in their decisions to drink and drive. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Power requirements and environmental impact of a pedelec. A case study based on real-life applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abagnale, Carmelina, E-mail: c.abagnale@unina.it; Cardone, Massimo, E-mail: massimo.cardone@unina.it; Iodice, Paolo, E-mail: paolo.iodice@unina.it

2015-07-15

This paper describes the methodologies to appraise the power requests and environmental analysis of an electrically assisted bicycle under real driving conditions, also containing regulations and technical-science-related aspects. For this purpose, in this study, the on-road test program of an electrically assisted bicycle was executed in the urban area of Naples on different test tracks, so a general assessment about its driving behavior under several driving conditions was performed. The power requirements in different typical riding situations were estimated by a procedure based on the experimental kinematic parameters that characterize the driving dynamics collected during the real-life applications. An environmentalmore » analysis was also performed, with a methodology that takes into account the environmental assessment of a moped by measuring the experimental moped exhaust emissions of the regulated pollutants. Starting from the results acquired during the different test samples, besides, an assessment of the electric traction offered by this pedelec on the driving comfort was evaluated for different riding situations. - Highlights: • The power requirements of a pedelec in typical riding conditions were identified. • The estimated electricity consumption for battery recharging was defined. • An environmental valuation of the tested pedelec and of a moped was performed. • Emissions that could be saved utilizing a pedelec instead of a moped were derived.« less

Low cognitive load and reduced arousal impede practice effects on executive functioning, metacognitive confidence and decision making.

PubMed

Jackson, Simon A; Kleitman, Sabina; Aidman, Eugene

2014-01-01

The present study investigated the effects of low cognitive workload and the absence of arousal induced via external physical stimulation (motion) on practice-related improvements in executive (inhibitory) control, short-term memory, metacognitive monitoring and decision making. A total of 70 office workers performed low and moderately engaging passenger tasks in two successive 20-minute simulated drives and repeated a battery of decision making and inhibitory control tests three times—before, between and after these drives. For half the participants, visual simulation was synchronised with (moderately arousing) motion generated through LAnd Motion Platform, with vibration levels corresponding to a well-maintained unsealed road. The other half performed the same simulated drive without motion. Participants' performance significantly improved over the three test blocks, which is indicative of typical practice effects. The magnitude of these improvements was the highest when both motion and moderate cognitive load were present. The same effects declined either in the absence of motion (low arousal) or following a low cognitive workload task, thus suggesting two distinct pathways through which practice-related improvements in cognitive performance may be hampered. Practice, however, degraded certain aspects of metacognitive performance, as participants became less likely to detect incorrect decisions in the decision-making test with each subsequent test block. Implications include consideration of low cognitive load and arousal as factors responsible for performance decline and targets for the development of interventions/strategies in low load/arousal conditions such as autonomous vehicle operations and highway driving.

The Longitudinal Impact of Cognitive Speed of Processing Training on Driving Mobility

PubMed Central

Edwards, Jerri D.; Myers, Charlsie; Ross, Lesley A.; Roenker, Daniel L.; Cissell, Gayla M.; McLaughlin, Alexis M.; Ball, Karlene K.

2009-01-01

Purpose: To examine how cognitive speed of processing training affects driving mobility across a 3-year period among older drivers. Design and Methods: Older drivers with poor Useful Field of View (UFOV) test performance (indicating greater risk for subsequent at-fault crashes and mobility declines) were randomly assigned to either a speed of processing training or a social and computer contact control group. Driving mobility of these 2 groups was compared with a group of older adults who did not score poorly on the UFOV test (reference group) across a 3-year period. Results: Older drivers with poor UFOV test scores who did not receive training experienced greater mobility declines as evidenced by decreased driving exposure and space and increased driving difficulty at 3 years. Those at risk for mobility decline who received training did not differ across the 3-year period from older adults in the reference group with regard to driving exposure, space, and most aspects of driving difficulty. Implications: Cognitive speed of processing training can not only improve cognitive performance but also protect against mobility declines among older drivers. Scientifically proven cognitive training regimens have the potential to enhance the everyday lives of older adults. PMID:19491362

Can "the voices in the car" persuade drivers to go green?: effects of benefit appeals from in-vehicle voice agents and the role of drivers' affective states on eco-driving.

PubMed

Joo, Yeon Kyoung; Lee, Jong-Eun Roselyn

2014-04-01

The present research investigated the possibility of using an in-vehicle voice agent to promote eco-driving. Considering that both types of benefit appeals--egoistic (emphasizing benefits to the self) and altruistic (emphasizing benefits to others)--could be employed to promote eco-driving behavior, we explored the effects of benefit appeals delivered by an in-vehicle voice agent on driving performance. In particular, we tested whether and how the valence (positive vs. negative) of drivers' affective states moderates the effects, drawing on the functionalist affect-cognition framework, which has theorized that positive affect leads people to focus more on self-interest, whereas negative affect leads people to become more sensitive to social norms. An experiment was conducted in which participants, after undergoing affect (happy vs. sad) elicitation, received messages (egoistic vs. altruistic) promoting eco-driving from an in-vehicle voice agent while performing a simulated driving task. Results were partially consistent with the functionalist affect-cognition framework. Happy participants performed better on eco-driving when they were exposed to egoistic appeals than to altruistic appeals. On the other hand, the driving performance data from sad participants did not yield a significant difference between the egoistic condition and the altruistic condition. Participants' driving performance data further revealed that the joint effects of benefit appeals and affective states on safe driving performance mirrored the joint effects on eco-driving performance, confirming a close relationship between the two driving behaviors. Theoretical and practical implications for the use of in-vehicle voice agents and benefit appeals in promoting eco-driving and safe driving are discussed.

Evidence from a cohort of able bodied adults to support the need for driver training for motorized scooters before community participation.

PubMed

Nitz, Jennifer C

2008-02-01

This study sought to utilize the implementation of a new competency test in order to define skills required to safely drive a motorized scooter. This test endeavours to reduce the number of driving and pedestrian related accidents, by determining an acceptable level of driver skill and awareness. Healthy subjects, who might at some time use a motorized scooter for mobility, were recruited from the local community. Each undertook a driver competency test including basic driving skills, traffic and multiple tasks. Ten subjects repeated the test three times to determine practice effect on proficiency. Thirty-three of the 50 participating subjects (mean age 34 years) failed at least one test item. Basic skills of reversing, weave and zigzag, and all traffic and performing multiple simultaneous tasks produced failures. Driving skills for motorized scooters need to be taught and learned with assessment for competency recommended before unrestricted community driving is allowed. Basic driving skills including weaving, steering in reverse and traffic and multiple tasking need to be taught and tested for all new users of this equipment.

Hypoglycaemia and driving in people with insulin-treated diabetes: adherence to recommendations for avoidance.

PubMed

Graveling, A J; Warren, R E; Frier, B M

2004-09-01

Hypoglycaemia impairs driving performance, so drivers with insulin-treated diabetes should try to avoid hypoglycaemia when driving, and treat it effectively if it occurs. It is not known how many insulin-treated drivers are familiar with, or adhere to, recommended safe practice. We surveyed a representative sample of 202 current drivers with insulin-treated diabetes (115 with Type 1 diabetes), using a structured questionnaire. Data were obtained on driving history, estimated frequency of hypoglycaemia, and measures taken to avoid and treat hypoglycaemia when driving. The licensing authority (DVLA) and motor insurance company had been informed by almost all participants. Sixty-four participants (31.7%) had experienced hypoglycaemia while driving, and 27 (13.4%) reported that this had occurred within the preceding year. A minimum blood glucose level of 4.0 mmol/l or higher was considered necessary for driving by 151 drivers (74.8%), and 176 (87.1%) reported always keeping carbohydrate in their vehicle. However, 77 (38.1%) reported never carrying a glucose meter when driving, and 121 (59.9%) that they never test blood glucose before driving, or test only if symptomatic of hypoglycaemia. Most participants (89%) would stop driving to treat hypoglycaemia and would not resume driving immediately, although only 28 (13.9%) would wait longer than 30 min. Almost half of participants were failing to observe at least one essential aspect of safe driving. Compliance with statutory requirements to inform the licensing authority and motor insurer is good, and drivers' perceptions of the minimum safe blood glucose level for driving are encouraging. However, most drivers rely on symptoms to detect hypoglycaemia while driving, and seldom test blood glucose before driving. Patient education should emphasize the role of blood glucose monitoring in relation to driving, and highlight the potential deterioration in driving performance when blood glucose falls below 4.0 mmol/l.

Impact of External Cue Validity on Driving Performance in Parkinson's Disease

PubMed Central

Scally, Karen; Charlton, Judith L.; Iansek, Robert; Bradshaw, John L.; Moss, Simon; Georgiou-Karistianis, Nellie

2011-01-01

This study sought to investigate the impact of external cue validity on simulated driving performance in 19 Parkinson's disease (PD) patients and 19 healthy age-matched controls. Braking points and distance between deceleration point and braking point were analysed for red traffic signals preceded either by Valid Cues (correctly predicting signal), Invalid Cues (incorrectly predicting signal), and No Cues. Results showed that PD drivers braked significantly later and travelled significantly further between deceleration and braking points compared with controls for Invalid and No-Cue conditions. No significant group differences were observed for driving performance in response to Valid Cues. The benefit of Valid Cues relative to Invalid Cues and No Cues was significantly greater for PD drivers compared with controls. Trail Making Test (B-A) scores correlated with driving performance for PDs only. These results highlight the importance of external cues and higher cognitive functioning for driving performance in mild to moderate PD. PMID:21789275

Driving simulator and neuropsychological [corrected] testing in OSAS before and under CPAP therapy.

PubMed

Orth, M; Duchna, H-W; Leidag, M; Widdig, W; Rasche, K; Bauer, T T; Walther, J W; de Zeeuw, J; Malin, J-P; Schultze-Werninghaus, G; Kotterba, S

2005-11-01

Patients with obstructive sleep apnoea syndrome (OSAS) have an increased car accident rate. Investigations on accident frequency are based on case history, insurance reports and driving simulator studies. The present study combines neuropsychological testing of different attention aspects engaged in driving a car and driving simulation to evaluate a suitable instrument for assessing therapeutic effects of continuous positive airway pressure (CPAP). Driving simulator investigation and neuropsychological testing of alertness, vigilance and divided attention were performed in 31 patients with polysomnographically confirmed OSAS (apnoea-hypopnoea index 24.8+/-21.5.h(-1)) before, and 2 and 42 days after initiation of CPAP. Divided attention and alertness improved significantly during CPAP, whereas vigilance remained unchanged. However, accident frequency (OSAS before therapy: 2.7+/-2.0; 2 days after CPAP: 1.5+/-1.4; 42 days after CPAP: 0.9+/-1.3) and frequency of concentration faults (OSAS before therapy: 12.4+/-5.1; 2 days after CPAP: 6.5+/-3.9; 42 days after CPAP: 4.9+/-3.3) decreased in the simulated driving situation after 2 and 42 days of therapy. There was no relation between accident frequency, concentration faults and daytime sleepiness, as measured by the Epworth Sleepiness Scale, and polysomnographic or neuropsychological findings, respectively. In conclusion, the present results suggest that driving simulation is a possible benchmark parameter of driving performance in obstructive sleep apnoea syndrome patients.

EEG alpha spindles and prolonged brake reaction times during auditory distraction in an on-road driving study.

PubMed

Sonnleitner, Andreas; Treder, Matthias Sebastian; Simon, Michael; Willmann, Sven; Ewald, Arne; Buchner, Axel; Schrauf, Michael

2014-01-01

Driver distraction is responsible for a substantial number of traffic accidents. This paper describes the impact of an auditory secondary task on drivers' mental states during a primary driving task. N=20 participants performed the test procedure in a car following task with repeated forced braking on a non-public test track. Performance measures (provoked reaction time to brake lights) and brain activity (EEG alpha spindles) were analyzed to describe distracted drivers. Further, a classification approach was used to investigate whether alpha spindles can predict drivers' mental states. Results show that reaction times and alpha spindle rate increased with time-on-task. Moreover, brake reaction times and alpha spindle rate were significantly higher while driving with auditory secondary task opposed to driving only. In single-trial classification, a combination of spindle parameters yielded a median classification error of about 8% in discriminating the distracted from the alert driving. Reduced driving performance (i.e., prolonged brake reaction times) during increased cognitive load is assumed to be indicated by EEG alpha spindles, enabling the quantification of driver distraction in experiments on public roads without verbally assessing the drivers' mental states. Copyright © 2013 Elsevier Ltd. All rights reserved.

The relationship between driving simulation performance and obstructive sleep apnoea risk, daytime sleepiness, obesity and road traffic accident history of commercial drivers in Turkey.

PubMed

Demirdöğen Çetinoğlu, Ezgi; Görek Dilektaşlı, Aslı; Demir, Nefise Ateş; Özkaya, Güven; Acet, Nilüfer Aylin; Durmuş, Eda; Ursavaş, Ahmet; Karadağ, Mehmet; Ege, Ercüment

2015-09-01

Driving performance is known to be very sensitive to cognitive-psychomotor impairment. The aim of the study was to determine the relationship between obesity, risk of obstructive sleep apnoea (OSA), daytime sleepiness, history of road traffic accident (RTA) and performance on a driving simulator, among commercial drivers. We examined commercial vehicle drivers admitted to Psycho-Technical Assessment System (PTAS), which is a computer-aided system that includes a driving simulator test and tests assessing psychomotor-cognitive skills required for driving. Risk of OSA and daytime sleepiness were assessed by the Berlin Questionnaire and the Epworth Sleepiness Scale (ESS), respectively. A total of 282 commercial vehicle drivers were consecutively enrolled. The age range was 29-76 years. Thirty drivers were at high risk of OSA. Median ESS of the group was 2 (0-20). Forty-seven percent of the subjects at high risk of OSA failed in early reaction time test, while 28% of the drivers with low risk of OSA failed (p = 0.03). The obese drivers failed the peripheral vision test when compared with non-obese drivers (p = 0.02). ESS was higher for drivers with a history of RTA when compared to those without RTA (p = 0.02). Cognitive-psychomotor functions can be impaired in obese and high risk of OSA patients. In our opinion, requiring obese and/or high risk of OSA drivers to take PTAS tests that assess driving skills and psychomotor-cognitive functions crucial to those skills would significantly improve road traffic safety, which is of considerable importance to public health.

Automobile driver on-road performance test. Volume 3, Examiner's manual

DOT National Transportation Integrated Search

1981-09-30

This report provides procedures for administering and scoring the Automobile Driver On-Road Performance Test (ADOPT). The ADOPT checks 21 separate driving performances. Performances are checked at pre-determined locations along a 10-minute route and ...

Automobile driver on-road performance test. Volume 2, Administrator's manual

DOT National Transportation Integrated Search

1981-09-30

This report provides procedures for setting up, administering, and scoring the Automobile Driver On-Road Performance Test (ADOPT). The ADOPT checks 21 separate driving performances. Performances are checked at pre-determined locations along a 10-minu...

Evolutionary algorithm for vehicle driving cycle generation.

PubMed

Perhinschi, Mario G; Marlowe, Christopher; Tamayo, Sergio; Tu, Jun; Wayne, W Scott

2011-09-01

Modeling transit bus emissions and fuel economy requires a large amount of experimental data over wide ranges of operational conditions. Chassis dynamometer tests are typically performed using representative driving cycles defined based on vehicle instantaneous speed as sequences of "microtrips", which are intervals between consecutive vehicle stops. Overall significant parameters of the driving cycle, such as average speed, stops per mile, kinetic intensity, and others, are used as independent variables in the modeling process. Performing tests at all the necessary combinations of parameters is expensive and time consuming. In this paper, a methodology is proposed for building driving cycles at prescribed independent variable values using experimental data through the concatenation of "microtrips" isolated from a limited number of standard chassis dynamometer test cycles. The selection of the adequate "microtrips" is achieved through a customized evolutionary algorithm. The genetic representation uses microtrip definitions as genes. Specific mutation, crossover, and karyotype alteration operators have been defined. The Roulette-Wheel selection technique with elitist strategy drives the optimization process, which consists of minimizing the errors to desired overall cycle parameters. This utility is part of the Integrated Bus Information System developed at West Virginia University.

DriveSafe and DriveAware Assessment Tools Are a Measure of Driving-Related Function and Predicts Self-Reported Restriction for Older Drivers.

PubMed

Allan, Claire; Coxon, Kristy; Bundy, Anita; Peattie, Laura; Keay, Lisa

2016-06-01

Safety concerns together with aging of the driving population has prompted research into clinic-based driving assessments. This study investigates the relationship between the DriveSafe and DriveAware assessments and restriction of driving. Community-dwelling adults aged more than 75 (n = 380) were recruited in New South Wales, Australia. Questionnaires were administered to assess driving habits and functional assessments to assess driving-related function. Self-reported restriction was prevalent in this cross-sectional sample (62%) and was related to DriveSafe scores and personal circumstances but not DriveAware scores. DriveSafe scores were correlated with better performance on the Trail-Making Test (TMT; β = -2.94, p < .0001) and better contrast sensitivity (β = 48.70, p < .0001). Awareness was associated with better performance on the TMT (β = 0.08, p < .0001). Our data suggest that DriveSafe and DriveAware are sensitive to deficits in vision and cognition, and drivers with worse DriveSafe scores self-report restricting their driving. © The Author(s) 2015.

A prospective study of psychomotor performance of driving among two kinds of shift work in Iran

PubMed Central

Saadat, Soheil; Karbakhsh, Mojgan; Saremi, Mahnaz; Alimohammadi, Iraj; Ashayeri, Hassan; Fayaz, Mahsa; Rostami, Reza

2018-01-01

Background and aim Driving after a night shift imposes a risk on health care professionals and other road users. The aim of this study was to measure psychomotor performance of driving of night shift nurses compared to day-shift nurses. Methods Forty-seven volunteer female nurses working at Sina hospital in Tehran, Iran, with a call in all departments of hospital, participated in this study (23 night shift and 24 day shift nurses) in 2016. The tests included RT for simple reaction time, ATAVT for perceptual speed, LVT for visual orientation and ZBA for time anticipation. Data collection tools were individual characteristics, 11-item circadian type inventory (CTI), Stanford sleepiness scale (SSS), and Swedish occupational fatigue inventory (SOFI-20) questionnaires. Psychomotor driving performance was assessed using validated computerized traffic psychological battery of Vienna Test System (VTS), before and after the shifts. Data analysis was performed using paired-samples t-test and Linear Regression. Results The mean age of day and night-shift nurses were 31.4±5.6 and 28.7±3.9 years respectively, no significant difference between two groups. Thirty percent of night shift and 16.7% of day shift nurses reported traffic accidents in the past year. The results revealed that, scores based on viewing times in visual orientation test (p=0.005), and median reaction time score in choice reaction time and reactive stress tolerance test (p=0.045), had a significant association with a 12-hour night shift with a 3-hour nap. Conclusions Twelve-hour night shift work impairs choice reaction time and visual orientation in nurses, even though they take a 3- hour nap during the shift. These skills are required for safe driving. PMID:29629067

Alzheimer Disease Biomarkers and Driving in Clinically Normal Older Adults: Role of Spatial Navigation Abilities.

PubMed

Allison, Samantha; Babulal, Ganesh M; Stout, Sarah H; Barco, Peggy P; Carr, David B; Fagan, Anne M; Morris, John C; Roe, Catherine M; Head, Denise

2018-01-01

Older adults experience impaired driving performance, and modify their driving habits, including limiting amount and spatial extent of travel. Alzheimer disease (AD)-related pathology, as well as spatial navigation difficulties, may influence driving performance and driving behaviors in clinically normal older adults. We examined whether AD biomarkers [cerebrospinal fluid (CSF) concentrations of Aβ42, tau, and ptau181] were associated with lower self-reported spatial navigation abilities, and whether navigation abilities mediated the relationship of AD biomarkers with driving performance and extent. Clinically normal older adults (n=112; aged 65+) completed an on-road driving test, the Santa Barbara Sense of Direction scale (self-report measure of spatial navigation ability), and the Driving Habits Questionnaire for an estimate of driving extent (composite of driving exposure and driving space). All participants had a lumbar puncture to obtain CSF. CSF Aβ42, but not tau or ptau181, was associated with self-reported navigation ability. Lower self-reported navigation was associated with reduced driving extent, but not driving errors. Self-reported navigation mediated the relationship between CSF Aβ42 and driving extent. Findings suggest that cerebral amyloid deposition is associated with lower perceived ability to navigate the environment, which may lead older adults with AD pathology to limit their driving extent.

Medicinal Δ(9) -tetrahydrocannabinol (dronabinol) impairs on-the-road driving performance of occasional and heavy cannabis users but is not detected in Standard Field Sobriety Tests.

PubMed

Bosker, Wendy M; Kuypers, Kim P C; Theunissen, Eef L; Surinx, Anke; Blankespoor, Roos J; Skopp, Gisela; Jeffery, Wayne K; Walls, H Chip; van Leeuwen, Cees J; Ramaekers, Johannes G

2012-10-01

The acute and chronic effects of dronabinol [medicinal Δ(9) -tetrahydrocannabinol (THC)] on actual driving performance and the Standard Field Sobriety Test (SFST) were assessed. It was hypothesized that occasional users would be impaired on these tests and that heavy users would show less impairment due to tolerance. Double-blind, placebo-controlled, randomized, three-way cross-over study. Twelve occasional and 12 heavy cannabis users (14 males/10 females) received single doses of placebo, 10 and 20 mg dronabinol. Standard deviation of lateral position (SDLP; i.e. weaving) is the primary measure of road-tracking control. Time to speed adaptation (TSA) is the primary reaction-time measure in the car-following test. Percentage of impaired individuals on the SFST and subjective high on a visual analogue scale were secondary measures. Superiority tests showed that SDLP (P = 0.008) and TSA (P = 0.011) increased after dronabinol in occasional users. Equivalence tests demonstrated that dronabinol-induced increments in SDLP were bigger than impairment associated with BAC of 0.5 mg/ml in occasional and heavy users, although the magnitude of driving impairment was generally less in heavy users. The SFST did not discriminate between conditions. Levels of subjective high were comparable in occasional and heavy users. Dronabinol (medicinal tetrahydrocannabinol) impairs driving performance in occasional and heavy users in a dose-dependent way, but to a lesser degree in heavy users due possibly to tolerance. The Standard Field Sobriety Test is not sensitive to clinically relevant driving impairment caused by oral tetrahydrocannabinol. © 2012 The Authors. Addiction © 2012 Society for the Study of Addiction.

Driving with homonymous visual field loss: a review of the literature

PubMed Central

Bowers, Alex R.

2016-01-01

Driving is an important rehabilitation goal for patients with homonymous field defects (HFDs); however, whether or not people with HFDs should be permitted to drive is not clear. Over the last 15 years there has been a marked increase in the number of studies evaluating the effects of HFDs on driving performance. This review of the literature provides a much-needed summary for practitioners and researchers, addressing the following topics: regulations pertaining to driving with HFDs, self-reported driving difficulties, pass rates in on-road tests, the effects of HFDs on lane position and steering stability, the effects of HFDs on scanning and detection of potential hazards, screening for potential fitness to drive, evaluating practical fitness to drive, and the efficacy of interventions to improve driving of persons with HFDs. Although there is clear evidence from on-road studies that some people with HFDs may be rated as safe to drive, others are reported to have significant deficits in skills important for safe driving including taking a lane position too close to one side of the travel lane, unstable steering and inadequate viewing (scanning) behaviors. Driving simulator studies have provided strong evidence of a wide range in compensatory scanning abilities and detection performance, despite similar amounts of visual field loss. Conventional measurements of visual field extent (in which eye movements are not permitted) do not measure such compensatory abilities and are not predictive of on-road driving performance; thus, there is a need to develop better tests to screen for visual fitness to drive of people with HFDs. We are not yet at a point where we can predict which HFD patient is likely to be a safe driver. Therefore, it seems only fair to provide an opportunity for individualized assessments of practical fitness to drive either on the road and/or in a driving simulator. PMID:27535208

Driving with homonymous visual field loss: a review of the literature.

PubMed

Bowers, Alex R

2016-09-01

Driving is an important rehabilitation goal for patients with homonymous field defects (HFDs); however, whether or not people with HFDs should be permitted to drive is not clear. Over the last 15 years, there has been a marked increase in the number of studies evaluating the effects of HFDs on driving performance. This review of the literature provides a much-needed summary for practitioners and researchers, addressing the following topics: regulations pertaining to driving with HFDs, self-reported driving difficulties, pass rates in on-road tests, the effects of HFDs on lane position and steering stability, the effects of HFDs on scanning and detection of potential hazards, screening for potential fitness to drive, evaluating practical fitness to drive and the efficacy of interventions to improve driving of persons with HFDs. Although there is clear evidence from on-road studies that some people with HFDs may be rated as safe to drive, others are reported to have significant deficits in skills important for safe driving, including taking a lane position too close to one side of the travel lane, unstable steering and inadequate viewing (scanning) behaviour. Driving simulator studies have provided strong evidence of a wide range in compensatory scanning abilities and detection performance, despite similar amounts of visual field loss. Conventional measurements of visual field extent (in which eye movements are not permitted) do not measure such compensatory abilities and are not predictive of on-road driving performance. Thus, there is a need to develop better tests to screen people with HFDs for visual fitness to drive. We are not yet at a point where we can predict which HFD patient is likely to be a safe driver. Therefore, it seems only fair to provide an opportunity for individualised assessments of practical fitness to drive either on the road and/or in a driving simulator. © 2016 Optometry Australia.

Cumulative meta-analysis of the relationship between useful field of view and driving performance in older adults: current and future implications.

PubMed

Clay, Olivio J; Wadley, Virginia G; Edwards, Jerri D; Roth, David L; Roenker, Daniel L; Ball, Karlene K

2005-08-01

Driving is a complex behavior that requires the utilization of a wide range of individual abilities. Identifying assessments that not only capture individual differences, but also are related to older adults' driving performance would be beneficial. This investigation examines the relationship between the Useful Field of View (UFOV) assessment and objective measures of retrospective or concurrent driving performance, including state-recorded accidents, on-road driving, and driving simulator performance. The PubMed and PsycINFO databases were searched to retrieve eight studies that reported bivariate relationships between UFOV and these objective driving measures. Cumulative meta-analysis techniques were used to combine the effect sizes in an attempt to determine whether the strength of the relationship was stable across studies and to assess whether a sufficient number of studies have been conducted to validate the relationship between UFOV and driving performance. A within-group homogeneity of effect sizes test revealed that the samples could be thought of as being drawn from the same population, Q [7] = 11.29, p (one-tailed) = 0.13. Therefore, the effect sizes of eight studies were combined for the present cumulative meta-analysis. The weighted mean effect size across the studies revealed a large effect (Cohen's d = 0.945), with poorer UFOV performance associated with negative driving outcomes. This relationship was robust across multiple indices of driving performance and several research laboratories. This convergence of evidence across numerous studies using different methodologies confirms the importance of the UFOV assessment as a valid and reliable index of driving performance and safety. Recent prospective studies have confirmed a relationship between UFOV performance and future crashes, further supporting the use of this instrument as a potential screening measure for at-risk older drivers.

Gear Design Effects on the Performance of High Speed Helical Gear Trains as Used in Aerospace Drive Systems

NASA Technical Reports Server (NTRS)

Handschuh, R.; Kilmain, D.; Ehinger, R.; Sinusas, E.

2013-01-01

The performance of high-speed helical gear trains is of particular importance for tiltrotor aircraft drive systems. These drive systems are used to provide speed reduction/torque multiplication from the gas turbine output shaft and provide the necessary offset between these parallel shafts in the aircraft. Four different design configurations have been tested in the NASA Glenn Research Center, High Speed Helical Gear Train Test Facility. The design configurations included the current aircraft design, current design with isotropic superfinished gear surfaces, double helical design (inward and outward pumping), increased pitch (finer teeth), and an increased helix angle. All designs were tested at multiple input shaft speeds (up to 15,000 rpm) and applied power (up to 5,000 hp). Also two lubrication, system-related, variables were tested: oil inlet temperature (160 to 250 F) and lubricating jet pressure (60 to 80 psig). Experimental data recorded from these tests included power loss of the helical system under study, the temperature increase of the lubricant from inlet to outlet of the drive system and fling off temperatures (radially and axially). Also, all gear systems were tested with and without shrouds around the gears. The empirical data resulting from this study will be useful to the design of future helical gear train systems anticipated for next generation rotorcraft drive systems.

Gear Design Effects on the Performance of High Speed Helical Gear Trains as Used in Aerospace Drive Systems

NASA Technical Reports Server (NTRS)

Handschuh, R.; Kilmain, C.; Ehinger, R.; Sinusas, E.

2013-01-01

The performance of high-speed helical gear trains is of particular importance for tiltrotor aircraft drive systems. These drive systems are used to provide speed reduction / torque multiplication from the gas turbine output shaft and provide the necessary offset between these parallel shafts in the aircraft. Four different design configurations have been tested in the NASA Glenn Research Center, High Speed Helical Gear Train Test Facility. The design configurations included the current aircraft design, current design with isotropic superfinished gear surfaces, double helical design (inward and outward pumping), increased pitch (finer teeth), and an increased helix angle. All designs were tested at multiple input shaft speeds (up to 15,000 rpm) and applied power (up to 5,000 hp). Also two lubrication, system-related, variables were tested: oil inlet temperature (160 to 250 degF) and lubricating jet pressure (60 to 80 psig). Experimental data recorded from these tests included power loss of the helical system under study, the temperature increase of the lubricant from inlet to outlet of the drive system and fling off temperatures (radially and axially). Also, all gear systems were tested with and without shrouds around the gears. The empirical data resulting from this study will be useful to the design of future helical gear train systems anticipated for next generation rotorcraft drive systems.

Effects of alcohol on attention orienting and dual-task performance during simulated driving: an event-related potential study.

PubMed

Wester, Anne E; Verster, Joris C; Volkerts, Edmund R; Böcker, Koen B E; Kenemans, J Leon

2010-09-01

Driving is a complex task and is susceptible to inattention and distraction. Moreover, alcohol has a detrimental effect on driving performance, possibly due to alcohol-induced attention deficits. The aim of the present study was to assess the effects of alcohol on simulated driving performance and attention orienting and allocation, as assessed by event-related potentials (ERPs). Thirty-two participants completed two test runs in the Divided Attention Steering Simulator (DASS) with blood alcohol concentrations (BACs) of 0.00%, 0.02%, 0.05%, 0.08% and 0.10%. Sixteen participants performed the second DASS test run with a passive auditory oddball to assess alcohol effects on involuntary attention shifting. Sixteen other participants performed the second DASS test run with an active auditory oddball to assess alcohol effects on dual-task performance and active attention allocation. Dose-dependent impairments were found for reaction times, the number of misses and steering error, even more so in dual-task conditions, especially in the active oddball group. ERP amplitudes to novel irrelevant events were also attenuated in a dose-dependent manner. The P3b amplitude to deviant target stimuli decreased with blood alcohol concentration only in the dual-task condition. It is concluded that alcohol increases distractibility and interference from secondary task stimuli, as well as reduces attentional capacity and dual-task integrality.

DESIGN AND DEVELOPMENT REPORT ON TREAT CONTROL ROD DRIVE II

DOE Office of Scientific and Technical Information (OSTI.GOV)

Batch, R.V.

1961-05-01

A discussion is given of the development of TREAT control rod drive II, which describes the basic design, the problems involved with the design, the various design methods pursued, the testing procedures, and the evaluation of the performance characteristics of the final drive. (B.O.G.)

Actual driving performance and psychomotor function in healthy subjects after acute and subchronic treatment with escitalopram, mirtazapine, and placebo: a crossover trial.

PubMed

Wingen, Marleen; Bothmer, John; Langer, Stefan; Ramaekers, Johannes G

2005-04-01

The effects of escitalopram 10 to 20 mg/day and mirtazapine 30 to 45 mg/day on actual driving and psychomotor performance of 18 healthy subjects were determined in a randomized, double-blind, placebo-controlled, multiple-dose, 3-way crossover trial. Each treatment period lasted for 15 days and was separated from the next period by a washout period of at least 13 days. Subjects received an evening dose of escitalopram 10 mg, mirtazapine 30 mg, or placebo from days 1 to 7 and an evening dose of escitalopram 20 mg, mirtazapine 45 mg, or placebo from days 8 to 15. On days 2, 9, and 16, reflecting acute period, dose increase, and steady state, respectively, the Road Tracking Test was performed. The main parameter was standard deviation of lateral position. Psychomotor performance was also assessed on days 2, 9, and 16 by laboratory computer tasks. Subjective sleep quality was measured with the Groninger Sleep Quality Scale, and mood was measured by visual analogue scales. Treatment differences were apparent during the acute treatment period, in which subjects treated with mirtazapine 30 mg performed less well on the driving test as compared to placebo. The Divided Attention Task results also revealed a significant increase in tracking error after a single dose of mirtazapine 30 mg as compared to placebo. Mirtazapine decreased feelings of alertness and contentedness. Mirtazapine did not affect performance on days 9 and 16 of treatment. Escitalopram did not affect driving, psychomotor performance, or subjective mood throughout treatment. Driving performance, as well as psychomotor functioning, was not affected by escitalopram treatment in healthy subjects. Driving performance was significantly impaired after ingestion of mirtazapine 30 mg during the acute treatment period.

Effects on driving performance of interacting with an in-vehicle music player: a comparison of three interface layout concepts for information presentation.

PubMed

Mitsopoulos-Rubens, Eve; Trotter, Margaret J; Lenné, Michael G

2011-05-01

Interface design is an important factor in assessing the potential effects on safety of interacting with an in-vehicle information system while driving. In the current study, the layout of information on a visual display was manipulated to explore its effect on driving performance in the context of music selection. The comparative effects of an auditory-verbal (cognitive) task were also explored. The driving performance of 30 participants was assessed under both baseline and dual task conditions using the Lane Change Test. Concurrent completion of the music selection task with driving resulted in significant impairment to lateral driving performance (mean lane deviation and percentage of correct lane changes) relative to the baseline, and significantly greater mean lane deviation relative to the combined driving and the cognitive task condition. The magnitude of these effects on driving performance was independent of layout concept, although significant differences in subjective workload estimates and performance on the music selection task across layout concepts highlights that potential uncertainty regarding design use as conveyed through layout concept could be disadvantageous. The implications of these results for interface design and safety are discussed. Copyright © 2010 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Driving Simulator Performance in Patients with Possible and Probable Alzheimer’s Disease

PubMed Central

Stein, Anthony C.; Dubinsky, Richard M.

2011-01-01

Drivers with more advanced stages of Alzheimer’s disease (AD) have been previously associated with an increased rate of motor vehicle accidents. Drivers suffering from early AD are also involved in, and may even cause motor vehicle accidents with greater frequency than “normal” drivers. Consequently there is considerable public concern regarding traffic safety issues for those with AD and subsequently for society, but there has been little research in understanding whether deterioration in driving ability is progressive, or has a sudden onset once the disease has reached a certain severity. The purpose of this study was to identify possible degradation in simulated driving performance that may occur at the earliest stages of AD, and compare these decrements to a control group of normal drivers. Using a single blind design, seventeen AD subjects, eight at a Clinical Dementia Rating (CDR) of 0.5 (possible AD) and nine at a CDR of 1 (probable AD), were compared to 63 cognitively normal, elderly controls. All subjects were trained to drive a computerized interactive driving simulator and then tested on a 19.3 km (12 mile) test course. The AD subjects demonstrated impaired driving performance when compared to the controls. The simulated driving performance of the CDR 1 AD subjects was so degraded that it would be regarded as unsafe by standard assessment criteria. The CDR 0.5 subjects made similar errors, suggesting that driving impairment may occur at the earliest stages of the disease. Further work will be necessary to determine the significance of these findings. PMID:22105407

Comparing treatment effects of oral THC on simulated and on-the-road driving performance: testing the validity of driving simulator drug research.

PubMed

Veldstra, J L; Bosker, W M; de Waard, D; Ramaekers, J G; Brookhuis, K A

2015-08-01

The driving simulator provides a safe and controlled environment for testing driving behaviour efficiently. The question is whether it is sensitive to detect drug-induced effects. The primary aim of the current study was to investigate the sensitivity of the driving simulator for detecting drug effects. As a case in point, we investigated the dose-related effects of oral ∆(9)-tetrahydrocannabinol (THC), i.e. dronabinol, on simulator and on-the-road driving performance in equally demanding driving tasks. Twenty-four experienced driver participants were treated with dronabinol (Marinol®; 10 and 20 mg) and placebo. Dose-related effects of the drug on the ability to keep a vehicle in lane (weaving) and to follow the speed changes of a lead car (car following) were compared within subjects for on-the-road versus in-simulator driving. Additionally, the outcomes of equivalence testing to alcohol-induced effects were investigated. Treatment effects found on weaving when driving in the simulator were comparable to treatment effects found when driving on the road. The effect after 10 mg dronabinol was however less strong in the simulator than on the road and inter-individual variance seemed higher in the simulator. There was, however, a differential treatment effect of dronabinol on reactions to speed changes of a lead car (car following) when driving on the road versus when driving in the simulator. The driving simulator was proven to be sensitive for demonstrating dronabinol-induced effects particularly at higher doses. Treatment effects of dronabinol on weaving were comparable with driving on the road but inter-individual variability seemed higher in the simulator than on the road which may have potential effects on the clinical inferences made from simulator driving. Car following on the road and in the simulator were, however, not comparable.

Alcohol, Drugs and Driving: Implications for Evaluating Driver Impairment

PubMed Central

Brown, Timothy; Milavetz, Gary; Murry, Daryl J.

2013-01-01

Impaired driving is a significant traffic safety problem, and alcohol and drugs taken before driving contribute substantially to this problem. With the increase in use of prescription medication and the decriminalization of some drugs, it has become increasingly important to understand the manifestation of driver impairment. Building upon previous alcohol research conducted at the National Advanced Driving Simulator (NADS), this study enrolled commercial bus drivers to evaluate the effect of triazolam on driving performance to assess difference between placebo, 0.125, and 0.25 mg doses in a randomized and double-blind design. On each of three randomized visits, subjects drove a simulator scenario that had previously been used to demonstrate effects of alcohol on driving performance. Plasma triazolam levels were obtained before the simulator drive. The protocol included participants receiving study medication and placebo over a 3-week period of time one to two weeks apart. The simulator drives used for this analysis occurred approximately 140 minutes after dosing—after the subjects had completed four bus simulator drives and neuropsychological tests over a 2-hour period of time surrounding dosing. The driving scenario contained representative situations on three types of roadways (urban, freeway, and rural) under nighttime driving conditions. Lane keeping performance (ability to drive straight in the lane) under the three doses of triazolam demonstrates that at the 0.25 mg dose, statistically significant effects on performance are observed, but no effects are found at the 0.125 mg level when testing at this time period after dosing. This differs from the effects of alcohol, which shows impairing effects at a 0.05% blood alcohol concentration (BAC) and a greater effect at 0.10% BAC. These results demonstrate the importance of understanding how different types of drugs affect driving performance in realistic driving environments. Although some compounds may have an effect that correlates linearly to dosage, that is not always the case. An understanding of these differences and how they vary across driving tasks is essential to developing a robust evaluation protocol that can accurately describe the effects of a wide variety of drugs on driver impairment. This information can be used to reduce the risk of deleterious effects of therapeutic medications while ensuring their safe and beneficial use. PMID:24406943

Vision-related fitness to drive mobility scooters: A practical driving test.

PubMed

Cordes, Christina; Heutink, Joost; Tucha, Oliver M; Brookhuis, Karel A; Brouwer, Wiebo H; Melis-Dankers, Bart J M

2017-03-06

To investigate practical fitness to drive mobility scooters, comparing visually impaired participants with healthy controls. Between-subjects design. Forty-six visually impaired (13 with very low visual acuity, 10 with low visual acuity, 11 with peripheral field defects, 12 with multiple visual impairment) and 35 normal-sighted controls. Participants completed a practical mobility scooter test-drive, which was recorded on video. Two independent occupational therapists specialized in orientation and mobility evaluated the videos systematically. Approximately 90% of the visually impaired participants passed the driving test. On average, participants with visual impairments performed worse than normal-sighted controls, but were judged sufficiently safe. In particular, difficulties were observed in participants with peripheral visual field defects and those with a combination of low visual acuity and visual field defects. People with visual impairment are, in practice, fit to drive mobility scooters; thus visual impairment on its own should not be viewed as a determinant of safety to drive mobility scooters. However, special attention should be paid to individuals with visual field defects with or without a combined low visual acuity. The use of an individual practical fitness-to-drive test is advised.

Driving Intervention for Returning Combat Veterans.

PubMed

Classen, Sherrilene; Winter, Sandra; Monahan, Miriam; Yarney, Abraham; Link Lutz, Amanda; Platek, Kyle; Levy, Charles

2017-04-01

Increased crash incidence following deployment and veterans' reports of driving difficulty spurred traffic safety research for this population. We conducted an interim analysis on the efficacy of a simulator-based occupational therapy driving intervention (OT-DI) compared with traffic safety education (TSE) in a randomized controlled trial. During baseline and post-testing, OT-Driver Rehabilitation Specialists and one OT-Certified Driver Rehabilitation Specialist measured driving performance errors on a DriveSafety CDS-250 high-fidelity simulator. The intervention group ( n = 13) received three OT-DI sessions addressing driving errors and visual-search retraining. The control group ( n = 13) received three TSE sessions addressing personal factors and defensive driving. Based on Wilcoxon rank-sum analysis, the OT-DI group's errors were significantly reduced when comparing baseline with Post-Test 1 ( p < .0001) and comparing the OT-DI group with the TSE group at Post-Test 1 ( p = .01). These findings provide support for the efficacy of the OT-DI and set the stage for a future effectiveness study.

Supertaskers: Profiles in extraordinary multitasking ability.

PubMed

Watson, Jason M; Strayer, David L

2010-08-01

Theory suggests that driving should be impaired for any motorist who is concurrently talking on a cell phone. But is everybody impaired by this dual-task combination? We tested 200 participants in a high-fidelity driving simulator in both single- and dual-task conditions. The dual task involved driving while performing a demanding auditory version of the operation span (OSPAN) task. Whereas the vast majority of participants showed significant performance decrements in dual-task conditions (compared with single-task conditions for either driving or OSPAN tasks), 2.5% of the sample showed absolutely no performance decrements with respect to performing single and dual tasks. In single-task conditions, these "supertaskers" scored in the top quartile on all dependent measures associated with driving and OSPAN tasks, and Monte Carlo simulations indicated that the frequency of supertaskers was significantly greater than chance. These individual differences help to sharpen our theoretical understanding of attention and cognitive control in naturalistic settings.

Integrated Eye Tracking and Neural Monitoring for Enhanced Assessment of Mild TBI

DTIC Science & Technology

2015-04-01

virtual reality driving simulator data acquisition. Data collection for the pilot study is nearly complete and data analyses are currently under way...Training for primary study procedures including neuropsychological testing, eye- tracking, virtual reality driving simulator, and EEG data acquisition is...the virtual reality driving simulator. Participants are instructed to drive along a coastal highway while performing the target detection task

Interventions to evaluate fitness to drive among people with chronic conditions: Systematic review of literature.

PubMed

Marino, Marta; de Belvis, Antonio; Basso, Danila; Avolio, Maria; Pelone, Ferruccio; Tanzariello, Maria; Ricciardi, Walter

2013-01-01

When an health condition has been identified, the question of whether to continue driving depends not on a medical diagnosis, but on the functional consequences of the illness. The complex nature of physical and mental impairments and their relationship with safe driving make the availability of evidence based tools necessary for health professionals. The review aims at identifying and summarizing scientific findings concerning the relationship between neuropsychological and clinical screening tests and fitness to drive among people with chronic conditions. Studies were searched for driving ability evaluation by road test or simulator, clinical/neuropsychological examinations of participants with chronic diseases or permanent disablement impairing driving performance, primary outcomes as fatal/non-fatal traffic injuries and secondary outcomes as fitness to drive assessment. Twenty-seven studies fulfilled the inclusion criteria. Some studies included more than one clinical condition. The illness investigated were Alzheimer Disease (n=6), Parkinson Disease (n=8), Cardiovascular Accident (n=4), Traumatic Brain Injuries (n=3), Sleep Apnea Syndrome (n=2), Narcolepsy (n=1), Multiple Sclerosis (n=1) and Hepatic Encephalopathy (n=1), comorbidities (n=3). No studies match inclusion criteria about Myasthenia Gravis, Diabetes Mellitus, Renal Diseases, Hearing Disorders and Sight Diseases. No studies referred to primary outcomes. The selected studies provided opposite evidences. It would be reasonable to argue that some clinical and neuropsychological tests are effective in predicting fitness to drive even if contrasting results support that driving performance decreases as a function of clinical and neuropsychological decline in some chronic diseases. Nevertheless we found no evidence that clinical and neuropsychological screening tests would lead to a reduction in motor vehicle crashes involving chronic disabled drivers. It seems necessary to develop tests with proven validity for identifying high-risk drivers so that physicians can provide guidance to their patients in chronic conditions, and also to medical advisory boards working with licensing offices. Copyright © 2012 Elsevier Ltd. All rights reserved.

Development of a test for recording both visual and auditory reaction times, potentially useful for future studies in patients on opioids therapy

PubMed Central

Miceli, Luca; Bednarova, Rym; Rizzardo, Alessandro; Samogin, Valentina; Della Rocca, Giorgio

2015-01-01

Objective Italian Road Law limits driving while undergoing treatment with certain kinds of medication. Here, we report the results of a test, run as a smartphone application (app), assessing auditory and visual reflexes in a sample of 300 drivers. The scope of the test is to provide both the police force and medication-taking drivers with a tool that can evaluate the individual’s capacity to drive safely. Methods The test is run as an app for Apple iOS and Android mobile operating systems and facilitates four different reaction times to be assessed: simple visual and auditory reaction times and complex visual and auditory reaction times. Reference deciles were created for the test results obtained from a sample of 300 Italian subjects. Results lying within the first three deciles were considered as incompatible with safe driving capabilities. Results Performance is both age-related (r>0.5) and sex-related (female reaction times were significantly slower than those recorded for male subjects, P<0.05). Only 21% of the subjects were able to perform all four tests correctly. Conclusion We developed and fine-tuned a test called Safedrive that measures visual and auditory reaction times through a smartphone mobile device; the scope of the test is two-fold: to provide a clinical tool for the assessment of the driving capacity of individuals taking pain relief medication; to promote the sense of social responsibility in drivers who are on medication and provide these individuals with a means of testing their own capacity to drive safely. PMID:25709406

Development of a test for recording both visual and auditory reaction times, potentially useful for future studies in patients on opioids therapy.

PubMed

Miceli, Luca; Bednarova, Rym; Rizzardo, Alessandro; Samogin, Valentina; Della Rocca, Giorgio

2015-01-01

Italian Road Law limits driving while undergoing treatment with certain kinds of medication. Here, we report the results of a test, run as a smartphone application (app), assessing auditory and visual reflexes in a sample of 300 drivers. The scope of the test is to provide both the police force and medication-taking drivers with a tool that can evaluate the individual's capacity to drive safely. The test is run as an app for Apple iOS and Android mobile operating systems and facilitates four different reaction times to be assessed: simple visual and auditory reaction times and complex visual and auditory reaction times. Reference deciles were created for the test results obtained from a sample of 300 Italian subjects. Results lying within the first three deciles were considered as incompatible with safe driving capabilities. Performance is both age-related (r>0.5) and sex-related (female reaction times were significantly slower than those recorded for male subjects, P<0.05). Only 21% of the subjects were able to perform all four tests correctly. We developed and fine-tuned a test called Safedrive that measures visual and auditory reaction times through a smartphone mobile device; the scope of the test is two-fold: to provide a clinical tool for the assessment of the driving capacity of individuals taking pain relief medication; to promote the sense of social responsibility in drivers who are on medication and provide these individuals with a means of testing their own capacity to drive safely.

Low Cognitive Load and Reduced Arousal Impede Practice Effects on Executive Functioning, Metacognitive Confidence and Decision Making

PubMed Central

Jackson, Simon A.; Kleitman, Sabina; Aidman, Eugene

2014-01-01

The present study investigated the effects of low cognitive workload and the absence of arousal induced via external physical stimulation (motion) on practice-related improvements in executive (inhibitory) control, short-term memory, metacognitive monitoring and decision making. A total of 70 office workers performed low and moderately engaging passenger tasks in two successive 20-minute simulated drives and repeated a battery of decision making and inhibitory control tests three times – before, between and after these drives. For half the participants, visual simulation was synchronised with (moderately arousing) motion generated through LAnd Motion Platform, with vibration levels corresponding to a well-maintained unsealed road. The other half performed the same simulated drive without motion. Participants’ performance significantly improved over the three test blocks, which is indicative of typical practice effects. The magnitude of these improvements was the highest when both motion and moderate cognitive load were present. The same effects declined either in the absence of motion (low arousal) or following a low cognitive workload task, thus suggesting two distinct pathways through which practice-related improvements in cognitive performance may be hampered. Practice, however, degraded certain aspects of metacognitive performance, as participants became less likely to detect incorrect decisions in the decision-making test with each subsequent test block. Implications include consideration of low cognitive load and arousal as factors responsible for performance decline and targets for the development of interventions/strategies in low load/arousal conditions such as autonomous vehicle operations and highway driving. PMID:25549327

Predictors of driving safety in early Alzheimer disease

PubMed Central

Dawson, J D.; Anderson, S W.; Uc, E Y.; Dastrup, E; Rizzo, M

2009-01-01

Objective: To measure the association of cognition, visual perception, and motor function with driving safety in Alzheimer disease (AD). Methods: Forty drivers with probable early AD (mean Mini-Mental State Examination score 26.5) and 115 elderly drivers without neurologic disease underwent a battery of cognitive, visual, and motor tests, and drove a standardized 35-mile route in urban and rural settings in an instrumented vehicle. A composite cognitive score (COGSTAT) was calculated for each subject based on eight neuropsychological tests. Driving safety errors were noted and classified by a driving expert based on video review. Results: Drivers with AD committed an average of 42.0 safety errors/drive (SD = 12.8), compared to an average of 33.2 (SD = 12.2) for drivers without AD (p < 0.0001); the most common errors were lane violations. Increased age was predictive of errors, with a mean of 2.3 more errors per drive observed for each 5-year age increment. After adjustment for age and gender, COGSTAT was a significant predictor of safety errors in subjects with AD, with a 4.1 increase in safety errors observed for a 1 SD decrease in cognitive function. Significant increases in safety errors were also found in subjects with AD with poorer scores on Benton Visual Retention Test, Complex Figure Test-Copy, Trail Making Subtest-A, and the Functional Reach Test. Conclusion: Drivers with Alzheimer disease (AD) exhibit a range of performance on tests of cognition, vision, and motor skills. Since these tests provide additional predictive value of driving performance beyond diagnosis alone, clinicians may use these tests to help predict whether a patient with AD can safely operate a motor vehicle. GLOSSARY AD = Alzheimer disease; AVLT = Auditory Verbal Learning Test; Blocks = Block Design subtest; BVRT = Benton Visual Retention Test; CFT = Complex Figure Test; CI = confidence interval; COWA = Controlled Oral Word Association; CS = contrast sensitivity; FVA = far visual acuity; JLO = Judgment of Line Orientation; MCI = mild cognitive impairment; MMSE = Mini-Mental State Examination; NVA = near visual acuity; SFM = structure from motion; TMT = Trail-Making Test; UFOV = Useful Field of View. PMID:19204261

The Crosstalk Hypothesis: Why Language Interferes with Driving

ERIC Educational Resources Information Center

Bergen, Benjamin; Medeiros-Ward, Nathan; Wheeler, Kathryn; Drews, Frank; Strayer, David

2013-01-01

Performing two cognitive tasks at the same time can degrade performance for either domain-general reasons (e.g., both tasks require attention) or domain-specific reasons (e.g., both tasks require visual working memory). We tested predictions of these two accounts of interference on the task of driving while using language, a naturally occurring…

Driving and Low Vision: Validity of Assessments for Predicting Performance of Drivers

ERIC Educational Resources Information Center

Strong, J. Graham; Jutai, Jeffrey W.; Russell-Minda, Elizabeth; Evans, Mal

2008-01-01

The authors conducted a systematic review to examine whether vision-related assessments can predict the driving performance of individuals who have low vision. The results indicate that measures of visual field, contrast sensitivity, cognitive and attention-based tests, and driver screening tools have variable utility for predicting real-world…

Driver distraction by smartphone use (WhatsApp) in different age groups.

PubMed

Ortiz, C; Ortiz-Peregrina, S; Castro, J J; Casares-López, M; Salas, C

2018-08-01

This paper investigates the effect that texting with WhatsApp, one of the most common applications for instant messaging, exerts on driving performance. Because distracted driving also affects older drivers, who can have seriously compromised vision, we also analysed the associations between visual-function parameters and driving performance. A total of 75 drivers, experienced in sending WhatsApp messages (≥10WhatsApp messages/week), participated in this study and were divided into four age categories. Visual-function tests included contrast sensitivity with and without glare, retinal straylight and objective assessment of optical quality. Simulated driving performance was assessed under a baseline driving condition (without distraction) as well as a texting condition (WhatsApp messages) while driving. The participants used their own mobile phone. Lastly, objective results of driving performance were compared with subjective self-report data from the Driver Behaviour Questionnaire (DBQ). The analysis indicated that functional changes occurring with age, such as a lower contrast sensitivity and greater retinal straylight, were correlated with a higher number of collisions, longer distances driven outside the lane, and greater standard deviation of lateral position (SDLP). The results showed a significant main effect of age for the driving-performance parameters. Also, compared to the baseline, texting WhatsApp messages while driving worsens driving performance for all age groups, most notably among older participants. Thus, the older drivers' SDLP was ∼14% higher than that for the baseline average of all the other drivers and rose to 29% under distraction, reflecting the impact of secondary tasks. The negative effect of the use of the smartphone during driving was also reflected in the number of collisions, with a greater risk of accidents in all the groups of drivers (by 8.3% for young adults, 25.0% for adults, 80.5% for middle-aged adults, and 134.5% for older drivers). Lastly, participants' subjective responses indicated that younger drivers (18-24 years) had a higher risk of deliberately violating safe driving practices (p < 0.05). The present study demonstrates that texting WhatsApp messages while driving significantly impairs the ability to drive safely, with older drivers being the group most adversely affected. It would be recommendable to include other nonstandard vision tests, which have shown associations with driving performance, in the examination for driver licensing. This would help raise the awareness of older drivers concerning their visual limitations, permitting them to adopt compensatory measures to improve their driving safety. Nevertheless, it is also necessary to raise awareness among the younger drivers of the risks involved in behaviour behind the wheel. Copyright © 2018 Elsevier Ltd. All rights reserved.

Risk Mitigation Testing with the BepiColombo MPO SADA

NASA Astrophysics Data System (ADS)

Zemann, J.; Heinrich, B.; Skulicz, A.; Madsen, M.; Weisenstein, W.; Modugno, F.; Althaus, F.; Panhofer, T.; Osterseher, G.

2013-09-01

A Solar Array (SA) Drive Assembly (SADA) for the BepiColombo mission is being developed and qualified at RUAG Space Zürich (RSSZ). The system is consisting of the Solar Array Drive Mechanism (SADM) and the Solar Array Drive Electronics (SADE) which is subcontracted to RUAG Space Austria (RSA).This paper deals with the risk mitigation activities and the lesson learnt from this development. In specific following topics substantiated by bread board (BB) test results will be addressed in detail:Slipring Bread Board Test: Verification of lifetime and electrical performance of carbon brush technology Potentiometer BB Tests: Focus on lifetime verification (> 650000 revolution) and accuracy requirement SADM EM BB Test: Subcomponent (front-bearing and gearbox) characterization; complete test campaign equivalent to QM test.EM SADM/ SADE Combined Test: Verification of combined performance (accuracy, torque margin) and micro-vibration testing of SADA systemSADE Bread Board Test: Parameter optimization; Test campaign equivalent to QM testThe main improvements identified in frame of BB testing and already implemented in the SADM EM/QM and SADE EQM are:• Improved preload device for gearbox• Improved motor ball-bearing assembly• Position sensor improvements• Calibration process for potentiometer• SADE motor controller optimization toachieve required running smoothness• Overall improvement of test equipment.

ALCOHOL AND DISTRACTION INTERACT TO IMPAIR DRIVING PERFORMANCE

PubMed Central

Harrison, Emily L. R.; Fillmore, Mark T.

2011-01-01

Background Recognition of the risks associated with alcohol intoxication and driver distraction has led to a wealth of simulated driving research aimed at studying the adverse effects of each of these factors. Research on driving has moved beyond the individual, separate examination of these factors to the examination of potential interactions between alcohol intoxication and driver distraction. In many driving situations, distractions are commonplace and might have little or no disruptive influence on primary driving functions. Yet, such distractions might become disruptive to a driver who is intoxicated. Methods The present study examined the interactive impairing effects of alcohol intoxication and driver distraction on simulated driving performance in 40 young adult drivers using a divided attention task as a distracter activity. The interactive influence of alcohol and distraction was tested by having drivers perform the driving task under four different conditions: 0.65 g/kg alcohol; 0.65 g/kg alcohol + divided attention; placebo; and placebo + divided attention. Results As hypothesized, divided attention had no impairing effect on driving performance in sober drivers. However, under alcohol, divided attention exacerbated the impairing effects of alcohol on driving precision. Conclusions Alcohol and distraction continue to be appropriate targets for research into ways to reduce the rates of driving-related fatalities and injuries. Greater consideration of how alcohol and distraction interact to impair aspects of driving performance can further efforts to create prevention and intervention measures to protect drivers, particularly young adults. PMID:21277119

Alcohol and distraction interact to impair driving performance.

PubMed

Harrison, Emily L R; Fillmore, Mark T

2011-08-01

Recognition of the risks associated with alcohol intoxication and driver distraction has led to a wealth of simulated driving research aimed at studying the adverse effects of each of these factors. Research on driving has moved beyond the individual, separate examination of these factors to the examination of potential interactions between alcohol intoxication and driver distraction. In many driving situations, distractions are commonplace and might have little or no disruptive influence on primary driving functions. Yet, such distractions might become disruptive to a driver who is intoxicated. The present study examined the interactive impairing effects of alcohol intoxication and driver distraction on simulated driving performance in 40 young adult drivers using a divided attention task as a distracter activity. The interactive influence of alcohol and distraction was tested by having drivers perform the driving task under four different conditions: 0.65 g/kg alcohol; 0.65 g/kg alcohol+divided attention; placebo; and placebo+divided attention. As hypothesized, divided attention had no impairing effect on driving performance in sober drivers. However, under alcohol, divided attention exacerbated the impairing effects of alcohol on driving precision. Alcohol and distraction continue to be appropriate targets for research into ways to reduce the rates of driving-related fatalities and injuries. Greater consideration of how alcohol and distraction interact to impair aspects of driving performance can further efforts to create prevention and intervention measures to protect drivers, particularly young adults. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Assessment of driving-related performance in chronic whiplash using an advanced driving simulator.

PubMed

Takasaki, Hiroshi; Treleaven, Julia; Johnston, Venerina; Rakotonirainy, Andry; Haines, Andrew; Jull, Gwendolen

2013-11-01

Driving is often nominated as problematic by individuals with chronic whiplash associated disorders (WAD), yet driving-related performance has not been evaluated objectively. The purpose of this study was to test driving-related performance in persons with chronic WAD against healthy controls of similar age, gender and driving experience to determine if driving-related performance in the WAD group was sufficiently impaired to recommend fitness to drive assessment. Driving-related performance was assessed using an advanced driving simulator during three driving scenarios; freeway, residential and a central business district (CBD). Total driving duration was approximately 15min. Five driving tasks which could cause a collision (critical events) were included in the scenarios. In addition, the effect of divided attention (identify red dots projected onto side or rear view mirrors) was assessed three times in each scenario. Driving performance was measured using the simulator performance index (SPI) which is calculated from 12 measures. z-Scores for all SPI measures were calculated for each WAD subject based on mean values of the control subjects. The z-scores were then averaged for the WAD group. A z-score of ≤-2 indicated a driving failing grade in the simulator. The number of collisions over the five critical events was compared between the WAD and control groups as was reaction time and missed response ratio in identifying the red dots. Seventeen WAD and 26 control subjects commenced the driving assessment. Demographic data were comparable between the groups. All subjects completed the freeway scenario but four withdrew during the residential and eight during the CBD scenario because of motion sickness. All scenarios were completed by 14 WAD and 17 control subjects. Mean z-scores for the SPI over the three scenarios was statistically lower in the WAD group (-0.3±0.3; P<0.05) but the score was not below the cut-off point for safe driving. There were no differences in the reaction time and missed response ratio in divided attention tasks between the groups (All P>0.05). Assessment of driving in an advanced driving simulator for approximately 15min revealed that driving-related performance in chronic WAD was not sufficiently impaired to recommend the need for fitness to drive assessment. Copyright © 2013 Elsevier Ltd. All rights reserved.

Assessment of wheelchair driving performance in a virtual reality-based simulator

PubMed Central

Mahajan, Harshal P.; Dicianno, Brad E.; Cooper, Rory A.; Ding, Dan

2013-01-01

Objective To develop a virtual reality (VR)-based simulator that can assist clinicians in performing standardized wheelchair driving assessments. Design A completely within-subjects repeated measures design. Methods Participants drove their wheelchairs along a virtual driving circuit modeled after the Power Mobility Road Test (PMRT) and in a hallway with decreasing width. The virtual simulator was displayed on computer screen and VR screens and participants interacted with it using a set of instrumented rollers and a wheelchair joystick. Driving performances of participants were estimated and compared using quantitative metrics from the simulator. Qualitative ratings from two experienced clinicians were used to estimate intra- and inter-rater reliability. Results Ten regular wheelchair users (seven men, three women; mean age ± SD, 39.5 ± 15.39 years) participated. The virtual PMRT scores from the two clinicians show high inter-rater reliability (78–90%) and high intra-rater reliability (71–90%) for all test conditions. More research is required to explore user preferences and effectiveness of the two control methods (rollers and mathematical model) and the display screens. Conclusions The virtual driving simulator seems to be a promising tool for wheelchair driving assessment that clinicians can use to supplement their real-world evaluations. PMID:23820148

Driver’s Cognitive Workload and Driving Performance under Traffic Sign Information Exposure in Complex Environments: A Case Study of the Highways in China

PubMed Central

Lyu, Nengchao; Xie, Lian; Wu, Chaozhong; Fu, Qiang; Deng, Chao

2017-01-01

Complex traffic situations and high driving workload are the leading contributing factors to traffic crashes. There is a strong correlation between driving performance and driving workload, such as visual workload from traffic signs on highway off-ramps. This study aimed to evaluate traffic safety by analyzing drivers’ behavior and performance under the cognitive workload in complex environment areas. First, the driving workload of drivers was tested based on traffic signs with different quantities of information. Forty-four drivers were recruited to conduct a traffic sign cognition experiment under static controlled environment conditions. Different complex traffic signs were used for applying the cognitive workload. The static experiment results reveal that workload is highly related to the amount of information on traffic signs and reaction time increases with the information grade, while driving experience and gender effect are not significant. This shows that the cognitive workload of subsequent driving experiments can be controlled by the amount of information on traffic signs; Second, driving characteristics and driving performance were analyzed under different secondary task driving workload levels using a driving simulator. Drivers were required to drive at the required speed on a designed highway off-ramp scene. The cognitive workload was controlled by reading traffic signs with different information, which were divided into four levels. Drivers had to make choices by pushing buttons after reading traffic signs. Meanwhile, the driving performance information was recorded. Questionnaires on objective workload were collected right after each driving task. The results show that speed maintenance and lane deviations are significantly different under different levels of cognitive workload, and the effects of driving experience and gender groups are significant. The research results can be used to analyze traffic safety in highway environments, while considering more drivers’ cognitive and driving performance. PMID:28218696

On-the-road driving performance and driving-related skills in older untreated insomnia patients and chronic users of hypnotics.

PubMed

Leufkens, T R M; Ramaekers, J G; de Weerd, A W; Riedel, W J; Vermeeren, A

2014-07-01

Many older adults report sleep problems and use of hypnotics. Several studies have shown that hypnotics can have acute adverse effects on driving the next morning. It is unclear however whether driving of chronic hypnotic users is impaired. Therapeutic effects on insomnia and development of tolerance may reduce the residual effects on driving. The present study aimed to compare actual driving performance and driving-related skills of chronic hypnotic users to good sleepers. To determine whether insomnia itself affects driving performance, driving and driving-related skills were compared between insomnia patients who do not or infrequently use hypnotics and good sleepers. Twenty-two frequent users of hypnotics (using hypnotics ≥ 4 nights per week for more than 3 months), 20 infrequent users (using hypnotics ≤ 3 nights per week), and 21 healthy, age-matched controls participated in this study. On the night before testing, all subjects were hospitalized for an 8-h sleep recorded by polysomnography. Frequent hypnotic users used their regular medication at bedtime (2330 hours), while infrequent users and controls received no medication. Cognitive performance (word learning, digit span, tracking, divided attention, vigilance, and inhibitory control) was assessed 8.5 h and driving performance between 10 and 11 h after bedtime and dosing. Polysomnographic recordings did not significantly differ between the groups, but the insomnia patients, treated or untreated, still reported subjective sleep complaints. Results show no differences in driving performance and driving-related skills between both groups of insomnia patients and controls. Driving performance in chronic users of hypnotics and untreated insomnia patients is not impaired. For chronic users, this may be due to prescription of relatively safe drugs and low doses. For untreated insomniacs, this corroborates previous findings showing an absence of neuropsychological deficits in this group of patients.

Is it really good to talk? Testing the impact of providing concurrent verbal protocols on driving performance.

PubMed

Salmon, Paul Matthew; Goode, Natassia; Spiertz, Antje; Thomas, Miles; Grant, Eryn; Clacy, Amanda

2017-06-01

Questions have been raised regarding the impact that providing concurrent verbal protocols has on task performance in various settings; however, there has been little empirical testing of this in road transport. The aim of this study was to examine the impact of providing concurrent verbal protocols on driving performance. Participants drove an instrumented vehicle around a set route, twice whilst providing a concurrent verbal protocol, and twice without. A comparison revealed no differences in behaviour related to speed, braking and steering wheel angle when driving mid-block, but a significant difference in aspects of braking and acceleration at roundabouts. When not providing a verbal protocol, participants were found to brake harder on approach to a roundabout and accelerate more heavily coming out of roundabouts. It is concluded that providing verbal protocols may have a positive effect on braking and accelerating. Practical implications related to driver training and future research are discussed. Practitioner Summary: Verbal protocol analysis is used by ergonomists to understand aspects of cognition and decision-making during complex tasks such as driving and control room operation. This study examines the impact that it has on driving performance, providing evidence to support its continued use in ergonomics applications.

Rotating rake design for unique measurement of fan-generated spinning acoustic modes

NASA Technical Reports Server (NTRS)

Konno, Kevin E.; Hausmann, Clifford R.

1993-01-01

In light of the current emphasis on noise reduction in subsonic aircraft design, NASA has been actively studying the source of and propagation of noise generated by subsonic fan engines. NASA/LeRC has developed and tested a unique method of accurately measuring these spinning acoustic modes generated by an experimental fan. This mode measuring method is based on the use of a rotating microphone rake. Testing was conducted in the 9 x 15 Low-speed Wind Tunnel. The rotating rake was tested with the Advanced Ducted Propeller (ADP) model. This memorandum discusses the design and performance of the motor/drive system for the fan-synchronized rotating acoustic rake. This novel motor/drive design approach is now being adapted for additional acoustic mode studies in new test rigs as baseline data for the future design of active noise control for subsonic fan engines. Included in this memorandum are the research requirements, motor/drive specifications, test performance results, and a description of the controls and software involved.

Effects of Age-Related Macular Degeneration on Driving Performance

PubMed Central

Wood, Joanne M.; Black, Alex A.; Mallon, Kerry; Kwan, Anthony S.; Owsley, Cynthia

2018-01-01

Purpose To explore differences in driving performance of older adults with age-related macular degeneration (AMD) and age-matched controls, and to identify the visual determinants of driving performance in this population. Methods Participants included 33 older drivers with AMD (mean age [M] = 76.6 ± 6.1 years; better eye Age-Related Eye Disease Study grades: early [61%] and intermediate [39%]) and 50 age-matched controls (M = 74.6 ± 5.0 years). Visual tests included visual acuity, contrast sensitivity, visual fields, and motion sensitivity. On-road driving performance was assessed in a dual-brake vehicle by an occupational therapist (masked to drivers' visual status). Outcome measures included driving safety ratings (scale of 1–10, where higher values represented safer driving), types of driving behavior errors, locations at which errors were made, and number of critical errors (CE) requiring an instructor intervention. Results Drivers with AMD were rated as less safe than controls (4.8 vs. 6.2; P = 0.012); safety ratings were associated with AMD severity (early: 5.5 versus intermediate: 3.7), even after adjusting for age. Drivers with AMD had higher CE rates than controls (1.42 vs. 0.36, respectively; rate ratio 3.05, 95% confidence interval 1.47–6.36, P = 0.003) and exhibited more observation, lane keeping, and gap selection errors and made more errors at traffic light–controlled intersections (P < 0.05). Only motion sensitivity was significantly associated with driving safety in the AMD drivers (P = 0.005). Conclusions Drivers with early and intermediate AMD can exhibit impairments in their driving performance, particularly during complex driving situations; motion sensitivity was most strongly associated with driving performance. These findings have important implications for assessing the driving ability of older drivers with visual impairment. PMID:29340641

Effect of the teen driving plan on the driving performance of teenagers before licensure: a randomized clinical trial.

PubMed

Mirman, Jessica H; Curry, Allison E; Winston, Flaura K; Wang, Wenli; Elliott, Michael R; Schultheis, Maria T; Fisher Thiel, Megan C; Durbin, Dennis R

2014-08-01

Many studies have failed to show an effect of parent-supervised practice driving on the driving performance of teenagers; nevertheless, most Graduated Driver Licensing programs have provisions that require supervised practice. To determine whether a web-based intervention, the Teen Driving Plan (TDP), can improve the driving performance of teenagers before licensure as measured by the Teen On-road Driving Assessment (tODA). Randomized, single-blind, clinical trial among 217 dyads (1 parent: 1 teenaged learner's-permit holder) to test TDP effectiveness on increasing the quantity and diversity of supervised practice and improving the teenagers' prelicensed driving performance. The study was conducted from December 2011 through January 2013 in Southeastern Pennsylvania. Dyads were randomized (3:2) to receive the TDP or the Pennsylvania driver's manual (control group). The TDP is a psychoeducational intervention designed to increase the quantity and diversity of parent-supervised practice. Materials are grouped by the following driving environments: empty parking lots, suburban residential streets, intermediate (1- or 2-lane) roads, highways, rural roads with curves and elevation changes, and commercial districts. The main outcomes were self-reported practice driving across 6 environments and 2 conditions and driving performance as measured by the teenagers' completion of the standardized and validated tODA 24 weeks after enrollment. Certified professional driving evaluators blinded to randomization status terminated the tODA if they determined that the teenager could not safely complete it. We examined mean differences in the quantity of supervised practice, differences in the overall proportion of teenagers in each group that had assessments terminated for unsafe driving, and the point of termination during the assessment. The TDP dyads reported more practice in 5 of the 6 environments and at night and in bad weather compared with the control dyads. Overall, 5 of 86 TDP teenagers (6%) had the tODA terminated compared with 10 of 65 control teenagers (15%) (risk difference [TDP - control], -9% [95% CI, -21% to 2%]; P = .06). The hazard ratio for exposure to TDP was 0.35 (95% CI, 0.12-1.03; P = .05, log-rank test). Preliminary evidence suggests that the TDP improves supervised practice and the driving performance of prelicensed teenaged drivers. Future studies can explore how to revise the TDP to enhance the treatment effect and how best to disseminate the TDP without compromising implementation fidelity. clinicaltrials.gov Identifier: NCT01498575.

Residual effect of zolpidem 10 mg and zopiclone 7.5 mg versus flunitrazepam 1 mg and placebo on driving performance and ocular saccades.

PubMed

Bocca, M L; Le Doze, F; Etard, O; Pottier, M; L'Hoste, J; Denise, P

1999-04-01

Studies report contradictory results concerning the residual effects of zolpidem and zopiclone. Moreover, residual effects of these compounds on healthy subjects have not yet been simultaneously assessed. The present study with healthy subjects investigated the residual effects of zolpidem 10 mg and zopiclone 7.5 mg on driving performance and on ocular saccade and compared them to those under flunitrazepam 1 mg and placebo. The study involved 16 subjects divided into two groups, a 9:00 a.m. group and a 11:00 a.m. group, in a balanced, double-blind, cross-over design. In the 9:00 a.m. group, zolpidem had no residual effects while zopiclone and flunitrazepam both impaired driving performance (P < 0.001 for both) and increased saccadic latency (P < 0.005; P = 0.052, respectively). Zopiclone impaired driving performance 5 times less than did flunitrazepam. In the 11:00 a.m. group, zolpidem and zopiclone had no residual effects, while flunitrazepam increased saccadic latency (P = 0.065) but did not impair driving performance. Zopiclone and flunitrazepam had residual effects in the first part of the morning, whereas zolpidem had no residual effects. The hierarchical character of the effects of the molecules differed according to the test administered. This is probably linked more to drug-induced specific alterations than to different sensitivities of the tests.

On-road Driving Performance of Patients with Bilateral Moderate and Advanced Glaucoma

PubMed Central

Bhorade, Anjali M.; Yom, Victoria H.; Barco, Peggy; Wilson, Bradley; Gordon, Mae; Carr, David

2017-01-01

Purpose To compare on-road driving performance of patients with moderate or advanced glaucoma to controls and evaluate factors associated with unsafe driving. Design Case-control pilot study. Methods A consecutive sample of 21 patients with bilateral moderate or advanced glaucoma from Washington University, St. Louis, MO and 38 community-dwelling controls were enrolled. Participants, ages 55–90 years, underwent a comprehensive clinical evaluation by a trained occupational therapist and an on-road driving evaluation by a masked driver rehabilitation specialist. Overall driving performance of pass vs. marginal/fail and number of wheel and/or brake interventions were recorded. Results Fifty-two percent of glaucoma participants scored a marginal/fail compared to 21% of controls (odds ratio [OR], 4.1; 95% CI, 1.30–13.14;p=.02). Glaucoma participants had a higher risk of wheel interventions than controls (OR, 4.67; 95% CI, 1.03–21.17;p=.046). There were no differences detected between glaucoma participants who scored a pass vs. marginal/fail for visual field mean deviation of the better (p=.62) or worse (p=.88) eye, binocular distance (p=.15) or near (p=.23) visual acuity, contrast sensitivity (p=.28) or glare (p=.88). However, glaucoma participants with a marginal/fail score performed worse on Trail Making Tests A (p=.03) and B (p=.05), right-sided Jamar grip strength (p=.02), Rapid Pace Walk (p=.03), Braking Response Time (p=.03), and identifying traffic signs (p=.05). Conclusions and Relevance Patients with bilateral moderate or advanced glaucoma are at risk for unsafe driving – particularly those with impairments on psychometric and mobility tests. A comprehensive clinical assessment and on-road driving evaluation is recommended to effectively evaluate driving safety of these patients. PMID:26949136

Longitudinal decline of driving safety in Parkinson disease.

PubMed

Uc, Ergun Y; Rizzo, Matthew; O'Shea, Amy M J; Anderson, Steven W; Dawson, Jeffrey D

2017-11-07

To longitudinally assess and predict on-road driving safety in Parkinson disease (PD). Drivers with PD (n = 67) and healthy controls (n = 110) drove a standardized route in an instrumented vehicle and were invited to return 2 years later. A professional driving expert reviewed drive data and videos to score safety errors. At baseline, drivers with PD performed worse on visual, cognitive, and motor tests, and committed more road safety errors compared to controls (median PD 38.0 vs controls 30.5; p < 0.001). A smaller proportion of drivers with PD returned for repeat testing (42.8% vs 62.7%; p < 0.01). At baseline, returnees with PD made fewer errors than nonreturnees with PD (median 34.5 vs 40.0; p < 0.05) and performed similar to control returnees (median 33). Baseline global cognitive performance of returnees with PD was better than that of nonreturnees with PD, but worse than for control returnees ( p < 0.05). After 2 years, returnees with PD showed greater cognitive decline and larger increase in error counts than control returnees (median increase PD 13.5 vs controls 3.0; p < 0.001). Driving error count increase in the returnees with PD was predicted by greater error count and worse visual acuity at baseline, and by greater interval worsening of global cognition, Unified Parkinson's Disease Rating Scale activities of daily living score, executive functions, visual processing speed, and attention. Despite drop out of the more impaired drivers within the PD cohort, returning drivers with PD, who drove like controls without PD at baseline, showed many more driving safety errors than controls after 2 years. Driving decline in PD was predicted by baseline driving performance and deterioration of cognitive, visual, and functional abnormalities on follow-up. © 2017 American Academy of Neurology.

On-road particle number measurements using a portable emission measurement system (PEMS)

NASA Astrophysics Data System (ADS)

Gallus, Jens; Kirchner, Ulf; Vogt, Rainer; Börensen, Christoph; Benter, Thorsten

2016-01-01

In this study the on-road particle number (PN) performance of a Euro-5 direct-injection (DI) gasoline passenger car was investigated. PN emissions were measured using the prototype of a portable emission measurement system (PEMS). PN PEMS correlations with chassis dynamometer tests show a good agreement with a chassis dynamometer set-up down to emissions in the range of 1·1010 #/km. Parallel on-line soot measurements by a photo acoustic soot sensor (PASS) were applied as independent measurement technique and indicate a good on-road performance for the PN-PEMS. PN-to-soot ratios were 1.3·1012 #/mg, which was comparable for both test cell and on-road measurements. During on-road trips different driving styles as well as different road types were investigated. Comparisons to the world harmonized light-duty test cycle (WLTC) 5.3 and to European field operational test (euroFOT) data indicate the PEMS trips to be representative for normal driving. Driving situations in varying traffic seem to be a major contributor to a high test-to-test variability of PN emissions. However, there is a trend to increasing PN emissions with more severe driving styles. A cold start effect is clearly visible for PN, especially at low ambient temperatures down to 8 °C.

Car driving in schizophrenia: can visual memory and organization make a difference?

PubMed

Lipskaya-Velikovsky, Lena; Kotler, Moshe; Weiss, Penina; Kaspi, Maya; Gamzo, Shimrit; Ratzon, Navah

2013-09-01

Driving is a meaningful occupation which is ascribed to functional independence in schizophrenia. Although it is estimated that individuals with schizophrenia have two times more traffic accidents, little research has been done in this field. Present research explores differences in mental status, visual working memory and visual organization between drivers and non-drivers with schizophrenia in comparison to healthy drivers. There were three groups in the study: 20 drivers with schizophrenia, 20 non-driving individuals with schizophrenia and 20 drivers without schizophrenia (DWS). Visual perception was measured with Rey-Osterrieth Complex Figure test and a general cognitive status with Mini-Mental State Examination. The general cognitive status predicted actual driving situation in people with schizophrenia. No statistically significant differences were found between driving and non-driving persons with schizophrenia on any of the visual parameters tested, although these abilities were significantly lower than those of DWS. The research demonstrates that impairment of visual abilities does not prevent people with schizophrenia from driving and emphasizes the importance of general cognitive status for complex and multidimensional everyday tasks. The findings support the need for further investigation in the field of car driving for this population - a move that will considerably contribute to the participation and well-being. Implication for Rehabilitation Unique approach for driving evaluation in schizophrenia should be designed since direct applications of knowledge and practice acquired from other populations are not reliable. This research demonstrates that visual perception deficits in schizophrenia do not prevent clients from driving, and general cognitive status appeared to be a valid determinant for actual driving. We recommended usage of a general test of cognition such as Mini-Mental State Examination, or conjunction number of cognitive factors such as executive functions (e.g., Trail Making Test) and attention (e.g., Continuous Performance Test) in addition to spatial-visual ability tests (e.g., Rey-Osterrieth Complex Figure test) for considering driving status in schizophrenia.

A neuropsychological instrument measuring age-related cerebral decline in older drivers: development, reliability, and validity of MedDrive

PubMed Central

Vaucher, Paul; Cardoso, Isabel; Veldstra, Janet L.; Herzig, Daniela; Herzog, Michael; Mangin, Patrice; Favrat, Bernard

2014-01-01

When facing age-related cerebral decline, older adults are unequally affected by cognitive impairment without us knowing why. To explore underlying mechanisms and find possible solutions to maintain life-space mobility, there is a need for a standardized behavioral test that relates to behaviors in natural environments. The aim of the project described in this paper was therefore to provide a free, reliable, transparent, computer-based instrument capable of detecting age-related changes on visual processing and cortical functions for the purposes of research into human behavior in computational transportation science. After obtaining content validity, exploring psychometric properties of the developed tasks, we derived (Study 1) the scoring method for measuring cerebral decline on 106 older drivers aged ≥70 years attending a driving refresher course organized by the Swiss Automobile Association to test the instrument's validity against on-road driving performance (106 older drivers). We then validated the derived method on a new sample of 182 drivers (Study 2). We then measured the instrument's reliability having 17 healthy, young volunteers repeat all tests included in the instrument five times (Study 3) and explored the instrument's psychophysical underlying functions on 47 older drivers (Study 4). Finally, we tested the instrument's responsiveness to alcohol and effects on performance on a driving simulator in a randomized, double-blinded, placebo, crossover, dose-response, validation trial including 20 healthy, young volunteers (Study 5). The developed instrument revealed good psychometric properties related to processing speed. It was reliable (ICC = 0.853) and showed reasonable association to driving performance (R2 = 0.053), and responded to blood alcohol concentrations of 0.5 g/L (p = 0.008). Our results suggest that MedDrive is capable of detecting age-related changes that affect processing speed. These changes nevertheless do not necessarily affect driving behavior. PMID:25346674

In Patients With Cirrhosis, Driving Simulator Performance Is Associated With Real-life Driving.

PubMed

Lauridsen, Mette M; Thacker, Leroy R; White, Melanie B; Unser, Ariel; Sterling, Richard K; Stravitz, Richard T; Matherly, Scott; Puri, Puneet; Sanyal, Arun J; Gavis, Edith A; Luketic, Velimir; Siddiqui, Muhammad S; Heuman, Douglas M; Fuchs, Michael; Bajaj, Jasmohan S

2016-05-01

Minimal hepatic encephalopathy (MHE) has been linked to higher real-life rates of automobile crashes and poor performance in driving simulation studies, but the link between driving simulator performance and real-life automobile crashes has not been clearly established. Furthermore, not all patients with MHE are unsafe drivers, but it is unclear how to distinguish them from unsafe drivers. We investigated the link between performance on driving simulators and real-life automobile accidents and traffic violations. We also aimed to identify features of unsafe drivers with cirrhosis and evaluated changes in simulated driving skills and MHE status after 1 year. We performed a study of outpatients with cirrhosis (n = 205; median 55 years old; median model for end-stage liver disease score, 9.5; none with overt hepatic encephalopathy or alcohol or illicit drug use within previous 6 months) seen at the Virginia Commonwealth University and McGuire Veterans Administration Medical Center, from November 2008 through April 2014. All participants were given paper-pencil tests to diagnose MHE (98 had MHE; 48%), and 163 patients completed a standardized driving simulation. Data were collected on traffic violations and automobile accidents from the Virginia Department of Motor Vehicles and from participants' self-assessments when they entered the study, and from 73 participants 1 year later. Participants also completed a questionnaire about alcohol use and cessation patterns. The driving simulator measured crashes, run-time, road center and edge excursions, and illegal turns during navigation; before and after each driving simulation session, patients were asked to rate their overall driving skills. Drivers were classified as safe or unsafe based on crashes and violations reported on official driving records; simulation results were compared with real-life driving records. Multivariable regression analyses of real-life crashes and violations was performed using data on demographics, cirrhosis details, MHE status, and alcohol cessation patterns, at baseline and at 1 year. Drivers categorized as unsafe had more crashes and made more illegal turns on the driving simulator than drivers categorized as safe; a higher proportion of subjects with MHE were categorized as unsafe drivers at baseline (16%) than subjects without MHE (7%; P = .02), and at 1-year follow-up (18% vs 0%; P = .02). Alcohol cessation within <1 year and illegal turns during simulator navigation tasks were associated with real-life automobile crashes and MHE in regression analysis; road edge excursions in the simulator were associated with real-life traffic violations. Personal assessment of driving skills improved after each simulation episode. In a study of 205 patients with cirrhosis, we associated results from driving simulation tests with real-life driving records and MHE. Traffic safety counseling should focus on patients with cirrhosis who recently quit consuming alcohol and perform poorly on driving simulation. Copyright © 2016 AGA Institute. Published by Elsevier Inc. All rights reserved.

Age-related changes in perception of movement in driving scenes.

PubMed

Lacherez, Philippe; Turner, Laura; Lester, Robert; Burns, Zoe; Wood, Joanne M

2014-07-01

Age-related changes in motion sensitivity have been found to relate to reductions in various indices of driving performance and safety. The aim of this study was to investigate the basis of this relationship in terms of determining which aspects of motion perception are most relevant to driving. Participants included 61 regular drivers (age range 22-87 years). Visual performance was measured binocularly. Measures included visual acuity, contrast sensitivity and motion sensitivity assessed using four different approaches: (1) threshold minimum drift rate for a drifting Gabor patch, (2) Dmin from a random dot display, (3) threshold coherence from a random dot display, and (4) threshold drift rate for a second-order (contrast modulated) sinusoidal grating. Participants then completed the Hazard Perception Test (HPT) in which they were required to identify moving hazards in videos of real driving scenes, and also a Direction of Heading task (DOH) in which they identified deviations from normal lane keeping in brief videos of driving filmed from the interior of a vehicle. In bivariate correlation analyses, all motion sensitivity measures significantly declined with age. Motion coherence thresholds, and minimum drift rate threshold for the first-order stimulus (Gabor patch) both significantly predicted HPT performance even after controlling for age, visual acuity and contrast sensitivity. Bootstrap mediation analysis showed that individual differences in DOH accuracy partly explained these relationships, where those individuals with poorer motion sensitivity on the coherence and Gabor tests showed decreased ability to perceive deviations in motion in the driving videos, which related in turn to their ability to detect the moving hazards. The ability to detect subtle movements in the driving environment (as determined by the DOH task) may be an important contributor to effective hazard perception, and is associated with age, and an individuals' performance on tests of motion sensitivity. The locus of the processing deficits appears to lie in first-order, rather than second-order motion pathways. © 2014 The Authors Ophthalmic & Physiological Optics © 2014 The College of Optometrists.

Relative benefits of stimulant therapy with OROS methylphenidate versus mixed amphetamine salts extended release in improving the driving performance of adolescent drivers with attention-deficit/hyperactivity disorder.

PubMed

Cox, Daniel J; Merkel, R Lawrence; Moore, Melissa; Thorndike, Frances; Muller, Carrie; Kovatchev, Boris

2006-09-01

Automobile accidents are the leading cause of death among adolescents, and collisions are 2 to 4 times more likely to occur among adolescents with attention-deficit/hyperactivity disorder. Studies have demonstrated that stimulants improve driving performance. This study compared 2 long-acting stimulant medications during daytime and evening driving evaluations. Adolescent drivers with attention-deficit/hyperactivity disorder were compared on a driving simulator after taking 72 mg of OROS methylphenidate, 30 mg of mixed amphetamine salts extended release, or placebo in a randomized, double-blind, placebo-controlled, crossover study design. During laboratory testing, adolescents drove a driving simulator at 5:00 pm, 8:00 pm, and 11:00 pm. Driving performance was rated by adolescents and investigators. The study included 35 adolescent drivers with attention-deficit/hyperactivity disorder (19 boys/16 girls). The mean age was 17.8 years. The overall Impaired Driving Score demonstrated that OROS methylphenidate led to better driving performance compared with placebo and mixed amphetamine salts extended release, whereas mixed amphetamine salts extended release demonstrated no statistical improvement over placebo. Specifically, relative to placebo, OROS methylphenidate resulted in less time driving off the road, fewer instances of speeding, less erratic speed control, more time executing left turns, and less inappropriate use of brakes. OROS methylphenidate and mixed amphetamine salts extended release worked equally well for male and female adolescents and equally as well with teenagers who have combined and inattentive subtypes of attention-deficit/hyperactivity disorder. This study validates the use of stimulants to improve driving performance in adolescents with attention-deficit/hyperactivity disorder. In the study, OROS methylphenidate promoted significantly improved driving performance compared with placebo and mixed amphetamine salts extended release.

Low levels of alcohol impair driving simulator performance and reduce perception of crash risk in partially sleep deprived subjects.

PubMed

Banks, Siobhan; Catcheside, Peter; Lack, Leon; Grunstein, Ron R; McEvoy, R Doug

2004-09-15

Partial sleep deprivation and alcohol consumption are a common combination, particularly among young drivers. We hypothesized that while low blood alcohol concentration (<0.05 g/dL) may not significantly increase crash risk, the combination of partial sleep deprivation and low blood alcohol concentration would cause significant performance impairment. Experimental Sleep Disorders Unit Laboratory 20 healthy volunteers (mean age 22.8 years; 9 men). Subjects underwent driving simulator testing at 1 am on 2 nights a week apart. On the night preceding simulator testing, subjects were partially sleep deprived (5 hours in bed). Alcohol consumption (2-3 standard alcohol drinks over 2 hours) was randomized to 1 of the 2 test nights, and blood alcohol concentrations were estimated using a calibrated Breathalyzer. During the driving task subjects were monitored continuously with electroencephalography for sleep episodes and were prompted every 4.5 minutes for answers to 2 perception scales-performance and crash risk. Mean blood alcohol concentration on the alcohol night was 0.035 +/- 0.015 g/dL. Compared with conditions during partial sleep deprivation alone, subjects had more microsleeps, impaired driving simulator performance, and poorer ability to predict crash risk in the combined partial sleep deprivation and alcohol condition. Women predicted crash risk more accurately than did men in the partial sleep deprivation condition, but neither men nor women predicted the risk accurately in the sleep deprivation plus alcohol condition. Alcohol at legal blood alcohol concentrations appears to increase sleepiness and impair performance and the detection of crash risk following partial sleep deprivation. When partially sleep deprived, women appear to be either more perceptive of increased crash risk or more willing to admit to their driving limitations than are men. Alcohol eliminated this behavioral difference.

Heavy-Duty Vehicle Port Drayage Drive Cycle Characterization and Development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prohaska, Robert; Konan, Arnaud; Kelly, Kenneth

In an effort to better understand the operational requirements of port drayage vehicles and their potential for adoption of advanced technologies, National Renewable Energy Laboratory (NREL) researchers collected over 36,000 miles of in-use duty cycle data from 30 Class 8 drayage trucks operating at the Port of Long Beach and Port of Los Angeles in Southern California. These data include 1-Hz global positioning system location and SAE J1939 high-speed controller area network information. Researchers processed the data through NREL's Drive-Cycle Rapid Investigation, Visualization, and Evaluation tool to examine vehicle kinematic and dynamic patterns across the spectrum of operations. Using themore » k-medoids clustering method, a repeatable and quantitative process for multi-mode drive cycle segmentation, the analysis led to the creation of multiple drive cycles representing four distinct modes of operation that can be used independently or in combination. These drive cycles are statistically representative of real-world operation of port drayage vehicles. When combined with modeling and simulation tools, these representative test cycles allow advanced vehicle or systems developers to efficiently and accurately evaluate vehicle technology performance requirements to reduce cost and development time while ultimately leading to the commercialization of advanced technologies that meet the performance requirements of the port drayage vocation. The drive cycles, which are suitable for chassis dynamometer testing, were compared to several existing test cycles. This paper presents the clustering methodology, accompanying results of the port drayage duty cycle analysis and custom drive cycle creation.« less

Heavy-Duty Vehicle Port Drayage Drive Cycle Characterization and Development: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prohaska, Robert; Konan, Arnaud; Kelly, Kenneth

In an effort to better understand the operational requirements of port drayage vehicles and their potential for adoption of advanced technologies, National Renewable Energy Laboratory (NREL) researchers collected over 36,000 miles of in-use duty cycle data from 30 Class 8 drayage trucks operating at the Port of Long Beach and Port of Los Angeles in Southern California. These data include 1-Hz global positioning system location and SAE J1939 high-speed controller area network information. Researchers processed the data through NREL's Drive-Cycle Rapid Investigation, Visualization, and Evaluation tool to examine vehicle kinematic and dynamic patterns across the spectrum of operations. Using themore » k-medoids clustering method, a repeatable and quantitative process for multi-mode drive cycle segmentation, the analysis led to the creation of multiple drive cycles representing four distinct modes of operation that can be used independently or in combination. These drive cycles are statistically representative of real-world operation of port drayage vehicles. When combined with modeling and simulation tools, these representative test cycles allow advanced vehicle or systems developers to efficiently and accurately evaluate vehicle technology performance requirements to reduce cost and development time while ultimately leading to the commercialization of advanced technologies that meet the performance requirements of the port drayage vocation. The drive cycles, which are suitable for chassis dynamometer testing, were compared to several existing test cycles. This paper presents the clustering methodology, accompanying results of the port drayage duty cycle analysis and custom drive cycle creation.« less

Heavy-Duty Vehicle Port Drayage Drive Cycle Characterization and Development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prohaska, Robert; Konan, Arnaud; Kelly, Kenneth

2016-05-02

In an effort to better understand the operational requirements of port drayage vehicles and their potential for adoption of advanced technologies, National Renewable Energy Laboratory (NREL) researchers collected over 36,000 miles of in-use duty cycle data from 30 Class 8 drayage trucks operating at the Port of Long Beach and Port of Los Angeles in Southern California. These data include 1-Hz global positioning system location and SAE J1939 high-speed controller area network information. Researchers processed the data through NREL's Drive-Cycle Rapid Investigation, Visualization, and Evaluation tool to examine vehicle kinematic and dynamic patterns across the spectrum of operations. Using themore » k-medoids clustering method, a repeatable and quantitative process for multi-mode drive cycle segmentation, the analysis led to the creation of multiple drive cycles representing four distinct modes of operation that can be used independently or in combination. These drive cycles are statistically representative of real-world operation of port drayage vehicles. When combined with modeling and simulation tools, these representative test cycles allow advanced vehicle or systems developers to efficiently and accurately evaluate vehicle technology performance requirements to reduce cost and development time while ultimately leading to the commercialization of advanced technologies that meet the performance requirements of the port drayage vocation. The drive cycles, which are suitable for chassis dynamometer testing, were compared to several existing test cycles. This paper presents the clustering methodology, accompanying results of the port drayage duty cycle analysis and custom drive cycle creation.« less

Leukoaraiosis Significantly Worsens Driving Performance of Ordinary Older Drivers

PubMed Central

Zheng, Rencheng; Fang, Fang; Ohori, Masanori; Nakamura, Hiroki; Kumagai, Yasuhiho; Okada, Hiroshi; Teramura, Kazuhiko; Nakayama, Satoshi; Irimajiri, Akinori; Taoka, Hiroshi; Okada, Satoshi

2014-01-01

Background Leukoaraiosis is defined as extracellular space caused mainly by atherosclerotic or demyelinated changes in the brain tissue and is commonly found in the brains of healthy older people. A significant association between leukoaraiosis and traffic crashes was reported in our previous study; however, the reason for this is still unclear. Method This paper presents a comprehensive evaluation of driving performance in ordinary older drivers with leukoaraiosis. First, the degree of leukoaraiosis was examined in 33 participants, who underwent an actual-vehicle driving examination on a standard driving course, and a driver skill rating was also collected while the driver carried out a paced auditory serial addition test, which is a calculating task given verbally. At the same time, a steering entropy method was used to estimate steering operation performance. Results The experimental results indicated that a normal older driver with leukoaraiosis was readily affected by external disturbances and made more operation errors and steered less smoothly than one without leukoaraiosis during driving; at the same time, their steering skill significantly deteriorated. Conclusions Leukoaraiosis worsens the driving performance of older drivers because of their increased vulnerability to distraction. PMID:25295736

A randomized trial on the acute and steady-state effects of a new antidepressant, vortioxetine (Lu AA21004), on actual driving and cognition.

PubMed

Theunissen, E L; Street, D; Højer, A-M; Vermeeren, A; van Oers, A; Ramaekers, J G

2013-06-01

The aim of this study was to assess the effects of a novel antidepressant, vortioxetine 10 mg, on driving, cognitive, and psychomotor performance in 24 healthy subjects in a double-blind, placebo-controlled, three-way crossover design. Mirtazapine 30 mg was included as an active comparator. Drugs were administered in the evening of 15 consecutive days. Performance was measured in the morning of days 2 and 16, using standardized tests measuring on-the-road driving, memory, tracking, divided attention, and vigilance. The statistical analysis on the primary measure of driving, i.e., SD of lateral position showed noninferiority of vortioxetine on days 2 and 16, and inferiority for mirtazapine on day 2. Vortioxetine did not cause cognitive or psychomotor impairment. Mirtazapine, however, impaired cognitive and psychomotor performance on day 2. Most of these effects disappeared after multiple doses of mirtazapine. To conclude, vortioxetine did not impair driving, cognitive, or psychomotor performance after single or multiple doses.

Experimental research made during a city cycle on the feasibility of electrically charged SI engines

NASA Astrophysics Data System (ADS)

Kocsis, Levente B.; Burnete, Nicolae

2014-06-01

The paper presents experimental research on performance improvements in a city cycle (operating mostly transient) of a compact class vehicle equipped with a turbocharged SI engine which had attached an electric charger, to improve engine response at low operational speeds. During tests, functional parameters, energy consumption of the electric charger and vehicle performances were measured while driving in two operating conditions: with active and inactive electric charger. The tests were carried out on a well-defined path, in the same driving style, by the same driver.

Effect of single-dose Ginkgo biloba and Panax ginseng on driving performance.

PubMed

LaSala, Gregory S; McKeever, Rita G; Patel, Urvi; Okaneku, Jolene; Vearrier, David; Greenberg, Michael I

2015-02-01

Panax ginseng and Gingko biloba are commonly used herbal supplements in the United States that have been reported to increase alertness and cognitive function. The objective of this study was to investigate the effects of these specific herbals on driving performance. 30 volunteers were tested using the STISIM3® Driving Simulator (Systems Technology Inc., Hawthorne, CA, USA) in this double-blind, placebo-controlled study. The subjects were randomized into 3 groups of 10 subjects per group. After 10-min of simulated driving, subjects received either ginseng (1200 mg), Gingko (240 mg), or placebo administered orally. The test herbals and placebo were randomized and administered by a research assistant outside of the study to maintain blinding. One hour following administration of the herbals or placebo, the subjects completed an additional 10-min of simulated driving. Standard driving parameters were studied including reaction time, standard deviation of lateral positioning, and divided attention. Data collected for the divided attention parameter included time to response and number of correct responses. The data was analyzed with repeated-measures analysis of variance (ANOVA) and Kruskal-Wallis test using SPSS 22 (IBM, Armonk, NY, USA). There was no difference in reaction time or standard deviation of lateral positioning for both the ginseng and Ginkgo arms. For the divided attention parameter, the response time in the Ginkgo arm decreased from 2.9 to 2.5 s. The ginseng arm also decreased from 3.2 to 2.4 s. None of these values were statistically significant when between group differences were analyzed. The data suggests there was no statistically significant difference between ginseng, Ginkgo or placebo on driving performance. We postulate this is due to the relatively small numbers in our study. Further study with a larger sample size may be needed in order to elucidate more fully the effects of Ginkgo and ginseng on driving ability.

Prediction of Fitness to Drive in Patients with Alzheimer's Dementia

PubMed Central

Piersma, Dafne; Fuermaier, Anselm B. M.; de Waard, Dick; Davidse, Ragnhild J.; de Groot, Jolieke; Doumen, Michelle J. A.; Bredewoud, Ruud A.; Claesen, René; Lemstra, Afina W.; Vermeeren, Annemiek; Ponds, Rudolf; Verhey, Frans; Brouwer, Wiebo H.; Tucha, Oliver

2016-01-01

The number of patients with Alzheimer’s disease (AD) is increasing and so is the number of patients driving a car. To enable patients to retain their mobility while at the same time not endangering public safety, each patient should be assessed for fitness to drive. The aim of this study is to develop a method to assess fitness to drive in a clinical setting, using three types of assessments, i.e. clinical interviews, neuropsychological assessment and driving simulator rides. The goals are (1) to determine for each type of assessment which combination of measures is most predictive for on-road driving performance, (2) to compare the predictive value of clinical interviews, neuropsychological assessment and driving simulator evaluation and (3) to determine which combination of these assessments provides the best prediction of fitness to drive. Eighty-one patients with AD and 45 healthy individuals participated. All participated in a clinical interview, and were administered a neuropsychological test battery and a driving simulator ride (predictors). The criterion fitness to drive was determined in an on-road driving assessment by experts of the CBR Dutch driving test organisation according to their official protocol. The validity of the predictors to determine fitness to drive was explored by means of logistic regression analyses, discriminant function analyses, as well as receiver operating curve analyses. We found that all three types of assessments are predictive of on-road driving performance. Neuropsychological assessment had the highest classification accuracy followed by driving simulator rides and clinical interviews. However, combining all three types of assessments yielded the best prediction for fitness to drive in patients with AD with an overall accuracy of 92.7%, which makes this method highly valid for assessing fitness to drive in AD. This method may be used to advise patients with AD and their family members about fitness to drive. PMID:26910535

Systematic review of the quality and generalizability of studies on the effects of opioids on driving and cognitive/psychomotor performance.

PubMed

Mailis-Gagnon, Angela; Lakha, Shehnaz Fatima; Furlan, Andrea; Nicholson, Keith; Yegneswaran, Balaji; Sabatowski, Rainer

2012-07-01

The effect of opioids on driving performance has been much debated. Driving is a complex task requiring integration of psychomotor, cognitive, motor and decision-making skills, visual-spatial abilities, divided attention, and behavioral and emotional control. The objective of this systematic review was to assess the quality of studies and to revisit the concept that patients on stable opioids are safe to drive as it applies to everyday practice. We searched MEDLINE, EMBASE, PSYCinfo, CENTRAL, TRANSPORT, CINAHL, reference lists of retrieved articles and narrative reviews, for studies on chronic cancer and noncancer pain patients on opioids, tested by driving, driving simulator, or cognitive/psychomotor tests. Methodological quality was assessed with Methodological Index for Nonrandomized Studies, cognitive/psychomotor tests were appraised regarding their sensitivity and validation, and whether confounding variables potentially affecting the study conclusions were recorded. The results were analyzed both quantitatively and qualitatively. We included 35 studies (2044 patients, 1994 controls), 9% of the studies were of poor, 54% of fair, and 37% of high quality; 3 quarters of the studies used high sensitivity cognitive tests. Amount and dose of opioids varied largely in many studies. Mean number of possible but unreported confounders was 2.2 (range, 0 to 4), relating to failure of the studies to mention co-prescriptions with psychotropic effects, pain severity, sleep disorder or daytime somnolence, and/or significant depressive or anxiety-related problems. The commonly held concept that "chronic pain patients on stable opioids are safe to drive" cannot be generalized to all such patients in everyday practice, but may be applicable only to a subset who meet certain criteria.

Effectiveness of a visual attention retraining program on the driving performance of clients with stroke.

PubMed

Mazer, Barbara L; Sofer, Susan; Korner-Bitensky, Nicol; Gelinas, Isabelle; Hanley, James; Wood-Dauphinee, Sharon

2003-04-01

To compare the effectiveness of a visual attention retraining program using the Useful Field of View (UFOV) with a traditional visuoperception treatment program on the driving performance of clients with stroke. Randomized controlled trial. Rehabilitation hospital located in Quebec, Canada. Ninety-seven individuals referred for driving evaluation after a stroke. Participants were randomized to receive 20 sessions of either UFOV training of visual processing speed, divided attention, and selective attention or traditional computerized visuoperception retraining. Subjects were evaluated with an on-road driving evaluation, visuoperception tests, and the Test of Everyday Attention. An occupational therapist unaware of group assignment conducted all evaluations. Eighty-four participants completed the outcome evaluation. There were no significant differences between groups on any of the outcome measures. There was, however, almost a 2-fold increase (52.4% vs 28.6%) in the rate of success on the on-road driving evaluation after UFOV training for subjects with right-sided lesions. Rehabilitation that targets visual attention skills was not significantly more beneficial than traditional perceptual training in improving the outcome of an on-road driving evaluation. However, results suggest a potential improvement for subjects with right-sided lesions, indicating that training must target specific skills.

[Effect of air-electric fields on driving and reaction patterns. Test subjects in the car driving simulator (author's transl)].

PubMed

Anselm, D; Danner, M; Kirmaier, N; König, H L; Müller-Limmroth, W; Reis, A; Schauerte, W

1977-06-10

In the relevant frequency range of about 10 Hertz cars can be considered very largely as Faraday cages and consequently as screens against air-electric fields. This may have a negative influence on driving and reaction patterns as a result. In an extensive investigation 48 subjects in a driving simulator were exposed to definite artificially produced air-electric fields. The self-rating of the performance and concentration of the subjects, reaction times and driving errors were determined. While the reaction times remained practically constant, the driving behavior of the subjects improved.

Off-Design Performance of a Multi-Stage Supersonic Turbine

NASA Technical Reports Server (NTRS)

Dorney, Daniel J.; Griffin, Lisa W.; Huber, Frank; Sondak, Douglas L.

2003-01-01

The drive towards high-work turbines has led to designs which can be compact, transonic, supersonic, counter rotating, or use a dense drive gas. These aggressive designs can lead to strong unsteady secondary flows and flow separation. The amplitude and extent of these unsteady flow phenomena can be amplified at off-design operating conditions. Pre-test off-design predictions have been performed for a new two-stage supersonic turbine design that is currently being tested in air. The simulations were performed using a three-dimensional unsteady Navier-Stokes analysis, and the predicted results have been compared with solutions from a validated meanline analysis.

The effects of moderate alcohol concentrations on driving and cognitive performance during ascending and descending blood alcohol concentrations.

PubMed

Starkey, Nicola J; Charlton, Samuel G

2014-07-01

Alcohol has an adverse effect on driving performance; however, the effects of moderate doses on different aspects of the driving task are inconsistent and differ across the intoxication curve. This research aimed to investigate driving and cognitive performance asymmetries (acute tolerance and acute protracted error) accompanying the onset and recovery from moderate alcohol consumption. Sixty-one participants received a placebo, medium (target blood alcohol concentration [BAC] 0.05 mg/ml) or high (target BAC 0.08 mg/ml) dose of alcohol. Participants completed a simulated drive, cognitive tests and subjective rating scales five times over a 3.5 h period. When ascending and descending BACs (0.05 and 0.09 mg/ml) were compared participants' self-ratings of intoxication and willingness to drive showed acute tolerance. Acute protracted errors were observed for response speed, maze learning errors, time exceeding the speed limit and exaggerated steering responses to hazards. Participants' estimates of their level of intoxication were poorly related to their actual BAC levels (and hence degree of impairment), and various aspects of driving and cognitive performance worsened during descending BACs. This indicates that drivers are not good at judging their fitness to drive after drinking only moderate amounts of alcohol and suggests an important focus for public education regarding alcohol and driving. Copyright © 2014 John Wiley & Sons, Ltd.

Naturalistic distraction and driving safety in older drivers.

PubMed

Aksan, Nazan; Dawson, Jeffrey D; Emerson, Jamie L; Yu, Lixi; Uc, Ergun Y; Anderson, Steven W; Rizzo, Matthew

2013-08-01

In this study, we aimed to quantify and compare performance of middle-aged and older drivers during a naturalistic distraction paradigm (visual search for roadside targets) and to predict older drivers performance given functioning in visual, motor, and cognitive domains. Distracted driving can imperil healthy adults and may disproportionally affect the safety of older drivers with visual, motor, and cognitive decline. A total of 203 drivers, 120 healthy older (61 men and 59 women, ages 65 years and older) and 83 middle-aged drivers (38 men and 45 women, ages 40 to 64 years), participated in an on-road test in an instrumented vehicle. Outcome measures included performance in roadside target identification (traffic signs and restaurants) and concurrent driver safety. Differences in visual, motor, and cognitive functioning served as predictors. Older drivers identified fewer landmarks and drove slower but committed more safety errors than did middle-aged drivers. Greater familiarity with local roads benefited performance of middle-aged but not older drivers.Visual cognition predicted both traffic sign identification and safety errors, and executive function predicted traffic sign identification over and above vision. Older adults are susceptible to driving safety errors while distracted by common secondary visual search tasks that are inherent to driving. The findings underscore that age-related cognitive decline affects older drivers' management of driving tasks at multiple levels and can help inform the design of on-road tests and interventions for older drivers.

Useful field of view predicts driving in the presence of distracters.

PubMed

Wood, Joanne M; Chaparro, Alex; Lacherez, Philippe; Hickson, Louise

2012-04-01

The Useful Field of View (UFOV) test has been shown to be highly effective in predicting crash risk among older adults. An important question which we examined in this study is whether this association is due to the ability of the UFOV to predict difficulties in attention-demanding driving situations that involve either visual or auditory distracters. Participants included 92 community-living adults (mean age 73.6 ± 5.4 years; range 65-88 years) who completed all three subtests of the UFOV involving assessment of visual processing speed (subtest 1), divided attention (subtest 2), and selective attention (subtest 3); driving safety risk was also classified using the UFOV scoring system. Driving performance was assessed separately on a closed-road circuit while driving under three conditions: no distracters, visual distracters, and auditory distracters. Driving outcome measures included road sign recognition, hazard detection, gap perception, time to complete the course, and performance on the distracter tasks. Those rated as safe on the UFOV (safety rating categories 1 and 2), as well as those responding faster than the recommended cut-off on the selective attention subtest (350 msec), performed significantly better in terms of overall driving performance and also experienced less interference from distracters. Of the three UFOV subtests, the selective attention subtest best predicted overall driving performance in the presence of distracters. Older adults who were rated as higher risk on the UFOV, particularly on the selective attention subtest, demonstrated poorest driving performance in the presence of distracters. This finding suggests that the selective attention subtest of the UFOV may be differentially more effective in predicting driving difficulties in situations of divided attention which are commonly associated with crashes.

Effects of alcohol (BAC 0.5‰) and ecstasy (MDMA 100 mg) on simulated driving performance and traffic safety.

PubMed

Veldstra, Janet L; Brookhuis, Karel A; de Waard, Dick; Molmans, Barbara H W; Verstraete, Alain G; Skopp, Gisela; Jantos, Ricarda

2012-08-01

An increasing number of fatal road-accidents have been reported in which ecstasy was found in the blood of drivers. Although, ecstasy is frequently found to have been used in combination with alcohol, studies on the acute effects of ecstasy co-administered with alcohol on driving performance are relatively rare. The present study was designed to establish the extent of driver impairment as a consequence of ecstasy or combined ecstasy and alcohol use as compared to driving under the influence of 0.3‰, 0.5‰ and 0.8‰ alcohol. Furthermore, subjective performance was also assessed. Alcohol and ecstasy mainly influenced automated driving performance such as lateral and speed control. However, small to no effects of the substances were found on more complex driving behaviour. Overall, variance within the different driving measures was high especially when participants were treated with 3.4-methylenedioxy-methamphetamine (MDMA) and alcohol. Furthermore, equivalence testing showed that combined use may lead to impaired driving for some, but not all, drivers. Participants rated their own performance to be slightly worse than normal in both studies. Since driving was actually seriously deteriorated, this was a falsely positive assessment of their condition. The dissociation between subjective perceptions and objective performance decrements are important notions for traffic safety since this may affect a driver's judgement of whether or not it is safe to drive. For example, an intoxicated individual might decide to drive because the feelings of alertness caused by MDMA cloud the impairing effects of other drugs such as alcohol, thereby creating a potentially serious risk for traffic safety.

Drivers who self-estimate lower blood alcohol concentrations are riskier drivers after drinking.

PubMed

Laude, Jennifer R; Fillmore, Mark T

2016-04-01

Alcohol increases the tendency for risky driving in some individuals but not others. Little is known about the factors underlying this individual difference. Studies find that those who underestimate their blood alcohol concentration (BAC) following a dose of alcohol tend to be more impulsive and report greater willingness to drive after drinking than those who estimate their BACs to be greater than their actual BAC. BAC underestimation could contribute to risky driving behavior following alcohol as such drivers might perceive little impairment in their driving ability and thus no need for caution. This study was designed to test the relationship between drivers' BAC estimations following a dose of alcohol or a placebo and the degree of risky driving they displayed during a simulated driving test. Forty adult drivers performed a simulated driving test and estimated their blood alcohol concentration after receiving a dose of alcohol (0.65 g/kg for men and 0.56 g/kg for women) or a placebo. Alcohol increased risk-taking and impaired driving skill. Those who estimated their BAC to be lower were the riskiest drivers following both alcohol and placebo. The tendency to estimate lower BACs could support a series of high-risk decisions, regardless of one's actual BAC. This could include the decision to drive after drinking.

Changes in driving behavior and cognitive performance with different breath alcohol concentration levels.

PubMed

Liu, Yung-Ching; Fu, Shing-Mei

2007-06-01

This study examines the changes in driving behavior and cognitive performance of drivers with different breath alcohol concentration (BrAC) levels. Eight licensed drivers, aged between 20 and 30 years, with BrAC levels of 0.00, 0.25, 0.4 and 0.5 mg/l performed simulated driving tests under high- and low-load conditions. Subjects were asked to assess their subjective psychological load at specified intervals and perform various tasks. The outcome was measured in terms of reaction times for task completion, accuracy rates, and driver's driving behavior. The effects of BrAC vary depending on the task. Performance of tasks involving attention shift, information processing, and short-term memory showed significant deterioration with increasing BrAC, while dangerous external vehicle driving behavior occurred only when the BrAC reached 0.4 mg/l and the deterioration was marked. We can conclude that the cognitive faculty is the first to be impaired by drinking resulting in deteriorated performance in tasks related to divided attention, short-term memory, logical reasoning, followed by visual perception. On the other hand, increasing alcohol dose may not pose an immediate impact on the external vehicle driving behavior but may negatively affect the driver's motor behavior even at low BrAC levels. Experience and will power could compensate for the negative influence of alcohol enabling the drivers to remain in full steering control. This lag between alcohol consumption and impaired driving performance may mislead the drivers in thinking that they are still capable of safe steering and cause them to ignore the potential dangers of drunk driving.

Drug-resistant MS spasticity treatment with Sativex(®) add-on and driving ability.

PubMed

Freidel, M; Tiel-Wilck, K; Schreiber, H; Prechtl, A; Essner, U; Lang, M

2015-01-01

The aim of the present observational study was to determine the effects of a delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) oromucosal spray (Sativex(®) spray), brand name Sativex(®), indicated for drug-resistant MS spasticity, on the driving ability of treated MS patients. The study was conducted over a period of 4-6 weeks. Thirty-three MS patients with moderate to severe treatment-resistant spasticity and planned to begin add-on treatment with Sativex(®) were enrolled at three specialized MS centres in Germany. A set of five driving test procedures from a validated computerized test battery was used to evaluate the driving ability of eligible patients. Tests were performed by patients at baseline and repeated after 4-6 weeks of treatment with Sativex(®) oromucosal spray. According to German normative data, the test thresholds achieved by the general population served as a reference to allow for a fitness/unfitness to drive classification. Patients showed comparable driving test results at baseline and at final visits. Only two patients changed classification shifting from 'unfit' to drive to 'fit' and vice versa. The mean severity of spasticity, as self-reported by the patients, improved with statistical significance. Sativex(®) was generally well tolerated. Treatment of MS patients with Sativex(®) does not negatively impact on driving ability and may improve moderate to severe treatment-resistant MS spasticity. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Characterization testing of Lockheed Martin high-power micro pulse tube cryocooler

NASA Astrophysics Data System (ADS)

McKinley, I. M.; Hummel, C. D.; Johnson, D. L.; Rodriguez, J. I.

2017-12-01

This paper describes the thermal vacuum, microphonics, magnetics, and radiation testing and results of a Lockheed Martin high-power micro pulse tube cryocooler. The thermal performance of the microcooler was measured in vacuum for heat reject temperatures between 185 and 300 K. The cooler was driven with a Chroma 61602 AC power source for input powers ranging from 10 to 60 W and drive frequency between 115 and 140 Hz during thermal performance testing. The optimal drive frequency was dependent on both input power and heat reject temperature. In addition, the microphonics of the cooler were measured with the cooler driven by Iris Technologies LCCE-2 and HP-LCCE drive electronics for input powers ranging from 10 to 60 W and drive frequency between 135 and 145 Hz. The exported forces were strongly dependent on input power while only weakly dependent on the drive frequency. Moreover, the exported force in the compressor axis was minimized by closed loop control with the HP-LCCE. The cooler also survived a 500 krad radiation dose while being continuously operated with 30 W of input power at 220 K heat rejection temperature in vacuum. Finally, the DC and AC magnetic fields around the cooler were measured at various locations.

Preliminary report of the Hepatic Encephalopathy Assessment Driving Simulator (HEADS) score.

PubMed

Baskin-Bey, Edwina S; Stewart, Charmaine A; Mitchell, Mary M; Bida, John P; Rosenthal, Theodore J; Nyberg, Scott L

2008-01-01

Audiovisual simulations of real-life driving (ie, driving simulators) have been used to assess neurologic dysfunction in a variety of medical applications. However, the use of simulated driving to assess neurologic impairment in the setting of liver disease (ie, hepatic encephalopathy) is limited. The aim of this analysis was to develop a scoring system based on simulated driving performance to assess mild cognitive impairment in cirrhotic patients with hepatic encephalopathy. This preliminary analysis was conducted as part of the Hepatic Encephalopathy Assessment Driving Simulator (HEADS) pilot study. Cirrhotic volunteers initially underwent a battery of neuropsychological tests to identify those cirrhotic patients with mild cognitive impairment. Performance during an audiovisually simulated course of on-road driving was then compared between mildly impaired cirrhotic patients and healthy volunteers. A scoring system was developed to quantify the likelihood of cognitive impairment on the basis of data from the simulated on-road driving. Mildly impaired cirrhotic patients performed below the level of healthy volunteers on the driving simulator. Univariate logistic regression and correlation models indicated that several driving simulator variables were significant predictors of cognitive impairment. Five variables (run time, total map performance, number of collisions, visual divided attention response, and average lane position) were incorporated into a quantitative model, the HEADS scoring system. The HEADS score (0-9 points) showed a strong correlation with cognitive impairment as measured by area under the receiver-operator curve (.89). The HEADS system appears to be a promising new tool for the assessment of mild hepatic encephalopathy.

Single- and dual-task performance during on-the-road driving at a low and moderate dose of alcohol: A comparison between young novice and more experienced drivers.

PubMed

Jongen, Stefan; van der Sluiszen, Nick N J J M; Brown, Dennis; Vuurman, Eric F P M

2018-05-01

Driving experience and alcohol are two factors associated with a higher risk of crash involvement in young novice drivers. Driving a car is a complex task involving multiple tasks leading to dividing attention. The aim of this study was to compare the single and combined effects of a low and moderate dose of alcohol on single- and dual-task performance between young novice and more experienced young drivers during actual driving. Nine healthy novice drivers were compared with 9 more experienced drivers in a three-way, placebo-controlled, cross-over study design. Driving performance was measured in actual traffic, with standard deviation of lateral position as the primary outcome variable. Secondary task performance was measured with an auditory word learning test during driving. Results showed that standard deviation of lateral position increased dose-dependently at a blood alcohol concentration (BAC) of 0.2 and 0.5 g/L in both novice and experienced drivers. Secondary task performance was impaired in both groups at a BAC of 0.5 g/L. Furthermore, it was found that driving performance in novice drivers was already impaired at a BAC of 0.2 g/L during dual-task performance. The findings suggest that young inexperienced drivers are especially vulnerable to increased mental load while under the influence of alcohol. © 2018 The Authors Human Psychopharmacology: Clinical and Experimental Published by John Wiley & Sons Ltd.

Vehicle Dynamics Control of In-wheel Electric Motor Drive Vehicles Based on Averaging of Tire Force Usage

NASA Astrophysics Data System (ADS)

Masaki, Nobuo; Iwano, Haruo; Kamada, Takayoshi; Nagai, Masao

For in-wheel electric motor drive vehicles, a new vehicle dynamics control which is based on the tire force usage rate is proposed. The new controller adopts non-linear optimal control could manage the interference between direct yaw-moment control and the tire force usage rate. The new control is considered total longitudinal and transverse tire force. Therefore the controller can prevent tire force saturation near tire force limit during cornering. Simulations and test runs by the custom made four wheel drive in-wheel motor electric vehicle show that higher driving stability performance compared to the performance of the same vehicle without control.

Simulated Driving Assessment (SDA) for Teen Drivers: Results from a Validation Study

PubMed Central

McDonald, Catherine C.; Kandadai, Venk; Loeb, Helen; Seacrist, Thomas S.; Lee, Yi-Ching; Winston, Zachary; Winston, Flaura K.

2015-01-01

Background Driver error and inadequate skill are common critical reasons for novice teen driver crashes, yet few validated, standardized assessments of teen driving skills exist. The purpose of this study was to evaluate the construct and criterion validity of a newly developed Simulated Driving Assessment (SDA) for novice teen drivers. Methods The SDA's 35-minute simulated drive incorporates 22 variations of the most common teen driver crash configurations. Driving performance was compared for 21 inexperienced teens (age 16–17 years, provisional license ≤90 days) and 17 experienced adults (age 25–50 years, license ≥5 years, drove ≥100 miles per week, no collisions or moving violations ≤3 years). SDA driving performance (Error Score) was based on driving safety measures derived from simulator and eye-tracking data. Negative driving outcomes included simulated collisions or run-off-the-road incidents. A professional driving evaluator/instructor reviewed videos of SDA performance (DEI Score). Results The SDA demonstrated construct validity: 1.) Teens had a higher Error Score than adults (30 vs. 13, p=0.02); 2.) For each additional error committed, the relative risk of a participant's propensity for a simulated negative driving outcome increased by 8% (95% CI: 1.05–1.10, p<0.01). The SDA demonstrated criterion validity: Error Score was correlated with DEI Score (r=−0.66, p<0.001). Conclusions This study supports the concept of validated simulated driving tests like the SDA to assess novice driver skill in complex and hazardous driving scenarios. The SDA, as a standard protocol to evaluate teen driver performance, has the potential to facilitate screening and assessment of teen driving readiness and could be used to guide targeted skill training. PMID:25740939

Cross-sectional study assessing the addition of contrast sensitivity to visual acuity when testing for fitness to drive

PubMed Central

Spreng, Lucie; Favrat, Bernard; Borruat, François-Xavier; Vaucher, Paul

2018-01-01

Objectives The aim of this study is to quantify the importance of loss of contrast sensitivity (CS) and its relationship to loss of visual acuity (VA), driving restrictions and daytime, on-road driving evaluations in drivers aged 70+. Design A predictive cross-sectional study. Setting Volunteer participants to a drivers’ refresher course for adults aged 70+ delivered by the Swiss Automobile Club in western Switzerland from 2011 to 2013. Participants 162 drivers, male and female, aged 70 years or older. Clinical predictors We used a vision screener to estimate VA and the The Mars Letter Contrast Sensitivity Test to test CS. Outcomes We asked drivers to report whether they found five driving restrictions useful for their condition; restrict driving to known roads, avoid driving on highways, avoid driving in the dark, avoid driving in dense traffic and avoid driving in fog. All participants also underwent a standardised on-road evaluation carried out by a driving instructor. Results Moderate to severe loss of CS for at least one eye was frequent (21.0% (95% CI 15.0% to 28.1%)) and often isolated from a loss of VA (11/162 cases had a VA ≥0.8 decimal and a CS of ≤1.5 log(CS); 6.8% (95% CI 3.4% to 11.8%)). Drivers were more likely (R2=0.116, P=0.004) to report a belief that self-imposed driving restrictions would be useful if they had reduced CS in at least one eye. Daytime evaluation of driving performance seems limited in its ability to correctly identify difficulties related to CS loss (VA: R2=0.004, P=0.454; CS: R2=0.006, P=0.332). Conclusion CS loss is common for older drivers. Screening CS and referring for cataract surgery even in the absence of VA loss could help maintain mobility. Reduced CS and moderate reduction of VA were both poor predictors of daytime on-road driving performances in this research study. PMID:29374663

On-the-Road Driving Performance the Morning after Bedtime Use of Suvorexant 20 and 40 mg: A Study in Non-Elderly Healthy Volunteers.

PubMed

Vermeeren, Annemiek; Sun, Hong; Vuurman, Eric F P M; Jongen, Stefan; Van Leeuwen, Cees J; Van Oers, Anita C M; Palcza, John; Li, Xiadong; Laethem, Tine; Heirman, Ingeborg; Bautmans, An; Troyer, Matthew D; Wrishko, Rebecca; McCrea, Jacqueline

2015-11-01

To evaluate next-morning driving performance in adults younger than 65 years, after single and repeated doses of suvorexant 20 and 40 mg. Double-blind, placebo-controlled, 4-period crossover study. Maastricht University, The Netherlands. 28 healthy volunteers (15 females), aged 23 to 64 years. Suvorexant (20 and 40 mg) for 8 consecutive nights; zopiclone 7.5 mg nightly on day 1 and 8; placebo. Performance on day 2 and 9 (9 h after dosing) using a one-hour standardized highway driving test in normal traffic, measuring standard deviation of lateral position (SDLP). Drug-placebo changes in SDLP > 2.4 cm were considered to reflect meaningful driving impairment. Mean drug-placebo changes in SDLP following suvorexant 20 and 40 mg were 1.01 and 1.66 cm on day 2, and 0.48 and 1.31 cm on Day 9, respectively. The 90% CIs of these changes were all below 2.4 cm. Symmetry analysis showed that more subjects had SDLP changes > 2.4 cm than < -2.4 cm following suvorexant 20 and 40 mg on day 2, and following suvorexant 40 mg on day 9. Four female subjects requested that a total of 5 driving tests--all following suvorexant--stop prematurely due to self-reported somnolence. As assessed by mean changes in standard deviation of lateral position (SDLP), there was no clinically meaningful residual effect of suvorexant in doses of 20 and 40 mg on next-morning driving (9 h after bedtime dosing) in healthy subjects < 65 years old. There may be some individuals who experience next-day effects, as suggested by individual changes in SDLP and prematurely stopped tests. clinicaltrials.gov NCT01311882. © 2015 Associated Professional Sleep Societies, LLC.

Drivers' and non-drivers' performance in a change detection task with static driving scenes: is there a benefit of experience?

PubMed

Zhao, Nan; Chen, Wenfeng; Xuan, Yuming; Mehler, Bruce; Reimer, Bryan; Fu, Xiaolan

2014-01-01

The 'looked-but-failed-to-see' phenomenon is crucial to driving safety. Previous research utilising change detection tasks related to driving has reported inconsistent effects of driver experience on the ability to detect changes in static driving scenes. Reviewing these conflicting results, we suggest that drivers' increased ability to detect changes will only appear when the task requires a pattern of visual attention distribution typical of actual driving. By adding a distant fixation point on the road image, we developed a modified change blindness paradigm and measured detection performance of drivers and non-drivers. Drivers performed better than non-drivers only in scenes with a fixation point. Furthermore, experience effect interacted with the location of the change and the relevance of the change to driving. These results suggest that learning associated with driving experience reflects increased skill in the efficient distribution of visual attention across both the central focus area and peripheral objects. This article provides an explanation for the previously conflicting reports of driving experience effects in change detection tasks. We observed a measurable benefit of experience in static driving scenes, using a modified change blindness paradigm. These results have translational opportunities for picture-based training and testing tools to improve driver skill.

Chronotype-dependent circadian rhythmicity of driving safety.

PubMed

Del Rio-Bermudez, Carlos; Diaz-Piedra, Carolina; Catena, Andrés; Buela-Casal, Gualberto; Di Stasi, Leandro Luigi

2014-05-01

Among the factors associated with driving safety, sleep-related variables constitute a leading cause of road accidents. Circadian fluctuations of driver's somnolence has been previously linked to road safety. However, the role of chronotype in this relationship has been poorly investigated. Thus, the aim of the present work was to address whether driving performance is influenced by circadian patterns, in turn modulated by the driver's chronotype and the time of day (i.e. synchrony effect). We assessed 47 healthy young adults with specific chronotypes in several simulated driving sessions, both in the morning and in the evening. We collected driving performance data, along with self-reported levels of activation prior to each driving session and other sleep-related variables. Participants drove less safely when testing times took place outside their optimal time of day, as determined by their chronotype and confirmed by self-reported levels of activation. These differences were more pronounced in the morning, when morning types shown a better driving performance. Our results suggest that chronotype plays an important role as a modulator of the relationship between the time of day and driving safety. Therefore, it is necessary to acknowledge this variable in theoretical models of driving behavior, and for the improvement of occupational accidents prevention programs.

A New Design of the Test Rig to Measure the Transmission Error of Automobile Gearbox

NASA Astrophysics Data System (ADS)

Hou, Yixuan; Zhou, Xiaoqin; He, Xiuzhi; Liu, Zufei; Liu, Qiang

2017-12-01

Noise and vibration affect the performance of automobile gearbox. And transmission error has been regarded as an important excitation source in gear system. Most of current research is focused on the measurement and analysis of single gear drive, and few investigations on the transmission error measurement in complete gearbox were conducted. In order to measure transmission error in a complete automobile gearbox, a kind of electrically closed test rig is developed. Based on the principle of modular design, the test rig can be used to test different types of gearbox by adding necessary modules. The test rig for front engine, rear-wheel-drive gearbox is constructed. And static and modal analysis methods are taken to verify the performance of a key component.

Driving while drinking: performance impairments resulting from social drinking.

PubMed

Charlton, Samuel G; Starkey, Nicola J

2015-01-01

Previous research has shown that the effects of alcohol on drivers' performance can differ depending on whether blood alcohol concentrations are increasing or decreasing. The present research used a more ecologically representative alcohol consumption protocol in order to determine whether the same pattern of driver impairment would occur when drinking occurred in social groups over a longer period of time. Forty-four participants were assigned to one of two alcohol dose conditions or a placebo control group and consumed alcohol in groups of three (typically one participant from each condition) such that they gradually reached their target BAC (.05 or .08) and maintained it for 1 h. The participants completed a series of cognitive tests (Cogstate test battery) and a simulated driving task (driver attention inhibition and reaction test) over the course of their intoxication curve (approximately 4 h). The results showed strong placebo effects on ratings of subjective intoxication. Driving and cognitive performance both showed dose-dependent alcohol impairment, and some measures displayed acute protracted error. The findings provide strong evidence of expectancy effects in contributing to self-perceptions of intoxication. Copyright © 2014 Elsevier Ltd. All rights reserved.

Quantitative assessment of driving performance in Parkinson's disease

PubMed Central

Wood, J; Worringham, C; Kerr, G; Mallon, K; Silburn, P

2005-01-01

Objectives: The primary aim of this study was to determine how Parkinson's disease (PD) affects driving performance. It also examined whether changes in driver safety were related to specific clinical disease markers or an individual's self rating of driving ability. Methods: The driving performance of 25 patients with idiopathic PD and 21 age matched controls was assessed on a standardised open road route by an occupational therapist and driving instructor, to provide overall safety ratings and specific driving error scores. Results: The drivers with PD were rated as significantly less safe (p<0.05) than controls, and more than half of the drivers with PD would not have passed a state based driving test. The driver safety ratings were more strongly related to disease duration (r = –0.60) than to their on time Unified Parkinson's Disease Rating Scale (r = –0.24). Drivers with PD made significantly more errors than the control group during manoeuvres that involved changing lanes and lane keeping, monitoring their blind spot, reversing, car parking, and traffic light controlled intersections. The driving instructor also had to intervene to avoid an incident significantly more often for drivers with PD than for controls. Interestingly, driver safety ratings were unrelated to an individual's rating of their own driving performance, and this was the case for all participants. Conclusions: As a group, drivers with PD are less safe to drive than age matched controls. Standard clinical markers cannot reliably predict driver safety. Further studies are required to ascertain whether the identified driving difficulties can be ameliorated. PMID:15654027

Problems Encountered During the Recertification of the GLORY Solar Array Dual Axis Gimbal Drive Actuators

NASA Technical Reports Server (NTRS)

Saltzman, Marc; Schepis, Jospeh P.; Bruckner, Michael J.

2009-01-01

The Glory observatory is the current incarnation of the Vegetation Canopy Lidar (VCL) mission spacecraft bus. The VCL spacecraft bus, having been cancelled for programmatic reasons in 2000, was nearly integrated when it was put into storage for possible future use. The Glory mission was a suitable candidate for using this spacecraft and in 2006 an effort to recertify the two axis solar array gimbal drive after its extended storage was begun. What was expected to be a simple performance validation of the two dual axis gimbal stepper motors became a serious test, diagnosis and repair task once questions arose on the flight worthiness of the hardware. A significant test program logic flow was developed which identified decisions that could be made based on the results of individual recertification tests. Without disassembling the bi-axial gimbals, beginning with stepper motor threshold voltage measurements and relating these to powered drive torque measurements, both performed at the spacecraft integrator s facility, a confusing picture of the health of the actuators came to light. Tests at the gimbal assembly level and tests of the disassembled actuators were performed by the manufacturer to validate our results and torque discrepancies were noted. Further disassembly to the component level of the actuator revealed the source of the torque loss.

Identifying at-risk drivers : a survey of state programs : final report.

DOT National Transportation Integrated Search

1990-01-01

Motor vehicle administrators have long realized that certain drivers present more of safety problem than others. Tests of static visual acuity, knowledge of the rules of the road, and on-the-road driving performance are used to ensure that each drive...

Road sign recognition during computer testing versus driving simulator performance for stroke and stroke+aphasia groups.

DOT National Transportation Integrated Search

2015-07-01

Driving is essential to maintaining independence. For most Americans preserving personal mobility is a : key element to retaining jobs, friends, activities and the basic necessities to maintain a household. This : is particularly true for older peopl...

Alcohol impairment of performance on steering and discrete tasks in a driving simulator

DOT National Transportation Integrated Search

1974-12-01

In this program a simplified laboratory simulator was developed to test two types of tasks used in driving on the open road: a continuous "steering task" to regulate against gust induced disturbances and an intermittent "discrete response task" requi...

Experimental modeling of the effect of hurricane wind forces on driving behavior and vehicle performance.

PubMed

Rodriguez, Jose M; Codjoe, Julius; Osman, Osama; Ishak, Sherif; Wolshon, Brian

2015-01-01

While traffic planning is important for developing a hurricane evacuation plan, vehicle performance on the roads during extreme weather conditions is critical to the success of the planning process. This novel study investigates the effect of gusty hurricane wind forces on the driving behavior and vehicle performance. The study explores how the parameters of a driving simulator could be modified to reproduce wind loadings experienced by three vehicle types (passenger car, ambulance, and bus) during gusty hurricane winds, through manipulation of appropriate software. Thirty participants were then tested on the modified driving simulator under five wind conditions (ranging from normal to hurricane category 4). The driving performance measures used were heading error and lateral displacement. The results showed that higher wind forces resulted in more varied and greater heading error and lateral displacement. The ambulance had the greatest heading errors and lateral displacements, which were attributed to its large lateral surface area and light weight. Two mathematical models were developed to estimate the heading error and lateral displacements for each of the vehicle types for a given change in lateral wind force. Through a questionnaire, participants felt the different characteristics while driving each vehicle type. The findings of this study demonstrate the valuable use of a driving simulator to model the behavior of different vehicle types and to develop mathematical models to estimate and quantify driving behavior and vehicle performance under hurricane wind conditions.

Effects of alcohol on automated and controlled driving performances.

PubMed

Berthelon, Catherine; Gineyt, Guy

2014-05-01

Alcohol is the most frequently detected substance in fatal automobile crashes, but its precise mode of action is not always clear. The present study was designed to establish the influence of blood alcohol concentration as a function of the complexity of the scenarios. Road scenarios implying automatic or controlled driving performances were manipulated in order to identify which behavioral parameters were deteriorated. A single blind counterbalanced experiment was conducted on a driving simulator. Sixteen experienced drivers (25.3 ± 2.9 years old, 8 men and 8 women) were tested with 0, 0.3, 0.5, and 0.8 g/l of alcohol. Driving scenarios varied: road tracking, car following, and an urban scenario including events inspired by real accidents. Statistical analyses were performed on driving parameters as a function of alcohol level. Automated driving parameters such as standard deviation of lateral position measured with the road tracking and car following scenarios were impaired by alcohol, notably with the highest dose. More controlled parameters such as response time to braking and number of crashes when confronted with specific events (urban scenario) were less affected by the alcohol level. Performance decrement was greater with driving scenarios involving automated processes than with scenarios involving controlled processes.

Naturalistic drive cycle synthesis for pickup trucks.

PubMed

Liu, Zifan; Ivanco, Andrej; Filipi, Zoran

2015-09-01

Future pick-up trucks are meeting much stricter fuel economy and exhaust emission standards. Design tradeoffs will have to be carefully evaluated to satisfy consumer expectations within the regulatory and cost constraints. Boundary conditions will obviously be critical for decision making: thus, the understanding of how customers are driving in naturalistic settings is indispensable. Federal driving schedules, while critical for certification, do not capture the richness of naturalistic cycles, particularly the aggressive maneuvers that often shape consumer perception of performance. While there are databases with large number of drive cycles, applying all of them directly in the design process is impractical. Therefore, representative drive cycles that capture the essence of the naturalistic driving should be synthesized from naturalistic driving data. Naturalistic drive cycles are firstly categorized by investigating their micro-trip components, defined as driving activities between successive stops. Micro-trips are expected to characterize underlying local traffic conditions, and separate different driving patterns. Next, the transitions from one vehicle state to another vehicle state in each cycle category are captured with Transition Probability Matrix (TPM). Candidate drive cycles can subsequently be synthesized using Markov Chain based on TPMs for each category. Finally, representative synthetic drive cycles are selected through assessment of significant cycle metrics to identify the ones with smallest errors. This paper provides a framework for synthesis of representative drive cycles from naturalistic driving data, which can subsequently be used for efficient optimization of design or control of pick-up truck powertrains. Manufacturers will benefit from representative drive cycles in several aspects, including quick assessments of vehicle performance and energy consumption in simulations, component sizing and design, optimization of control strategies, and vehicle testing under real-world conditions. This is in contrast to using federal certification test cycles, which were never intended to capture pickup truck segment. Copyright © 2015 Elsevier Ltd and National Safety Council. All rights reserved.

Driving performance in persons with mild to moderate symptoms of multiple sclerosis.

PubMed

Devos, Hannes; Brijs, Tom; Alders, Geert; Wets, Geert; Feys, Peter

2013-08-01

To investigate whether driving performance is impaired in persons with mild to moderate multiple sclerosis (MS). This study included 15 persons with MS (pwMS) and 17 healthy controls. The MS group exhibited mild to moderate impairments on the Expanded Disability Status Scale (median, Q1-Q3; 3.5, 2.5-4). The driving simulation required participants to drive in daily traffic while attending to a divided attention (DA) task. Computerized measures on the driving task included number of accidents, tickets, speed maintenance, standard deviation of lateral position, and time to collision. Response times and accuracy on the DA task were also computer generated. Additionally, pwMS completed a clinical evaluation encompassing motor, functional, visual, psychosocial and cognitive tests. No differences between healthy controls and pwMS were observed on all measures of the primary driving task. PwMS performed worse than healthy controls on DA response time (3.10 s, 2.87-3.68 versus 2.15 s, 2.04-2.43; p = 0.001) and accuracy (15 correct answers, 11-18 versus 24 correct answers, 22-25; p < 0.0001). Depression was significantly associated with time to collision (r = -0.77; p < 0.01). Subjects with mild to moderate MS are able to prioritize the driving task above the DA task. The relationship between depression and driving performance in MS merits further investigation.

Drunk driving detection based on classification of multivariate time series.

PubMed

Li, Zhenlong; Jin, Xue; Zhao, Xiaohua

2015-09-01

This paper addresses the problem of detecting drunk driving based on classification of multivariate time series. First, driving performance measures were collected from a test in a driving simulator located in the Traffic Research Center, Beijing University of Technology. Lateral position and steering angle were used to detect drunk driving. Second, multivariate time series analysis was performed to extract the features. A piecewise linear representation was used to represent multivariate time series. A bottom-up algorithm was then employed to separate multivariate time series. The slope and time interval of each segment were extracted as the features for classification. Third, a support vector machine classifier was used to classify driver's state into two classes (normal or drunk) according to the extracted features. The proposed approach achieved an accuracy of 80.0%. Drunk driving detection based on the analysis of multivariate time series is feasible and effective. The approach has implications for drunk driving detection. Copyright © 2015 Elsevier Ltd and National Safety Council. All rights reserved.

Development of a drive system for a sequential space camera

NASA Technical Reports Server (NTRS)

Sharpsteen, J. T.; Solheim, C. D.; Stoap, L. J.

1976-01-01

An electronically commutated dc motor is reported for driving the camera claw and magazine, and a stepper motor is described for driving the shutter with the two motors synchronized electrically. Subsequent tests on the breadboard positively proved the concept, but further development beyond this study should be done. The breadboard testing also established that the electronically commutated motor can control speed over a wide dynamic range, and has a high torque capability for accelerating loads. This performance suggested the possibility of eliminating the clutch from the system while retaining all of the other mechanical features of the DAC, if the requirement for independent shutter speeds and frame rates can be removed. Therefore, as a final step in the study, the breadboard shutter and shutter drive were returned to the original DAC configuration, while retaining the brushless dc motor drive.

Tau and Amyloid Positron Emission Tomography Imaging Predict Driving Performance Among Older Adults with and without Preclinical Alzheimer's Disease.

PubMed

Roe, Catherine M; Babulal, Ganesh M; Mishra, Shruti; Gordon, Brian A; Stout, Sarah H; Ott, Brian R; Carr, David B; Ances, Beau M; Morris, John C; Benzinger, Tammie L S

2018-01-01

Abnormal levels of Alzheimer's disease (AD) biomarkers, measured by positron emission tomography imaging using amyloid-based radiotracers and cerebrospinal fluid, are associated with impaired driving performance in older adults. We examined whether preclinical AD staging, defined using amyloid imaging and tau imaging using the radiotracer T807 (AKA flortaucipir or AV-1451), was associated with receiving a marginal/fail rating on a standardized road test (n = 42). Participants at Stage 2 (positive amyloid and tau scans) of preclinical AD were more likely to receive a marginal/fail rating compared to participants at Stage 0 or 1. Stage 2 preclinical AD may manifest in worse driving performance.

The effects of using a portable music player on simulated driving performance and task-sharing strategies.

PubMed

Young, Kristie L; Mitsopoulos-Rubens, Eve; Rudin-Brown, Christina M; Lenné, Michael G

2012-07-01

This study examined the effects of performing scrollable music selection tasks using a portable music player (iPod Touch™) on simulated driving performance and task-sharing strategies, as evidenced through eye glance behaviour and secondary task performance. A total of 37 drivers (18-48 yrs) completed the PC-based MUARC Driver Distraction Test (DDT) while performing music selection tasks on an iPod Touch. Drivers' eye glance behaviour was examined using faceLAB eye tracking equipment. Results revealed that performing music search tasks while driving increased the amount of time that drivers spent with their eyes off the roadway and decreased their ability to maintain a constant lane position and time headway from a lead vehicle. There was also evidence, however, that drivers attempted to regulate their behaviour when distracted by decreasing their speed and taking a large number of short glances towards the device. Overall, results suggest that performing music search tasks while driving is problematic and steps to prohibit this activity should be taken. Copyright © 2011 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Initial test results with single cylinder rhombic drive Stirling engine

NASA Technical Reports Server (NTRS)

Cairelli, J. E.

1978-01-01

A brief description is given of the GPU 3-2 hardware, the test methods used, and the result of these tests. Comparison is made to unpublished data from similar hydrogen tests performed by the U.S. Army.

Neuropsychiatric Symptoms and Alzheimer's Disease Biomarkers Predict Driving Decline: Brief Report.

PubMed

Babulal, Ganesh M; Stout, Sarah H; Head, Denise; Holtzman, David M; Fagan, Anne M; Morris, John C; Roe, Catherine M

2017-01-01

We examined whether neuropsychiatric symptoms (NPS) interact with cerebrospinal fluid (CSF) biomarkers (amyloid-β42 [Aβ42], tau, phosphorylated tau181 [ptau181], tau/Aβ42, and ptau181/Aβ42) of Alzheimer's disease pathology to predict driving decline among cognitively-normal older adults (N = 116) aged ≥65. Cox proportional hazards models examined time to receiving a rating of marginal or fail on the driving test. Age, education, and gender were adjusted in the models. Participants with more abnormal CSF (Aβ42, tau/Aβ42, ptau181/Aβ42) and NPS were faster to receive a marginal/fail on the road test compared to those without NPS. NPS interact with abnormal CSF biomarkers to impact driving performance among cognitively-normal older adults.

Sensorimotor and postural control factors associated with driving safety in a community-dwelling older driver population.

PubMed

Lacherez, Philippe; Wood, Joanne M; Anstey, Kaarin J; Lord, Stephen R

2014-02-01

To establish whether sensorimotor function and balance are associated with on-road driving performance in older adults. The performance of 270 community-living adults aged 70-88 years recruited via the electoral roll was measured on a battery of peripheral sensation, strength, flexibility, reaction time, and balance tests and on a standardized measure of on-road driving performance. Forty-seven participants (17.4%) were classified as unsafe based on their driving assessment. Unsafe driving was associated with reduced peripheral sensation, lower limb weakness, reduced neck range of motion, slow reaction time, and poor balance in univariate analyses. Multivariate logistic regression analysis identified poor vibration sensitivity, reduced quadriceps strength, and increased sway on a foam surface with eyes closed as significant and independent risk factors for unsafe driving. These variables classified participants into safe and unsafe drivers with a sensitivity of 74% and specificity of 70%. A number of sensorimotor and balance measures were associated with driver safety and the multivariate model comprising measures of sensation, strength, and balance was highly predictive of unsafe driving in this sample. These findings highlight important determinants of driver safety and may assist in developing efficacious driver safety strategies for older drivers.

Attention following traumatic brain injury: Neuropsychological and driving simulator data, and association with sleep, sleepiness, and fatigue.

PubMed

Beaulieu-Bonneau, Simon; Fortier-Brochu, Émilie; Ivers, Hans; Morin, Charles M

2017-03-01

The objectives of this study were to compare individuals with traumatic brain injury (TBI) and healthy controls on neuropsychological tests of attention and driving simulation performance, and explore their relationships with participants' characteristics, sleep, sleepiness, and fatigue. Participants were 22 adults with moderate or severe TBI (time since injury ≥ one year) and 22 matched controls. They completed three neuropsychological tests of attention, a driving simulator task, night-time polysomnographic recordings, and subjective ratings of sleepiness and fatigue. Results showed that participants with TBI exhibited poorer performance compared to controls on measures tapping speed of information processing and sustained attention, but not on selective attention measures. On the driving simulator task, a greater variability of the vehicle lateral position was observed in the TBI group. Poorer performance on specific subsets of neuropsychological variables was associated with poorer sleep continuity in the TBI group, and with a greater increase in subjective sleepiness in both groups. No significant relationship was found between cognitive performance and fatigue. These findings add to the existing evidence that speed of information processing is still impaired several years after moderate to severe TBI. Sustained attention could also be compromised. Attention seems to be associated with sleep continuity and daytime sleepiness; this interaction needs to be explored further.

Driving simulation in the clinic: testing visual exploratory behavior in daily life activities in patients with visual field defects.

PubMed

Hamel, Johanna; Kraft, Antje; Ohl, Sven; De Beukelaer, Sophie; Audebert, Heinrich J; Brandt, Stephan A

2012-09-18

Patients suffering from homonymous hemianopia after infarction of the posterior cerebral artery (PCA) report different degrees of constraint in daily life, despite similar visual deficits. We assume this could be due to variable development of compensatory strategies such as altered visual scanning behavior. Scanning compensatory therapy (SCT) is studied as part of the visual training after infarction next to vision restoration therapy. SCT consists of learning to make larger eye movements into the blind field enlarging the visual field of search, which has been proven to be the most useful strategy(1), not only in natural search tasks but also in mastering daily life activities(2). Nevertheless, in clinical routine it is difficult to identify individual levels and training effects of compensatory behavior, since it requires measurement of eye movements in a head unrestrained condition. Studies demonstrated that unrestrained head movements alter the visual exploratory behavior compared to a head-restrained laboratory condition(3). Martin et al.(4) and Hayhoe et al.(5) showed that behavior demonstrated in a laboratory setting cannot be assigned easily to a natural condition. Hence, our goal was to develop a study set-up which uncovers different compensatory oculomotor strategies quickly in a realistic testing situation: Patients are tested in the clinical environment in a driving simulator. SILAB software (Wuerzburg Institute for Traffic Sciences GmbH (WIVW)) was used to program driving scenarios of varying complexity and recording the driver's performance. The software was combined with a head mounted infrared video pupil tracker, recording head- and eye-movements (EyeSeeCam, University of Munich Hospital, Clinical Neurosciences). The positioning of the patient in the driving simulator and the positioning, adjustment and calibration of the camera is demonstrated. Typical performances of a patient with and without compensatory strategy and a healthy control are illustrated in this pilot study. Different oculomotor behaviors (frequency and amplitude of eye- and head-movements) are evaluated very quickly during the drive itself by dynamic overlay pictures indicating where the subjects gaze is located on the screen, and by analyzing the data. Compensatory gaze behavior in a patient leads to a driving performance comparable to a healthy control, while the performance of a patient without compensatory behavior is significantly worse. The data of eye- and head-movement-behavior as well as driving performance are discussed with respect to different oculomotor strategies and in a broader context with respect to possible training effects throughout the testing session and implications on rehabilitation potential.

Naturalistic distraction and driving safety in older drivers

PubMed Central

Aksan, Nazan; Dawson, Jeffrey D.; Emerson, Jamie L.; Yu, Lixi; Uc, Ergun Y.; Anderson, Steven W.; Rizzo, Matthew

2013-01-01

Objective This study aimed to quantify and compare performance of middle-aged and older drivers during a naturalistic distraction paradigm (visual search for roadside targets) and predict older driver performance given functioning in visual, motor, and cognitive domains. Background Distracted driving can imperil healthy adults and may disproportionally affect the safety of older drivers with visual, motor, and cognitive decline. Methods Two hundred and three drivers, 120 healthy older (61 men and 59 women, ages 65 years or greater) and 83 middle-aged drivers (38 men and 45 women, ages 40–64 years), participated in an on-road test in an instrumented vehicle. Outcome measures included performance in roadside target identification (traffic signs and restaurants) and concurrent driver safety. Differences in visual, motor, and cognitive functioning served as predictors. Results Older drivers identified fewer landmarks and drove slower but committed more safety errors than middle-aged drivers. Greater familiarity with local roads benefited performance of middle-aged but not older drivers. Visual cognition predicted both traffic sign identification and safety errors while executive function predicted traffic sign identification over and above vision. Conclusion Older adults are susceptible to driving safety errors while distracted by common secondary visual search tasks that are inherent to driving. The findings underscore that age-related cognitive decline affects older driver management of driving tasks at multiple levels, and can help inform the design of on-road tests and interventions for older drivers. PMID:23964422

Drivers who self-estimate lower blood alcohol concentrations are riskier drivers after drinking

PubMed Central

Laude, Jennifer R.; Fillmore, Mark T.

2016-01-01

Rationale Alcohol increases the tendency for risky driving in some individuals, but not others. Little is known about the factors underlying this individual difference. Studies find that those who underestimate their blood alcohol concentration (BAC) following a dose of alcohol tend to be more impulsive and report greater willingness to drive after drinking than those who estimate their BACs to be greater than their actual BAC. BAC underestimation could contribute to risky driving behavior following alcohol as such drivers might perceive little impairment in their driving ability and thus no need for caution. Objectives This study was designed to test the relationship between drivers’ BAC estimations following a dose of alcohol or a placebo and the degree of risky driving they displayed during a simulated driving test. Methods Forty adult drivers performed a simulated driving test and estimated their blood alcohol concentration after receiving a dose of alcohol (0.65 g/kg for men; 0.56 g/kg for women) or a placebo. . Results Alcohol increased risk taking and impaired driving skill. Those who estimated their BAC to be lower were the riskiest drivers following both alcohol and placebo. Conclusions The tendency to estimate lower BACs could support a series of high-risk decisions, regardless of one’s actual BAC. This could include the decision to drive after drinking. PMID:26861796

Study on compensation algorithm of head skew in hard disk drives

NASA Astrophysics Data System (ADS)

Xiao, Yong; Ge, Xiaoyu; Sun, Jingna; Wang, Xiaoyan

2011-10-01

In hard disk drives (HDDs), head skew among multiple heads is pre-calibrated during manufacturing process. In real applications with high capacity of storage, the head stack may be tilted due to environmental change, resulting in additional head skew errors from outer diameter (OD) to inner diameter (ID). In case these errors are below the preset threshold for power on recalibration, the current strategy may not be aware, and drive performance under severe environment will be degraded. In this paper, in-the-field compensation of small DC head skew variation across stroke is proposed, where a zone table has been equipped. Test results demonstrating its effectiveness to reduce observer error and to enhance drive performance via accurate prediction of DC head skew are provided.

Low-frequency oscillation amplitude elevation of prefrontal cerebral hemodynamics with driving duration during prolonged driving test

NASA Astrophysics Data System (ADS)

Deng, Zishan; Gao, Yuan; Li, Ting

2018-02-01

It has been observed that there is a low-frequency oscillation (LFO) around 0.1 Hz in cerebral hemodynamics related to brain activity. Since functional near-infrared spectroscopy (fNIRS) is a novel technique to monitor hemodynamic responses noninvasively, we applied it to detect LFOs of cerebral hemodynamic parameters, such as oxyhemoglobin and deoxyhemoglobin, during prolonged driving. We performed an experiment lasting for 7 hours and an experimental test was done every hour and 8 times altogether. 7 subjects were recruited and the data of 3 of them were analyzed. By means of Fourier transformation, the amplitude of the three parameters during each test at 0.1 Hz in frequency domain was extracted. The results showed an increasing trend in the 0.1 Hz amplitudes of the three hemodynamic parameters during 7 hours' simulated driving test. Our findings indicated the potential of LFOs of prefrontal cerebral hemodynamics in brain research and brain function evaluation.

Genesis Pilot Human Factors Test, Human Factors Evaluation Of Driver Multitasking And Message Formats, Final Report

DOT National Transportation Integrated Search

1996-02-01

THE WORK REPORTED HERE WAS ON TWO SEPARATE TOPICS. THE FIRST OF THESE WAS THE MULTITASKING EFFECTS ON DRIVING PERFORMANCE OF USING PAGERS OR PDAS WHILE DRIVING. THE LITERATURE SHOWED THAT SUCH EFFECTS CAN OCCUR BUT THAT THEY ARE TASK SPECIFIC. FINDIN...

Definition of simulated driving tests for the evaluation of drivers' reactions and responses.

PubMed

Bartolozzi, Riccardo; Frendo, Francesco

2014-01-01

This article aims at identifying the most significant measures in 2 perception-response (PR) tests performed at a driving simulator: a braking test and a lateral skid test, which were developed in this work. Forty-eight subjects (26 females and 22 males) with a mean age of 24.9 ± 3.0 years were enrolled for this study. They were asked to perform a drive on the driving simulator at the University of Pisa (Italy) following a specific test protocol, including 8-10 braking tests and 8-10 lateral skid tests. Driver input signals and vehicle model signals were recorded during the drives and analyzed to extract measures such as the reaction time, first response time, etc. Following a statistical procedure (based on analysis of variance [ANOVA] and post hoc tests), all test measures (3 for the braking test and 8 for the lateral skid test) were analyzed in terms of statistically significant differences among different drivers. The presented procedure allows evaluation of the capability of a given test to distinguish among different drivers. In the braking test, the reaction time showed a high dispersion among single drivers, leading to just 4.8 percent of statistically significant driver pairs (using the Games-Howell post hoc test), whereas the pedal transition time scored 31.9 percent. In the lateral skid test, 28.5 percent of the 2 × 2 comparisons showed significantly different reaction times, 19.5 percent had different response times, 35.2 percent had a different second peak of the steering wheel signal, and 33 percent showed different values of the integral of the steering wheel signal. For the braking test, which has been widely employed in similar forms in the literature, it was shown how the reaction time, with respect to the pedal transition time, can have a higher dispersion due to the influence of external factors. For the lateral skid test, the following measures were identified as the most significant for application studies: the reaction time for the reaction phase, the second peak of the steering wheel angle for the first instinctive response, and the integral of the steering wheel angle for the complete response. The methodology used to analyze the test measures was founded on statistically based and objective evaluation criteria and could be applied to other tests. Even if obtained with a fixed-base simulator, the obtained results represent useful information for applications of the presented PR tests in experimental campaigns with driving simulators.

A Pilot Evaluation of On-Road Detection Performance by Drivers with Hemianopia Using Oblique Peripheral Prisms

PubMed Central

Bowers, Alex R.; Tant, Mark; Peli, Eli

2012-01-01

Aims. Homonymous hemianopia (HH), a severe visual consequence of stroke, causes difficulties in detecting obstacles on the nonseeing (blind) side. We conducted a pilot study to evaluate the effects of oblique peripheral prisms, a novel development in optical treatments for HH, on detection of unexpected hazards when driving. Methods. Twelve people with complete HH (median 49 years, range 29–68) completed road tests with sham oblique prism glasses (SP) and real oblique prism glasses (RP). A masked evaluator rated driving performance along the 25 km routes on busy streets in Ghent, Belgium. Results. The proportion of satisfactory responses to unexpected hazards on the blind side was higher in the RP than the SP drive (80% versus 30%; P = 0.001), but similar for unexpected hazards on the seeing side. Conclusions. These pilot data suggest that oblique peripheral prisms may improve responses of people with HH to blindside hazards when driving and provide the basis for a future, larger-sample clinical trial. Testing responses to unexpected hazards in areas of heavy vehicle and pedestrian traffic appears promising as a real-world outcome measure for future evaluations of HH rehabilitation interventions aimed at improving detection when driving. PMID:23316415

Impaired driving from medical conditions: A 70-year-old man trying to decide if he should continue driving

PubMed Central

Rizzo, Matthew

2012-01-01

Some medical disorders can impair performance, increasing the risk of driving safety errors that can lead to vehicle crashes. The causal pathway often involves a concatenation of factors or events, some of which can be prevented or controlled. Effective interventions can operate before, during, or after a crash occurs at the levels of driver capacity, vehicle and road design, and public policy. A variety of systemic, neurological, psychiatric, and developmental disorders put drivers at potential increased risk of a car crash in the short or long term. Medical diagnosis and age alone are usually insufficient criteria for determining fitness to drive. Strategies are needed for determining what types and levels of reduced function provide a threshold for disqualification in drivers with medical disorders. Evidence of decreased mileage, self-restriction to driving in certain situations, collisions, moving violations, aggressive driving, sleepiness, alcohol abuse, metabolic disorders, and multiple medications may trigger considerations of driver safety. A general framework for evaluating driver fitness relies on a functional evaluation of multiple domains (cognitive, motor, perceptual, and psychiatric) that are important for safe driving and can be applied across many disorders, including conditions that have rarely been studied with respect to driving, and in patients with multiple conditions and medications. Neurocognitive tests, driving simulation, and road tests provide complementary sources of evidence to evaluate driver safety. No single test is sufficient to determine who should drive and who should not. PMID:21364126

Impaired driving from medical conditions: a 70-year-old man trying to decide if he should continue driving.

PubMed

Rizzo, Matthew

2011-03-09

Some medical disorders can impair performance, increasing the risk of driving safety errors that can lead to vehicle crashes. The causal pathway often involves a concatenation of factors or events, some of which can be prevented or controlled. Effective interventions can operate before, during, or after a crash occurs at the levels of driver capacity, vehicle and road design, and public policy. A variety of systemic, neurological, psychiatric, and developmental disorders put drivers at potential increased risk of a car crash in the short or long term. Medical diagnosis and age alone are usually insufficient criteria for determining fitness to drive. Strategies are needed for determining what types and levels of reduced function provide a threshold for disqualification in drivers with medical disorders. Evidence of decreased mileage, self-restriction to driving in certain situations, collisions, moving violations, aggressive driving, sleepiness, alcohol abuse, metabolic disorders, and multiple medications may trigger considerations of driver safety. A general framework for evaluating driver fitness relies on a functional evaluation of multiple domains (cognitive, motor, perceptual, and psychiatric) that are important for safe driving and can be applied across many disorders, including conditions that have rarely been studied with respect to driving, and in patients with multiple conditions and medications. Neurocognitive tests, driving simulation, and road tests provide complementary sources of evidence to evaluate driver safety. No single test is sufficient to determine who should drive and who should not.

Driving home from the night shift: a bright light intervention study.

PubMed

Weisgerber, Denise M; Nikol, Maria; Mistlberger, Ralph E

2017-02-01

Sleep deprivation (SD) impairs vigilance and increases the risk of driving accidents during the commute home after night work. Bright light (BL) can enhance alertness and cognitive performance. We examined the effects of BL (5600 lux) versus dim light (DL, 35 lux) at the end of a night awake on driving performance. Subjects (N = 19, 22.8 ± 4 ya) completed three conditions, counterbalanced for order at >1 week intervals. The two overnight SD conditions began in the lab at usual bedtime. After six hours in DL, subjects were exposed to 45 min BL or continued DL, and then completed a 44 min driving test (two lap circuit) in a high fidelity simulator. In the rested condition, subjects slept at home until habitual wakeup time, were transported to the lab and ∼45 min after wakeup, received BL and then the driving test. Oral temperature decreased while reaction time and sleepiness increased across both SD nights. BL suppressed salivary melatonin but had little or no effect on sleepiness or reaction time. SD markedly increased incidents and accidents. Five subjects (26%) sustained a terminal accident (eg, car flip) in the SD-DL condition, but none did so in the SD-BL or rested-BL conditions. Compared to SD-DL, SD-BL was associated with fewer incidents and accidents overall, and with better performance on the second lap of the circuit on several performance measures. BL at the end of a night shift may have potential as a countermeasure to improve driving following night work. Copyright © 2016 Elsevier B.V. All rights reserved.

40 CFR 85.2230 - Steady state test dynamometer-EPA 91.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM MOBILE SOURCES Emission Control System Performance... applicability. The requirements of § 85.2229 apply concurrently for tests conducted under Emission Performance... capable of applying a load to the vehicle's driving tire surfaces at the horsepower and speed levels...

Design of an immersive simulator for assisted power wheelchair driving.

PubMed

Devigne, Louise; Babel, Marie; Nouviale, Florian; Narayanan, Vishnu K; Pasteau, Francois; Gallien, Philippe

2017-07-01

Driving a power wheelchair is a difficult and complex visual-cognitive task. As a result, some people with visual and/or cognitive disabilities cannot access the benefits of a power wheelchair because their impairments prevent them from driving safely. In order to improve their access to mobility, we have previously designed a semi-autonomous assistive wheelchair system which progressively corrects the trajectory as the user manually drives the wheelchair and smoothly avoids obstacles. Developing and testing such systems for wheelchair driving assistance requires a significant amount of material resources and clinician time. With Virtual Reality technology, prototypes can be developed and tested in a risk-free and highly flexible Virtual Environment before equipping and testing a physical prototype. Additionally, users can "virtually" test and train more easily during the development process. In this paper, we introduce a power wheelchair driving simulator allowing the user to navigate with a standard wheelchair in an immersive 3D Virtual Environment. The simulation framework is designed to be flexible so that we can use different control inputs. In order to validate the framework, we first performed tests on the simulator with able-bodied participants during which the user's Quality of Experience (QoE) was assessed through a set of questionnaires. Results show that the simulator is a promising tool for future works as it generates a good sense of presence and requires rather low cognitive effort from users.

Police custody following drink-driving: a prospective study.

PubMed

Lepresle, Aude; Mahindhoratep, Tiao Saysouda; Chiadmi, Fouad; Schlatter, Joël; Boraud, Cyril; Chariot, Patrick

2012-11-01

Drink-driving is a crime and traffic offences are a common cause of detention in police custody. Legal assessment of alcohol intoxication is based on breath or blood testing. We hypothesize that refusal of breath alcohol testing or inability to perform it can correspond to singular medical characteristics of the detainee, possibly assaulted or injured during the arrest. Our objective was to determine medical characteristics of detainees held in custody for drink-driving. Prospective monocentric study (April-October, 2010) of drink-drive arrestees. Controls were persons aged over 18 detained for other reasons than drink-driving. Data collected concerned persons' characteristics and reported assaults or observed injuries. 223 drivers were tested positive for breath alcohol level and 55 suspected drink-drivers refused or were not able to complete breath test. 2212 consecutively examined persons served as controls. Drink-drive arrestees requested medical examination more rarely (18% and 7%, vs. 43%, P<0.0001) and drivers tested positive for breath alcohol were more frequently alcohol abusers (25% vs. 14%, P<0.0001) than controls. Drivers who did not complete breath test more often reported assaults than those tested positive for breath alcohol (22% vs. 8%, P=0.007). They had more frequent traumatic injuries than those tested positive and than controls (29% vs. 11% and 17%, P=0.003 and 0.02). Only 1% of drink drivers were unfit for detention after medical examination. Physicians need to give attentive care to detained drink-drivers. Special attention should be paid to drink-drivers who refused or were not able to complete breath alcohol measurement. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

EEG-based decoding of error-related brain activity in a real-world driving task

NASA Astrophysics Data System (ADS)

Zhang, H.; Chavarriaga, R.; Khaliliardali, Z.; Gheorghe, L.; Iturrate, I.; Millán, J. d. R.

2015-12-01

Objectives. Recent studies have started to explore the implementation of brain-computer interfaces (BCI) as part of driving assistant systems. The current study presents an EEG-based BCI that decodes error-related brain activity. Such information can be used, e.g., to predict driver’s intended turning direction before reaching road intersections. Approach. We executed experiments in a car simulator (N = 22) and a real car (N = 8). While subject was driving, a directional cue was shown before reaching an intersection, and we classified the presence or not of an error-related potentials from EEG to infer whether the cued direction coincided with the subject’s intention. In this protocol, the directional cue can correspond to an estimation of the driving direction provided by a driving assistance system. We analyzed ERPs elicited during normal driving and evaluated the classification performance in both offline and online tests. Results. An average classification accuracy of 0.698 ± 0.065 was obtained in offline experiments in the car simulator, while tests in the real car yielded a performance of 0.682 ± 0.059. The results were significantly higher than chance level for all cases. Online experiments led to equivalent performances in both simulated and real car driving experiments. These results support the feasibility of decoding these signals to help estimating whether the driver’s intention coincides with the advice provided by the driving assistant in a real car. Significance. The study demonstrates a BCI system in real-world driving, extending the work from previous simulated studies. As far as we know, this is the first online study in real car decoding driver’s error-related brain activity. Given the encouraging results, the paradigm could be further improved by using more sophisticated machine learning approaches and possibly be combined with applications in intelligent vehicles.

The effects of alcohol on driver performance in a decision making situation

NASA Technical Reports Server (NTRS)

Allen, R. W.; Schwartz, S. H.; Stein, A. C.; Hogge, J. R.

1978-01-01

The results are reviewed of driving simulator and in-vehicle field test experiments of alcohol effects on driver risk taking. The objective was to investigate changes in risk taking under alcoholic intoxication and relate these changes to effects on traffic safety. The experiments involved complex 15 minute driving scenarios requiring decision making and steering and speed control throughout a series of typical driving situations. Monetary rewards and penalties were employed to simulate the real-world motivations inherent in driving. A full placebo experimental design was employed, and measures related to traffic safety, driver/vehicle performance and driver behavior were obtained. Alcohol impairment was found to increase the rate of accidents and speeding tickets. Behavioral measures showed these traffic safety effects to be due to impaired psychomotor performance and perceptual distortions. Subjective estimates of risk failed to show any change in the driver's willingness to take risks when intoxicated.

Study on Stability of High Speed Traction Drive CVT for Aircraft Generator

NASA Astrophysics Data System (ADS)

Goi, Tatsuhiko; Tanaka, Hirohisa; Nakashima, Kenichi; Watanabe, Koji

A half-toroidal traction drive CVT has a feature of small spin at traction pitch in whole speed ratio range of 1:4, which suits to transmit high rotational speed with minimum temperature increase of traction surface. Research activity on traction drive CVT has commenced in 1996 for applying it to an aircraft 24,000rpm constant-speed generator instead of a hydro-static transmission. This paper shows fundamental design of 90kW traction drive integrated drive generator, ``T-IDG", and stability analysis on a sensor-less electro-hydraulic speed control servo-mechanism by bond graphs. The performance test of T-IDG mounted on a test bench and an actual jet engine proved that the control system using sensor-less servomechanism can keep the generator speed within MIL-STD-704E allowable limit against steep changes of speed and load.

Accurate method for luminous transmittance and signal detection quotients measurements in sunglasses lenses

NASA Astrophysics Data System (ADS)

Loureiro, A. D.; Gomes, L. M.; Ventura, L.

2018-02-01

The international standard ISO 12312-1 proposes transmittance tests that quantify how dark sunglasses lenses are and whether or not they are suitable for driving. To perform these tests a spectrometer is required. In this study, we present and analyze theoretically an accurate alternative method for performing these measurements using simple components. Using three LEDs and a four-channel sensor we generated weighting functions similar to the standard ones for luminous and traffic lights transmittances. From 89 sunglasses lens spectroscopy data, we calculated luminous transmittance and signal detection quotients using our obtained weighting functions and the standard ones. Mean-difference Tukey plots were used to compare the results. All tested sunglasses lenses were classified in the right category and correctly as suitable or not for driving. The greatest absolute errors for luminous transmittance and red, yellow, green and blue signal detection quotients were 0.15%, 0.17, 0.06, 0.04 and 0.18, respectively. This method will be used in a device capable to perform transmittance tests (visible, traffic lights and ultraviolet (UV)) according to the standard. It is important to measure rightly luminous transmittance and relative visual attenuation quotients to report correctly whether or not sunglasses are suitable for driving. Moreover, standard UV requirements depend on luminous transmittance.

Development of real-world driving cycles and estimation of emission factors for in-use light-duty gasoline vehicles in urban areas.

PubMed

Hwa, Mei-Yin; Yu, Tai-Yi

2014-07-01

This investigation adopts vehicle tracking manner to establish real-world driving patterns and estimates emission factors with dynamometers with 23 traffic-driving variables for 384 in-use light-duty passenger vehicles during non-rush hour. Adequate numbers of driving variables were decided with factor analysis and cluster analysis. The dynamometer tests were performed on FTP75 cycle and five local driving cycles derived from real-world speed profiles. Results presented that local driving cycles and FTP75 cycle were completely different in driving characteristic parameters of typical driving cycles and emission factors. The highest values of emission factor ratios of local driving cycle and FTP75 cycle for CO, NMHC, NO x , CH4, and CO2 were 1.38, 1.65, 1.58, 1.39, and 1.14, respectively.

Novel Observer Scheme of Fuzzy-MRAS Sensorless Speed Control of Induction Motor Drive

NASA Astrophysics Data System (ADS)

Chekroun, S.; Zerikat, M.; Mechernene, A.; Benharir, N.

2017-01-01

This paper presents a novel approach Fuzzy-MRAS conception for robust accurate tracking of induction motor drive operating in a high-performance drives environment. Of the different methods for sensorless control of induction motor drive the model reference adaptive system (MRAS) finds lot of attention due to its good performance. The analysis of the sensorless vector control system using MRAS is presented and the resistance parameters variations and speed observer using new Fuzzy Self-Tuning adaptive IP Controller is proposed. In fact, fuzzy logic is reminiscent of human thinking processes and natural language enabling decisions to be made based on vague information. The present approach helps to achieve a good dynamic response, disturbance rejection and low to plant parameter variations of the induction motor. In order to verify the performances of the proposed observer and control algorithms and to test behaviour of the controlled system, numerical simulation is achieved. Simulation results are presented and discussed to shown the validity and the performance of the proposed observer.

Night driving simulation in a randomized prospective comparison of Visian toric implantable collamer lens and conventional PRK for moderate to high myopic astigmatism.

PubMed

Schallhorn, Steven; Tanzer, David; Sanders, Donald R; Sanders, Monica; Brown, Mitch; Kaupp, Sandor E

2010-05-01

To compare changes in simulated night driving performance after Visian Toric Implantable Collamer Lens (TICL; STAAR Surgical) implantation and photorefractive keratectomy (PRK) for the correction of moderate to high myopic astigmatism. This prospective, randomized study consisted of 43 eyes implanted with the TICL (20 bilateral cases) and 45 eyes receiving conventional PRK (VISX Star S3 excimer laser) with mitomycin C (22 bilateral cases) for moderate to high myopia (-6.00 to -20.00 diopters[D] sphere) measured at the spectacle plane and 1.00 to 4.00 D of astigmatism. As a substudy, 27 eyes of 14 TICL patients and 41 eyes of 21 PRK patients underwent a simulated night driving test. The detection and identification distances of road signs and hazards with the Night Driving Simulator (Vision Sciences Research Corp) were measured with and without a glare source before and 6 months after each procedure. No significant difference was noted in the pre- to postoperative Night Driving Simulator in detection distances with and without the glare source between the TICL and PRK groups. The differences in identification distances without glare were significantly better for business and traffic road signs and pedestrian hazards in the TICL group relative to the PRK group whereas with glare, only the pedestrian hazards were significantly better. A clinically relevant change of Night Driving Simulator performance (>0.5 seconds change in ability to identify tasks postoperatively) was significantly better in the TICL group (with and without glare) for all identification tasks. The TICL performed better than conventional PRK in the pre- to postoperative Night Driving Simulator testing with and without a glare source present. Copyright 2010, SLACK Incorporated.

Effects of central nervous system drugs on driving: speed variability versus standard deviation of lateral position as outcome measure of the on-the-road driving test.

PubMed

Verster, Joris C; Roth, Thomas

2014-01-01

The on-the-road driving test in normal traffic is used to examine the impact of drugs on driving performance. This paper compares the sensitivity of standard deviation of lateral position (SDLP) and SD speed in detecting driving impairment. A literature search was conducted to identify studies applying the on-the-road driving test, examining the effects of anxiolytics, antidepressants, antihistamines, and hypnotics. The proportion of comparisons (treatment versus placebo) where a significant impairment was detected with SDLP and SD speed was compared. About 40% of 53 relevant papers did not report data on SD speed and/or SDLP. After placebo administration, the correlation between SDLP and SD speed was significant but did not explain much variance (r = 0.253, p = 0.0001). A significant correlation was found between ΔSDLP and ΔSD speed (treatment-placebo), explaining 48% of variance. When using SDLP as outcome measure, 67 significant treatment-placebo comparisons were found. Only 17 (25.4%) were significant when SD speed was used as outcome measure. Alternatively, for five treatment-placebo comparisons, a significant difference was found for SD speed but not for SDLP. Standard deviation of lateral position is a more sensitive outcome measure to detect driving impairment than speed variability.

Baseline tests of the Kordesh hybrid passenger vehicle

NASA Technical Reports Server (NTRS)

Soltis, R. F.; Bozek, J. M.; Denington, R. J.; Dustin, M. O.

1978-01-01

Performance test results are presented for a four-passenger Austin A40 sedan that was converted to a heat-engine-alternator-and battery-powered hybrid. It is propelled by a conventional, gasoline-fueled, heat-engine-driven alternator and a traction pack powering a series-wound, 10 hp direct-current electric drive motor. The 16 hp gasoline engine drives the 7 kilowatt alternator, which provides electrical power to the drive motor or to the 96 volt traction battery through a rectifier. The propulsion battery consists of eight 12 volt batteries connected in series. The electric motor is coupled to a four-speed standard transmission, which drives the rear wheels. Power to the motor is controlled by a three-step foot throttle, which actuates relays that control armature current and field excitation. Conventional hydraulic brakes are used.

Design and control of a high precision drive mechanism

NASA Astrophysics Data System (ADS)

Pan, Bo; He, Yongqiang; Wang, Haowei; Zhang, Shuyang; Zhang, Donghua; Wei, Xiaorong; Jiang, Zhihong

2017-01-01

This paper summarizes the development of a high precision drive mechanism (HPDM) for space application, such as the directional antenna, the laser communication device, the mobile camera and other pointing mechanisms. In view of the great practical significance of high precision drive system, control technology for permanent magnet synchronous motor (PMSM) servo system is also studied and a PMSM servo controller is designed in this paper. And the software alignment was applied to the controller to eliminate the steady error of the optical encoder, which helps to realize the 1 arcsec (1σ) control precision. To assess its capabilities, the qualification environment testing including the thermal vacuum cycling testing, and the sinusoidal and random vibration were carried out. The testing results show that the performance of the HPDM is almost the same between the former and the end of each testing.

Improvement of driving skills in persons with relapsing-remitting multiple sclerosis: a pilot study.

PubMed

Akinwuntan, Abiodun Emmanuel; Devos, Hannes; Baker, Kelly; Phillips, Kendra; Kumar, Vibha; Smith, Suzanne; Williams, Mitzi Joi

2014-03-01

To determine the potential to improve driving-related skills using a simulator-based program in persons with relapsing-remitting multiple sclerosis (RRMS). Pre-post intervention. A university driving simulator laboratory. Participants (N=50) with RRMS and Expanded Disability Status Scale (EDSS) scores between 1 and 7 were enrolled. Pre- and posttraining data from 36 participants (mean age ± SD, 46±11y; 30 women) who received training and 6 participants (mean age ± SD, 48±13y; 5 women) who did not receive training (control group) were compared. Five hours of driving training in a simulator. Performance on a road test at pre- and posttraining. Secondary outcome measures were performance on visual, physical, and cognitive tests. Overall, no significant differences were observed between the training and control groups before and after training. However, 4 of the 7 participants in the training group who failed the road test at pretraining passed posttraining, while the only participant in the control group who failed at pretraining still failed at posttraining. The training group also improved on perception of red and colored numbers, the Paced Auditory Serial Addition Test, and the dot cancellation test of the Stroke Driver Screening Assessment battery and reported less fatigue. These improvements were most pronounced among those with an EDSS score between 3 and 7. This pilot study demonstrates the potential of using a simulator to improve driving-related visual, cognitive, and on-road skills in individuals with RRMS, particularly those with an EDSS score >3. Future randomized controlled trials with adequate power are needed to expand this field of study. Copyright © 2014 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Experimental Performance Evaluation of a High Speed Permanent Magnet Synchronous Motor and Drive for a Flywheel Application at Different Frequencies

NASA Technical Reports Server (NTRS)

Nagorny, Aleksandr S.; Jansen, Ralph H.; Kankam, M. David

2007-01-01

This paper presents the results of an experimental performance characterization study of a high speed, permanent magnet motor/generator (M/G) and drive applied to a flywheel module. Unlike the conventional electric machine the flywheel M/G is not a separated unit; its stator and rotor are integrated into a flywheel assembly. The M/G rotor is mounted on a flywheel rotor, which is magnetically levitated and sealed within a vacuum chamber during the operation. Thus, it is not possible to test the M/G using direct load measurements with a dynamometer and torque transducer. Accordingly, a new in-situ testing method had to be developed. The paper describes a new flywheel M/G and drive performance evaluation technique, which allows the estimation of the losses, efficiency and power quality of the flywheel high speed permanent magnet M/G, while working in vacuum, over wide frequency and torque ranges. This method does not require any hardware modification nor any special addition to the test rig. This new measurement technique is useful for high-speed applications, when applying an external load is technically difficult.

An improved driving waveform reference grayscale of electrophoretic displays

NASA Astrophysics Data System (ADS)

Wang, Li; Yi, Zichuan; Peng, Bao; Zhou, Guofu

2015-10-01

Driving waveform is an important component for gray scale display on the electrophoretic display (EPD). In the traditional driving waveform, a white reference gray scale is formed before writing a new image. However, the reflectance value can not reach agreement in each gray scale transformation. In this paper, a new driving waveform, which has a short waiting time after the formation of reference gray scale, is proposed to improve the consistency of reference gray scale. Firstly, the property of the particles in the microcapsule is analyzed and the change of the EPD reflectance after the white reference gray scale formation is studied. Secondly, the reflectance change curve is fitted by using polynomial and the duration of the waiting time is determined. Thirdly, a set of the new driving waveform is designed by using the rule of DC balance and some real E-ink commercial EPDs are used to test the performance. Experimental results show that the effect of the new driving waveform has a better performance than traditional waveforms.

Simulated Driving Assessment (SDA) for teen drivers: results from a validation study.

PubMed

McDonald, Catherine C; Kandadai, Venk; Loeb, Helen; Seacrist, Thomas S; Lee, Yi-Ching; Winston, Zachary; Winston, Flaura K

2015-06-01

Driver error and inadequate skill are common critical reasons for novice teen driver crashes, yet few validated, standardised assessments of teen driving skills exist. The purpose of this study is to evaluate the construct and criterion validity of a newly developed Simulated Driving Assessment (SDA) for novice teen drivers. The SDA's 35 min simulated drive incorporates 22 variations of the most common teen driver crash configurations. Driving performance was compared for 21 inexperienced teens (age 16-17 years, provisional license ≤90 days) and 17 experienced adults (age 25-50 years, license ≥5 years, drove ≥100 miles per week, no collisions or moving violations ≤3 years). SDA driving performance (Error Score) was based on driving safety measures derived from simulator and eye-tracking data. Negative driving outcomes included simulated collisions or run-off-the-road incidents. A professional driving evaluator/instructor (DEI Score) reviewed videos of SDA performance. The SDA demonstrated construct validity: (1) teens had a higher Error Score than adults (30 vs. 13, p=0.02); (2) For each additional error committed, the RR of a participant's propensity for a simulated negative driving outcome increased by 8% (95% CI 1.05 to 1.10, p<0.01). The SDA-demonstrated criterion validity: Error Score was correlated with DEI Score (r=-0.66, p<0.001). This study supports the concept of validated simulated driving tests like the SDA to assess novice driver skill in complex and hazardous driving scenarios. The SDA, as a standard protocol to evaluate teen driver performance, has the potential to facilitate screening and assessment of teen driving readiness and could be used to guide targeted skill training. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

The Alabama VIP older driver study rationale and design: examining the relationship between vision impairment and driving using naturalistic driving techniques.

PubMed

Owsley, Cynthia; McGwin, Gerald; Antin, Jonathan F; Wood, Joanne M; Elgin, Jennifer

2018-02-07

Older drivers aged ≥70 years old have among the highest rates of motor vehicle collisions (MVC) compared to other age groups. Driving is a highly visual task, and older adults have a high prevalence of vision impairment compared to other ages. Most studies addressing visual risk factors for MVCs by older drivers utilize vehicle accident reports as the primary outcome, an approach with several methodological limitations. Naturalistic driving research methods overcome these challenges and involve installing a high-tech, unobtrusive data acquisition system (DAS) in an older driver's own vehicle. The DAS continuously records multi-channel video of driver and roadway, sensor-based kinematics, GPS location, and presence of nearby objects in front of the vehicle, providing an objective measure of driving exposure. In this naturalistic driving study, the purpose is to examine the relationship between vision and crashes and near-crashes, lane-keeping, turning at intersections, driving performance during secondary tasks demands, and the role of front-seat passengers. An additional aim is to compare results of the on-road driving evaluation by a certified driving rehabilitation specialist to objective indicators of driving performance derived from the naturalistic data. Drivers ≥70 years old are recruited from ophthalmology clinics and a previous population-based study of older drivers, with the goal of recruiting persons with wide ranging visual function. Target samples size is 195 drivers. At a baseline visit, the DAS is installed in the participant's vehicle and a battery of health and functional assessments are administered to the driver including visual-sensory and visual-cognitive tests. The DAS remains installed in the vehicle for six months while the participant goes about his/her normal driving with no imposed study restrictions. After six months, the driver returns for DAS de-installation, repeat vision testing, and an on-road driving evaluation by a certified driving rehabilitation specialist (CDRS). The data streams recorded by the DAS are uploaded to the data coordinating center for analysis. The Alabama VIP Older Driver Study is the first naturalistic older driver study specifically focused on the enrollment of drivers with vision impairment in order to study the relationship between visual dysfunction and driver safety and performance.

Neuropsychological deficits associated with driving performance in Parkinson’s and Alzheimer’s disease

PubMed Central

GRACE, JANET; AMICK, MELISSA M.; D’ABREU, ANELYSSA; FESTA, ELENA K.; HEINDEL, WILLIAM C.; OTT, BRIAN R.

2012-01-01

Neuropsychological and motor deficits in Parkinson’s disease that may contribute to driving impairment were examined in a cohort study comparing patients with Parkinson’s disease (PD) to patients with Alzheimer’s disease (AD) and to healthy elderly controls. Nondemented individuals with Parkinson’s disease [Hoehn & Yahr (H&Y) stage I–III], patients with Alzheimer’s disease [Clinical Demetia Rating scale (CDR) range 0–1], and elderly controls, who were actively driving, completed a neuropsychological battery and a standardized road test administered by a professional driving instructor. On-road driving ability was rated on number of driving errors and a global rating of safe, marginal, or unsafe. Overall, Alzheimer’s patients were more impaired drivers than Parkinson’s patients. Parkinson’s patients distinguished themselves from other drivers by a head-turning deficiency. Drivers with neuropsychological impairment were more likely to be unsafe drivers in both disease groups compared to controls. Compared to controls, unsafe drivers with Alzheimer’s disease were impaired across all neuropsychological measures except finger tapping. Driving performance in Parkinson’s patients was related to disease severity (H&Y), neuropsychological measures [Rey Osterreith Complex Figure (ROCF), Trails B, Hopkins Verbal List Learning Test (HVLT)-delay], and specific motor symptoms (axial rigidity, postural instability), but not to the Unified Parkinson Disease Rating Scale (UPDRS) motor score. Multifactorial measures (ROCF, Trails B) were useful in distinguishing safe from unsafe drivers in both patient groups. PMID:16248912

Effect of simulator training on driving after stroke: a randomized controlled trial.

PubMed

Akinwuntan, A E; De Weerdt, W; Feys, H; Pauwels, J; Baten, G; Arno, P; Kiekens, C

2005-09-27

Neurologically impaired persons seem to benefit from driving-training programs, but there is no convincing evidence to support this notion. The authors therefore investigated the effect of simulator-based training on driving after stroke. Eighty-three first-ever subacute stroke patients entered a 5-week 15-hour training program in which they were randomly allocated to either an experimental (simulator-based training) or control (driving-related cognitive tasks) group. Performance in off-road evaluations and an on-road test were used to assess the driving ability of subjects pre- and post-training. Outcome of an official predriving assessment administered 6 to 9 months poststroke was also considered. Both groups significantly improved in a visual and many neuropsychological evaluations and in the on-road test after training. There were no significant differences between both groups in improvements from pre- to post-training except in the "road sign recognition test" in which the experimental subjects improved more. Significant improvements in the three-class decision ("fit to drive," "temporarily unfit to drive," and "unfit to drive") were found in favor of the experimental group post-training. Academic qualification and overall disability together determined subjects that benefited most from the simulator-based driving training. Significantly more experimental subjects (73%) than control subjects (42%) passed the follow-up official predriving assessment and were legally allowed to resume driving. Simulator-based driving training improved driving ability, especially for well educated and less disabled stroke patients. However, the findings of the study may have been modified as a result of the large number of dropouts and the possibility of some neurologic recovery unrelated to training.

77 FR 39561 - Advanced Braking Technologies That Rely on Forward-Looking Sensors; Request for Comments

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-03

... test scenarios: driving over a 1-inch thick steel plate lying flat on the pavement (a plate often used... provide specific recommendations for other surrogate vehicle design considerations that should be... perform as designed (e.g., driving in the dark or in adverse weather)? What information should be...

Carryover effects of highly automated convoy driving on subsequent manual driving performance.

PubMed

Skottke, Eva-Maria; Debus, Günter; Wang, Lei; Huestegge, Lynn

2014-11-01

In the present study, we tested to what extent highly automated convoy driving involving small spacing ("platooning") may affect time headway (THW) and standard deviation of lateral position (SDLP) during subsequent manual driving. Although many previous studies have reported beneficial effects of automated driving, some research has also highlighted potential drawbacks, such as increased speed and reduced THW during the activation of semiautomated driving systems. Here, we rather focused on the question of whether switching from automated to manual driving may produce unwanted carryover effects on safety-relevant driving performance. We utilized a pre-post simulator design to measure THW and SDLP after highly automated driving and compared the data with those for a control group (manual driving throughout). Our data revealed that THW was reduced and SDLP increased after leaving the automation mode. A closer inspection of the data suggested that specifically the effect on THW is likely due to sensory and/or cognitive adaptation processes. Behavioral adaptation effects need to be taken into account in future implementations of automated convoy systems. Potential application areas of this research comprise automated freight traffic (truck convoys) and the design of driver assistance systems in general. Potential countermeasures against following at short distance as behavioral adaptation should be considered.

Interrater Reliability of the Power Mobility Road Test in the Virtual Reality-Based Simulator-2.

PubMed

Kamaraj, Deepan C; Dicianno, Brad E; Mahajan, Harshal P; Buhari, Alhaji M; Cooper, Rory A

2016-07-01

To assess interrater reliability of the Power Mobility Road Test (PMRT) when administered through the Virtual Reality-based SIMulator-version 2 (VRSIM-2). Within-subjects repeated-measures design. Participants interacted with VRSIM-2 through 2 display options (desktop monitor vs immersive virtual reality screens) using 2 control interfaces (roller system vs conventional movement-sensing joystick), providing 4 different driving scenarios (driving conditions 1-4). Participants performed 3 virtual driving sessions for each of the 2 display screens and 1 session through a real-world driving course (driving condition 5). The virtual PMRT was conducted in a simulated indoor office space, and an equivalent course was charted in an open space for the real-world assessment. After every change in driving condition, participants completed a self-reported workload assessment questionnaire, the Task Load Index, developed by the National Aeronautics and Space Administration. A convenience sample of electric-powered wheelchair (EPW) athletes (N=21) recruited at the 31st National Veterans Wheelchair Games. Not applicable. Total composite PMRT score. The PMRT had high interrater reliability (intraclass correlation coefficient [ICC]>.75) between the 2 raters in all 5 driving conditions. Post hoc analyses revealed that the reliability analyses had >80% power to detect high ICCs in driving conditions 1 and 4. The PMRT has high interrater reliability in conditions 1 and 4 and could be used to assess EPW driving performance virtually in VRSIM-2. However, further psychometric assessment is necessary to assess the feasibility of administering the PMRT using the different interfaces of VRSIM-2. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Split-Stirling-cycle displacer linear-electric drive

NASA Technical Reports Server (NTRS)

Ackermann, R. A.; Bhate, S. K.; Byrne, D. V.

1983-01-01

The retrofit of a 1/4-W split-Stirling cooler with a linear driven on the displacer was achieved and its performance characterized. The objective of this work was to demonstrate that a small linear motor could be designed to meet the existing envelope specifications of the cooler and that an electric linear drive on the displacer could improve the cooler's reliability and performance. The paper describes the characteristics of this motor and presents cooler test results.

Feasibility model of a high reliability five-year tape transport, Volume 1. [development, performance, and test results

NASA Technical Reports Server (NTRS)

Eshleman, R. L.; Meyers, A. P.; Davidson, W. A.; Gortowski, R. C.; Anderson, M. E.

1973-01-01

The development, performance, and test results for the spaceborne magnetic tape transport are discussed. An analytical model of the tape transport was used to optimize its conceptual design. Each of the subsystems was subjected to reliability analyses which included structural integrity, maintenance of system performance within acceptable bounds, and avoidance of fatigue failure. These subsystems were also compared with each other in order to evaluate reliability characteristics. The transport uses no mechanical couplings. Four drive motors, one for each reel and one for each of two capstans, are used in a differential mode. There are two hybrid, spherical, cone tapered-crown rollers for tape guidance. Storage of the magnetic tape is provided by a reel assembly which includes the reel, a reel support structure and bearings, dust seals, and a dc drive motor. A summary of transport test results on tape guidance, flutter, and skew is provided.

EFFECTS OF DIFFERENT WARM-UP PROGRAMS ON GOLF PERFORMANCE IN ELITE MALE GOLFERS

PubMed Central

Macfarlane, Alison

2012-01-01

Background: The physical demands required of the body to execute a shot in golf are enormous. Current evidence suggests that warm-up involving static stretching is detrimental to immediate performance in golf as opposed to active dynamic stretching. However the effect of resistance exercises during warm-up before golf on immediate performance is unknown. Therefore, the purpose of this study was to assess the effects of three different warm-up programs on immediate golf performance. Methods: Fifteen elite male golfers completed three different warm-up programs over three sessions on non-consecutive days. After each warm-up program each participant hit ten maximal drives with the ball flight and swing analyzed with Flightscope® to record maximum club head speed (MCHS), maximal driving distance (MDD), driving accuracy (DA), smash factor (SF) and consistent ball strike (CBS). Results: Repeated measures ANOVA tests showed statistically significant difference within 3 of the 5 factors of performance (MDD, CBS and SF). Subsequently, a paired t-test then showed statistically significant (p<0.05) improvements occurred in each of these three factors in the group performing a combined active dynamic and functional resistance (FR) warm-up as opposed to either the active dynamic (AD) warm-up or the combined AD with weights warm-up (WT). There were no statistically significant differences observed between the AD warm-up and the WT warm-up for any of the five performance factors and no statistical significant difference between any of the warm-ups for maximum clubhead speed (MCHS) and driving accuracy (DA). Conclusion: Performing a combined AD and FR warm up with Theraband® leads to significant increase in immediate performance of certain factors of the golf drive compared to performing an AD warm-up by itself or a combined AD with WT warm-up. No significant difference was observed between the three warm-up groups when looking at immediate effect on driving accuracy or maximum club head speed. The addition of functional resistance activities to active dynamic stretching has immediate benefits to elite male golfers in relation to some factors of their performance. Level of Evidence: This study is a Quantitative Experimental design using repeated measures and multiple crossovers. It cannot be classified using the descriptive level of evidence. PMID:23936749

The impact of antipsychotics on psychomotor performance with regards to car driving skills.

PubMed

Brunnauer, Alexander; Laux, Gerd; Geiger, Elisabeth; Möller, Hans-Jürgen

2004-04-01

Cognitive and psychomotor impairments are a core feature of most patients with schizophrenia and may have an important influence on driving ability. The present study investigated the effects of neuroleptic monotherapy on psychomotor functions related to car driving skills in schizophrenic patients. Consecutively admitted schizophrenic inpatients (n = 120) were tested under steady state plasma level conditions before discharge to outpatient treatment. Patients met the International Classification of Diseases, Tenth Revision criteria for schizophrenia. The study followed a naturalistic nonrandomized design. Data were collected with the computerized Act & React Testsystem and were analyzed according to medication, severity of illness, and age. Only 32.5% of the schizophrenic inpatients passed the tests without major impairments. Patients treated with atypical neuroleptics or clozapine showed a better test performance on skills related to driving ability when compared with patients on typical neuroleptics. Differences were most pronounced in measures of divided attention, stress tolerance, and attention. Data also suggest that treatment with clozapine had an overall positive impact on measures of reactivity and stress tolerance. These results show that even under steady state pharmacologic conditions psychomotor functions of most schizophrenic patients partly remitted must be considered as impaired. To evaluate these effects, a systematic neuropsychologic examination is recommended.

Eye Movement Patterns for Novice Teen Drivers Does 6 Months of Driving Experience Make a Difference?

PubMed Central

Olsen, Erik C. B.; Lee, Suzanne E.; Simons-Morton, Bruce G.

2009-01-01

Attention to the road is essential to safe driving, but the development of appropriate eye glance scanning behaviors may require substantial driving experience. Novice teen drivers may focus almost exclusively on the road ahead rather than scanning the mirrors, and when performing secondary tasks, they may spend more time with eyes on the task than on the road. This paper examines the extent to which the scanning of novice teens improves with experience. For this study, 18 novice teen (younger than 17.5 years old) and 18 experienced adult drivers performed a set of in-vehicle tasks and a baseline driving segment on a test track, the teens within 4 weeks of licensure and then again 6 months later. This paper addresses the following questions: Did teen eye glance performance improve from initial assessment? Did teens and adults still differ after 6 months? Results for some tasks showed that rearview and left mirror–window (LM-W) glances improved for teens from initial testing to the 6-month follow-up and that some differences between teens and adults at initial testing were no longer significant at the 6-month follow-up, suggesting significant learning effects. The frequency of rearview and LM-W glances during secondary tasks improved among teens at the 6-month follow-up, but teens still had significantly fewer glances to mirrors than did adults when engaged in a secondary task. PMID:19763225

Extra-Vehicular Activity (EVA) glove evaluation test protocol

NASA Technical Reports Server (NTRS)

Hinman-Sweeney, E. M.

1994-01-01

One of the most critical components of a space suit is the gloves, yet gloves have traditionally presented significant design challenges. With continued efforts at glove development, a method for evaluating glove performance is needed. This paper presents a pressure-glove evaluation protocol. A description of this evaluation protocol, and its development is provided. The protocol allows comparison of one glove design to another, or any one design to bare-handed performance. Gloves for higher pressure suits may be evaluated at current and future design pressures to drive out differences in performance due to pressure effects. Using this protocol, gloves may be evaluated during design to drive out design problems and determine areas for improvement, or fully mature designs may be evaluated with respect to mission requirements. Several different test configurations are presented to handle these cases. This protocol was run on a prototype glove. The prototype was evaluated at two operating pressures and in the unpressurized state, with results compared to bare-handed performance. Results and analysis from this test series are provided, as is a description of the configuration used for this test.

Highly loaded multi-stage fan drive turbine - performance of initial seven configurations

NASA Technical Reports Server (NTRS)

Wolfmeyer, G. W.; Thomas, M. W.

1974-01-01

Experimental results of a three-stage highly loaded fan drive turbine test program are presented. A plain blade turbine, a tandem blade turbine, and a tangentially leaned stator turbine were designed for the same velocity diagram and flowpath. Seven combinations of bladerows were tested to evaluate stage performances and effects of the tandem blading and leaned stator. The plain blade turbine design point total-to-total efficiency was 0.886. The turbine with the stage three leaned stator had the same efficiency with an improved exit swirl profile and increased hub reaction. Two-stage group tests showed that the two-stage turbine with tandem stage two stator had an efficiency of 0.880 compared to 0.868 for the plain blade two-stage turbine.

Predicting fitness-to-drive following stroke using the Occupational Therapy - Driver Off Road Assessment Battery.

PubMed

Unsworth, Carolyn A; Baker, Anne; Lannin, Natasha; Harries, Priscilla; Strahan, Janene; Browne, Matthew

2018-02-28

It is difficult to determine if, or when, individuals with stroke are ready to undergo on-road fitness-to-drive assessment. The Occupational Therapy - Driver Off Road Assessment Battery was developed to determine client suitability to resume driving. The predictive validity of the Battery needs to be verified for people with stroke. Examine the predictive validity of the Occupational Therapy - Driver Off Road Assessment Battery for on-road performance among people with stroke. Off-road data were collected from 148 people post stroke on the Battery and the outcome of their on-road assessment was recorded as: fit-to-drive or not fit-to-drive. The majority of participants (76%) were able to resume driving. A classification and regression tree (CART) analysis using four subtests (three cognitive and one physical) from the Battery demonstrated an area under the curve (AUC) of 0.8311. Using a threshold of 0.5, the model correctly predicted 98/112 fit-to-drive (87.5%) and 26/36 people not fit-to-drive (72.2%). The three cognitive subtests from the Occupational Therapy - Driver Off Road Assessment Battery and potentially one of the physical tests have good predictive validity for client fitness-to-drive. These tests can be used to screen client suitability for proceeding to an on-road test following stroke. Implications for Rehabilitation: Following stroke, drivers should be counseled (including consideration of local legislation) concerning return to driving. The Occupational Therapy - Driver Off Road Assessment Battery can be used in the clinic to screen people for suitability to undertake on road assessment. Scores on four of the Occupational Therapy - Driver Off Road Assessment Battery subtests are predictive of resumption of driving following stroke.

Testing the effects of safety climate and disruptive children behavior on school bus drivers performance: A multilevel model.

PubMed

Zohar, Dov; Lee, Jin

2016-10-01

The study was designed to test a multilevel path model whose variables exert opposing effects on school bus drivers' performance. Whereas departmental safety climate was expected to improve driving safety, the opposite was true for in-vehicle disruptive children behavior. The driving safety path in this model consists of increasing risk-taking practices starting with safety shortcuts leading to rule violations and to near-miss events. The study used a sample of 474 school bus drivers in rural areas, driving children to school and school-related activities. Newly developed scales for measuring predictor, mediator and outcome variables were validated with video data taken from inner and outer cameras, which were installed in 29 buses. Results partially supported the model by indicating that group-level safety climate and individual-level children distraction exerted opposite effects on the driving safety path. Furthermore, as hypothesized, children disruption moderated the strength of the safety rule violation-near miss relationship, resulting in greater strength under high disruptiveness. At the same time, the hypothesized interaction between the two predictor variables was not supported. Theoretical and practical implications for studying safety climate in general and distracted driving in particular for professional drivers are discussed. Copyright © 2016 Elsevier Ltd. All rights reserved.

The 3600 hp split-torque helicopter transmission

NASA Technical Reports Server (NTRS)

White, G.

1985-01-01

Final design details of a helicopter transmission that is powered by GE twin T 700 engines each rated at 1800 hp are presented. It is demonstrated that in comparison with conventional helicopter transmission arrangements the split torque design offers: weight reduction of 15%; reduction in drive train losses of 9%; and improved reliability resulting from redundant drive paths between the two engines and the main shaft. The transmission fits within the NASA LeRC 3000 hp Test Stand and accepts the existing positions for engine inputs, main shaft, connecting drive shafts, and the cradle attachment points. One necessary change to the test stand involved gear trains of different ratio in the tail drive gearbox. Progressive uprating of engine input power from 3600 to 4500 hp twin engine rating is allowed for in the design. In this way the test transmission will provide a base for several years of analytical, research, and component development effort targeted at improving the performance and reliability of helicopter transmission.

The impact of cognitive deficit on self-reported car crashes in ultra-octogenarian population: data of an Italian population-based study.

PubMed

Rozzini, Luca; Riva, Maddalena; Zanetti, Marina; Gottardi, Federica; Caratozzolo, Salvatore; Vicini Chilovi, Barbara; Trabucchi, Marco; Padovani, Alessandro

2013-06-01

To examine the usefulness of specific neurocognitive tests for predicting the crash involvement in ultra-octogenarian population. A total of 800 subjects (mean age 82.4 + 3.1 years) underwent a battery of neuropsychological tests. Global intellectual functioning was assessed using the Mini Mental State Examination, mental flexibility and information processing speed were assessed using the Trail Making Test parts A and B (TMT-A and TMT-B), long-term memory was evaluated with the short story, and visuo-spatial skills were tested with Clock Drawing Test. One year after this evaluation, 343 (43%) participants have been interviewed by a telephone call to know if they were currently driving and if they had a car crash during this period. Two hundred ninety-seven subjects had their driving license renewed and completed the follow-up 1 year after. Data shows that less than 11% of this group had a car crash during the first year of observation (Crash Involved). Older subjects involved in a car crash showed significant worse performances on TMT-B (TMT-B pathological Crash Involved vs. Noncrash Involved 47% vs. 27%; p = 0.02) and on short story (short story pathological Crash Involved vs. Noncrash Involved 19% vs. 5%; p = 0.02). Trail Making test B and short story have been demonstrated to provide a predictive value of driving performance of older people. Therefore, we suggest that a simple and standardized battery of neuropsychological tests, lasting about 30 min and administered by an experienced staff, is a good diagnostic instrument for risk prevention of driving activity of older drivers. Copyright © 2012 John Wiley & Sons, Ltd.

Awareness of driving disability in people with stroke tested in a simulator.

PubMed

Patomella, Ann-Helen; Kottorp, Anders; Tham, Kerstin

2008-09-01

The aim of this study was to explore and describe awareness of driving disability in people with driving difficulties after stroke. The study comprised a consecutive sample of 38 participants with stroke who showed difficulties in a technically advanced, interactive driving simulator. Driving ability in the simulator was measured using Performance Analysis of Driving Ability (P-Drive). Awareness of driving disability was measured using a modified version of Assessment of Awareness of Disability (AAD), measuring the discrepancy between observed driving actions and self-reported disability after a driving evaluation in a simulator. A majority of the participants (n = 36) demonstrated driving ability that was below the cut-off criterion for P-Drive. Furthermore, a majority of the items measuring awareness of driving disability were scored low, indicating that participants with stroke who did not pass a driving evaluation also had limited awareness of driving disability. A General Linear Model analysis indicated that awareness of driving disability and cognitive screening outcome explained 74% of the variance in driving ability. This study indicated that a majority of the people with stroke who fail a driving evaluation also have limited awareness of their disability, which indicates the need to address awareness in driving evaluations.

The Longitudinal Impact of Cognitive Speed of Processing Training on Driving Mobility

ERIC Educational Resources Information Center

Edwards, Jerri D.; Myers, Charlsie; Ross, Lesley A.; Roenker, Daniel L.; Cissell, Gayla M.; McLaughlin, Alexis M.; Ball, Karlene K.

2009-01-01

Purpose: To examine how cognitive speed of processing training affects driving mobility across a 3-year period among older drivers. Design and Methods: Older drivers with poor Useful Field of View (UFOV) test performance (indicating greater risk for subsequent at-fault crashes and mobility declines) were randomly assigned to either a speed of…

The Effects of Target Orientation on the Dynamic Contrast Sensitivity Function

DTIC Science & Technology

1994-01-01

tests: A comparative evaluation. Journal of Amlied ychology, 50, 460-466. Burg, A. (1971). Vision and driving: A report on research. Human Factors...evaluation. Journal of Applied Ps ogy, 50, 460-466. Burg, A. (1971). Vision and driving: A report on research. Human Factors, 13, 79-87. Campbell, F. W...FUNDING NUMBERS 6. AUTHOR(S)G~ioD A- 0ecoKT, ) 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER AFIT Student

Fuel and Emissions Reduction in Electric Power Take-Off Equipped Utility Vehicles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Konan, Arnaud; Ragatz, Adam; Prohaska, Robert

The National Renewable Energy Laboratory (NREL) evaluated the performance of Pacific Gas and Electric plug-in hybrid electric power take off (ePTO) utility trucks equipped with Altec, Inc.'s Jobsite Energy Management System. NREL collected on-road performance data from Class 5 utility 'trouble trucks' and Class 8 material handlers and developed representative drive cycles for chassis dynamometer testing. The drive cycles were analyzed and jobsite energy use was quantified for impacts and potential further hybridization for the utility truck vocation.

Modeling Human Steering Behavior During Path Following in Teleoperation of Unmanned Ground Vehicles.

PubMed

Mirinejad, Hossein; Jayakumar, Paramsothy; Ersal, Tulga

2018-04-01

This paper presents a behavioral model representing the human steering performance in teleoperated unmanned ground vehicles (UGVs). Human steering performance in teleoperation is considerably different from the performance in regular onboard driving situations due to significant communication delays in teleoperation systems and limited information human teleoperators receive from the vehicle sensory system. Mathematical models capturing the teleoperation performance are a key to making the development and evaluation of teleoperated UGV technologies fully simulation based and thus more rapid and cost-effective. However, driver models developed for the typical onboard driving case do not readily address this need. To fill the gap, this paper adopts a cognitive model that was originally developed for a typical highway driving scenario and develops a tuning strategy that adjusts the model parameters in the absence of human data to reflect the effect of various latencies and UGV speeds on driver performance in a teleoperated path-following task. Based on data collected from a human subject test study, it is shown that the tuned model can predict both the trend of changes in driver performance for different driving conditions and the best steering performance of human subjects in all driving conditions considered. The proposed model with the tuning strategy has a satisfactory performance in predicting human steering behavior in the task of teleoperated path following of UGVs. The established model is a suited candidate to be used in place of human drivers for simulation-based studies of UGV mobility in teleoperation systems.

Method for Assessing Contrast Performance under Lighting Conditions such as Entering a Tunnel on Sunny Day.

PubMed

Huang, Y; Menozzi, M

2015-04-01

Clinical assessment of dark adaptation is time consuming and requires a specialised instrumentation such as a nyktometer. It is therefore not surprising that dark adaptation is rarely tested in practice. As for the case of testing fitness of a driver, demands on adaptation in daily driving tasks mostly depart from settings in a nyktometer. In daily driving, adaptation is stressed by high and fast transitions of light levels, and the period of time which is relevant to safe driving starts right after a transition and ends several seconds later. In the nyktometer dark adaptation is tested after completion of the adaptation process. RESULTS of a nyktometer test may therefore deliver little information about adaptation shortly after light transitions. In an attempt to develop a clinical test aiming to fulfill both a short measurement time and offering test conditions comparable to conditions in driving, we conducted a preliminary study in which contrast sensitivity thresholds were recorded for light transitions as found in daily driving tasks and for various times after transition onsets. Contrast sensitivity performance is compared to dark adaptation performance as assessed by a myktometer. Contrast sensitivity thresholds were recorded in 17 participants by means of a twin projection apparatus. The apparatus enabled the projection of an adapting field and of a Landolt ring both with a variable luminance. Five different stepwise transitions in levels of adapting luminance were tested. All transitions occurred from bright to dark. The Landolt ring was flashed 100 or 500 ms after the transition had occurred. Participants were instructed to report the orientation of the Landolt ring. A Rodenstock Nyktometer, Plate 501, was used to record dark adaptation threshold. Experimental data from the proposed test revealed a noticeably increasing contrast detection threshold measured in dark adaptation in the stronger transition from 14 000 to 8 cd/m2 than in the weaker transition from 2000 to 8 cd/m2. By raising the dark adaption luminance level from 8 to 60 cd/m2 in the stronger transition case, the contrast detection threshold was then improved by a factor of four. Another main finding showed that for the adaptation process from strong glare stimuli to the dark adaptation, a peak deterioration in contrast sensitivity occurred at the light adaptation level of 6000 cd/m2. Comparing the contrast performance assessed by the proposed test with that of the nyktometer test, there was no clear correlation between the two methods. Our suggested method to assess dark adaptation performance proved to be practical in use and, since the patient does not have to spend a long time to attain complete dark adaptation, the method required a short time for measurement. Our negative experience in the use of the myktometer was in agreement with reported experience in the literature. Georg Thieme Verlag KG Stuttgart · New York.

Integrated chassis control for a three-axle electric bus with distributed driving motors and active rear steering system

NASA Astrophysics Data System (ADS)

Liu, Wei; He, Hongwen; Sun, Fengchun; Lv, Jiangyi

2017-05-01

This paper describes an integrated chassis control framework for a novel three-axle electric bus with active rear steering (ARS) axle and four motors at the middle and rear wheels. The proposed integrated framework consists of four parts: (1) an active speed limiting controller is designed for anti-body slip control and rollover prevention; (2) an ARS controller is designed for coordinating the tyre wear between the driving wheels; (3) an inter-axle torque distribution controller is designed for optimal torque distribution between the axles, considering anti-wheel slip and battery power limitations and (4) a data acquisition and estimation module for collecting the measured and estimated vehicle states. To verify the performances, a simulation platform is established in Trucksim software combined with Simulink. Three test cases are particularly designed to show the performances. The proposed algorithm is compared with a simple even control algorithm. The test results show satisfactory lateral stability and rollover prevention performances under severe steering conditions. The desired tyre wear coordinating performance is also realised, and the wheel slip ratios are restricted within stable region during intensive driving and emergency braking with complicated road conditions.

Assessment of Driver's Reaction Times in Diverisified Research Environments

NASA Astrophysics Data System (ADS)

Guzek, Marek; Lozia, Zbigniew; Zdanowicz, Piotr; Jurecki, Rafał S.; Stańczyk, Tomasz L.; Pieniążek, Wiesław

2012-06-01

Reaction time is one of the basic parameters that characterize the driver and very important in the analysis of accident situations in road traffic. This paper describes research studies on the reaction time evaluation as conducted in three environments: on a typical device used in the transport psychology labs (the so-called reflexometer), in the driving simulator (autoPW) and on the driving test track (the Kielce Test Track). In all environments, the tests were performed for the same group of drivers. The article presents the characteristics of research in each environment as well as shows and compares exemplary results.

Magnetostrictive direct drive motors

NASA Technical Reports Server (NTRS)

Naik, Dipak; Dehoff, P. H.

1990-01-01

Developing magnetostrictive direct drive research motors to power robot joints is discussed. These type motors are expected to produce extraordinary torque density, to be able to perform microradian incremental steps and to be self-braking and safe with the power off. Several types of motor designs have been attempted using magnetostrictive materials. One of the candidate approaches (the magnetostrictive roller drive) is described. The method in which the design will function is described as is the reason why this approach is inherently superior to the other approaches. Following this, the design will be modelled and its expected performance predicted. This particular candidate design is currently undergoing detailed engineering with prototype construction and testing scheduled for mid 1991.

Sensitivity of subjective questionnaires to cognitive loading while driving with navigation aids: a pilot study.

PubMed

Smyth, Christopher C

2007-05-01

Developers of future forces are implementing automated aiding for driving tasks. In designing such systems, the effect of cognitive task interference on driving performance is important. The crew of such vehicles may have to occasionally perform communication and planning tasks while driving. Subjective questionnaires may aid researchers to parse out the sources of task interference in crew station designs. In this preliminary study, sixteen participants drove a vehicle simulator with automated road-turn cues (i.e., visual, audio, combined, or neither) along a course marked on a map display while replying to spoken test questions (i.e., repeating sentences, math and logical puzzles, route planning, or none) and reporting other vehicles in the scenario. Following each trial, a battery of subjective questionnaires was administered to determine the perceived effects of the loading on their cognitive functionality. Considering the performance, the participants drove significantly faster with the road-turn cues than with just the map. They recalled fewer vehicle sightings with the cognitive tests than without them. Questionnaire results showed that their reasoning was more straightforward, the quantity of information for understanding higher, and the trust greater with the combined cues than the map-only. They reported higher perceived workload with the cognitive tests. The capacity for maintaining situational awareness was reduced with the cognitive tests because of the increased division of attention and the increase in the instability, variability, and complexity of the demands. The association and intuitiveness of cognitive processing were lowest and the subjective stress highest for the route planning test. Finally, the confusability in reasoning was greater for the auditory cue with the route planning than the auditory cue without the cognitive tests. The subjective questionnaires are sensitive to the effects of the cognitive loading and, therefore, may be useful for guiding the development of automated aid designs.

Mobility scooter driving ability in visually impaired individuals.

PubMed

Cordes, Christina; Heutink, Joost; Brookhuis, Karel A; Brouwer, Wiebo H; Melis-Dankers, Bart J M

2018-06-01

To investigate how well visually impaired individuals can learn to use mobility scooters and which parts of the driving task deserve special attention. A mobility scooter driving skill test was developed to compare driving skills (e.g. reverse driving, turning) between 48 visually impaired (very low visual acuity = 14, low visual acuity = 10, peripheral field defects = 11, multiple visual impairments = 13) and 37 normal-sighted controls without any prior experience with mobility scooters. Performance on this test was rated on a three-point scale. Furthermore, the number of extra repetitions on the different elements were noted. Results showed that visually impaired participants were able to gain sufficient driving skills to be able to use mobility scooters. Participants with visual field defects combined with low visual acuity showed most problems learning different skills and needed more training. Reverse driving and stopping seemed to be most difficult. The present findings suggest that visually impaired individuals are able to learn to drive mobility scooters. Mobility scooter allocators should be aware that these individuals might need more training on certain elements of the driving task. Implications for rehabilitation Visual impairments do not necessarily lead to an inability to acquire mobility scooter driving skills. Individuals with peripheral field defects (especially in combination with reduced visual acuity) need more driving ability training compared to normal-sighted people - especially to accomplish reversing. Individual assessment of visually impaired people is recommended, since participants in this study showed a wide variation in ability to learn driving a mobility scooter.

Experimental examination of the effects of televised motor vehicle commercials on risk-positive attitudes, emotions and risky driving inclinations.

PubMed

Vingilis, Evelyn; Roseborough, James E W; Wiesenthal, David L; Vingilis-Jaremko, Larissa; Nuzzo, Valentina; Fischer, Peter; Mann, Robert E

2015-02-01

This study examined the short-term effects of risky driving motor vehicle television commercials on risk-positive attitudes, emotions and risky driving inclinations in video-simulated critical road traffic situations among males and females, within an experimental design. Participants were randomly assigned to one of three televised commercial advertising conditions embedded in a television show: a risky driving motor vehicle commercial condition, a non-risky driving motor vehicle commercial condition and a control non-motor vehicle commercial condition. Participants subsequently completed the Implicit Attitude Test (IAT) to measure risk-positive attitudes, Driver Thrill Seeking Scale (DTSS) to measure risk-positive emotions and the Vienna Risk-Taking Test - Traffic (WRBTV) to measure risky driving inclinations. ANOVA analyses indicated that type of commercial participants watched did not affect their performance on the IAT, DTSS or WRBTV. However, a main effect of heightened risk-positive emotions and risky driving inclinations was found for males. Despite public and governmental concern that risky driving motor vehicle commercials may increase the likelihood that people exposed to these commercials engage in risky driving, this experimental study found no immediate effect of brief exposure to a risky driving motor vehicle commercial on risk-positive attitudes, emotions or risky driving inclinations. Subsequent research should examine the effects of cumulative exposure to risky driving motor vehicle television commercials and print advertisements. Copyright © 2014 Elsevier Ltd. All rights reserved.

Satellite-instrument system engineering best practices and lessons

NASA Astrophysics Data System (ADS)

Schueler, Carl F.

2009-08-01

This paper focuses on system engineering development issues driving satellite remote sensing instrumentation cost and schedule. A key best practice is early assessment of mission and instrumentation requirements priorities driving performance trades among major instrumentation measurements: Radiometry, spatial field of view and image quality, and spectral performance. Key lessons include attention to technology availability and applicability to prioritized requirements, care in applying heritage, approaching fixed-price and cost-plus contracts with appropriate attention to risk, and assessing design options with attention to customer preference as well as design performance, and development cost and schedule. A key element of success either in contract competition or execution is team experience. Perhaps the most crucial aspect of success, however, is thorough requirements analysis and flowdown to specifications driving design performance with sufficient parameter margin to allow for mistakes or oversights - the province of system engineering from design inception to development, test and delivery.

[Driving ability and dementia].

PubMed

Lukas, Albert; Nikolaus, Thorsten

2009-06-01

Physiological changes in cognitive competence in the elderly are clearly different to pathological changes such as dementia. Diagnosing dementia is not to be equated with absolute driving inability. During the course of dementia, the risk of an accident increases significantly. Detailed observation and regular checks serve to determine the appropriate time to hand in the driving licence. The basis of each decision should be a detailed history of the person and his or her immediate family. Attention should be paid to incorrect driving practise, unusual behaviour and uncertainty whilst driving as well as involvement in any accidents. An MMSE score below 24 or a CCT score up to 3 should result in an additional assessment being carried out, e.g. neuro-psychological tests, driving simulator or, if necessary on-road tests performed with specialists. Also helpful is the determination of functional status. Limitations in ADL or IADL function normally indicate an advanced stage of dementia. Due to the progression of the illness, the possibility of handing in the driving licence should be addressed as soon as possible. In this context, it is helpful to consider alternative forms of transportation. Individual wishes and needs must to be balanced against general road safety requirements.

Reading Text While Driving

PubMed Central

Horrey, William J.; Hoffman, Joshua D.

2015-01-01

Objective In this study, we investigated how drivers adapt secondary-task initiation and time-sharing behavior when faced with fluctuating driving demands. Background Reading text while driving is particularly detrimental; however, in real-world driving, drivers actively decide when to perform the task. Method In a test track experiment, participants were free to decide when to read messages while driving along a straight road consisting of an area with increased driving demands (demand zone) followed by an area with low demands. A message was made available shortly before the vehicle entered the demand zone. We manipulated the type of driving demands (baseline, narrow lane, pace clock, combined), message format (no message, paragraph, parsed), and the distance from the demand zone when the message was available (near, far). Results In all conditions, drivers started reading messages (drivers’ first glance to the display) before entering or before leaving the demand zone but tended to wait longer when faced with increased driving demands. While reading messages, drivers looked more or less off road, depending on types of driving demands. Conclusions For task initiation, drivers avoid transitions from low to high demands; however, they are not discouraged when driving demands are already elevated. Drivers adjust time-sharing behavior according to driving demands while performing secondary tasks. Nonetheless, such adjustment may be less effective when total demands are high. Application This study helps us to understand a driver’s role as an active controller in the context of distracted driving and provides insights for developing distraction interventions. PMID:25850162

Cold-air performance of compressor-drive turbine of department of energy upgraded automobile gas turbine engine. 3: Performance of redesigned turbine

NASA Technical Reports Server (NTRS)

Roelke, R. J.; Haas, J. E.

1984-01-01

The aerodynamic performance of a redesigned compressor drive turbine of the gas turbine engine is determined in air at nominal inlet conditions of 325 K and 0.8 bar absolute. The turbine is designed with a lower flow factor, higher rotor reaction and a redesigned inlet volute compared to the first turbine. Comparisons between this turbine and the originally designed turbine show about 2.3 percentage points improvement in efficiency at the same rotor tip clearance. Two versions of the same rotor are tested: (1) an as cast rotor, and (2) the same rotor with reduced surface roughness. The effect of reducing surface roughness is about one half percentage point improvement in efficiency. Tests made to determine the effect of Reynolds number on the turbine performance show no effect for the range from 100,000 to 500,000.

[Effects of marijuana and amphetamine (and its derivatives on driving performance based on the driving simulator studies].

PubMed

Drabek, Marcin; Andysz, Aleksandra

2011-01-01

This article presents the results of the driving simulator studies of the effects of marijuana and amphetamines on driving performance. The majority of these studies have been focused on identifying the impact of the tested substances on cognitive and psychomotor functions. Most of the findings on marijuana reveal its modest effect on driving ability that increases with the increasing frequency of its use and when used in conjuction with other drugs and alcohol. Similarly, small doses of amphetamines can cause a positive stimulating effect, improving certain cognitive functions, such as vigilance, but it decreases when they are overused and combined with alcohol. The results of the research on drivers' behavior under the influence of amphetamines also indicate deficits in their cognitive functions and tendency to recklessness on the road. The authors also discuss strong and weak points of simulation studies of the effects of psychoactive substances on the driving ability. An attempt was also made to clarify certain ambiguities, which occur in this field of research. A central role of the ethical and methodological limitations of simulation studies were discussed as well.

Medications and impaired driving.

PubMed

Hetland, Amanda; Carr, David B

2014-04-01

To describe the association of specific medication classes with driving outcomes and provide clinical recommendations. The MEDLINE and EMBASE databases were searched for articles published from January 1973 to June 2013 on classes of medications associated with driving impairment. The search included outcome terms such as automobile driving, motor vehicle crash, driving simulator, and road tests. Only English-language articles that contained findings from observational or interventional designs with ≥ 10 participants were included in this review. Cross-sectional studies, case series, and case reports were excluded. Driving is an important task and activity for the majority of adults. Some commonly prescribed medications have been associated with driving impairment measured by road performance, driving simulation, and/or motor vehicle crashes. This review of 30 studies identified findings with barbiturates, benzodiazepines, hypnotics, antidepressants, opioid and nonsteroidal analgesics, anticonvulsants, antipsychotics, antiparkinsonian agents, skeletal muscle relaxants, antihistamines, anticholinergic medications, and hypoglycemic agents. Additional studies of medication impact on sedation, sleep latency, and psychomotor function, as well as the role of alcohol, are also discussed. Psychotropic agents and those with central nervous system side effects were associated with measures of impaired driving performance. It is difficult to determine if such associations are actually a result of medication use or the medical diagnosis itself. Regardless, clinicians should be aware of the increased risk of impaired driving with specific classes of medications, educate their patients, and/or consider safer alternatives.

A pooled analysis of on-the-road highway driving studies in actual traffic measuring standard deviation of lateral position (i.e., "weaving") while driving at a blood alcohol concentration of 0.5 g/L.

PubMed

Jongen, S; Vermeeren, A; van der Sluiszen, N N J J M; Schumacher, M B; Theunissen, E L; Kuypers, K P C; Vuurman, E F P M; Ramaekers, J G

2017-03-01

The on-the-road highway driving test is generally regarded as a gold standard for assessing drug-induced driving impairment. The primary outcome measure is the standard deviation of lateral position (SDLP), a measure of road tracking error or "weaving". The test has been calibrated for incremental doses of alcohol almost 30 years ago in order to define the impact of drug-induced impairment in terms of blood alcohol concentration (BAC) equivalents. Drug-induced changes in SDLP exceeding 2.4 cm have been evaluated as clinically relevant ever since. The present analysis was conducted to assess the robustness of the alcohol effect in a range of on-the-road driving studies which have been conducted since the initial alcohol calibration study. The present study pooled data of 182 participants from nine placebo-controlled crossover studies who performed the highway driving test, while their BAC was at or just below the legal limit for drivers (i.e., 0.5 g/L). Overall, mean SDLP increased with 2.5 cm (95% CI 2.0-2.9 cm). Equivalence testing showed that the clinical relevance criterion value of 2.4 cm fell well within the 95% CI in each individual study. Gender did not affect alcohol-induced changes in SDLP. These results demonstrate the robustness and validity of the clinical relevance criterion for SDLP as measured during on-the-road driving.

Effect of Cognitive Demand on Functional Visual Field Performance in Senior Drivers with Glaucoma.

PubMed

Gangeddula, Viswa; Ranchet, Maud; Akinwuntan, Abiodun E; Bollinger, Kathryn; Devos, Hannes

2017-01-01

Purpose: To investigate the effect of cognitive demand on functional visual field performance in drivers with glaucoma. Method: This study included 20 drivers with open-angle glaucoma and 13 age- and sex-matched controls. Visual field performance was evaluated under different degrees of cognitive demand: a static visual field condition (C1), dynamic visual field condition (C2), and dynamic visual field condition with active driving (C3) using an interactive, desktop driving simulator. The number of correct responses (accuracy) and response times on the visual field task were compared between groups and between conditions using Kruskal-Wallis tests. General linear models were employed to compare cognitive workload, recorded in real-time through pupillometry, between groups and conditions. Results: Adding cognitive demand (C2 and C3) to the static visual field test (C1) adversely affected accuracy and response times, in both groups ( p < 0.05). However, drivers with glaucoma performed worse than did control drivers when the static condition changed to a dynamic condition [C2 vs. C1 accuracy; glaucoma: median difference (Q1-Q3) 3 (2-6.50) vs. 2 (0.50-2.50); p = 0.05] and to a dynamic condition with active driving [C3 vs. C1 accuracy; glaucoma: 2 (2-6) vs. 1 (0.50-2); p = 0.02]. Overall, drivers with glaucoma exhibited greater cognitive workload than controls ( p = 0.02). Conclusion: Cognitive demand disproportionately affects functional visual field performance in drivers with glaucoma. Our results may inform the development of a performance-based visual field test for drivers with glaucoma.

Use of reward-penalty structures in human experimentation

NASA Technical Reports Server (NTRS)

Stein, A. C.; Allen, R. W.; Schwartz, S. H.

1978-01-01

The use of motivational techniques in human performance research is reviewed and an example study employing a reward-penalty structure to simulate the motivations inherent in a real-world situation is presented. Driver behavior in a decision-making driving scenario was studied. The task involved control of an instrumented car on a cooperative test course. Subjects were penalized monetarily for tickets and accidents and rewarded for saving driving time. Two groups were assigned different ticket penalties. The group with the highest penalties tended to drive more conservatively. However, the average total payoff to each group was the same, as the conservative drivers traded off slower driving times with lower ticket penalties.

Post and during event effect of cell phone talking and texting on driving performance--a driving simulator study.

PubMed

Thapa, Raju; Codjoe, Julius; Ishak, Sherif; McCarter, Kevin S

2015-01-01

A number of studies have been done in the field of driver distraction, specifically on the use of cell phone for either conversation or texting while driving. Researchers have focused on the driving performance of drivers when they were actually engaged in the task; that is, during the texting or phone conversation event. However, it is still unknown whether the impact of cell phone usages ceases immediately after the end of task. The primary objective of this article is to analyze the post-event effect of cell phone usage (texting and conversation) in order to verify whether the distracting effect lingers after the actual event has ceased. This study utilizes a driving simulator study of 36 participants to test whether a significant decrease in driver performance occurs during cell phone usage and after usage. Surrogate measures used to represent lateral and longitudinal control of the vehicle were standard deviation (SD) of lane position and mean velocity, respectively. RESULTS suggest that there was no significant decrease in driver performance (both lateral and longitudinal control) during and after the cell phone conversation. For the texting event, there were significant decreases in driver performance in both the longitudinal and lateral control of the vehicle during the actual texting task. The diminished longitudinal control ceased immediately after the texting event but the diminished lateral control lingered for an average of 3.38 s. The number of text messages exchanged did not affect the magnitude or duration of the diminished lateral control. The result indicates that the distraction and subsequent elevated crash risk of texting while driving linger even after the texting event has ceased. This finding has safety and policy implications in reducing distracted driving.

Cryogenic actuator testing for the SAFARI ground calibration setup

NASA Astrophysics Data System (ADS)

de Jonge, C.; Eggens, M.; Nieuwenhuizen, A. C. T.; Detrain, A.; Smit, H.; Dieleman, P.

2012-09-01

For the on-ground calibration setup of the SAFARI instrument cryogenic mechanisms are being developed at SRON Netherlands Institute for Space Research, including a filter wheel, XYZ-scanner and a flipmirror mechanism. Due to the extremely low background radiation requirement of the SAFARI instrument, all of these mechanisms will have to perform their work at 4.5 Kelvin and low-dissipative cryogenic actuators are required to drive these mechanisms. In this paper, the performance of stepper motors, piezoelectric actuators and brushless DC-motors as cryogenic actuators are compared. We tested stepper motor mechanical performance and electrical dissipation at 4K. The actuator requirements, test setup and test results are presented. Furthermore, design considerations and early performance tests of the flipmirror mechanism are discussed. This flipmirror features a 102 x 72 mm aluminum mirror that can be rotated 45°. A Phytron stepper motor with reduction gearbox has been chosen to drive the flipmirror. Testing showed that this motor has a dissipation of 49mW at 4K with a torque of 60Nmm at 100rpm. Thermal modeling of the flipmirror mechanism predicts that with proper thermal strapping the peak temperature of the flipmirror after a single action will be within the background level requirements of the SAFARI instrument. Early tests confirm this result. For low-duty cycle operations commercial stepper motors appear suitable as actuators for test equipment in the SAFARI on ground calibration setup.

Upgraded demonstration vehicle task report

NASA Technical Reports Server (NTRS)

Bryant, J.; Hardy, K.; Livingston, R.; Sandberg, J.

1981-01-01

Vehicle/battery performance capabilities and interface problems that occurred when upgraded developmental batteries were integrated with upgraded versions of comercially available electric vehicles were investigated. Developmental batteries used included nickel zinc batteries, a nickel iron battery, and an improved lead acid battery. Testing of the electric vehicles and upgraded batteries was performed in the complete vehicle system environment to characterize performance and identify problems unique to the vehicle/battery system. Constant speed tests and driving schedule range tests were performed on a chassis dynamometer. The results from these tests of the upgraded batteries and vehicles were compared to performance capabilities for the same vehicles equipped with standard batteries.

Visual acuity and legal visual requirement to drive a passenger vehicle.

PubMed

Kiel, A W; Butler, T; Alwitry, A

2003-07-01

(1). To test the consistency and ease with which number-plates of different component figures can be read under DVLA driving test conditions; (2). to test the relative difficulty of reading corresponding figures on registration plates of white and yellow backgrounds.Design Prospective study of consecutive eligible clinic patients. Ophthalmology outpatients. 210 individuals with a corrected visual acuity with both eyes open of between 6/9 and 6/12. The ability to read three different number-plates under standard DVLA driving-test conditions (ie at 20.5 m in good daylight with glasses if worn) and the ability to read identical number-plates against a white and a yellow background. There is a significant difference between the ease with which three different number-plates can be read depending on their letter and numeral composition, although this did not seem to be significantly affected by whether they were printed on a yellow or white background. Only 92.3% of subjects could read all the number-plates at the legal distance, 96.7% could read at least one number-plate at the legal distance and 3.3% of the test subjects could not read any of the number-plates at 20.5 m. The current test protocol used to obtain a driving licence and, moreover, the test the police will employ to assess visual competence to drive, is highly variable and is unlikely to give consistent repeatable results. The performance of those with equally good visual acuity is unpredictable and is highly dependent on the number-plate they are asked to read. This variability could exclude some who would otherwise pass the test or pass an individual with a visual acuity below accepted standards. The forthcoming changes in the regulations for design of number-plates is an ideal opportunity to standardise the whole testing procedure for driving visual acuity.

White LED performance

NASA Astrophysics Data System (ADS)

Gu, Yimin; Narendran, Nadarajah; Freyssinier, Jean Paul

2004-10-01

Two life tests were conducted to compare the effects of drive current and ambient temperature on the degradation rate of 5 mm and high-flux white LEDs. Tests of 5 mm white LED arrays showed that junction temperature increases produced by drive current had a greater effect on the rate of light output degradation than junction temperature increases from ambient heat. A preliminary test of high-flux white LEDs showed the opposite effect, with junction temperature increases from ambient heat leading to a faster depreciation. However, a second life test is necessary to verify this finding. The dissimilarity in temperature effect among 5 mm and high-flux LEDs is likely caused by packaging differences between the two device types.

High-voltage Array Ground Test for Direct-drive Solar Electric Propulsion

NASA Technical Reports Server (NTRS)

Howell, Joe T.; Mankins, John C.; O'Neill, Mark J.

2005-01-01

Development is underway on a unique high-power solar concentrator array called Stretched Lens Array (SLA) for direct drive electric propulsion. These SLA performance attributes closely match the critical needs of solar electric propulsion (SEP) systems, which may be used for "space tugs" to fuel-efficiently transport cargo from low earth orbit (LEO) to low lunar orbit (LLO), in support of NASA s robotic and human exploration missions. Later SEP systems may similarly transport cargo from the earth-moon neighborhood to the Mars neighborhood. This paper will describe the SLA SEP technology, discuss ground tests already completed, and present plans for future ground tests and future flight tests of SLA SEP systems.

CLIC RF High Power Production Testing Program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Syratchev, I.; Riddone, G.; /CERN

The CLIC Power Extraction and Transfer Structure (PETS) is a passive microwave device in which bunches of the drive beam interact with the impedance of the periodically loaded waveguide and generate RF power for the main linac accelerating structure. The demands on the high power production ({approx} 150 MW) and the needs to transport the 100 A drive beam for about 1 km without losses, makes the PETS design rather unique and the operation very challenging. In the coming year, an intense PETS testing program will be implemented. The target is to demonstrate the full performance of the PETS operation.more » The testing program overview and test results available to date are presented.« less

Transistorized PWM inverter-induction motor drive system

NASA Technical Reports Server (NTRS)

Peak, S. C.; Plunkett, A. B.

1982-01-01

This paper describes the development of a transistorized PWM inverter-induction motor traction drive system. A vehicle performance analysis was performed to establish the vehicle tractive effort-speed requirements. These requirements were then converted into a set of inverter and motor specifications. The inverter was a transistorized three-phase bridge using General Electric power Darlington transistors. The description of the design and development of this inverter is the principal object of this paper. The high-speed induction motor is a design which is optimized for use with an inverter power source. The primary feedback control is a torque angle control with voltage and torque outer loop controls. A current-controlled PWM technique is used to control the motor voltage. The drive has a constant torque output with PWM operation to base motor speed and a constant horsepower output with square wave operation to maximum speed. The drive system was dynamometer tested and the results are presented.

Vehicle test report: Jet Industries Electra Van 600

NASA Technical Reports Server (NTRS)

Price, T. W.; Wirth, V. A., Jr.

1982-01-01

The Electra Van 600, an electric vehicle, was tested. Tests were performed to characterize parameters of the Electra Van 600 and to provide baseline data to be used for comparison of improved batteries and to which will be incorporated into the vehicle. The vehicle tests concentrated on the electrical drive subsystem, the batteries, controller, and motor; coastdowns to characterize the road load and range evaluation for cyclic and constant speed conditions; and qualitative performance was evaluated. It is found that the Electra Van 600 range performance is approximately equal to the majority of the vehicles tested previously.

ACD16-0001-023

NASA Image and Video Library

2016-01-06

Senior executives from the Renault-Nissan Alliance, including Carlos Ghosn, chairman and CEO of Nissan, and Jose Munoz, chairman of Nissan North America, visited Ames for meetings and a showcase of the technical partnership between NASA and Nissan North America. The partnership allows researchers to develop and test autonomy algorithms, concepts, and integrated prototypes for a variety of vehicular transport applications – from rovers to self-driving cars. After briefings, a group take a ride in the autonomous vehicle to observed testing of Nissan’s all-electric LEAF as it performed safe autonomous drives across the center.

Driving errors of learner teens: frequency, nature and their association with practice.

PubMed

Durbin, Dennis R; Mirman, Jessica H; Curry, Allison E; Wang, Wenli; Fisher Thiel, Megan C; Schultheis, Maria; Winston, Flaura K

2014-11-01

Despite demonstrating basic vehicle operations skills sufficient to pass a state licensing test, novice teen drivers demonstrate several deficits in tactical driving skills during the first several months of independent driving. Improving our knowledge of the types of errors made by teen permit holders early in the learning process would assist in the development of novel approaches to driver training and resources for parent supervision. The purpose of the current analysis was to describe driving performance errors made by teens during the permit period, and to determine if there were differences in the frequency and type of errors made by teens: (1) in comparison to licensed, safe, and experienced adult drivers; (2) by teen and parent-supervisor characteristics; and (3) by teen-reported quantity of practice driving. Data for this analysis were combined from two studies: (1) the control group of teens in a randomized clinical trial evaluating an intervention to improve parent-supervised practice driving (n=89 parent-teen dyads) and (2) a sample of 37 adult drivers (mean age 44.2 years), recruited and screened as an experienced and competent reference standard in a validation study of an on-road driving assessment for teens (tODA). Three measures of performance: drive termination (i.e., the assessment was discontinued for safety reasons), safety-relevant critical errors, and vehicle operation errors were evaluated at the approximate mid-point (12 weeks) and end (24 weeks) of the learner phase. Differences in driver performance were compared using the Wilcoxon rank sum test for continuous variables and Pearson's Chi-square test for categorical variables. 10.4% of teens had their early assessment terminated for safety reasons and 15.4% had their late assessment terminated, compared to no adults. These teens reported substantially fewer behind the wheel practice hours compared with teens that did not have their assessments terminated: tODAearly (9.0 vs. 20.0, p<0.001) and tODAlate (19.0 vs. 58.3, p<0.001). With respect to critical driving errors, 55% of teens committed a total of 85 critical errors (range of 1-5 errors per driver) on the early tODA; by comparison, only one adult committed a critical error (p<0.001). On the late tODA, 54% of teens committed 67 critical errors (range of 1-8 errors per driver) compared with only one adult (p<0.001). No differences in teen or parent gender, parent/teen relationship type or parent prior experience teaching a teen to drive were observed between teens who committed a critical error on either route and teens that committed no critical errors. A borderline association between median teen-reported practice quantity and critical error commission was observed for the late tODA. The overall median proportion of vehicle operation errors for teens was higher than that of adults on both assessments, though median error proportions were less than 10% for both teens and adults. In comparison to a group of experienced adult drivers, a substantially higher proportion of learner teens committed safety-relevant critical driving errors at both time points of assessment. These findings, as well as the associations between practice quantity and the driving performance outcomes studied suggest that further research is needed to better understand how teens might effectively learn skills necessary for safe independent driving while they are still under supervised conditions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Useful field of view as a reliable screening measure of driving performance in people with Parkinson's disease: results of a pilot study.

PubMed

Classen, S; McCarthy, D P; Shechtman, O; Awadzi, K D; Lanford, D N; Okun, M S; Rodriguez, R L; Romrell, J; Bridges, S; Kluger, B; Fernandez, H H

2009-12-01

To determine the correlations of the Useful Field of View (UFOV), compared to other clinical tests of Parkinson's disease (PD); vision; and cognition with measures of on-road driving assessments and to quantify the UFOV's ability to indicate passing/failing an on-road test in people with PD. Nineteen randomly selected people with idiopathic PD, mean age = 74.8 (6.1), 14 (73.7%) men, 18 (94.7%) Caucasians, were age-matched to 104 controls without PD. The controls had a mean age of 75.4 (6.4), 59 (56.7%) men, 96 (92.3%) Caucasians. Both groups were referred for a driving evaluation after institutional review board approval. Compared to neuropsychological and clinical tests of vision and cognition, the UFOV showed the strongest correlations (r > .75, p < 0.05) with measures of failing a standardized road test and number of driving errors. Among PD patients, the UFOV Risk Index score of 3 (range 1-5) was established as the optimal cutoff value for passing the on-road test, with sensitivity 87 percent and specificity 82 percent, AUC = 92 percent (SE 0.61, p = .002). Similarly, the UFOV 2 (divided attention) optimum cutoff value is 223 ms (range 16-500 ms), sensitivity 87.5 percent, specificity 81.8 percent, AUC = 91 percent (SE 0.73, p = .003). The UFOV 3 (selected attention) optimal cutoff value is 273 ms (range 16-500 ms), sensitivity 75 percent, specificity 72.7 percent, AUC = 87 percent (SE 0.81, p = .007). In this pilot study among PD patients, the UFOV may be a superior screening measure (compared to other measures of disease, cognition, and vision) for predicting on-road driving performance but its rigor must be verified in a larger sample of people with PD.

Evaluation of the intelligent cruise control system : volume 1 : study results

DOT National Transportation Integrated Search

1999-10-01

The Intelligent Cruise Control (ICC) system evaluation was based on an ICC Field Operational Test (FOT) performed in Michigan. The FOT involved 108 volunteers recruited to drive ten ICC-equipped Chrysler Concordes. Testing was initiated in July 1996 ...

A combined field and laboratory design for assessing the impact of night shift work on police officer operational performance.

PubMed

Waggoner, Lauren B; Grant, Devon A; Van Dongen, Hans P A; Belenky, Gregory; Vila, Bryan

2012-11-01

This study assessed the utility of a combined field and laboratory research design for measuring the impact of consecutive night shift work on the sleepiness, vigilance, and driving performance of police patrol officers. For police patrol officers working their normal night shift duty cycles, simulated driving performance and psychomotor vigilance were measured in a laboratory on two separate occasions: in the morning after the last of five consecutive 10.7-h night shifts, and at the same time in the morning after three consecutive days off duty. Order of participation in conditions was randomized among subjects. Subjects experienced manipulation of sleep schedules due to working night shifts in a real operational environment, but performance testing was conducted under controlled laboratory conditions. N = 29 active-duty police patrol officers (27 male, 2 female; age 37.1 ± 6.3 years) working night shift schedules participated in this study. Simulated driving performance, psychomotor vigilance, and subjective sleepiness were significantly degraded following 5 consecutive night shifts as compared to 3 consecutive days off duty, indicating that active-duty police officers are susceptible to performance degradation as a consequence of working nights. This combined field and laboratory research design succeeded in bridging the gap between the realism of the operational environment and the control of laboratory performance testing, demonstrating that this is a useful approach for addressing the relationship between shift work induced fatigue and critical operational task performance.

Advanced turboprop testbed systems study. Volume 1: Testbed program objectives and priorities, drive system and aircraft design studies, evaluation and recommendations and wind tunnel test plans

NASA Technical Reports Server (NTRS)

Bradley, E. S.; Little, B. H.; Warnock, W.; Jenness, C. M.; Wilson, J. M.; Powell, C. W.; Shoaf, L.

1982-01-01

The establishment of propfan technology readiness was determined and candidate drive systems for propfan application were identified. Candidate testbed aircraft were investigated for testbed aircraft suitability and four aircraft selected as possible propfan testbed vehicles. An evaluation of the four candidates was performed and the Boeing KC-135A and the Gulfstream American Gulfstream II recommended as the most suitable aircraft for test application. Conceptual designs of the two recommended aircraft were performed and cost and schedule data for the entire testbed program were generated. The program total cost was estimated and a wind tunnel program cost and schedule is generated in support of the testbed program.

Concepts for Variable/Multi-Speed Rotorcraft Drive System

NASA Technical Reports Server (NTRS)

Stevens, Mark A.; Handschuh, Robert F.; Lewicki, David G.

2008-01-01

In several recent studies and on-going developments for advanced rotorcraft, the need for variable or multi-speed capable rotors has been raised. A speed change of up to 50 percent has been proposed for future rotorcraft to improve overall vehicle performance. Accomplishing rotor speed changes during operation requires both a rotor that can perform effectively over the operation speed/load range, and a propulsion system that can enable these speed changes. A study has been completed to investigate possible drive system arrangements that can accommodate up to the 50 percent speed change. Several concepts will be presented and evaluated. The most promising configurations will be identified and developed for future testing in a sub-scaled test facility to validate operational capability.

Design and performance testing of an ultrasonic linear motor with dual piezoelectric actuators.

PubMed

Smithmaitrie, Pruittikorn; Suybangdum, Panumas; Laoratanakul, Pitak; Muensit, Nantakan

2012-05-01

In this work, design and performance testing of an ultrasonic linear motor with dual piezoelectric actuator patches are studied. The motor system consists of a linear stator, a pre-load weight, and two piezoelectric actuator patches. The piezoelectric actuators are bonded with the linear elastic stator at specific locations. The stator generates propagating waves when the piezoelectric actuators are subjected to harmonic excitations. Vibration characteristics of the linear stator are analyzed and compared with finite element and experimental results. The analytical, finite element, and experimental results show agreement. In the experiments, performance of the ultrasonic linear motor is tested. Relationships between velocity and pre-load weight, velocity and applied voltage, driving force and applied voltage, and velocity and driving force are reported. The design of the dual piezoelectric actuators yields a simpler structure with a smaller number of actuators and lower stator stiffness compared with a conventional design of an ultrasonic linear motor with fully laminated piezoelectric actuators.

Association Between Executive Function and Problematic Adolescent Driving.

PubMed

Pope, Caitlin N; Ross, Lesley A; Stavrinos, Despina

Motor vehicle collisions (MVCs) are one of the leading causes of injury and death for adolescents. Driving is a complex activity that is highly reliant on executive function (EF) to safely navigate through the environment. Little research has examined the efficacy of using self-reported EF measures for assessing adolescent driving risk. This study examined the Behavior Rating Inventory of Executive Function (BRIEF) questionnaire and performance-based EF tasks as potential predictors of problematic driving outcomes in adolescents. Forty-six adolescent drivers completed the (1) BRIEF, (2) Trail Making Test, (3) Backwards Digit Span, and (4) self-report on 3 problematic driving outcomes: the number of times of having been pulled over by a police officer, the number of tickets issued, and the number of MVCs. Greater self-reported difficulty with planning and organization was associated with greater odds of having a MVC, whereas inhibition difficulties were associated with greater odds of receiving a ticket. Greater self-reported difficulty across multiple BRIEF subscales was associated with greater odds of being pulled over. Overall findings indicated that the BRIEF, an ecological measure of EF, showed significant association with self-reported problematic driving outcomes in adolescents. No relationship was found between performance-based EF measures and self-reported driving outcomes. The BRIEF could offer unique and quick insight into problematic driving behavior and potentially be an indicator of driving risk in adolescent drivers during clinical evaluations.

Report on the status of linear drive coolers for the Department of Defense Standard Advanced Dewar Assembly (SADA)

NASA Astrophysics Data System (ADS)

Salazar, William

2003-01-01

The Standard Advanced Dewar Assembly (SADA) is the critical module in the Department of Defense (DoD) standardization effort of scanning second-generation thermal imaging systems. DoD has established a family of SADA's to address requirements for high performance (SADA I), mid-to-high performance (SADA II), and compact class (SADA III) systems. SADA's consist of the Infrared Focal Plane Array (IRFPA), Dewar, Command and Control Electronics (C&CE), and the cryogenic cooler. SADA's are used in weapons systems such as Comanche and Apache helicopters, the M1 Abrams Tank, the M2 Bradley Fighting Vehicle, the Line of Sight Antitank (LOSAT) system, the Improved Target Acquisition System (ITAS), and Javelin's Command Launch Unit (CLU). DOD has defined a family of tactical linear drive coolers in support of the family of SADA's. The Stirling linear drive cryo-coolers are utilized to cool the SADA's Infrared Focal Plane Arrays (IRFPAs) to their operating cryogenic temperatures. These linear drive coolers are required to meet strict cool-down time requirements along with lower vibration output, lower audible noise, and higher reliability than currently fielded rotary coolers. This paper will (1) outline the characteristics of each cooler, (2) present the status and results of qualification tests, and (3) present the status and test results of efforts to increase linear drive cooler reliability.

Relationship Between Motor Vehicle Collisions and Results of Perimetry, Useful Field of View, and Driving Simulation in Drivers With Glaucoma.

PubMed

Tatham, Andrew J; Boer, Erwin R; Gracitelli, Carolina P B; Rosen, Peter N; Medeiros, Felipe A

2015-05-01

To examine the relationship between Motor Vehicle Collisions (MVCs) in drivers with glaucoma and standard automated perimetry (SAP), Useful Field of View (UFOV), and driving simulator assessment of divided attention. A cross-sectional study of 153 drivers from the Diagnostic Innovations in Glaucoma Study. All subjects had SAP and divided attention was assessed using UFOV and driving simulation using low-, medium-, and high-contrast peripheral stimuli presented during curve negotiation and car following tasks. Self-reported history of MVCs and average mileage driven were recorded. Eighteen of 153 subjects (11.8%) reported a MVC. There was no difference in visual acuity but the MVC group was older, drove fewer miles, and had worse binocular SAP sensitivity, contrast sensitivity, and ability to divide attention (UFOV and driving simulation). Low contrast driving simulator tasks were the best discriminators of MVC (AUC 0.80 for curve negotiation versus 0.69 for binocular SAP and 0.59 for UFOV). Adjusting for confounding factors, longer reaction times to driving simulator divided attention tasks provided additional value compared with SAP and UFOV, with a 1 standard deviation (SD) increase in reaction time (approximately 0.75 s) associated with almost two-fold increased odds of MVC. Reaction times to low contrast divided attention tasks during driving simulation were significantly associated with history of MVC, performing better than conventional perimetric tests and UFOV. The association between conventional tests of visual function and MVCs in drivers with glaucoma is weak, however, tests of divided attention, particularly using driving simulation, may improve risk assessment.

Acute effects of alcohol on inhibitory control and simulated driving in DUI offenders.

PubMed

Van Dyke, Nicholas; Fillmore, Mark T

2014-06-01

The public health costs associated with alcohol-related traffic accidents have prompted considerable research aimed at identifying characteristics of individuals who drive under the influence (DUI) in order to improve treatment and prevention strategies. Survey studies consistently show that DUI offenders self-report higher levels of impulsivity compared to their nonoffending counterparts. However, little is known about how individuals with a DUI history respond under alcohol. Inhibitory control is a behavioral component of impulsivity thought to underlie risky drinking and driving behaviors. The present study examined the degree to which DUI drivers display deficits of inhibitory control in response to alcohol and the degree to which alcohol impaired their simulated driving performance. It was hypothesized that DUI offenders would display an increased sensitivity to the acute impairing effects of alcohol on simulated driving performance. Young adult drivers with a history of DUI and a demographically-comparable group of drivers with no history of DUI (controls) were tested following a 0.65 g/kg dose of alcohol and a placebo. Inhibitory control was measured by using a cued go/no-go task. Drivers then completed a driving simulation task that yielded multiple indicators of driving performance, such as within-lane deviation, steering rate, centerline crossings and road edge excursions, and drive speed. Results showed that although DUI offenders self-reported greater levels of impulsivity than did controls, no group differences were observed in the degree to which alcohol impaired inhibitory control and driving performance. The findings point to the need to identify other aspects of behavioral dysfunction underlying the self-reported impulsivity among DUI offenders, and to better understand the specific driving situations that might pose greater risk to DUI offenders. The systematic study of candidate cognitive deficits in DUI offenders will provide important information on their role in risky driving behavior and decisions to drink and drive. Such information is critical for guiding new interventions for DUI offenders that will move treatment beyond general addiction counseling. Copyright © 2014 Elsevier B.V. All rights reserved.

Backset-stationary and during car driving.

PubMed

Jonsson, Bertil; Stenlund, Hans; Björnstig, Ulf

2008-12-01

The aim of the study was to measure and analyze backset, defined as the horizontal distance between the back of the occupant's head and a point located on the ventral/top aspect of the sewn rim of the head restraint, with the car stationary and during driving, in the driver's position in a modern car. A population of 65 subjects, 35 males and 30 females, was studied in a Volvo V70 car, model year 2007. The subjects were studied in the driver's position, in a self-selected posture. Stationary backset was measured with the technique described by Jonsson et al. (2007) and backset during driving with video analysis. Descriptive data were calculated, and variability and correlation analyses were performed. A t-test was used to test differences of means. Significance level was set to 0.05. In comparison to stationary backset, mean backset during driving was 43 mm greater in males and 41 mm greater in females. Driving backset was 44 mm larger in males than in females. Driving backset was moderately correlated (0.37-0.43) to stature, seated height, and seat back angle in males and moderately correlated (0.44-0.52) to hip width, waist circumference, and weight in females. The overall intraclass correlation coefficient for backset during driving was 0.81 (CI: 0.75-0.86). These results may be of use in designing future updates of test protocols/routines for geometric backset, such as RCAR and RCAR-IIWPG.

A Combination of Teacher-Led Assessment and Self-Assessment Drives the Learning Process in Online Master Degree in Transplantation

ERIC Educational Resources Information Center

Halawa, Ahmed; Sharma, Ajay; Bridson, Julie M.; Lyon, Sarah; Prescott, Denise; Guha, Arpan; Taylor, David

2017-01-01

Background: Good performance in a summative assessment does not always equate to educational gain following a course. An educational programme may focus on improving student's performance on a particular test instrument. For example, practicing multiple choice questions may lead to mastery of the instrument itself rather than testing the knowledge…

A method to estimate the environmental impact of an electric city car during six months of testing in an Italian city

NASA Astrophysics Data System (ADS)

Donateo, T.; Ingrosso, F.; Licci, F.; Laforgia, D.

2014-12-01

The present investigation describes the results of a research project (P.R.I.M.E.) aimed at testing the performance and the environmental impact of an electric city car in Italian cities. The vehicle considered in the project is the Daimler AG Smart ForTwo Electric Drive. A Smart ED vehicle was tested at the University of Salento for six months over different driving conditions (routes, traffic, use of auxiliaries). A data acquisition system has been designed on purpose and assembled on board to provide information about driving cycle and energy flows. The system was also used to evaluate the losses of energy during recharges due to the battery cooling system. The experimental tests were used to identify the average, minimum and maximum consumption of electricity in the Smart ED in Lecce according to driving conditions and in particular according to the usage of auxiliaries. The measured data of electric consumption have been used to quantify the emissions of CO2 and pollution of the vehicle using information about the Italian electricity production mix of each recharging event and the emissions factors of the Italian power plants with an innovative and comprehensive methodology.

Visual search and urban driving under the influence of marijuana and alcohol.

PubMed

Lamers, C. T. J.; Ramaekers, J. G.

2001-07-01

The purpose of the present study was to assess the effects of low doses of marijuana and alcohol, and their combination, on visual search at intersections and on general driving proficiency in the City Driving Test. Sixteen recreational users of alcohol and marijuana (eight males and eight females) were treated with these substances or placebo according to a balanced, 4-way, cross-over, observer- and subject-blind design. On separate evenings, subjects received weight-calibrated doses of THC, alcohol or placebo in each of the following treatment conditions: alcohol placebo + THC placebo, alcohol + THC placebo, THC 100 &mgr;g/kg + alcohol placebo, THC 100 &mgr;g/kg + alcohol. Alcohol doses administered were sufficient for achieving a blood alcohol concentration (BAC) of about 0.05 g/dl. Initial drinking preceded smoking by one hour. The City Driving Test commenced 15 minutes after smoking and lasted 45 minutes. The test was conducted over a fixed route within the city limits of Maastricht. An eye movement recording system was mounted on each subject's head for providing relative frequency measures of appropriate visual search at intersections. General driving quality was rated by a licensed driving instructor on a shortened version of the Royal Dutch Tourist Association's Driving Proficiency Test. After placebo treatment subjects searched for traffic approaching from side streets on the right in 84% of all cases. Visual search frequency in these subjects did not change when they were treated with alcohol or marijuana alone. However, when treated with the combination of alcohol and marijuana, the frequency of visual search dropped by 3%. Performance as rated on the Driving Proficiency Scale did not differ between treatments. It was concluded that the effects of low doses of THC (100 &mgr;g/kg) and alcohol (BAC < 0.05 g/dl) on higher-level driving skills as measured in the present study are minimal. Copyright 2001 John Wiley & Sons, Ltd.

The construction, testing, and installation of a 6500 r/min 15 000-hp adjustable-speed electric drive for a centrifugal gas compressor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lawrence, R.G.; Finney, D.; Davidson, D.F.

1988-07-01

The construction, testing, and installation of a 6500 r/min 15 000-hp adjustable-speed electric drive for a centrifugal gas compressor is presented. A power electronic converter is applied to control the speed of a 5-kV motor. The motor is directly coupled to a 6500 r/min compressor and replaced a steam turbine. Dual converters are used in a twelve-pulse arrangement at both the utility and the motor. The motor is of solid rotor construction, with dual 30/sup 0/ displaced stator windings. Finite-element analysis is used to optimize the motor designs for use with a variable-frequency static converter. Full-power tests are completed whichmore » confirm theoretical predictions on losses, performance, and operation. The electrical drive takes up considerably less space and is much more efficient than the steam turbine it replaced.« less

Axial force and efficiency tests of fixed center variable speed belt drive

NASA Technical Reports Server (NTRS)

Bents, D. J.

1981-01-01

An investigation of how the axial force varies with the centerline force at different speed ratios, speeds, and loads, and how the drive's transmission efficiency is affected by these related forces is described. The tests, intended to provide a preliminary performance and controls characterization for a variable speed belt drive continuously variable transmission (CVT), consisted of the design and construction of an experimental test rig geometrically similar to the CVT, and operation of that rig at selected speed ratios and power levels. Data are presented which show: how axial forces exerted on the driver and driven sheaves vary with the centerline force at constant values of speed ratio, speed, and output power; how the transmission efficiency varies with centerline force and how it is also a function of the V belt coefficient; and the axial forces on both sheaves as normalized functions of the traction coefficient.

Life Testing of the Vapor Compression Distillation Urine Processing Assembly (VCD/UPA) at the Marshall Space Flight Center

NASA Technical Reports Server (NTRS)

Wieland, Paul O.

1998-01-01

Wastewater and urine generated on the International Space Station will be processed to recover pure water. The method selected is vapor compression distillation (VCD). To verify the long-term reliability and performance of the VCD Urine Processing Assembly (UPA), accelerated life testing was performed at the Marshall Space Flight Center (MSFC) from January 1993 to April 1996. Two UPAS, the VCD-5 and VCD-5A, were tested for 204 days and 665 days, respectively. The compressor gears and the distillation centrifuge drive belt were found to have an operating life of approximately 4800 hours. Precise alignment of the flex-spline of the fluids pump is essential to avoid failure of the pump after about 400 hours of operation. Also, leakage around the seals of the drive shaft of the fluids pump and purge pump must be eliminated for continued good performance. Results indicate that, with some design and procedural modifications and suitable quality control, the required performance and operational life can be met with the VCD/UPA.

Overcoming urban GPS navigation challenges through the use of MEMS inertial sensors and proper verification of navigation system performance

NASA Astrophysics Data System (ADS)

Vinande, Eric T.

This research proposes several means to overcome challenges in the urban environment to ground vehicle global positioning system (GPS) receiver navigation performance through the integration of external sensor information. The effects of narrowband radio frequency interference and signal attenuation, both common in the urban environment, are examined with respect to receiver signal tracking processes. Low-cost microelectromechanical systems (MEMS) inertial sensors, suitable for the consumer market, are the focus of receiver augmentation as they provide an independent measure of motion and are independent of vehicle systems. A method for estimating the mounting angles of an inertial sensor cluster utilizing typical urban driving maneuvers is developed and is able to provide angular measurements within two degrees of truth. The integration of GPS and MEMS inertial sensors is developed utilizing a full state navigation filter. Appropriate statistical methods are developed to evaluate the urban environment navigation improvement due to the addition of MEMS inertial sensors. A receiver evaluation metric that combines accuracy, availability, and maximum error measurements is presented and evaluated over several drive tests. Following a description of proper drive test techniques, record and playback systems are evaluated as the optimal way of testing multiple receivers and/or integrated navigation systems in the urban environment as they simplify vehicle testing requirements.

Reading text while driving: understanding drivers' strategic and tactical adaptation to distraction.

PubMed

Liang, Yulan; Horrey, William J; Hoffman, Joshua D

2015-03-01

In this study, we investigated how drivers adapt secondary-task initiation and time-sharing behavior when faced with fluctuating driving demands. Reading text while driving is particularly detrimental; however, in real-world driving, drivers actively decide when to perform the task. In a test track experiment, participants were free to decide when to read messages while driving along a straight road consisting of an area with increased driving demands (demand zone) followed by an area with low demands. A message was made available shortly before the vehicle entered the demand zone. We manipulated the type of driving demands (baseline, narrow lane, pace clock, combined), message format (no message, paragraph, parsed), and the distance from the demand zone when the message was available (near, far). In all conditions, drivers started reading messages (drivers' first glance to the display) before entering or before leaving the demand zone but tended to wait longer when faced with increased driving demands. While reading messages, drivers looked more or less off road, depending on types of driving demands. For task initiation, drivers avoid transitions from low to high demands; however, they are not discouraged when driving demands are already elevated. Drivers adjust time-sharing behavior according to driving demands while performing secondary tasks. Nonetheless, such adjustment may be less effective when total demands are high. This study helps us to understand a driver's role as an active controller in the context of distracted driving and provides insights for developing distraction interventions. © 2014, Human Factors and Ergonomics Society.

On the road performance tests of electric test vehicle for correlation with road load simulator

NASA Technical Reports Server (NTRS)

Dustin, M. O.; Slavik, R. J.

1982-01-01

A dynamometer (road load simulator) is used to test and evaluate electric vehicle propulsion systems. To improve correlation between system tests on the road load simulator and on the road, similar performance tests are conducted using the same vehicle. The results of track tests on the electric propulsion system test vehicle are described. The tests include range at constant speeds and over SAE J227a driving cycles, maximum accelerations, maximum gradability, and tire rolling resistance determination. Road power requirements and energy consumption were also determined from coast down tests.

Voltage directive drive with claw pole motor and control without rotor position indicator

NASA Astrophysics Data System (ADS)

Stroenisch, Volker Ewald

Design and testing of a voltage directive drive for synchronous variable speed claw pole motor and control without rotor position indicator is described. Economic analysis of the designed regulation is performed. Computations of stationary and dynamic behavior are given and experimental operational behavior is determined. The motors can be used for electric transportation vehicles, diesel motors, and electric railway engines.

Drivers 55 Plus: Test Your Own Performance. A Self-Rating Form of Questions, Facts and Suggestions for Safe Driving.

ERIC Educational Resources Information Center

Malfetti, James L.; Winter, Darlene J.

This booklet contains a 15-question rating form that provides some guidance to older drivers in beginning to assess their driving skills. The pages following the self-rating form discuss the various questions on the form. After a general introduction, the discussion is divided into five areas that traffic safety authorities have judged critical to…

Carbon Corrosion in PEM Fuel Cells and the Development of Accelerated Stress Tests

DOE PAGES

Macauley, Natalia; Papadias, Dennis D.; Fairweather, Joseph; ...

2018-03-15

Here, carbon corrosion is an important degradation mechanism that can impair PEMFC performance through the destruction of catalyst connectivity, collapse of the electrode pore structure, loss of hydrophobic character, and an increase of the catalyst particle size. In this study, carbon corrosion was quantified in situ by measurement of carbon dioxide in the fuel cell exhaust gases through non-dispersive infrared spectroscopy during simulated drive cycle operations consisting of potential cycling with varying upper and lower potential limits. These studies were conducted for three different types of carbon supports. A reduction in the catalyst layer thickness was observed during a simulatedmore » drive cycle operation with a concomitant decrease in catalyst layer porosity, which led to performance losses due to increased mass transport limitations. The observed thickness reduction was primarily due to compaction of the catalyst layer, with the actual mass of carbon oxidation (loss) contributing only a small fraction (< 20%). The dynamics of carbon corrosion are presented along with a model that simulates the transient and dynamic corrosion rates observed in our experiments. Accelerated carbon corrosion stress tests are presented and their effects are compared to those observed for the drive cycle test.« less

Carbon Corrosion in PEM Fuel Cells and the Development of Accelerated Stress Tests

DOE Office of Scientific and Technical Information (OSTI.GOV)

Macauley, Natalia; Papadias, Dennis D.; Fairweather, Joseph

Here, carbon corrosion is an important degradation mechanism that can impair PEMFC performance through the destruction of catalyst connectivity, collapse of the electrode pore structure, loss of hydrophobic character, and an increase of the catalyst particle size. In this study, carbon corrosion was quantified in situ by measurement of carbon dioxide in the fuel cell exhaust gases through non-dispersive infrared spectroscopy during simulated drive cycle operations consisting of potential cycling with varying upper and lower potential limits. These studies were conducted for three different types of carbon supports. A reduction in the catalyst layer thickness was observed during a simulatedmore » drive cycle operation with a concomitant decrease in catalyst layer porosity, which led to performance losses due to increased mass transport limitations. The observed thickness reduction was primarily due to compaction of the catalyst layer, with the actual mass of carbon oxidation (loss) contributing only a small fraction (< 20%). The dynamics of carbon corrosion are presented along with a model that simulates the transient and dynamic corrosion rates observed in our experiments. Accelerated carbon corrosion stress tests are presented and their effects are compared to those observed for the drive cycle test.« less

Modeling the influence of Chevron alignment sign on young male driver performance: A driving simulator study.

PubMed

Wu, Yiping; Zhao, Xiaohua; Chen, Chen; He, Jiayuan; Rong, Jian; Ma, Jianming

2016-10-01

In China, the Chevron alignment sign on highways is a vertical rectangle with a white arrow and border on a blue background, which differs from its counterpart in other countries. Moreover, little research has been devoted to the effectiveness of China's Chevron signs; there is still no practical method to quantitatively describe the impact of Chevron signs on driver performance in roadway curves. In this paper, a driving simulator experiment collected data on the driving performance of 30 young male drivers as they navigated on 29 different horizontal curves under different conditions (presence of Chevron signs, curve radius and curve direction). To address the heterogeneity issue in the data, three models were estimated and tested: a pooled data linear regression model, a fixed effects model, and a random effects model. According to the Hausman Test and Akaike Information Criterion (AIC), the random effects model offers the best fit. The current study explores the relationship between driver performance (i.e., vehicle speed and lane position) and horizontal curves with respect to the horizontal curvature, presence of Chevron signs, and curve direction. This study lays a foundation for developing procedures and guidelines that would allow more uniform and efficient deployment of Chevron signs on China's highways. Copyright © 2016 Elsevier Ltd. All rights reserved.

Predicting perceived safety to drive the morning after drinking: The importance of hangover symptoms.

PubMed

Cameron, Elaine; French, David P

2016-07-01

People driving the day after drinking are at risk of impaired performance and accidents due to continued intoxication or the effects of alcohol hangover. Drivers are poor at estimating their own blood alcohol concentration, and some drive despite believing they are over the legal limit. It is therefore important to identify other factors influencing perceived ability to drive 'the morning after'. This study tested how accurately participants estimated their legal driving status, and the contribution of beliefs and hangover symptoms to the prediction of perceived driving safety. This cross-sectional study involved 193 students completing a questionnaire and alcohol breath test the morning after heavy alcohol consumption. Indicators of subjective intoxication, severity of hangover symptoms, estimated legal status and perceived safety to drive were measured. A hierarchical linear regression analysis was conducted. No participants thought they were under the English legal limit when they were not, and 47% thought they were over the limit when they were in fact legally permissible to drive. However, 20% of those believing they were over the limit nevertheless rated themselves as safe to drive. Hangover symptoms added 17% variance to the prediction of perceived safety to drive, over and above objective and subjective measures of intoxication. Perceived severity of hangover symptoms influence beliefs about driving ability: When judging safety to drive, people experiencing less severe symptoms believe they are less impaired. If this finding is robust, health promotion campaigns should aim to correct this misapprehension. [Cameron E, French D. Predicting perceived safety to drive the morning after drinking: The importance of hangover symptoms. Drug Alcohol Rev 2016;35:442-446]. © 2015 Australasian Professional Society on Alcohol and other Drugs.

In the eye of the beholder: A simulator study of the impact of Google Glass on driving performance.

PubMed

Young, Kristie L; Stephens, Amanda N; Stephan, Karen L; Stuart, Geoffrey W

2016-01-01

This study examined whether, and to what extent, driving is affected by reading text on Google Glass. Reading text requires a high level of visual resources and can interfere with safe driving. However, it is currently unclear if the impact of reading text on a head-mounted display, such as Google Glass (Glass), will differ from that found with more traditional head-down electronic devices, such as a dash-mounted smartphone. A total of 20 drivers (22-48 years) completed the Lane Change Test while driving undistracted and while reading text on Glass and on a smartphone. Measures of lateral vehicle control and event detection were examined along with subjective workload and secondary task performance. Results revealed that drivers' lane keeping ability was significantly impaired by reading text on both Glass and the smartphone. When using Glass, drivers also failed to detect a greater number of lane change signs compared to when using the phone or driving undistracted. In terms of subjective workload, drivers rated reading on Glass as subjectively easier than on the smartphone, which may possibly encourage greater use of this device while driving. Overall, the results suggest that, despite Glass allowing drivers to better maintain their visual attention on the forward scene, drivers are still not able to effectively divide their cognitive attention across the Glass display and the road environment, resulting in impaired driving performance. Copyright © 2015 Elsevier Ltd. All rights reserved.

Determining skill transferability of action games as a method to reduce in-vehicle phone distractions.

PubMed

Rupp, M; McConnell, D S; Smither, J A

2012-01-01

Distracted driving has been shown to be a safety issue in numerous studies. To combat this problem, in-vehicle technology, legislation, media interventions, and other methods have been proposed and attempted. However research indicates that the drivers themselves may circumvent, ignore, or not be able to react in time for these interventions to be effective. Therefore research into training programs for drivers may improve reaction time under distraction. Research indicates that action game players have faster reaction times and more attentional resources than non-players on paper-based tests. However, transferability to driving has not been studied yet. This paper outlines a study to determine if action game players perform better at a driving task based on frequency of game-play. Participants will be placed into two groups of play (high vs. low) and tested against two levels of distraction (none vs. phone conversation). It is expected that participants who play higher frequency of action games will perform better under distraction than lower frequency players. Driver performance, conversation recall, frequency and durations of eye fixations will be analyzed based on previous research which has validated those variables as a measure of distraction and higher workload.

Parenting and the Young Driver Problem

PubMed Central

Simons-Morton, Bruce G.; Ouimet, Marie Claude; Catalano, Richard F.

2008-01-01

Crash rates increase sharply at the age teenagers begin to drive and remain elevated relative to adult levels well into the twenties. Parents have important roles to play in managing the risk for teenage drivers before and after licensure. Parents can be involved in their teenagers’ driving, allowing them to test for permit and licensure, supervising practice driving, providing access to a vehicle, and setting and enforcing limits on driving privileges after licensure. However, the management practices of many parents may not be sufficient to provide safety effects. The literature indicates that the two most important decisions parents can make to reduce teenagers driving risk is to delay licensure and impose limits on high-risk driving conditions (such as driving at night and with teenage passengers) during the first year of licensure. Two intervention programs have been shown to increase parent limit setting as a means of reducing risky driving behaviors and improving driving performance among novice teenage drivers. This article describes the contexts of and opportunities for parent involvement in teenage driving and the efficacy of interventions to increase and improve parental management of young drivers. PMID:18702985

Using Speech Recall in Hearing Aid Fitting and Outcome Evaluation Under Ecological Test Conditions.

PubMed

Lunner, Thomas; Rudner, Mary; Rosenbom, Tove; Ågren, Jessica; Ng, Elaine Hoi Ning

2016-01-01

In adaptive Speech Reception Threshold (SRT) tests used in the audiological clinic, speech is presented at signal to noise ratios (SNRs) that are lower than those generally encountered in real-life communication situations. At higher, ecologically valid SNRs, however, SRTs are insensitive to changes in hearing aid signal processing that may be of benefit to listeners who are hard of hearing. Previous studies conducted in Swedish using the Sentence-final Word Identification and Recall test (SWIR) have indicated that at such SNRs, the ability to recall spoken words may be a more informative measure. In the present study, a Danish version of SWIR, known as the Sentence-final Word Identification and Recall Test in a New Language (SWIRL) was introduced and evaluated in two experiments. The objective of experiment 1 was to determine if the Swedish results demonstrating benefit from noise reduction signal processing for hearing aid wearers could be replicated in 25 Danish participants with mild to moderate symmetrical sensorineural hearing loss. The objective of experiment 2 was to compare direct-drive and skin-drive transmission in 16 Danish users of bone-anchored hearing aids with conductive hearing loss or mixed sensorineural and conductive hearing loss. In experiment 1, performance on SWIRL improved when hearing aid noise reduction was used, replicating the Swedish results and generalizing them across languages. In experiment 2, performance on SWIRL was better for direct-drive compared with skin-drive transmission conditions. These findings indicate that spoken word recall can be used to identify benefits from hearing aid signal processing at ecologically valid, positive SNRs where SRTs are insensitive.

PNNL streamlines energy-guzzling computers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beckman, Mary T.; Marquez, Andres

In a room the size of a garage, two rows of six-foot-tall racks holding supercomputer hard drives sit back-to-back. Thin tubes and wires snake off the hard drives, slithering into the corners. Stepping between the rows, a rush of heat whips around you -- the air from fans blowing off processing heat. But walk farther in, between the next racks of hard drives, and the temperature drops noticeably. These drives are being cooled by a non-conducting liquid that runs right over the hardworking processors. The liquid carries the heat away in tubes, saving the air a few degrees. This ismore » the Energy Smart Data Center at Pacific Northwest National Laboratory. The bigger, faster, and meatier supercomputers get, the more energy they consume. PNNL's Andres Marquez has developed this test bed to learn how to train the behemoths in energy efficiency. The work will help supercomputers perform better as well. Processors have to keep cool or suffer from "thermal throttling," says Marquez. "That's the performance threshold where the computer is too hot to run well. That threshold is an industry secret." The center at EMSL, DOE's national scientific user facility at PNNL, harbors several ways of experimenting with energy usage. For example, the room's air conditioning is isolated from the rest of EMSL -- pipes running beneath the floor carry temperature-controlled water through heat exchangers to cooling towers outside. "We can test whether it's more energy efficient to cool directly on the processing chips or out in the water tower," says Marquez. The hard drives feed energy and temperature data to a network server running specially designed software that controls and monitors the data center. To test the center’s limits, the team runs the processors flat out – not only on carefully controlled test programs in the Energy Smart computers, but also on real world software from other EMSL research, such as regional weather forecasting models. Marquez's group is also developing "power aware computing", where the computer programs themselves perform calculations more energy efficiently. Maybe once computers get smart about energy, they'll have tips for their users.« less

Quantitative psychomotor dysfunction in schizophrenia: a loss of drive, impaired movement execution or both?

PubMed

Docx, Lise; Sabbe, Bernard; Provinciael, Pieter; Merckx, Niel; Morrens, Manuel

2013-01-01

The aim of the present study was to investigate the predictive value of qualitative psychomotor performance levels and subaspects of the negative syndrome for quantitative motor activity levels in patients with schizophrenia. Twenty-seven stabilized patients with schizophrenia and 22 age- and sex-matched healthy controls were included in the study. An extensive battery of psychomotor performance tests (Finger Tapping Test, Purdue Pegboard Test, Line Copying Test, Neurological Evaluation Scale, Salpêtrière Retardation Rating Scale), clinical rating scales (Positive and Negative Syndrome Scale) and 24-hour actigraphy were administered to all participants. Correlational analyses showed that motor activity levels were associated with avolition as well as clinically assessed psychomotor slowing. However, in a regression model, only avolition was found to be a significant predictor for motor activity levels in patients with schizophrenia; none of the psychomotor performance tests nor the severity of emotional expressivity deficits contributed to the model. Qualitative and quantitative psychomotor deficits seem to be independent phenomena in stabilized patients with schizophrenia. The diminishing in motor activity in patients with schizophrenia is related to a loss of drive and not to problems in the quality of movement execution. © 2013 S. Karger AG, Basel.

Assessment of Joystick control during the performance of powered wheelchair driving tasks

PubMed Central

2011-01-01

Background Powered wheelchairs are essential for many individuals who have mobility impairments. Nevertheless, if operated improperly, the powered wheelchair poses dangers to both the user and to those in its vicinity. Thus, operating a powered wheelchair with some degree of proficiency is important for safety, and measuring driving skills becomes an important issue to address. The objective of this study was to explore the discriminate validity of outcome measures of driving skills based on joystick control strategies and performance recorded using a data logging system. Methods We compared joystick control strategies and performance during standardized driving tasks between a group of 10 expert and 13 novice powered wheelchair users. Driving tasks were drawn from the Wheelchair Skills Test (v. 4.1). Data from the joystick controller were collected on a data logging system. Joystick control strategies and performance outcome measures included the mean number of joystick movements, time required to complete tasks, as well as variability of joystick direction. Results In simpler tasks, the expert group's driving skills were comparable to those of the novice group. Yet, in more difficult and spatially confined tasks, the expert group required fewer joystick movements for task completion. In some cases, experts also completed tasks in approximately half the time with respect to the novice group. Conclusions The analysis of joystick control made it possible to discriminate between novice and expert powered wheelchair users in a variety of driving tasks. These results imply that in spatially confined areas, a greater powered wheelchair driving skill level is required to complete tasks efficiently. Based on these findings, it would appear that the use of joystick signal analysis constitutes an objective tool for the measurement of powered wheelchair driving skills. This tool may be useful for the clinical assessment and training of powered wheelchair skills. PMID:21609435

Rapid restoration of electric vehicle battery performance while driving at cold temperatures

NASA Astrophysics Data System (ADS)

Zhang, Guangsheng; Ge, Shanhai; Yang, Xiao-Guang; Leng, Yongjun; Marple, Dan; Wang, Chao-Yang

2017-12-01

Electric vehicles (EVs) driven in cold weather experience two major drawbacks of Li-ion batteries: drastic power loss (up to 10-fold at -30 °C) and restriction of regenerative braking at temperatures below 5-10 °C. Both factors greatly reduce cruise range, exacerbating drivers' range anxiety in winter. While preheating the battery before driving is a practice widely adopted to maintain battery power and EV drivability, it is time-consuming (on the order of 40 min) and prohibits instantaneous mobility. Here we reveal a control strategy that can rapidly restore EV battery power and permit full regeneration while driving at temperatures as low as -40 °C. The strategy involves heating the battery internally during regenerative braking and rest periods of driving. We show that this technique fully restores room-temperature battery power and regeneration in 13, 33, 46, 56 and 112 s into uninterrupted driving in 0, -10, -20, -30 and -40 °C environments, respectively. Correspondingly, the strategy significantly increases cruise range of a vehicle operated at cold temperatures, e.g. 49% at -40 °C in simulated US06 driving cycle tests. The present work suggests that smart batteries with embedded sensing/actuation can leapfrog in performance.

Fast Ordered Sampling of DNA Sequence Variants.

PubMed

Greenberg, Anthony J

2018-05-04

Explosive growth in the amount of genomic data is matched by increasing power of consumer-grade computers. Even applications that require powerful servers can be quickly tested on desktop or laptop machines if we can generate representative samples from large data sets. I describe a fast and memory-efficient implementation of an on-line sampling method developed for tape drives 30 years ago. Focusing on genotype files, I test the performance of this technique on modern solid-state and spinning hard drives, and show that it performs well compared to a simple sampling scheme. I illustrate its utility by developing a method to quickly estimate genome-wide patterns of linkage disequilibrium (LD) decay with distance. I provide open-source software that samples loci from several variant format files, a separate program that performs LD decay estimates, and a C++ library that lets developers incorporate these methods into their own projects. Copyright © 2018 Greenberg.

EPRI/SCE testing and evaluation of electric work vehicles: Jet 500, Volkswagen Type 2, DAUG Type GM2, and Battronic Minivan

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCluskey, R.K.; Arias, J.L.

1979-12-01

During the first 11 months of the EPRI/SCE Electric Vehicle Project, four electric vehicles (EVs) were tested and evaluated: the Jet Industries Electra-Van Model 500, the Volkswagen (VW) Type 2 Electrotransporter, a VW Type GM2 Transporter with DAUG electric drive, and the Battronic Minivan. The project emphasized road-testing of these vehicles to acquire data on their useful driving range, performance, and reliability. Each vehicle was driven more than 1000 miles along SCE-selected test routes to determine the effects of different terrains (level, slight grades, and steep grades), traffic conditions (one, two, three, and four stops/mile and freeway), and payload. Themore » vehicle component failures that occurred during testing are itemized and described briefly, and assessments of expected field reliability are made. Other vehicle characteristics and measurements of interest are presented. The data base on these test vehicles is intended to provide the reader an overview of the real world performance that can be expected from present-day state-of-the-art EVs.« less

Prefrontal transcranial direct current stimulation improves fundamental vehicle control abilities.

PubMed

Sakai, Hiroyuki; Uchiyama, Yuji; Tanaka, Satoshi; Sugawara, Sho K; Sadato, Norihiro

2014-10-15

Noninvasive brain stimulation techniques have increasingly attracted the attention of neuroscientists because they enable the identification of the causal role of a targeted brain region. However, few studies have applied such techniques to everyday life situations. Here, we investigate the causal role of the dorsolateral prefrontal cortex (DLPFC) in fundamental vehicle control abilities. Thirteen participants underwent a simulated driving task under prefrontal transcranial direct current stimulation (tDCS) on three separate testing days. Each testing day was randomly assigned to either anodal over the right with cathodal over the left DLPFC, cathodal over the right with anodal over the left DLPFC, or sham stimulation. The driving task required the participants to maintain an inter-vehicle distance to a leading car traveling a winding road with a constant speed. Driving performance was quantified using two metrics: the root-mean-square error of inter-vehicle distance as car-following performance, and the standard deviation of lateral position as lane-keeping performance. Results showed that both car-following and lane-keeping performances were significantly greater for right anodal/left cathodal compared with right cathodal/left cathodal and sham stimulation. These results suggest not only the causal involvement of the DLPFC in driving, but also right hemisphere dominance for vehicle control. The findings of this study indicate that tDCS can be a useful tool to examine the causal role of a specific brain region in ecologically valid environments, and also might be a help to drivers with difficulties in vehicle control. Copyright © 2014 Elsevier B.V. All rights reserved.

Effect of Cognitive Demand on Functional Visual Field Performance in Senior Drivers with Glaucoma

PubMed Central

Gangeddula, Viswa; Ranchet, Maud; Akinwuntan, Abiodun E.; Bollinger, Kathryn; Devos, Hannes

2017-01-01

Purpose: To investigate the effect of cognitive demand on functional visual field performance in drivers with glaucoma. Method: This study included 20 drivers with open-angle glaucoma and 13 age- and sex-matched controls. Visual field performance was evaluated under different degrees of cognitive demand: a static visual field condition (C1), dynamic visual field condition (C2), and dynamic visual field condition with active driving (C3) using an interactive, desktop driving simulator. The number of correct responses (accuracy) and response times on the visual field task were compared between groups and between conditions using Kruskal–Wallis tests. General linear models were employed to compare cognitive workload, recorded in real-time through pupillometry, between groups and conditions. Results: Adding cognitive demand (C2 and C3) to the static visual field test (C1) adversely affected accuracy and response times, in both groups (p < 0.05). However, drivers with glaucoma performed worse than did control drivers when the static condition changed to a dynamic condition [C2 vs. C1 accuracy; glaucoma: median difference (Q1–Q3) 3 (2–6.50) vs. controls: 2 (0.50–2.50); p = 0.05] and to a dynamic condition with active driving [C3 vs. C1 accuracy; glaucoma: 2 (2–6) vs. controls: 1 (0.50–2); p = 0.02]. Overall, drivers with glaucoma exhibited greater cognitive workload than controls (p = 0.02). Conclusion: Cognitive demand disproportionately affects functional visual field performance in drivers with glaucoma. Our results may inform the development of a performance-based visual field test for drivers with glaucoma. PMID:28912712

Adapting a Driving Simulator to Study Pedestrians' Street-Crossing Decisions: A Feasibility Study.

PubMed

Jäger, M; Nyffeler, T; Müri, R; Mosimann, U P; Nef, T

2015-01-01

The decision when to cross a street safely is a challenging task that poses high demands on perception and cognition. Both can be affected by normal aging, neurodegenerative disorder, and brain injury, and there is an increasing interest in studying street-crossing decisions. In this article, we describe how driving simulators can be modified to study pedestrians' street-crossing decisions. The driving simulator's projection system and the virtual driving environment were used to present street-crossing scenarios to the participants. New sensors were added to measure when the test person starts to cross the street. Outcome measures were feasibility, usability, task performance, and visual exploration behavior, and were measured in 15 younger persons, 15 older persons, and 5 post-stroke patients. The experiments showed that the test is feasible and usable, and the selected difficulty level was appropriate. Significant differences in the number of crashes between young participants and patients (p = .001) as well as between healthy older participants and patients (p = .003) were found. When the approaching vehicle's speed is high, significant differences between younger and older participants were found as well (p = .038). Overall, the new test setup was well accepted, and we demonstrated that driving simulators can be used to study pedestrians' street-crossing decisions.

Vehicle test report: Electric Vehicle Associates electric conversion of an AMC Pacer

NASA Technical Reports Server (NTRS)

Price, T. W.; Wirth, V. A., Jr.; Pampa, M. F.

1981-01-01

The change of pace, an electric vehicle was tested. These tests were performed to characterize certain parameters of the electric vehicle pacer and to provide baseline data that can be used for the comparison of improved batteries that may be incorporated into the vehicle at a later time. The vehicle tests were concentrated on the electrical drive subsystem, the batteries, controller and motor. Coastdowns to characterize the road load, and range evaluations for both cyclic and constant speed conditions were performed. The vehicle's performance was evaluated by comparing its constant speed range performance with described vehicles. It is found that the pacer performance is approximately equal to the majority of the vehicles tested in the 1977 assessment.

The effects of below-elbow immobilization on driving performance.

PubMed

Jones, Evan M; Barrow, Aaron E; Skordas, Nic J; Green, David P; Cho, Mickey S

2017-02-01

There is limited research to guide physicians and patients in deciding whether it is safe to drive while wearing various forms of upper extremity immobilization. The purpose of this study is to evaluate the effect of below-elbow removable splints and fiberglass casts on automobile driving performance. 20 healthy subjects completed 10 runs through a closed, cone-marked driving course while wearing a randomized sequence of four different types of immobilization on each extremity (short arm thumb spica fiberglass cast, short arm fiberglass cast, short arm thumb spica splint, and short arm wrist splint). The first and last driving runs were without immobilization and served as controls. Performance was measured based on evaluation by a certified driving instructor (pass/fail scoring), cones hit, run time, and subject-perceived driving difficulty (1-10 analogue scoring). The greatest number of instructor-scored failures occurred while immobilized in right arm spica casts (n=6; p=0.02) and left arm spica casts (n=5; p=0.049). The right arm spica cast had the highest subject-perceived difficulty (5.2±1.9; p<0.001). All forms of immobilization had significantly increased perceived difficulty compared to control, except for the left short arm splint (2.5±1.6; p>0.05). There was no significant difference in number of cones hit or driving time between control runs and runs with any type of immobilization. Drivers should use caution when wearing any of the forms of upper extremity immobilization tested in this study. All forms of immobilization, with exception of the left short arm splint significantly increased perceived driving difficulty. However, only the fiberglass spica casts (both left and right arm), significantly increased drive run failures due to loss of vehicle control. We recommend against driving when wearing a below-elbow fiberglass spica cast on either extremity. Copyright © 2016. Published by Elsevier Ltd.

Two-Speed Gearbox Dynamic Simulation Predictions and Test Validation

NASA Technical Reports Server (NTRS)

Lewicki, David G.; DeSmidt, Hans; Smith, Edward C.; Bauman, Steven W.

2010-01-01

Dynamic simulations and experimental validation tests were performed on a two-stage, two-speed gearbox as part of the drive system research activities of the NASA Fundamental Aeronautics Subsonics Rotary Wing Project. The gearbox was driven by two electromagnetic motors and had two electromagnetic, multi-disk clutches to control output speed. A dynamic model of the system was created which included a direct current electric motor with proportional-integral-derivative (PID) speed control, a two-speed gearbox with dual electromagnetically actuated clutches, and an eddy current dynamometer. A six degree-of-freedom model of the gearbox accounted for the system torsional dynamics and included gear, clutch, shaft, and load inertias as well as shaft flexibilities and a dry clutch stick-slip friction model. Experimental validation tests were performed on the gearbox in the NASA Glenn gear noise test facility. Gearbox output speed and torque as well as drive motor speed and current were compared to those from the analytical predictions. The experiments correlate very well with the predictions, thus validating the dynamic simulation methodologies.

The role of visual attention in predicting driving impairment in older adults.

PubMed

Hoffman, Lesa; McDowd, Joan M; Atchley, Paul; Dubinsky, Richard

2005-12-01

This study evaluated the role of visual attention (as measured by the DriverScan change detection task and the Useful Field of View Test [UFOV]) in the prediction of driving impairment in 155 adults between the ages of 63 and 87. In contrast to previous research, participants were not oversampled for visual impairment or history of automobile accidents. Although a history of automobile accidents within the past 3 years could not be predicted using any variable, driving performance in a low-fidelity simulator could be significantly predicted by performance in the change detection task and by the divided and selection attention subtests of the UFOV in structural equation models. The sensitivity and specificity of each measure in identifying at-risk drivers were also evaluated with receiver operating characteristic curves.

77 FR 11199 - Visual-Manual NHTSA Driver Distraction Guidelines for In-Vehicle Electronic Devices

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-24

...The National Highway Traffic Safety Administration (NHTSA) is concerned about the effects of distraction due to drivers' use of electronic devices on motor vehicle safety. Consequently, NHTSA is issuing nonbinding, voluntary NHTSA Driver Distraction Guidelines (NHTSA Guidelines) to promote safety by discouraging the introduction of excessively distracting devices in vehicles. This notice details the contents of the first phase of the NHTSA Driver Distraction Guidelines. These NHTSA Guidelines cover original equipment in-vehicle device secondary tasks (communications, entertainment, information gathering, and navigation tasks not required to drive are considered secondary tasks) performed by the driver through visual-manual means (meaning the driver looking at a device, manipulating a device-related control with the driver's hand, and watching for visual feedback). The proposed NHTSA Guidelines list certain secondary, non-driving related tasks that, based on NHTSA's research, are believed by the agency to interfere inherently with a driver's ability to safely control the vehicle. The Guidelines recommend that those in-vehicle devices be designed so that they cannot be used by the driver to perform such tasks while the driver is driving. For all other secondary, non-driving-related visual-manual tasks, the NHTSA Guidelines specify a test method for measuring the impact of task performance on driving safety while driving and time-based acceptance criteria for assessing whether a task interferes too much with driver attention to be suitable to perform while driving. If a task does not meet the acceptance criteria, the NHTSA Guidelines recommend that in- vehicle devices be designed so that the task cannot be performed by the driver while driving. In addition to identifying inherently distracting tasks and providing a means for measuring and evaluating the level of distraction associated with other non-driving-related tasks, the NHTSA Guidelines contain several design recommendations for in-vehicle devices in order to minimize their potential for distraction. NHTSA seeks comments on these NHTSA Guidelines and any suggestions for how to improve them so as to better enhance motor vehicle safety.

Development of a compact wearable pneumatic drive unit for a ventricular assist device.

PubMed

Homma, Akihiko; Taenaka, Yoshiyuki; Tatsumi, Eisuke; Akagawa, Eiki; Lee, Hwansung; Nishinaka, Tomohiro; Takewa, Yoshiaki; Mizuno, Toshihide; Tsukiya, Tomonori; Kakuta, Yukihide; Katagiri, Nobumasa; Shimosaki, Isao; Hamada, Shigeru; Mukaibayashi, Hiroshi; Iwaoka, Wataru

2008-01-01

The purpose of this study was to develop a compact wearable pneumatic drive unit for a ventricular assist device (VAD). This newly developed drive unit, 20 x 8.5 x 20 cm in size and weighing approximately 1.8 kg, consists of a brushless DC motor, noncircular gears, a crankshaft, a cylinder-piston, and air pressure regulation valves. The driving air pressure is generated by the reciprocating motion of the piston and is controlled by the air pressure regulation valves. The systolic ratio is determined by the noncircular gears, and so is fixed for a given configuration. As a result of an overflow-type mock circulation test, a drive unit with a 44% systolic ratio connected to a Toyobo VAD blood pump with a 70-ml stroke volume achieved a pump output of more than 7 l/min at 100 bpm against a 120 mmHg afterload. Long-term animal tests were also performed using drive units with systolic ratios of 45% and 53% in two Holstein calves weighing 62 kg and 74 kg; the tests were terminated on days 30 and 39, respectively, without any malfunction. The mean aortic pressure, bypass flow, and power consumption for the first calf were maintained at 90 x 13 mmHg, 3.9 x 0.9 l/min, and 12 x 1 W, and those for the second calf were maintained at 88 x 13 mmHg, 5.0 x 0.5 l/min, and 16 x 2 W, respectively. These results indicate that the newly developed drive unit may be used as a wearable pneumatic drive unit for the Toyobo VAD blood pump.

Motion perception tasks as potential correlates to driving difficulty in the elderly

NASA Astrophysics Data System (ADS)

Raghuram, A.; Lakshminarayanan, V.

2006-09-01

Changes in the demographics indicates that the population older than 65 is on the rise because of the aging of the ‘baby boom’ generation. This aging trend and driving related accident statistics reveal the need for procedures and tests that would assess the driving ability of older adults and predict whether they would be safe or unsafe drivers. Literature shows that an attention based test called the useful field of view (UFOV) was a significant predictor of accident rates compared to any other visual function tests. The present study evaluates a qualitative trend on using motion perception tasks as a potential visual perceptual correlates in screening elderly drivers who might have difficulty in driving. Data was collected from 15 older subjects with a mean age of 71. Motion perception tasks included—speed discrimination with radial and lamellar motion, time to collision using prediction motion and estimating direction of heading. A motion index score was calculated which was indicative of performance on all of the above-mentioned motion tasks. Scores on visual attention was assessed using UFOV. A driving habit questionnaire was also administered for a self report on the driving difficulties and accident rates. A qualitative trend based on frequency distributions show that thresholds on the motion perception tasks are successful in identifying subjects who reported to have had difficulty in certain aspects of driving and had accidents. Correlation between UFOV and motion index scores was not significant indicating that probably different aspects of visual information processing that are crucial to driving behaviour are being tapped by these two paradigms. UFOV and motion perception tasks together can be a better predictor for identifying at risk or safe drivers than just using either one of them.

Regional differences associated with drinking and driving in Brazil.

PubMed

De Boni, Raquel; von Diemen, Lisia; Duarte, Paulina do Carmo Arruda Vieira; Bumaguin, Daniela Benzano; Hilgert, Juliana Balbinot; Bozzetti, Mary Clarisse; Sordi, Anne; Pechansky, Flavio

2012-10-01

To evaluate regional differences and similarities associated with drinking and driving (DUI) in the five Brazilian macro-regions. A roadside survey was conducted in the 27 Brazilian state capitals. A total of 3,398 drivers were randomly selected and given a structured interview and a breathalyzer test. To determine the predictors of positive blood alcohol concentration (BAC) in each region, a MANOVA was performed, and 3 groups were used as follows: 1) North and Northeast, 2) South and Midwest, and 3) Southeast. A Poisson robust regression model was performed to assess the variables associated with positive BAC in each group. Of all surveyed drivers, 2,410 had consumed alcohol in the previous 12 months. Most were male, with a median age of 36. Leisure as the reason for travel was associated with positive BAC in all 3 groups. Low schooling, being older than 30, driving cars or motorcycles and having been given a breathalyzer test at least once in their lives predicted DUI in at least two different groups. Factors , especially low schooling and leisure as a reason for travel, associated with drinking and driving were similar among regions, although certain region-specific features were observed. This information is important for aiming to reduce DUI in the country.

Association between Executive Function and Problematic Adolescent Driving

PubMed Central

Pope, Caitlin N.; Ross, Lesley A.; Stavrinos, Despina

2016-01-01

Objective Motor vehicle collisions (MVCs) are one of the leading causes of injury and death for adolescents. Driving is a complex activity that is highly reliant on executive function to safely navigate through the environment. Little research has examined the efficacy of using self-reported executive function measures for assessing adolescent driving risk. This study examined the Behavior Rating Inventory of Executive Function (BRIEF) questionnaire and performance based-executive function tasks as potential predictors of problematic driving outcomes in adolescents. Methods Forty-six adolescent drivers completed the (1) BRIEF, (2) Trail Making Test (TMT), (3) Backwards Digit Span, and (4) self-report on three problematic driving outcomes: the number of times of having been pulled over by a police officer, the number of tickets issued, and the number of MVCs. Results Greater self-reported difficulty with planning and organization was associated with greater odds of having a MVC, while inhibition difficulties were associated with greater odds of receiving a ticket. Greater self-reported difficulty across multiple BRIEF subscales was associated with greater odds of being pulled over. Conclusion Overall findings indicated that the BRIEF, an ecological measure of executive function, showed significant association with self-reported problematic driving outcomes in adolescents. No relationship was found between performance-based executive function measures and self-reported driving outcomes. The BRIEF could offer unique and quick insight into problematic driving behavior and potentially be an indicator of driving risk in adolescent drivers during clinical evaluations. PMID:27661394

Analysis, design, and testing of a low cost, direct force command linear proof mass actuator for structural control

NASA Technical Reports Server (NTRS)

Slater, G. L.; Shelley, Stuart; Jacobson, Mark

1993-01-01

In this paper, the design, analysis, and test of a low cost, linear proof mass actuator for vibration control is presented. The actuator is based on a linear induction coil from a large computer disk drive. Such disk drives are readily available and provide the linear actuator, current feedback amplifier, and power supply for a highly effective, yet inexpensive, experimental laboratory actuator. The device is implemented as a force command input system, and the performance is virtually the same as other, more sophisticated, linear proof mass systems.

Engineering analysis and test results of the pre-stage planetary gear trains for wrist rotation and pitch assembly and azimuth and elevation assembly of the extendable stiff arm manipulator kit assembly

NASA Technical Reports Server (NTRS)

Morris, R. N.

1973-01-01

In order to improve the performance capability of the Extendable Stiff Arm Manipulator (ESAM) it was necessary to increase the overall gear ratio by a factor of approximately four. This is accomplished with minimum effect to existing hardware by the interposition of a planetary gear transmission between the respective drive motors and the harmonic drive transmissions. The engineering analysis in support of this design approach and the subsequent no-load test results are reported.

Sleep inertia associated with a 10-min nap before the commute home following a night shift: A laboratory simulation study.

PubMed

Hilditch, Cassie J; Dorrian, Jillian; Centofanti, Stephanie A; Van Dongen, Hans P; Banks, Siobhan

2017-02-01

Night shift workers are at risk of road accidents due to sleepiness on the commute home. A brief nap at the end of the night shift, before the commute, may serve as a sleepiness countermeasure. However, there is potential for sleep inertia, i.e. transient impairment immediately after awakening from the nap. We investigated whether sleep inertia diminishes the effectiveness of napping as a sleepiness countermeasure before a simulated commute after a simulated night shift. N=21 healthy subjects (aged 21-35 y; 12 females) participated in a 3-day laboratory study. After a baseline night, subjects were kept awake for 27h for a simulated night shift. They were randomised to either receive a 10-min nap ending at 04:00 plus a 10-min pre-drive nap ending at 07:10 (10-NAP) or total sleep deprivation (NO-NAP). A 40-min York highway driving task was performed at 07:15 to simulate the commute. A 3-min psychomotor vigilance test (PVT-B) and the Samn-Perelli Fatigue Scale (SP-Fatigue) were administered at 06:30 (pre-nap), 07:12 (post-nap), and 07:55 (post-drive). In the 10-NAP condition, total pre-drive nap sleep time was 9.1±1.2min (mean±SD), with 1.3±1.9min spent in slow wave sleep, as determined polysomnographically. There was no difference between conditions in PVT-B performance at 06:30 (before the nap). In the 10-NAP condition, PVT-B performance was worse after the nap (07:12) compared to before the nap (06:30); no change across time was found in the NO-NAP condition. There was no significant difference between conditions in PVT-B performance after the drive. SP-Fatigue and driving performance did not differ significantly between conditions. In conclusion, the pre-drive nap showed objective, but not subjective, evidence of sleep inertia immediately after awakening. The 10-min nap did not affect driving performance during the simulated commute home, and was not effective as a sleepiness countermeasure. Copyright © 2015 Elsevier Ltd. All rights reserved.

Evaluation of SAGE Electrochromic Devices: Cooperative Research and Development Final Report, CRADA Number CRD-15-579

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tenent, Robert C.

2017-12-06

NREL will conduct durability testing of Sage Electrochromics dynamic windows products using American Society for Testing and Materials (ASTM) standard methods and drive parameters as defined by Sage. Window units will be tested and standard analysis performed. Data will be summarized and reported back to Sage at the end of the testing period.

Gender differences in highway driving performance after administration of sleep medication: a review of the literature.

PubMed

Verster, Joris C; Roth, Thomas

2012-01-01

It is generally assumed that there are minimal gender differences in the safety and efficacy of central nervous system drugs, as is evidenced by men and women receiving the same drug dosage. There is, however, evidence that drugs may have a differential effect on performance in men and women, given reported differences in pharmacokinetics as well as the presence or absence and severity of adverse effects. It is especially important to verify whether gender differences in performance exist in case of activities that have potentially dangerous outcomes such as driving a car. This review summarizes the current scientific evidence on gender differences in driving performance after treatment with hypnotic drugs. A literature search was conducted to obtain all studies that conducted on-road driving tests to examine the effects hypnotic drugs on driving. Cross-references were checked and technical reports and raw data were obtained, if possible. Fourteen studies were evaluated. Many studies did not allow analyses of gender effects because only women were included. Others did not report data on gender analyses. Technical reports and additional data analyses revealed significant gender differences in driving performance the morning following bedtime administration of flurazepam (30 mg) and after middle-of-the-night administration of zolpidem (10 mg). No significant gender differences were found for ramelteon (8 mg), lormetazepam (1 and 2 mg), zaleplon (10 and 20 mg), and zopiclone (7.5 mg). Although the available data are limited, the results show that significant gender differences have been found for some drugs but not others. Therefore, in the future more research is needed to reveal potential gender differences and to determine what mediates them.

The effects of intranasal esketamine (84 mg) and oral mirtazapine (30 mg) on on-road driving performance: a double-blind, placebo-controlled study.

PubMed

van de Loo, Aurora J A E; Bervoets, Adriana C; Mooren, Loes; Bouwmeester, Noor H; Garssen, Johan; Zuiker, Rob; van Amerongen, Guido; van Gerven, Joop; Singh, Jaskaran; der Ark, Peter Van; Fedgchin, Maggie; Morrison, Randall; Wajs, Ewa; Verster, Joris C

2017-11-01

The purpose of this study is to evaluate the single dose effect of intranasal esketamine (84 mg) compared to placebo on on-road driving performance. Mirtazapine (oral, 30 mg) was used as a positive control, as this antidepressant drug is known to negatively affect driving performance. Twenty-six healthy volunteers aged 21 to 60 years were enrolled in this study. In the evening, 8 h after treatment administration, participants conducted the standardized 100-km on-road driving test. Primary outcome measure was the standard deviation of lateral position (SDLP), i.e., the weaving of the car. Mean lateral position, mean speed, and standard deviation of speed were secondary outcome measures. For SDLP, non-inferiority analyses were conducted, using +2.4 cm (relative to placebo) as a predefined non-inferiority margin for clinical relevant impairment. Twenty-four participants completed the study. No significant SDLP difference was found between esketamine and placebo (p = 0.7638), whereas the SDLP after mirtazapine was significantly higher when compared to placebo (p = 0.0001). The upper limit of the two-sided 95% confidence interval (CI) of the mean difference between esketamine and placebo was +0.86 cm, i.e., <+2.4 cm, thus demonstrating that esketamine was non-inferior to placebo. Non-inferiority could not be concluded for mirtazapine (+3.15 cm SDLP relative to placebo). No significant differences in mean speed, standard deviation of speed, and mean lateral position were observed between the active treatments and placebo. No significant difference in driving performance was observed 8 h after administering intranasal esketamine (84 mg) or placebo. In contrast, oral mirtazapine (30 mg) significantly impaired on road driving performance.

Integrated Advanced Microwave Sounding Unit-A (AMSU-A): Engineering Test Report: METSAT A2 Signal Processor (P/N 1331120-2, S/N F03) S/N 107

NASA Technical Reports Server (NTRS)

1998-01-01

This report presents a description of the tests performed, and the test data, for the A2 METSAT Signal Processor Assembly PN: 1331120-2, S/N F03. The assembly was tested in accordance with AE-26754, "METSAT Signal Processor Scan Drive Test and Integration Procedure."

Integrated Advanced Microwave Sounding Unit-A (AMSU-A): Engineering Test Report, METSAT A2 Signal Processor (P/N 1331120-2, S/N F04) S/N 108

NASA Technical Reports Server (NTRS)

1998-01-01

This report presents a description of the tests performed, and the test data, for the A2 METSAT Signal Processor Assembly PN: 1331120-2, S/N F04. The assembly was tested in accordance with AE-26754, "METSAT Signal Processor Scan Drive Test and Integration Procedure."

Traction Drives for Zero Stick-Slip Robots, and Reaction Free, Momentum Balanced Systems

NASA Technical Reports Server (NTRS)

Anderson, William J.; Shipitalo, William; Newman, Wyatt

1995-01-01

Two differential (dual input, single output) drives (a roller-gear and a pure roller), and a momentum balanced (single input, dual output) drive (pure roller ) were designed, fabricated, and tested. The differential drives are each rated at 295 rad/sec (2800 rpm) input speed, 450 N-m (4,000 in-lbf) output torque. The momentum balanced drive is rated at 302 rad/sec (2880 rpm) input speed, and dual output torques of 434N-m (3840 in-lbf). The Dual Input Differential Roller-Gear Drive (DC-700) has a planetary roller-gear system with a reduction ratio (one input driving the output with the second input fixed) of 29.23: 1. The Dual Input Differential Roller Drive (DC-500) has a planetary roller system with a reduction ratio of approximately 24:1. Each of the differential drives features dual roller-gear or roller arrangements consisting of a sun, four first row planets, four second row planets, and a ring. The Momentum Balanced (Grounded Ring) Drive (DC-400) has a planetary roller system with a reduction ratio of 24:1 with both outputs counterrotating at equal speed. Its single roller cluster consists of a sun, five first and five second row planets, a roller cage or spider and a ring. Outputs are taken from both the roller cage and the ring which counterrotate. Test results reported for all three drives include angular and torque ripple (linearity and cogging), viscous and Coulomb friction, and forward and reverse power efficiency. Of the two differential drives, the Differential Roller Drive had better linearity and less cogging than did the Differential Roller-Gear Drive, but it had higher friction and lower efficiency (particularly at low power throughput levels). Use of full preloading rather than a variable preload system in the Differential Roller Drive assessed a heavy penalty in part load efficiency. Maximum measured efficiency (ratio of power out to power in) was 95% for the Differential Roller-Gear Drive and 86% for the Differential Roller Drive. The Momentum Balanced (Grounded Ring) Drive performed as expected kinematically. Reduction r-atios to the two counterrotating outputs (design nominal=24:1) were measured to be 23.98:1 and 24.12:1 at zero load.. At 25ONm (2200 in-lbf) output torque the ratio changed 2% due to roller creep. This drive was the smoothest of all three as determined from linearity and cogging tests, and maximum measured efficiency (ratio of power out to power in) was 95%. The disadvantages of full preloading as comvared to variable preload were apparent in this drive as in the Differential Roller Drive. Efficiencies at part load were low, but improved dramatically with increases in torque. These were consistent with friction measurements which indicated losses primarily from Coulomb friction. The initial preload level setting was low so roller slip was encountered at higher torques during testing.

[Useful assessment for identifying unsafe driving].

PubMed

Gonthier, Régis; Fabrigoule, Colette; Domont, Alain

2005-03-01

Ability to drive safely is the resultant of interactions between the individual (the driver), the vector (the car) and the environment (the state of the road). For some aged drivers, an important decline of visual, musculosquelettic and cognitive performances, may affect the ability to drive and increase the rate of crashes per vehicle-kilometer-driven, and the morbidity and mortality related to crash. Therefore, each holder of a driving licence should be medically suited to control his driving ability. In case of transitory or lasting driving incapacity, drivers must, of their own initiative, stop driving according to the Highway code and the contractual obligations appearing in their vehicle insurance contract. A medical examination for aptitude to driving requires a standardized, reliable, reproducible procedure based on consensual assessment tools to avoid arbitrary decisions for driving cessation. We propose a multidisciplinary approach to detect important decline of visuospatial and motor skills, paroxystic drops of attention and vigilance, and decreased cognitive capacity to anticipate and adapt driving at every moment. This assessment is based on a semi-directed interview and simple diagnostic tests. According to the present French law, only twelve medical conditions or functional deficits are inconsistent with the retain of the driving licence for a light vehicle.

[Prevention of drink driving at academic festivals: «Tú decides» project].

PubMed

Malveiro, Jorge; de Jesus, Saul Neves; Viseo, Joao; Pechorro, Pedro; Pacheco, Eusébio; Lima-Rodríguez, Joaquín Salvador; Lima-Serrano, Marta

2015-01-01

Alcohol consumption among university students has reached worrying levels, its effects on driving being highly dangerous. This aspect emphasizes the need to develop prevention programs, intended to raise subjects' awareness about the effects of alcohol on driving. The aim of the present research is to evaluate the effectiveness of the intervention program «Tú decides», implemented at the Algarve University during several students festivals, between 2010-2014. Quasi-experimental study, pre-post test without control group. A total of 5,079 participants were inquired. They were asked, at two different moments, before and after the measurement of the blood alcohol level and giving an information session with technical recommendations to prevent driving under alcohol effects. One factor ANOVA test used, in order to perform a mean comparison, as well as the Chi-square statistics, to perform a proportion comparison (p<.05). It was found that the intention to drive was lower at the second moment (42.1%) (χ(2)=2078.71; p=.000). This intention was influenced by blood alcohol level different levels (χ(2)=338.252; p=.000), gender (χ(2)=35.718; p=.000), age (χ(2)=62.805; p=.000) and professional situation of the participants (χ(2)=27.397; p=.001). We can affirm that the main objective of this intervention was achieved, since the participants followed the technical recommendations based on the blood alcohol level results. Copyright © 2015 Elsevier España, S.L.U. All rights reserved.

Dynamic performances analysis of a real vehicle driving

NASA Astrophysics Data System (ADS)

Abdullah, M. A.; Jamil, J. F.; Salim, M. A.

2015-12-01

Vehicle dynamic is the effects of movement of a vehicle generated from the acceleration, braking, ride and handling activities. The dynamic behaviours are determined by the forces from tire, gravity and aerodynamic which acting on the vehicle. This paper emphasizes the analysis of vehicle dynamic performance of a real vehicle. Real driving experiment on the vehicle is conducted to determine the effect of vehicle based on roll, pitch, and yaw, longitudinal, lateral and vertical acceleration. The experiment is done using the accelerometer to record the reading of the vehicle dynamic performance when the vehicle is driven on the road. The experiment starts with weighing a car model to get the center of gravity (COG) to place the accelerometer sensor for data acquisition (DAQ). The COG of the vehicle is determined by using the weight of the vehicle. A rural route is set to launch the experiment and the road conditions are determined for the test. The dynamic performance of the vehicle are depends on the road conditions and driving maneuver. The stability of a vehicle can be controlled by the dynamic performance analysis.

Electric and hybrid vehicles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jacovides, L.J.; Cornell, E.P.; Kirk, R.

1981-01-01

A study of the energy utilization of gasoline and battery-electric powered special purpose vehicles is discussed along with the impact of electric cars on national energy consumption, the development of electric vehicles in Japan, the applicability of safety standards to electric and hybrid-vehicles, and crashworthiness tests on two electric vehicles. Aspects of energy storage are explored, taking into account a review of battery systems for electrically powered vehicles, the dynamic characterization of lead-acid batteries for vehicle applications, nickel-zinc storage batteries as energy sources for electric vehicles, and a high energy tubular battery for a 1800 kg payload electric delivery van.more » Subjects considered in connection with drive systems include the drive system of the DOE near-term electric vehicle, a high performance AC electric drive system, an electromechanical transmission for hybrid vehicle power trains, and a hybrid vehicle for fuel economy. Questions of vehicle development are examined, giving attention to the Electrovair electric car, special purpose urban cars, the system design of the electric test vehicle, a project for city center transport, and a digital computer program for simulating electric vehicle performance.« less

Thermally Simulated 32kW Direct-Drive Gas-Cooled Reactor: Design, Assembly, and Test

NASA Astrophysics Data System (ADS)

Godfroy, Thomas J.; Kapernick, Richard J.; Bragg-Sitton, Shannon M.

2004-02-01

One of the power systems under consideration for nuclear electric propulsion is a direct-drive gas-cooled reactor coupled to a Brayton cycle. In this system, power is transferred from the reactor to the Brayton system via a circulated closed loop gas. To allow early utilization, system designs must be relatively simple, easy to fabricate, and easy to test using non-nuclear heaters to closely mimic heat from fission. This combination of attributes will allow pre-prototypic systems to be designed, fabricated, and tested quickly and affordably. The ability to build and test units is key to the success of a nuclear program, especially if an early flight is desired. The ability to perform very realistic non-nuclear testing increases the success probability of the system. In addition, the technologies required by a concept will substantially impact the cost, time, and resources required to develop a successful space reactor power system. This paper describes design features, assembly, and test matrix for the testing of a thermally simulated 32kW direct-drive gas-cooled reactor in the Early Flight Fission - Test Facility (EFF-TF) at Marshall Space Flight Center. The reactor design and test matrix are provided by Los Alamos National Laboratories.

Driving simulator sickness: Impact on driving performance, influence of blood alcohol concentration, and effect of repeated simulator exposures.

PubMed

Helland, Arne; Lydersen, Stian; Lervåg, Lone-Eirin; Jenssen, Gunnar D; Mørland, Jørg; Slørdal, Lars

2016-09-01

Simulator sickness is a major obstacle to the use of driving simulators for research, training and driver assessment purposes. The purpose of the present study was to investigate the possible influence of simulator sickness on driving performance measures such as standard deviation of lateral position (SDLP), and the effect of alcohol or repeated simulator exposure on the degree of simulator sickness. Twenty healthy male volunteers underwent three simulated driving trials of 1h's duration with a curvy rural road scenario, and rated their degree of simulator sickness after each trial. Subjects drove sober and with blood alcohol concentrations (BAC) of approx. 0.5g/L and 0.9g/L in a randomized order. Simulator sickness score (SSS) did not influence the primary outcome measure SDLP. Higher SSS significantly predicted lower average speed and frequency of steering wheel reversals. These effects seemed to be mitigated by alcohol. Higher BAC significantly predicted lower SSS, suggesting that alcohol inebriation alleviates simulator sickness. The negative relation between the number of previous exposures to the simulator and SSS was not statistically significant, but is consistent with habituation to the sickness-inducing effects, as shown in other studies. Overall, the results suggest no influence of simulator sickness on SDLP or several other driving performance measures. However, simulator sickness seems to cause test subjects to drive more carefully, with lower average speed and fewer steering wheel reversals, hampering the interpretation of these outcomes as measures of driving impairment and safety. BAC and repeated simulator exposures may act as confounding variables by influencing the degree of simulator sickness in experimental studies. Copyright © 2016 Elsevier Ltd. All rights reserved.

Test Facility Simulation Results for Aerospace Loss-of-Lubrication of Spur Gears

NASA Technical Reports Server (NTRS)

Handschuh, Robert F.; Gargano, Lucas J.

2014-01-01

Prior to receiving airworthiness certification, extensive testing is required during the development of rotary wing aircraft drive systems. Many of these tests are conducted to demonstrate the drive system's ability to operate at extreme conditions, beyond that called for in the normal to maximum power operating range. One of the most extreme tests is referred to as the loss-of-lubrication or run dry test. During this test, the drive system is expected to last at least 30 min without failure while the primary lubrication system is disabled for predetermined, scripted flight conditions. Failure of this test can lead to a partial redesign of the drive system or the addition of an emergency lubrication system. Either of these solutions can greatly increase the aircraft drive system cost and weight and extend the schedule for obtaining airworthiness certification. Recent work at NASA Glenn Research Center focused on performing tests, in a relevant aerospace environment, to simulate the behavior of spur gears under loss-of-lubrication conditions. Tests were conducted using a test facility that was used in the past for spur gear contact fatigue testing. A loss-oflubrication test is initiated by shutting off the single into mesh lubricating jet. The test proceeds until the gears fail and can no longer deliver the applied torque. The observed failures are typically plastically deformed gear teeth, due to the high tooth temperatures, that are no longer in mesh. The effect of several different variables to gear tooth condition during loss-of-lubrication have been tested such as gear pitch, materials, shrouding, lubrication condition, and emergency supplied mist lubrication in earlier testing at NASA. Recent testing has focused on newer aerospace gear steels and imbedding thermocouples in the shrouding to measure the air-oil temperatures flung off the gear teeth. Along with the instrumented shrouding, an instrumented spur gear was also tested. The instrumented spur gear had five thermocouples installed at different locations on the gear tooth and web. The data from these two types of measurements provided important information as to the thermal environment during the loss-of-lubrication event. This data is necessary to validate on-going modeling efforts.

Performance-Based Assessment: Meeting the Needs of Diverse Learners

ERIC Educational Resources Information Center

Tung, Rosann

2017-01-01

Fueled by the No Child Left Behind Act (NCLB) and its focus on standardized testing, the U.S. assessment system has been driven by capitalism rather than educational benefit. Annually, the testing industry, which four companies monopolize, is valued at between $400 and $700 million. The testing industry drives Americans to spend $13.1 billion each…

Does the S.D.E.P. increase performance?

NASA Astrophysics Data System (ADS)

Syltebo, Andy

2003-05-01

Through the guidance of the program, "Physical Systems," at The Evergreen State College in Olympia Washington, Andy Syltebo will be investigating how the Surface Drive Enhancement Project will affect the performance of a planing hull powered by surface drive propulsion. A radio controlled model boat of the forementioned design is the prototype vehicle used for experimentation and analysis. The idea of this project revolves around harnessing the energy in the water of a rooster tail ejected from the wake of a surface drive propeller of a boat with a planing hull design. The Surface Drive Enhancement Project (S.D.E.P. for short) is an angled set of adjustable platforms placed in the path of the rooster tail. Theoretically, it experiences the normal force of the water on its surface which, through conservation of momentum, distributes a force on the boat, with which the S.D.E.P. is attached, in both the upwards and forwards directions. This design will be tested and documented to see if it increases forward velocity without sacrificing handling characteristics.

Research on Acceleration Compensation Strategy of Electric Vehicle Based on Fuzzy Control Theory

NASA Astrophysics Data System (ADS)

Zhu, Tianjun; Li, Bin; Zong, Changfu; Wei, Zhicheng

2017-09-01

Nowadays, the driving technology of electric vehicle is developing rapidly. There are many kinds of methods in driving performance control technology. The paper studies the acceleration performance of electric vehicle. Under the premise of energy management, an acceleration power compensation method by fuzzy control theory based on driver intention recognition is proposed, which can meet the driver’s subjective feelings better. It avoids the problem that the pedal opening and power output are single correspondence when the traditional vehicle accelerates. Through the simulation test, this method can significantly improve the performance of acceleration and output torque smoothly in non-emergency acceleration to ensure vehicle comfortable and stable.

Contributions of physical and cognitive impairments to self-reported driving difficulty in chronic whiplash-associated disorders.

PubMed

Takasaki, Hiroshi; Treleaven, Julia; Johnston, Venerina; Jull, Gwendolen

2013-08-15

Cross-sectional. To conduct a preliminary analysis of the physical, cognitive, and psychological domains contributing to self-reported driving difficulty after adjusting for neck pain, dizziness, and relevant demographics in chronic whiplash-associated disorders (WAD) using hierarchical regression modeling. Pain is a risk factor for car crashes, and dizziness may affect fitness to drive. Both symptoms are common in chronic WAD and difficulty driving is a common complaint in this group. Chronic WAD is often accompanied by physical, cognitive, and psychological impairments. These impairments may contribute to self-reported driving difficulty beyond neck pain, dizziness, and relevant demographics. Forty individuals with chronic WAD participated. Dependent variables were the magnitude of self-reported driving difficulty assessed in the strategic, tactical, and operational levels of the Neck Pain Driving Index. Three models were developed to assess the contributions of independent variables (physical, cognitive, and psychological domains) to each of the 3 dependent variables after adjusting for neck pain intensity, dizziness, and driving demographics. The measures included were: physical domain-range and maximum speed of head rotation, performances during gaze stability, eye-head coordination, and visual dependency tests; cognitive domain-self-reported cognitive symptoms including fatigue and the trail making tests; and psychological domain-general stress, traumatic stress, depression, and fear of neck movements and driving. Symptom duration was relevant to driving difficulty in the strategic and tactical levels. The cognitive domain increased statistical power to estimate the strategic and operational levels (P < 0.1) beyond other contributors. The physical domain increased statistical power to estimate the tactical level (P < 0.1) beyond other contributors. Physical and cognitive impairments independently contributed to self-reported driving difficulty in chronic WAD beyond neck pain, dizziness, and symptom duration. 3.

Oculomotor impairment during chronic partial sleep deprivation.

PubMed

Russo, M; Thomas, M; Thorne, D; Sing, H; Redmond, D; Rowland, L; Johnson, D; Hall, S; Krichmar, J; Balkin, T

2003-04-01

The effects of chronic partial sleep (sleep deprivation) and extended sleep (sleep augmentation) followed by recovery sleep on oculomotor function were evaluated in normal subjects to explore the usefulness of oculomotor assessment for alertness monitoring in fitness-for-duty testing. Sixty-six commercial drivers (24-62 years, 50m/16f) participated in a 15 day study composed of 3 training days with 8h time in bed per night, 7 experimental days with subjects randomly assigned to either 3, 5, 7, or 9h time in bed, and 3 recovery nights with 8h time in bed. Data from 57 subjects were used. Saccadic velocity (SV), initial pupil diameter (IPD), latency to pupil constriction (CL), and amplitude of pupil constriction (CA) were assessed and correlated with the sleep latency test (SLT), the Stanford sleepiness scale (SSS), and simulated driving performance. Regression analyses showed that SV slowed significantly in the 3 and 5h groups, IPD decreased significantly in the 9h group, and CL increased significantly in the 3h group. SLT and SSS significantly correlated with SV, IPD, CL, and driving accidents for the 3h group, and with CL for the 5h group. Analyses also showed a significant negative correlation between decreasing SV and increasing driving accidents in the 3h group and a significant negative correlation between IPD and driving accidents for the 7h group. The results demonstrate a sensitivity primarily of SV to sleepiness, and a correlation of SV and IPD to impaired simulated driving performance, providing evidence for the potential utility of oculomotor indicators in the detection of excessive sleepiness and deterioration of complex motor performance with chronic partial sleep restriction. This paper shows a relationship between sleep deprivation and oculomotor measures, and suggests a potential utility for oculometrics in assessing operational performance readiness under sleep restricted conditions.

Performance of Magnetic-Superconductor Non-Contact Harmonic Drive for Cryogenic Space Applications: Speed, Torque and Efficiency Measurements

NASA Astrophysics Data System (ADS)

Perez-Diaz, Jose Luis; Diez-Jimenez, Efren; Valiente-Blanco, Ignacio; Cristache, Cristian; Alvarez-Valenzuela, Marco-Antonio; Sanchez-Garcia-Casarrubios, Juan

2015-09-01

Harmonic Drives are widely used in space mainly because of their compactness, large reduction ratio ad zero backlash. However, their use in extreme environments like in cryogenic temperatures is still a challenge. Lubrication, lifetime and fatigue are still issues under these conditions.The MAGDRIVE project, funded by the EU Space FP7 was devoted to test a new concept of harmonic drive reducer. By using the magnetic distance force interactions of magnets and ferromagnetic materials, all the conventional mechanical elements of a Harmonic Drives (teeth, flexspline and ball bearings) are substituted by contactless mechanical components (magnetic gear and superconducting magnetic bearings). The absence of contact between any moving parts prevents wear, lubricants are no longer required and the operational life time is greatly increased. As the magnetic transmission is continuous there is no backlash in the reduction. MAG SOAR Company is already providing contactless mechanical components for space applications able to operate in a wide range of temperatures.In this paper the tests results of a -1:20 ratio MAGDRIVE prototype are reported. In these tests successful operation at 40 K and 10-3 Pa was demonstrated for more than 1.5 million input cycles. A maximum torque of 3 Nm and efficiency higher than 75% at 3000 rpm were demonstrated. The maximum tested input speed was 3000 rpm -six times the previous existing record for harmonic drives at cryogenic temperature.

Novel Digital Driving Method Using Dual Scan for Active Matrix Organic Light-Emitting Diode Displays

NASA Astrophysics Data System (ADS)

Jung, Myoung Hoon; Choi, Inho; Chung, Hoon-Ju; Kim, Ohyun

2008-11-01

A new digital driving method has been developed for low-temperature polycrystalline silicon, transistor-driven, active-matrix organic light-emitting diode (AM-OLED) displays by time-ratio gray-scale expression. This driving method effectively increases the emission ratio and the number of subfields by inserting another subfield set into nondisplay periods in the conventional digital driving method. By employing the proposed modified gravity center coding, this method can be used to effectively compensate for dynamic false contour noise. The operation and performance were verified by current measurement and image simulation. The simulation results using eight test images show that the proposed approach improves the average peak signal-to-noise ratio by 2.61 dB, and the emission ratio by 20.5%, compared with the conventional digital driving method.

Vehicle test report: Battronic pickup truck

NASA Technical Reports Server (NTRS)

Price, T. W.; Shain, T. W.; Freeman, R. J.; Pompa, M. F.

1982-01-01

An electric pickup truck was tested to characterize certain parameters and to provide baseline data that can be used for the comparison of improved batteries that may be incorporated into the vehicle at a later time. The vehicle tests were concentrated on the electrical drive subsystem; i.e., the batteries, controller, and motor. The tests included coastdowns to characterize the road load and range evaluations for both cyclic and constant speed conditions. A qualitative evaluation of the vehicle's performance was made by comparing its constant speed range performance with other vehicles.

Vehicle test report: Electric Vehicle Associates electric conversion of an AMC Pacer

NASA Technical Reports Server (NTRS)

Price, T. W.; Wirth, V. A., Jr.; Pompa, M. F.

1981-01-01

Tests were performed to characterize certain parameters of the EVA Pacer and to provide baseline data that can be used for the comparison of improved batteries that may be incorporated into the vehicle at a later time. The vehicle tests were concentrated on the electrical drive subsystem; i.e., the batteries, controller and motor. The tests included coastdowns to characterize the road load, and range evaluations for both cyclic and constant speed conditions. A qualitative evaluation of the vehicle's performance was made by comparing its constant speed range performance with other electric and hybrid vehicles. The Pacer performance was approximately equal to the majority of those vehicles assessed in 1977.

Effects of Armodafinil on Simulated Driving and Self-Report Measures in Obstructive Sleep Apnea Patients prior to Treatment with Continuous Positive Airway Pressure

PubMed Central

Kay, Gary G.; Feldman, Neil

2013-01-01

Study Objectives: Obstructive sleep apnea (OSA) has been associated with an increased risk of motor vehicle crashes. This driving risk can be reduced (≥ 50%) by treatment with continuous positive airway pressure (CPAP). However residual excessive daytime sleepiness (EDS) can persist for some patients who regularly use CPAP. The current study was designed to assess the effect of armodafinil on simulated driving performance and subsequent CPAP treatment compliance in newly diagnosed OSA patients with EDS during a 2-week “waiting period” prior to initiation of CPAP. Methods: Sixty-nine newly diagnosed OSA patients, awaiting CPAP therapy, were randomized (1:1) to placebo or armodafinil (150 mg/day) treatment. Simulated driving tests and self-report measures were completed at baseline, after 2 weeks of drug treatment, and following 6 weeks of CPAP treatment. CPAP compliance was evaluated at the end of 6 weeks of CPAP. Results: Compared to placebo, armodafinil improved simulated driving safety performance in OSA patients awaiting CPAP therapy (p = 0.03). Improvement was seen in lane position deviation (p = 0.002) and number of lane excursions (p = 0.02). Improvement was also observed on measures of sleepiness using the Epworth Sleepiness Scale (ESS) and sleep related quality of life. Following 6 weeks of CPAP, there was also significant improvement observed on multiple measures of simulated driving performance. CPAP compliance did not differ between armodafinil-treated and placebo-treated patients (p = 0.80). Conclusions: Armodafinil was found to improve simulated driving performance in OSA patients with EDS prior to initiation of CPAP. Treatment with armodafinil showed no effect on subsequent CPAP compliance. Citation: Kay GG; Feldman N. Effects of armodafinil on simulated driving and self-report measures in obstructive sleep apnea patients prior to treatment with continuous positive airway pressure. J Clin Sleep Med 2013;9(5):445-454. PMID:23674935

Predicting on-road assessment pass and fail outcomes in older drivers with cognitive impairment using a battery of computerized sensory-motor and cognitive tests.

PubMed

Hoggarth, Petra A; Innes, Carrie R H; Dalrymple-Alford, John C; Jones, Richard D

2013-12-01

To generate a robust model of computerized sensory-motor and cognitive test performance to predict on-road driving assessment outcomes in older persons with diagnosed or suspected cognitive impairment. A logistic regression model classified pass–fail outcomes of a blinded on-road driving assessment. Generalizability of the model was tested using leave-one-out cross-validation. Three specialist clinics in New Zealand. Drivers (n=279; mean age 78.4, 65% male) with diagnosed or suspected dementia, mild cognitive impairment, unspecified cognitive impairment, or memory problems referred for a medical driving assessment. A computerized battery of sensory-motor and cognitive tests and an on-road medical driving assessment. One hundred fifty-five participants (55.5%) received an on-road fail score. Binary logistic regression correctly classified 75.6% of the sample into on-road pass and fail groups. The cross-validation indicated accuracy of the model of 72.0% with sensitivity for detecting on-road fails of 73.5%, specificity of 70.2%, positive predictive value of 75.5%, and negative predictive value of 68%. The off-road assessment prediction model resulted in a substantial number of people who were assessed as likely to fail despite passing an on-road assessment and vice versa. Thus, despite a large multicenter sample, the use of off-road tests previously found to be useful in other older populations, and a carefully constructed and tested prediction model, off-road measures have yet to be found that are sufficiently accurate to allow acceptable determination of on-road driving safety of cognitively impaired older drivers. © 2013, Copyright the Authors Journal compilation © 2013, The American Geriatrics Society.

Life Testing of the Vapor Compression Distillation/Urine Processing Assembly (VCD/UPA) at the Marshall Space Flight Center (1993 to 1997)

NASA Technical Reports Server (NTRS)

Wieland, P.; Hutchens, C.; Long, D.; Salyer, B.

1998-01-01

Wastewater and urine generated on the International Space Station will be processed to recover pure water using vapor compression distillation (VCD). To verify the long-term reliability and performance of the VCD Urine Processor Assembly (UPA), life testing was performed at the Marshall Space Flight Center (MSFC) from January 1993 to April 1996. Two UPA'S, the VCD-5 and VCD-5A, were tested for 204 days and 665 days, respectively. The compressor gears and the distillation centrifuge drive belt were found to have operating lives of approximately 4,800 hours, equivalent to 3.9 years of operation on ISS for a crew of three at an average processing rate of 1.76 kg/h (3.97 lb/h). Precise alignment of the flex-splines of the fluids and purge pump motor drives is essential to avoid premature failure after about 400 hours of operation. Results indicate that, with some design and procedural modifications and suitable quality control, the required performance and operational life can be met with the VCD/UPA.

Parkinson's disease and driving ability

PubMed Central

Singh, Rajiv; Pentland, Brian; Hunter, John; Provan, Frances

2007-01-01

Objectives To explore the driving problems associated with Parkinson's disease (PD) and to ascertain whether any clinical features or tests predict driver safety. Methods The driving ability of 154 individuals with PD referred to a driving assessment centre was determined by a combination of clinical tests, reaction times on a test rig and an in‐car driving test. Results The majority of cases (104, 66%) were able to continue driving although 46 individuals required an automatic transmission and 10 others needed car modifications. Ability to drive was predicted by the severity of physical disease, age, presence of other associated medical conditions, particularly dementia, duration of disease, brake reaction, time on a test rig and score on a driving test (all p<0.001). The level of drug treatment and the length of driving history were not correlated. Discriminant analysis revealed that the most important features in distinguishing safety to drive were severe physical disease (Hoehn and Yahr stage 3), reaction time, moderate disease associated with another medical condition and high score on car testing. Conclusions Most individuals with PD are safe to drive, although many benefit from car modifications or from using an automatic transmission. A combination of clinical tests and in‐car driving assessment will establish safety to drive, and a number of clinical correlates can be shown to predict the likely outcome and may assist in the decision process. This is the largest series of consecutive patients seen at a driving assessment centre reported to date, and the first to devise a scoring system for on‐road driving assessment. PMID:17178820

Highly loaded multi-stage fan drive turbine: Plain blade configuration design

NASA Technical Reports Server (NTRS)

Evans, D. C.; Wolfmeyer, G. W.

1972-01-01

The constant-inside-diameter flowpath was scaled for testing in an existing turbine test facility. Blading detailed design is discussed, and design data are summarized. Predicted performance maps are presented. Steady-state stresses and vibratory behavior are discussed and the results of the mechanical design analysis are presented.

Approaches of truck drivers and non-truck drivers toward reckless on-road behavior.

PubMed

Rosenbloom, Tova; Eldror, Ehud; Shahar, Amit

2009-07-01

The purpose of the study was to compare the reported approaches of truck drivers to those of non-truck drivers toward reckless on-road behaviors. One hundred and sixty-seven adult males, including 70 non-truck drivers, completed the questionnaires voluntarily. The truck drivers were employees of a concrete manufacturing company working at various company plants throughout Israel. Seventy were professional mixer truckers and 27 were tip-truckers. The participants completed the Reckless Driving Self-Report Scale based on Taubman Ben-Ari et al. [Taubman Ben-Ari, O., Florian, V., Mikulincer, M., 1999. The impact of mortality salience on reckless driving: a test of terror management mechanisms. Journal of Personality and Social Psychology 76, 35-45], adapted for truck drivers for this study. It was expected that non-professional, as compared to professional (truck) drivers, would be more permissive regarding reckless driving, since driving risks are less prominent in their daily driving experience. An ANOVA performed on mean reckless-driving scores yielded significant results. The post hoc Schéffe test indicated significantly higher reckless-driving scores for automobile drivers as compared to both mixer-truck driver scores and tip-truck driver scores. In addition, the reckless-driving scores for mixer-truck drivers were significantly higher than the tip-truck driver scores. We discuss various explanations for the findings and consider possible implications for training strategies in organizations as well as for media campaigns focused on mutual safe road use of truck drivers and private vehicle drivers.

Evaluation of retroreflectometers.

DOT National Transportation Integrated Search

2002-08-01

This project performed field-testing and analysis of two pavement marking retroreflectometers: the Laserlux and the : LTL2000. The Laserlux is a vehiclemounted device that takes readings at driving speed and produces : computerized output. The LTL...

ADX: a high field, high power density, Advanced Divertor test eXperiment

NASA Astrophysics Data System (ADS)

Vieira, R.; Labombard, B.; Marmar, E.; Irby, J.; Shiraiwa, S.; Terry, J.; Wallace, G.; Whyte, D. G.; Wolfe, S.; Wukitch, S.; ADX Team

2014-10-01

The MIT PSFC and collaborators are proposing an advanced divertor experiment (ADX) - a tokamak specifically designed to address critical gaps in the world fusion research program on the pathway to FNSF/DEMO. This high field (6.5 tesla, 1.5 MA), high power density (P/S ~ 1.5 MW/m2) facility would utilize Alcator magnet technology to test innovative divertor concepts for next-step DT fusion devices (FNSF, DEMO) at reactor-level boundary plasma pressures and parallel heat flux densities while producing high performance core plasma conditions. The experimental platform would also test advanced lower hybrid current drive (LHCD) and ion-cyclotron range of frequency (ICRF) actuators and wave physics at the plasma densities and magnetic field strengths of a DEMO, with the unique ability to deploy launcher structures both on the low-magnetic-field side and the high-field side - a location where energetic plasma-material interactions can be controlled and wave physics is most favorable for efficient current drive, heating and flow drive. This innovative experiment would perform plasma science and technology R&D necessary to inform the conceptual development and accelerate the readiness-for-deployment of FNSF/DEMO - in a timely manner, on a cost-effective research platform. Supported by DE-FC02-99ER54512.

Improving Drive Files for Vehicle Road Simulations

NASA Astrophysics Data System (ADS)

Cherng, John G.; Goktan, Ali; French, Mark; Gu, Yi; Jacob, Anil

2001-09-01

Shaker tables are commonly used in laboratories for automotive vehicle component testing to study durability and acoustics performance. An example is development testing of car seats. However, it is difficult to repeat the measured road data perfectly with the response of a shaker table as there are basic differences in dynamic characteristics between a flexible vehicle and substantially rigid shaker table. In addition, there are performance limits in the shaker table drive systems that can limit correlation. In practice, an optimal drive signal for the actuators is created iteratively. During each iteration, the error between the road data and the response data is minimised by an optimising algorithm which is generally a part of the feed back loop of the shake table controller. This study presents a systematic investigation to the errors in time and frequency domains as well as joint time-frequency domain and an evaluation of different digital signal processing techniques that have been used in previous work. In addition, we present an innovative approach that integrates the dynamic characteristics of car seats and the human body into the error-minimising iteration process. We found that the iteration process can be shortened and the error reduced by using a weighting function created by normalising the frequency response function of the car seat. Two road data test sets were used in the study.

40 CFR 1066.410 - Dynamometer test procedure.

Code of Federal Regulations, 2014 CFR

2014-07-01

... drive mode. (For purposes of this paragraph (g), the term four-wheel drive includes other multiple drive... Dynamometer test procedure. (a) Dynamometer testing may consist of multiple drive cycles with both cold-start...-setting part identifies the driving schedules and the associated sample intervals, soak periods, engine...

Oscillating-flow loss test results in rectangular heat exchanger passages

NASA Technical Reports Server (NTRS)

Wood, J. Gary

1991-01-01

Test results of oscillating flow losses in rectangular heat exchanger passages of various aspect ratios are given. This work was performed in support of the design of a free-piston Stirling engine (FPSE) for a dynamic space power conversion system. Oscillating flow loss testing was performed using an oscillating flow rig, which was based on a variable stroke and variable frequency linear drive motor. Tests were run over a range of oscillating flow parameters encompassing the flow regimes of the proposed engine design. Test results are presented in both tabular and graphical form and are compared against analytical predictions.

Laser-driven Mach waves for gigabar-range shock experiments

NASA Astrophysics Data System (ADS)

Swift, Damian; Lazicki, Amy; Coppari, Federica; Saunders, Alison; Nilsen, Joseph

2017-10-01

Mach reflection offers possibilities for generating planar, supported shocks at higher pressures than are practical even with laser ablation. We have studied the formation of Mach waves by algebraic solution and hydrocode simulation for drive pressures at much than reported previously, and for realistic equations of state. We predict that Mach reflection continues to occur as the drive pressure increases, and the pressure enhancement increases monotonically with drive pressure even though the ``enhancement spike'' characteristic of low-pressure Mach waves disappears. The growth angle also increases monotonically with pressure, so a higher drive pressure seems always to be an advantage. However, there are conditions where the Mach wave is perturbed by reflections. We have performed trial experiments at the Omega facility, using a laser-heated halfraum to induce a Mach wave in a polystyrene cone. Pulse length and energy limitations meant that the drive was not maintained long enough to fully support the shock, but the results indicated a Mach wave of 25-30 TPa from a drive pressure of 5-6 TPa, consistent with simulations. A similar configuration should be tested at the NIF, and a Z-pinch driven configuration may be possible. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

A study on the flow characteristics of a direct drive turbine for energy conversion generation by experiment and CFD

NASA Astrophysics Data System (ADS)

Cho, Y. J.; Zullah, M. A.; Faizal, M.; Choi, Y. D.; Lee, Y. H.

2012-11-01

A variety of technologies has been proposed to capture the energy from waves. Some of the more promising designs are undergoing demonstration testing at commercial scales. Due to the complexity of most offshore wave energy devices and their motion response in different sea states, physical tank tests are common practice for WEC design. Full scale tests are also necessary, but are expensive and only considered once the design has been optimized. Computational Fluid Dynamics (CFD) is now recognized as an important complement to traditional physical testing techniques in offshore engineering. Once properly calibrated and validated to the problem, CFD offers a high density of test data and results in a reasonable timescale to assist with design changes and improvements to the device. The purpose of this study is to investigate the performance of a newly developed direct drive hydro turbine (DDT), which will be built in a caisson for extraction of wave energy. Experiments and CFD analysis are conducted to clarify the turbine performance and internal flow characteristics. The results show that commercial CFD code can be applied successfully to the simulation of the wave motion in the water tank. The performance of the turbine for wave energy converter is studied continuously for a ongoing project.

14 CFR 27.923 - Rotor drive system and control mechanism tests.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Rotor drive system and control mechanism....923 Rotor drive system and control mechanism tests. (a) Each part tested as prescribed in this section... affect test results may be conducted. (b) Each rotor drive system and control mechanism must be tested...

14 CFR 27.923 - Rotor drive system and control mechanism tests.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Rotor drive system and control mechanism....923 Rotor drive system and control mechanism tests. (a) Each part tested as prescribed in this section... affect test results may be conducted. (b) Each rotor drive system and control mechanism must be tested...

The use of the Color Trails Test in the assessment of driver competence: preliminary report of a culture-fair instrument.

PubMed

Elkin-Frankston, Seth; Lebowitz, Brian K; Kapust, Lissa R; Hollis, Ann M; O'Connor, Margaret G

2007-06-01

Studies have shown that the Trail Making Test (TMT) predicts real-world driving performance in individuals who have cognitive deficits. However, because this test requires knowledge of the Latin alphabet, the TMT may not be appropriate for individuals who are illiterate or for those whom English is not their primary language. Because the Color Trails Test (CTT) is not influenced by knowledge of the alphabet, the CTT may be a culture-fair alternative to the TMT. To date, the utility of the CTT in the evaluation of driver competence has not been established. In the current study, individuals referred for a comprehensive driving assessment underwent testing with the TMT and CTT. The results suggest that the CTT and the TMT provide similar information regarding road-test outcome. Thus, the CTT may be a culture-fair alternative to the TMT in the assessment of driver competence.

Cold-Flow Testing of a Proposed Integrated Center-Body Diffuser/Steam Blocker Concept for Plum Brook Station's B-2 Test Facility

NASA Technical Reports Server (NTRS)

Edwards, Daryl A.; Weaver, Harold F; Kastner, Carl E., Jr.

2009-01-01

The center-body diffuser (CBD) steam blocker (SB) system is a concept that incorporates a set of secondary drive nozzles into the envelope of a CBD, such that both nozzle systems (i.e., the rocket engine and the steam blocking nozzles) utilize the same supersonic diffuser, and will operate either singularly or concurrently. In this manner, the SB performs as an exhaust system stage when the rocket engine is not operating, and virtually eliminates discharge flow on rocket engine shutdown. A 2.25-percent scale model of a proposed SB integrated into a diffuser for the Plum Brook B-2 facility was constructed and cold-flow tested for the purpose of evaluating performance characteristics of various design options. These specific design options addressed secondary drive nozzle design (method of steam injection), secondary drive nozzle location relative to CBD throat, and center-body throat length to diameter (L/D) ratios. The objective of the test program is to identify the desired configuration to carry forward should the next phase of design proceed. The tested scale model can provide data for various pressure ratios; however, its design is based on a proposed B-2 spray chamber (SC) operating pressure of 4.0 psia and a steam supply pressure of 165 psia. Evaluation of the test data acquired during these tests indicate that either the discrete axial or annular nozzle configuration integrated into a CBD, with an annular throat length of 1.5 L/D at the nominal injection position, would be suitable to carry forward from the SB's perspective. Selection between these two then becomes more a function of constructability and implementation than performance. L/D also has some flexibility, and final L/D selection can be a function of constructability issues within a limited range.

Type 1 diabetic drivers with and without a history of recurrent hypoglycemia-related driving mishaps: physiological and performance differences during euglycemia and the induction of hypoglycemia.

PubMed

Cox, Daniel J; Kovatchev, Boris P; Anderson, Stacey M; Clarke, William L; Gonder-Frederick, Linda A

2010-11-01

Collisions are more common among drivers with type 1 diabetes than among their nondiabetic spouses. This increased risk appears to be attributable to a subgroup of drivers with type 1 diabetes. The hypothesis tested is that this vulnerable subgroup is more at risk for hypoglycemia and its disruptive effects on driving. Thirty-eight drivers with type 1 diabetes, 16 with (+history) and 22 without (-history) a recent history of recurrent hypoglycemia-related driving mishaps, drove a virtual reality driving simulator and watched a videotape of someone driving a simulator for 30-min periods. Driving and video testing occurred in a double-blind, randomized, crossover manner during euglycemia (5.5 mmol/l) and progressive hypoglycemia (3.9-2.5 mmol/l). Examiners were blind to which subjects were +/-history, whereas subjects were blind to their blood glucose levels and targets. During euglycemia, +history participants reported more autonomic and neuroglycopenic symptoms (P≤0.01) and tended to require more dextrose infusion to maintain euglycemia with the same insulin infusion (P<0.09). During progressive hypoglycemia, these subjects demonstrated less epinephrine release (P=0.02) and greater driving impairments (P=0.03). Findings support the speculation that there is a subgroup of type 1 diabetic drivers more vulnerable to experiencing hypoglycemia-related driving mishaps. This increased vulnerability may be due to more symptom "noise" (more symptoms during euglycemia), making it harder to detect hypoglycemia while driving; possibly greater carbohydrate utilization, rendering them more vulnerable to experiencing hypoglycemia; less hormonal counterregulation, leading to more profound hypoglycemia; and more neuroglycopenia, rendering them more vulnerable to impaired driving.

Effect of tailored on-road driving lessons on driving safety in older adults: A randomised controlled trial.

PubMed

Anstey, Kaarin J; Eramudugolla, Ranmalee; Kiely, Kim M; Price, Jasmine

2018-06-01

We evaluated the effectiveness of individually tailored driving lessons compared with a road rules refresher course for improving older driver safety. Two arm parallel randomised controlled trial, involving current drivers aged 65 and older (Mean age 72.0, 47.4% male) residing in Canberra, Australia. The intervention group (n = 28) received a two-hour class-based road rules refresher course, and two one-hour driving lessons tailored to improve poor driving skills and habits identified in a baseline on-road assessment. The control group (n = 29) received the road rules refresher course only. Tests of cognitive performance, and on-road driving were conducted at baseline and at 12-weeks. Main outcome measure was the Driver safety rating (DSR) on the on-road driving test. The number of Critical Errors made during the on-road was also recorded. 55 drivers completed the trial (intervention group: 27, control group: 28). Both groups showed reduction in dangerous/hazardous driver errors that required instructor intervention. From baseline to follow-up there was a greater reduction in the number of critical errors made by the intervention group relative to the control group (IRR = 0.53, SE = 0.1, p = .008). The intervention group improved on the DSR more than the control group (intervention mean change = 1.07 SD = 2.00, control group mean change = 0.32 SD = 1.61). The intervention group had 64% remediation of unsafe driving, where drivers who achieved a score of 'fail' at baseline, 'passed' at follow-up. The control group had 25% remediation. Tailored driving lessons reduced the critical driving errors made by older adults. Longer term follow-up and larger trials are required. Copyright © 2018 Elsevier Ltd. All rights reserved.

Long-Life, Lightweight, Multi-Roller Traction Drives for Planetary Vehicle Surface Exploration

NASA Technical Reports Server (NTRS)

Klein, Richard C.; Fusaro, Robert L.; Dimofte, Florin

2012-01-01

NASA s initiative for Lunar and Martian exploration will require long lived, robust drive systems for manned vehicles that must operate in hostile environments. The operation of these mechanical drives will pose a problem because of the existing extreme operating conditions. Some of these extreme conditions include operating at a very high or very cold temperature, operating over a wide range of temperatures, operating in very dusty environments, operating in a very high radiation environment, and operating in possibly corrosive environments. Current drive systems use gears with various configurations of teeth. These gears must be lubricated with oil (or grease) and must have some sort of a lubricant resupply system. For drive systems, oil poses problems such as evaporation, becoming too viscous and eventually freezing at cold temperatures, being too thin to lubricate at high temperatures, being degraded by the radiation environment, being contaminated by the regolith (soil), and if vaporized (and not sealed), it will contaminate the regolith. Thus, it may not be advisable or even possible to use oil because of these limitations. An oil-less, compact traction vehicle drive is a drive designed for use in hostile environments like those that will be encountered on planetary surfaces. Initially, traction roller tests in vacuum were conducted to obtain traction and endurance data needed for designing the drives. From that data, a traction drive was designed that would fit into a prototype lunar rover vehicle, and this design data was used to construct several traction drives. These drives were then tested in air to determine their performance characteristics, and if any final corrections to the designs were necessary. A limitation with current speed reducer systems such as planetary gears and harmonic drives is the high-contact stresses that occur at tooth engagement and in the harmonic drive wave generator interface. These high stresses induce high wear of solid lubricant coatings, thus necessitating the use of liquid lubricants for long life.

MOD-0A 200 kW wind turbine generator design and analysis report

NASA Astrophysics Data System (ADS)

Anderson, T. S.; Bodenschatz, C. A.; Eggers, A. G.; Hughes, P. S.; Lampe, R. F.; Lipner, M. H.; Schornhorst, J. R.

1980-08-01

The design, analysis, and initial performance of the MOD-OA 200 kW wind turbine generator at Clayton, NM is documented. The MOD-OA was designed and built to obtain operation and performance data and experience in utility environments. The project requirements, approach, system description, design requirements, design, analysis, system tests, installation, safety considerations, failure modes and effects analysis, data acquisition, and initial performance for the wind turbine are discussed. The design and analysis of the rotor, drive train, nacelle equipment, yaw drive mechanism and brake, tower, foundation, electricl system, and control systems are presented. The rotor includes the blades, hub, and pitch change mechanism. The drive train includes the low speed shaft, speed increaser, high speed shaft, and rotor brake. The electrical system includes the generator, switchgear, transformer, and utility connection. The control systems are the blade pitch, yaw, and generator control, and the safety system. Manual, automatic, and remote control are discussed. Systems analyses on dynamic loads and fatigue are presented.

MOD-0A 200 kW wind turbine generator design and analysis report

NASA Technical Reports Server (NTRS)

Anderson, T. S.; Bodenschatz, C. A.; Eggers, A. G.; Hughes, P. S.; Lampe, R. F.; Lipner, M. H.; Schornhorst, J. R.

1980-01-01

The design, analysis, and initial performance of the MOD-OA 200 kW wind turbine generator at Clayton, NM is documented. The MOD-OA was designed and built to obtain operation and performance data and experience in utility environments. The project requirements, approach, system description, design requirements, design, analysis, system tests, installation, safety considerations, failure modes and effects analysis, data acquisition, and initial performance for the wind turbine are discussed. The design and analysis of the rotor, drive train, nacelle equipment, yaw drive mechanism and brake, tower, foundation, electricl system, and control systems are presented. The rotor includes the blades, hub, and pitch change mechanism. The drive train includes the low speed shaft, speed increaser, high speed shaft, and rotor brake. The electrical system includes the generator, switchgear, transformer, and utility connection. The control systems are the blade pitch, yaw, and generator control, and the safety system. Manual, automatic, and remote control are discussed. Systems analyses on dynamic loads and fatigue are presented.

Bio-inspired piezoelectric linear motor driven by a single-phase harmonic wave with an asymmetric stator.

PubMed

Pan, Qiaosheng; Miao, Enming; Wu, Bingxuan; Chen, Weikang; Lei, Xiujun; He, Liangguo

2017-07-01

A novel, bio-inspired, single-phase driven piezoelectric linear motor (PLM) using an asymmetric stator was designed, fabricated, and tested to avoid mode degeneracy and to simplify the drive mechanism of a piezoelectric motor. A piezoelectric transducer composed of two piezoelectric stacks and a displacement amplifier was used as the driving element of the PLM. Two simple and specially designed claws performed elliptical motion. A numerical simulation was performed to design the stator and determine the feasibility of the design mechanism of the PLM. Moreover, an experimental setup was built to validate the working principles, as well as to evaluate the performance, of the PLM. The prototype motor outputs a no-load speed of 233.7 mm/s at a voltage of 180 V p-p and a maximum thrust force of 2.3 N under a preload of 10 N. This study verified the feasibility of the proposed design and provided a method to simplify the driving harmonic signal and structure of PLMs.

Older drivers and rapid deceleration events: Salisbury Eye Evaluation Driving Study.

PubMed

Keay, Lisa; Munoz, Beatriz; Duncan, Donald D; Hahn, Daniel; Baldwin, Kevin; Turano, Kathleen A; Munro, Cynthia A; Bandeen-Roche, Karen; West, Sheila K

2013-09-01

Drivers who rapidly change speed while driving may be more at risk for a crash. We sought to determine the relationship of demographic, vision, and cognitive variables with episodes of rapid decelerations during five days of normal driving in a cohort of older drivers. In the Salisbury Eye Evaluation Driving Study, 1425 older drivers aged 67-87 were recruited from the Maryland Motor Vehicle Administration's rolls for licensees in Salisbury, Maryland. Participants had several measures of vision tested: visual acuity, contrast sensitivity, visual fields, and the attentional visual field. Participants were also tested for various domains of cognitive function including executive function, attention, psychomotor speed, and visual search. A custom created driving monitoring system (DMS) was used to capture rapid deceleration events (RDEs), defined as at least 350 milli-g deceleration, during a five day period of monitoring. The rate of RDE per mile driven was modeled using a negative binomial regression model with an offset of the logarithm of the number of miles driven. We found that 30% of older drivers had one or more RDE during a five day period, and of those, about 1/3 had four or more. The rate of RDE per mile driven was highest for those drivers driving<59 miles during the 5-day period of monitoring. However, older drivers with RDE's were more likely to have better scores in cognitive tests of psychomotor speed and visual search, and have faster brake reaction time. Further, greater average speed and maximum speed per driving segment was protective against RDE events. In conclusion, contrary to our hypothesis, older drivers who perform rapid decelerations tend to be more "fit", with better measures of vision and cognition compared to those who do not have events of rapid deceleration. Copyright © 2012 Elsevier Ltd. All rights reserved.

Older Drivers and Rapid Deceleration Events: Salisbury Eye Evaluation Driving Study

PubMed Central

Keay, Lisa; Munoz, Beatriz; Duncan, Donald D; Hahn, Daniel; Baldwin, Kevin; Turano, Kathleen A; Munro, Cynthia A; Bandeen-Roche, Karen; West, Sheila K

2012-01-01

Drivers who rapidly change speed while driving may be more at risk for a crash. We sought to determine the relationship of demographic, vision, and cognitive variables with episodes of rapid decelerations during five days of normal driving in a cohort of older drivers. In the Salisbury Eye Evaluation Driving Study, 1425 older drivers ages 67 to 87 were recruited from the Maryland Motor Vehicle Administration’s rolls for licensees in Salisbury, Maryland. Participants had several measures of vision tested: visual acuity, contrast sensitivity, visual fields, and the attentional visual field. Participants were also tested for various domains of cognitive function including executive function, attention, psychomotor speed, and visual search. A custom created Driving Monitor System (DMS) was used to capture rapid deceleration events (RDE), defined as at least 350 milli-g deceleration, during a five day period of monitoring. The rate of RDE per mile driven was modeled using a negative binomial regression model with an offset of the logarithm of the number of miles driven. We found that 30% of older drivers had one or more RDE during a five day period, and of those, about 1/3 had four or more. The rate of RDE per mile driven was highest for those drivers driving <59 miles during the 5-day period of monitoring. However, older drivers with RDE’s were more likely to have better scores in cognitive tests of psychomotor speed and visual search, and have faster brake reaction time. Further, greater average speed and maximum speed per driving segment was protective against RDE events. In conclusion, contrary to our hypothesis, older drivers who perform rapid decelerations tend to be more “fit”, with better measures of vision and cognition compared to those who do not have events of rapid deceleration. PMID:22742775

Structural equation model analysis for the evaluation of overall driving performance: A driving simulator study focusing on driver distraction.

PubMed

Papantoniou, Panagiotis

2018-04-03

The present research relies on 2 main objectives. The first is to investigate whether latent model analysis through a structural equation model can be implemented on driving simulator data in order to define an unobserved driving performance variable. Subsequently, the second objective is to investigate and quantify the effect of several risk factors including distraction sources, driver characteristics, and road and traffic environment on the overall driving performance and not in independent driving performance measures. For the scope of the present research, 95 participants from all age groups were asked to drive under different types of distraction (conversation with passenger, cell phone use) in urban and rural road environments with low and high traffic volume in a driving simulator experiment. Then, in the framework of the statistical analysis, a correlation table is presented investigating any of a broad class of statistical relationships between driving simulator measures and a structural equation model is developed in which overall driving performance is estimated as a latent variable based on several individual driving simulator measures. Results confirm the suitability of the structural equation model and indicate that the selection of the specific performance measures that define overall performance should be guided by a rule of representativeness between the selected variables. Moreover, results indicate that conversation with the passenger was not found to have a statistically significant effect, indicating that drivers do not change their performance while conversing with a passenger compared to undistracted driving. On the other hand, results support the hypothesis that cell phone use has a negative effect on driving performance. Furthermore, regarding driver characteristics, age, gender, and experience all have a significant effect on driving performance, indicating that driver-related characteristics play the most crucial role in overall driving performance. The findings of this study allow a new approach to the investigation of driving behavior in driving simulator experiments and in general. By the successful implementation of the structural equation model, driving behavior can be assessed in terms of overall performance and not through individual performance measures, which allows an important scientific step forward from piecemeal analyses to a sound combined analysis of the interrelationship between several risk factors and overall driving performance.

GSA's Green Proving Ground: Identifying, Testing and Evaluating Innovative Technologies (Presentation)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kandt, A.; Lowell, M.

2012-05-01

GSA's Green Proving Ground (GPG) program utilizes GSA's real estate portfolio to test and evaluate innovative and underutilized sustainable building technologies and practices. Findings are used to support the development of GSA performance specifications and inform decision making within GSA, other federal agencies, and the real estate industry. The program aims to drive innovation in environmental performance in federal buildings and help lead market transformation through deployment of new technologies.

ACD16-0001-022

NASA Image and Video Library

2016-01-06

Senior executives from the Renault-Nissan Alliance, including Carlos Ghosn, chairman and CEO of Nissan, and Jose Munoz, chairman of Nissan North America, visited Ames for meetings and a showcase of the technical partnership between NASA and Nissan North America. The partnership allows researchers to develop and test autonomy algorithms, concepts, and integrated prototypes for a variety of vehicular transport applications – from rovers to self-driving cars. After briefings, a company of including Eugene Tu, Ames Center Director andLiam Pedersen, Nissan on right Carlos Ghosn, CE, Nissan on left climb into in the autonomous vehicle to observed testing of Nissan’s all-electric LEAF as it performed safe autonomous drives across the center.

Study on loading and unloading performance of new energy vehicle battery sensor

NASA Astrophysics Data System (ADS)

Wu, Bin; Ren, Kai; Liu, Ying

2017-04-01

This paper first introduces the 18650 battery, describes the importance of the battery temperature sensor, uses Ansys Workbench finite element simulation software and the mean of the combination of displacement constraint and reaction force, studies the force and the size of the change of new energy vehicle battery temperature sensor in the loading, translation and unloading of the three cases, then make the test to verify its accuracy. At last, the test results are compared with the usual maximum acceleration of the vehicle in driving which verified the sensor of the car will not fall off in the car driving process and work normally.

Performance tests of a power-electronics converter for multi-megawatt wind turbines using a grid emulator

NASA Astrophysics Data System (ADS)

Rizqy Averous, Nurhan; Berthold, Anica; Schneider, Alexander; Schwimmbeck, Franz; Monti, Antonello; De Doncker, Rik W.

2016-09-01

A vast increase of wind turbines (WT) contribution in the modern electrical grids have led to the development of grid connection requirements. In contrast to the conventional test method, testing power-electronics converters for WT using a grid emulator at Center for Wind Power Drives (CWD) RWTH Aachen University offers more flexibility for conducting test scenarios. Further analysis on the performance of the device under test (DUT) is however required when testing with grid emulator since the characteristic of the grid emulator might influence the performance of the DUT. This paper focuses on the performance analysis of the DUT when tested using grid emulator. Beside the issue regarding the current harmonics, the performance during Fault Ride-Through (FRT) is discussed in detail. A power hardware in the loop setup is an attractive solution to conduct a comprehensive study on the interaction between the power-electronics converters and the electrical grids.

Features of the solar array drive mechanism for the space telescope

NASA Technical Reports Server (NTRS)

Hostenkamp, R. G.

1985-01-01

The solar array drive mechanism for the Space Telescope embodies several features not customarily found on solar array drives. Power and signal transfer is achieved by means of a flexible wire harness for which the chosen solution, consisting of 168 standard wires, is described. The torque performance data of the harness over its temperature range are presented. The off load system which protects the bearings from the launch loads is released by a trigger made from Nitinol, the memory alloy. The benefits of memory alloy and the caveats for the design are briefly discussed. The design of the off load system is described and test experience is reported.

Medications and Impaired Driving: A Review of the Literature

PubMed Central

Hetland, Amanda; Carr, David B

2013-01-01

Objective To describe the association of specific medication classes with driving outcomes and provide clinical recommendations. Data sources The MEDLINE and EMBASE databases were searched for articles published from January 1973 to June 2013 on specific classes of medications known to be associated with driving impairment. The search included outcome terms such as automobile driving, motor vehicle crash, driving simulator, and road tests. Study selection and data extraction Only English-language articles that contained findings from observational or interventional designs were included. Cross-sectional studies, case series, and case reports were excluded. Studies of ≥ 10 subjects were included in this review. Data synthesis Driving is an important task and activity for the majority of adults. Unfortunately, some specific classes of commonly prescribed medications have been associated with driving impairment as measured by road performance, driving simulation, and/or motor vehicle crashes. This review of 30 studies identified findings with barbiturates, benzodiazepines, certain non-benzodiazepine hypnotics, various antidepressants, opioid and non-steroidal analgesics, anticonvulsants, antipsychotics, antiparkinsonian agents, skeletal muscle relaxants, antihistamines, anticholinergic medications, and hypoglycemic agents. Additional studies identifying medication impacts on sedation, sleep latency, and psychomotor function – as well as the role of alcohol – are also discussed. Conclusions Psychotropic agents and those with CNS side effects were associated with various measures of impaired driving performance. It is difficult to determine if such associations are actually a result of medication use or perhaps the medical diagnosis itself. Regardless, clinicians should be aware of the increased risk of impaired driving with specific populations and classes of medications when prescribing these agents, educate their patients, and/or consider safer alternatives. PMID:24473486

Electromechanical actuation for cryogenic valve control

NASA Technical Reports Server (NTRS)

Lister, M. J.; Reichmuth, D. M.

1993-01-01

The design and analysis of the electromechanical actuator (EMA) being developed for the NASA/Marshall Space Flight Center as part of the National Launch System (NLS) Propellant Control Effector Advanced Development Program (ADP) are addressed. The EMA design uses several proven technologies combined into a single modular package which includes single stage high ratio gear reduction, redundant electric motors mounted on a common drive shaft, redundant drive and control electronics, and digital technology for performing the closed loop position feedback, communication, and health monitoring functions. Results of tests aimed at evaluating both component characteristics and overall system performance demonstrated that the goal of low cost, reliable control in a cryogenic environment is feasible.

Variable/Multispeed Rotorcraft Drive System Concepts

NASA Technical Reports Server (NTRS)

Stevens, Mark A.; Handschuh, Robert F.; Lewicki, David G.

2009-01-01

Several recent studies for advanced rotorcraft have identified the need for variable, or multispeed-capable rotors. A speed change of up to 50 percent has been proposed for future rotorcraft to improve vehicle performance. Varying rotor speed during flight not only requires a rotor capable of performing effectively over the extended operation speed and load range, but also requires an advanced propulsion system to provide the required speed changes. A study has been completed, which investigated possible drive system arrangements to accommodate up to the 50 percent speed change. These concepts are presented. The most promising configurations are identified and will be developed for future validation testing.

Examining physiological responses across different driving maneuvers during an on-road driving task: a pilot study comparing older and younger drivers.

PubMed

Koppel, S; Kuo, J; Berecki-Gisolf, J; Boag, R; Hue, Y-X; Charlton, J L

2015-01-01

This pilot study aimed to investigate physiological responses during an on-road driving task for older and younger drivers. Five older drivers (mean age = 74.60 years [2.97]) and 5 younger drivers (mean age = 30.00 years [3.08]) completed a series of cognitive assessments (Montreal Cognitive Assessment [MoCA], Mini Mental Status Examination [MMSE]; Trail Making Test [Trails A and Trails B]) and an on-road driving task along a predetermined, standardized urban route in their own vehicle. Driving performance was observed and scored by a single trained observer using a standardized procedure, where driving behaviors (appropriate and inappropriate) were scored for intersection negotiation, lane changing, and merging. During the on-road driving task, participants' heart rate (HR) was monitored with an unobtrusive physiological monitor. Younger drivers performed significantly better on all cognitive assessments compared to older drivers (MoCA: t(8) = 3.882, P <.01; MMSE: t(8) = 2.954, P <.05; Trails A: t(8) = -2.499, P <.05; Trails B: t(8) = -3.262, P <.05). Analyses of participants' performance during the on-road driving task revealed a high level of appropriate overall driving behavior (M = 87%, SD = 7.62, range = 73-95%), including intersection negotiation (M = 89%, SD = 8.37%), lane changing (M = 100%), and merging (M = 53%, SD = 28.28%). The overall proportion of appropriate driving behavior did not significantly differ across age groups (younger drivers: M = 87.6%, SD = 9.04; older drivers: M = 87.0%, SD = 6.96; t(8) = 0.118, P =.91). Although older drivers scored lower than younger drivers on the cognitive assessments, there was no indication of cognitive overload among older drivers based on HR response to the on-road driving task. The results provide preliminary evidence that mild age-related cognitive impairment may not pose a motor vehicle crash hazard for the wider older driver population. To maintain safe mobility of the aging population, further research into the specific crash risk factors in the older driver population is warranted.

Miniaturized haploscope for testing binocular vision

NASA Technical Reports Server (NTRS)

Decker, T. A.

1973-01-01

Device can reproduce virtually all binocular stimulus conditions (target configuration, vergence angle, and accommodative distance) used to test binocular performance. All subsystems of electronic controls are open-loop and solid-state-controlled and, with the exception of vergence angle drive, utilize dc stepping motors as prime movers. Arrangement is also made for readouts of each variable.

Multi-mode energy management strategy for fuel cell electric vehicles based on driving pattern identification using learning vector quantization neural network algorithm

NASA Astrophysics Data System (ADS)

Song, Ke; Li, Feiqiang; Hu, Xiao; He, Lin; Niu, Wenxu; Lu, Sihao; Zhang, Tong

2018-06-01

The development of fuel cell electric vehicles can to a certain extent alleviate worldwide energy and environmental issues. While a single energy management strategy cannot meet the complex road conditions of an actual vehicle, this article proposes a multi-mode energy management strategy for electric vehicles with a fuel cell range extender based on driving condition recognition technology, which contains a patterns recognizer and a multi-mode energy management controller. This paper introduces a learning vector quantization (LVQ) neural network to design the driving patterns recognizer according to a vehicle's driving information. This multi-mode strategy can automatically switch to the genetic algorithm optimized thermostat strategy under specific driving conditions in the light of the differences in condition recognition results. Simulation experiments were carried out based on the model's validity verification using a dynamometer test bench. Simulation results show that the proposed strategy can obtain better economic performance than the single-mode thermostat strategy under dynamic driving conditions.

Driving experience and special skills reflected in eye movements

NASA Astrophysics Data System (ADS)

Paeglis, Roberts; Bluss, Kristaps; Atvars, Aigars

2011-10-01

When driving a vehicle, people use the central vision both to plan ahead and monitor their performance feedback (research by Donges, 1978 [1], and after). Discussion is ongoing if making eye movements do more than gathering information. Moving eyes may also prepare the following body movements like steering. Different paradigms exist to explore vision in driving. Our perspective was to quantify eye movements and fixation patterns of different proficiency individuals, a driving learner, a novice, an experienced driver and a European level car racer. Thus for safety reasons we started by asking them to follow a video tour through a known city, remote from an infrared eye tracker sampling at 250 Hz. We report that gaze strategy of an experienced driver differs qualitatively from that of an automobile sports master. Quantitative differences only were found between the latter and a driving learner or a novice driver. Experience in a motor action provides skills different from sports training. We are aiming at testing this finding in real world driving.

Do Older Drivers At-Risk for Crashes Modify Their Driving Over Time?

PubMed Central

Clay, Olivio J.; Edwards, Jerri D.; Ball, Karlene K.; Wadley, Virginia G.; Vance, David E.; Cissell, Gayla M.; Roenker, Daniel L.; Joyce, John J.

2009-01-01

Five-year driving habit trajectories among older adults (n = 645) at-risk for crashes were examined. Performance measures included Useful Field of View (UFOV). Motor-Free Visual Perception Test, Rapid Walk, and Foot Tap. Self-report measures included demographics and the Driving Habits Questionnaire. Longitudinal random-effects models revealed that drivers at-risk for subsequent crashes, based upon UFOV, regulated their driving more than the lower-risk participants. Restricted driving was present at baseline for the at-risk group and was observed in longitudinal trajectories that controlled for baseline differences. Results indicate that persons at-risk for subsequent crashes increasingly limit their driving over time. Despite this self-regulation, a larger sample of such older drivers was twice as likely to incur subsequent at-fault crashes. Results suggest that self-regulation among older drivers at-risk for crashes is an insufficient compensatory approach to eliminating increased crash risk. UFOV is a registered trademark of Visual Awareness, Inc. PMID:19196692

Cognition-Based and Affect-Based Trust as Mediators of Leader Behavior Influences on Team Performance

ERIC Educational Resources Information Center

Schaubroeck, John; Lam, Simon S. K.; Peng, Ann Chunyan

2011-01-01

We develop a model in which cognitive and affective trust in the leader mediate the relationship between leader behavior and team psychological states that, in turn, drive team performance. The model is tested on a sample of 191 financial services teams in Hong Kong and the U.S. Servant leadership influenced team performance through affect-based…

The Relationship between Cellular Phone Use, Performance, and Reaction Time among College Students: Implications for Cellular Phone Use while Driving

ERIC Educational Resources Information Center

Szyfman, Adam; Wanner, Gregory; Spencer, Leslie

2003-01-01

Two studies were performed to determine the relationship between cellular phone use and either reaction time or performance among college students. In the first study 60 undergraduates completed a computerized reaction time test. Mean reaction times were significantly higher when participants were talking on a cellular phone, either handheld or on…

Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Engineering Test Report: METSAT A1 Signal Processor (P/N 1331670-2, S/N F03)

NASA Technical Reports Server (NTRS)

Lund, D.

1998-01-01

This report presents a description of tests performed, and the test data, for the A1 METSAT Signal Processor Assembly PN: 1331679-2, S/N F03. This assembly was tested in accordance with AE-26754, "METSAT Signal Processor Scan Drive Test and Integration Procedure." The objective is to demonstrate functionality of the signal processor prior to instrument integration.

Simulated Driving Performance of Adults with ADHD: Comparisons with Alcohol Intoxication

PubMed Central

Weafer, Jessica; Camarillo, Daniel; Fillmore, Mark T.; Milich, Richard; Marczinski, Cecile A.

2015-01-01

Previous research has demonstrated that adults with ADHD are more likely to experience driving-related problems, which suggests that they may exhibit poorer driving performance. However, direct experimental evidence of this hypothesis is limited. The current study involved two experiments that evaluated driving performance in adults with ADHD in terms of the types of driving decrements typically associated with alcohol intoxication. Experiment 1 compared the simulated driving performance of 15 adults with ADHD to 23 adult control participants, who performed the task both while sober and intoxicated. Results showed that sober adults with ADHD exhibited decrements in driving performance compared to sober controls, and that the profile of impairment for the sober ADHD group did in fact resemble that of intoxicated drivers at the BAC level for legally impaired driving in the United States. Driving impairment of the intoxicated individuals was characterized by greater deviation of lane position, faster and more abrupt steering maneuvers, and increased speed variability. Experiment 2 was a dose-challenge study in which 8 adults with ADHD and 8 controls performed the driving simulation task under three doses of alcohol: 0.65 g/kg, 0.45 g/kg, and 0.0 g/kg (placebo). Results showed that driving performance in both groups was impaired in response to alcohol, and that individuals with ADHD exhibited generally poorer driving performance than did controls across all dose conditions. Together the findings provide compelling evidence to suggest that the cognitive and behavioral deficits associated with ADHD might impair driving performance in such a manner as to resemble that of an alcohol intoxicated driver. Moreover, alcohol might impair the performance of drivers with ADHD in an additive fashion that could considerably compromise their driving skill even at blood alcohol concentrations below the legal limit. PMID:18540785

Challenges associated with drunk driving measurement: combining police and self-reported data to estimate an accurate prevalence in Brazil.

PubMed

Sousa, Tanara; Lunnen, Jeffrey C; Gonçalves, Veralice; Schmitz, Aurinez; Pasa, Graciela; Bastos, Tamires; Sripad, Pooja; Chandran, Aruna; Pechansky, Flavio

2013-12-01

Drunk driving is an important risk factor for road traffic crashes, injuries and deaths. After June 2008, all drivers in Brazil were subject to a "Zero Tolerance Law" with a set breath alcohol concentration of 0.1 mg/L of air. However, a loophole in this law enabled drivers to refuse breath or blood alcohol testing as it may self-incriminate. The reported prevalence of drunk driving is therefore likely a gross underestimate in many cities. To compare the prevalence of drunk driving gathered from police reports to the prevalence gathered from self-reported questionnaires administered at police sobriety roadblocks in two Brazilian capital cities, and to estimate a more accurate prevalence of drunk driving utilizing three correction techniques based upon information from those questionnaires. In August 2011 and January-February 2012, researchers from the Centre for Drug and Alcohol Research at the Universidade Federal do Rio Grande do Sul administered a roadside interview on drunk driving practices to 805 voluntary participants in the Brazilian capital cities of Palmas and Teresina. Three techniques which include measures such as the number of persons reporting alcohol consumption in the last six hours but who had refused breath testing were used to estimate the prevalence of drunk driving. The prevalence of persons testing positive for alcohol on their breath was 8.8% and 5.0% in Palmas and Teresina respectively. Utilizing a correction technique we calculated that a more accurate prevalence in these sites may be as high as 28.2% and 28.7%. In both cities, about 60% of drivers who self-reported having drank within six hours of being stopped by the police either refused to perform breathalyser testing; fled the sobriety roadblock; or were not offered the test, compared to about 30% of drivers that said they had not been drinking. Despite the reduction of the legal limit for drunk driving stipulated by the "Zero Tolerance Law," loopholes in the legislation permit many drivers under the influence of alcohol to act with impunity. In this context the police/traffic officers are often powerless to enforce the law and thus drunk driving continues to go unchecked. Strong legislation and effective enforcement are necessary to reduce the prevalence of this dangerous behaviour. Correction techniques allow calculation of a truer prevalence of drunk driving, which can assist police and policymakers alike to redirect resources and align strategies. Copyright © 2013 Elsevier Ltd. All rights reserved.

Driving simulation for evaluation and rehabilitation of driving after stroke.

PubMed

Akinwuntan, Abiodun Emmanuel; Wachtel, Jerry; Rosen, Peter Newman

2012-08-01

Driving is an important activity of daily living. Loss of driving privileges can lead to depression, decreased access to medical care, and increased healthcare costs. The ability to drive is often affected after stroke. In approximately 30% of stroke survivors, it is clear from the onset that driving will no longer be possible. Approximately 33% of survivors will be able to return to driving with little or no retraining, and 35% will require driving-related rehabilitation before they can resume safe driving again. The ability to drive is not routinely evaluated after stroke, and there is no established rehabilitation program for poststroke driving. When driving evaluation does occur, it is not always clear which tests are the most salient for accurately assessing poststroke driving ability. Investigators have examined the efficacy of various methodologies to predict driving performance after stroke and have found mixed results, with each method having unique weaknesses, including poor predictive ability, poor face validity, poor sensitivity or specificity, and limited reliability. Here we review common models of driving to gain insight into why single-construct visual or cognitive off-road measures are inadequate for evaluating driving, a complex and dynamic activity that involves timely interaction of multiple motor, visual, cognitive, and perceptual skills. We also examine the potential for driving simulators to overcome the problems currently faced in the evaluation and rehabilitation of driving after stroke. Finally, we offer suggestions for the future direction of simulator-based poststroke driving evaluation and training. Copyright © 2012 National Stroke Association. Published by Elsevier Inc. All rights reserved.

49 CFR 383.77 - Substitute for driving skills tests for drivers with military CMV experience.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 5 2011-10-01 2011-10-01 false Substitute for driving skills tests for drivers... Testing and Licensing Procedures § 383.77 Substitute for driving skills tests for drivers with military CMV experience. At the discretion of a State, the driving skills test as specified in § 383.113 may be...

Evaluation of 2004 Toyota Prius Hybrid Electric Drive System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Staunton, R. H.; Ayers, C. W.; Marlino, L. D.

2006-05-01

The 2004 Toyota Prius is a hybrid automobile equipped with a gasoline engine and a battery- and generator-powered electric motor. Both of these motive-power sources are capable of providing mechanical-drive power for the vehicle. The engine can deliver a peak-power output of 57 kilowatts (kW) at 5000 revolutions per minute (rpm) while the motor can deliver a peak-power output of 50 kW over the speed range of 1200–1540 rpm. Together, this engine-motor combination has a specified peak-power output of 82 kW at a vehicle speed of 85 kilometers per hour (km/h). In operation, the 2004 Prius exhibits superior fuel economymore » compared to conventionally powered automobiles. To acquire knowledge and thereby improve understanding of the propulsion technology used in the 2004 Prius, a full range of design characterization studies were conducted to evaluate the electrical and mechanical characteristics of the 2004 Prius and its hybrid electric drive system. These characterization studies included (1) a design review, (2) a packaging and fabrication assessment, (3) bench-top electrical tests, (4) back-electromotive force (emf) and locked rotor tests, (5) loss tests, (6) thermal tests at elevated temperatures, and most recently (7) full-design-range performance testing in a controlled laboratory environment. This final test effectively mapped the electrical and thermal results for motor/inverter operation over the full range of speeds and shaft loads that these assemblies are designed for in the Prius vehicle operations. This testing was undertaken by the Oak Ridge National Laboratory (ORNL) as part of the U.S. Department of Energy (DOE) – Energy Efficiency and Renewable Energy (EERE) FreedomCAR and Vehicle Technologies (FCVT) program through its vehicle systems technologies subprogram. The thermal tests at elevated temperatures were conducted late in 2004, and this report does not discuss this testing in detail. The thermal tests explored the derating of the Prius motor design if operated at temperatures as high as is normally encountered in a vehicle engine. The continuous ratings at base speed (1200 rpm) with different coolant temperatures are projected from test data at 900 rpm. A separate, comprehensive report on this thermal control study is available. This report summarizes vehicle-level and subsystem-level test results obtained for the 2004 Prius and various electrical and mechanical subassemblies of its hybrid electric drive system. The primary objective of these tests was to (1) characterize the electrical and mechanical performance of the 2004 Prius, and (2) map the performance of the inverter/motor system over the full design speed and load ranges.« less

The impact of continuous driving time and rest time on commercial drivers' driving performance and recovery.

PubMed

Wang, Lianzhen; Pei, Yulong

2014-09-01

This real road driving study was conducted to investigate the effects of driving time and rest time on the driving performance and recovery of commercial coach drivers. Thirty-three commercial coach drivers participated in the study, and were divided into three groups according to driving time: (a) 2 h, (b) 3 h, and (c) 4 h. The Stanford Sleepiness Scale (SSS) was used to assess the subjective fatigue level of the drivers. One-way ANOVA was employed to analyze the variation in driving performance. The statistical analysis revealed that driving time had a significant effect on the subjective fatigue and driving performance measures among the three groups. After 2 h of driving, both the subjective fatigue and driving performance measures began to deteriorate. After 4 h of driving, all of the driving performance indicators changed significantly except for depth perception. A certain amount of rest time eliminated the negative effects of fatigue. A 15-minute rest allowed drivers to recover from a two-hour driving task. This needed to be prolonged to 30 min for driving tasks of 3 to 4 h of continuous driving. Drivers' attention, reactions, operating ability, and perceptions are all affected in turn after over 2 h of continuous driving. Drivers should take a certain amount of rest to recover from the fatigue effects before they continue driving. Copyright © 2014 National Safety Council and Elsevier Ltd. All rights reserved.

Drive cycle analysis of butanol/diesel blends in a light-duty vehicle.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miers, S. A.; Carlson, R. W.; McConnell, S. S.

2008-10-01

The potential exists to displace a portion of the petroleum diesel demand with butanol and positively impact engine-out particulate matter. As a preliminary investigation, 20% and 40% by volume blends of butanol with ultra low sulfur diesel fuel were operated in a 1999 Mercedes Benz C220 turbo diesel vehicle (Euro III compliant). Cold and hot start urban as well as highway drive cycle tests were performed for the two blends of butanol and compared to diesel fuel. In addition, 35 MPH and 55 MPH steady-state tests were conducted under varying road loads for the two fuel blends. Exhaust gas emissions,more » fuel consumption, and intake and exhaust temperatures were acquired for each test condition. Filter smoke numbers were also acquired during the steady-state tests.« less

Auto Indexer Auto-Indexer for Percussive Hammers: Vane Motor Dynamometer Testing

DOE Data Explorer

Su, Jiann

2012-01-01

Objectives Options associated with geothermal drilling operations are generally limited by factors such as formation temperature and rock strength. The objective of the research is to expand the "tool box" available to the geothermal driller by furthering the development of a high-temperature drilling motor that can be used in directional drilling applications for drilling high temperature geothermal formations. The motor is specifically designed to operate in conjunction with a pneumatic down-the-hole-hammer. It provides a more compact design compared to traditional drilling motors such as PDMs (positive displacement motors). The packaging can help to enhance directional drilling capabilities. It uses no elastomeric components, which enables it to operate in higher temperatures ( >250 °F). Current work on the motor has shown that is a capable of operating under pneumatic power with a down-the-hole-hammer. Further development work will include continued testing and refining motor components and evaluating motor capabilities. Targets/Milestones Complete testing current motor - 12/31/2010 Make final material and design decisions - 01/31/2011 Build and test final prototype - 04/31/2011 Final demonstration - 07/31/2011 Impacts The development of the motor will help to achieve program technical objectives by improving well construction capabilities. This includes enabling high-temperature drilling as well as enhancing directional drilling. A key component in the auto indexer is the drive motor. It is an air-driven vane motor that converts the energy stored in the compressed air to mechanical energy. The motor is attached to hammer-like components which impart an impulsive load onto the drive shaft. The impulsive force on the drive shaft in turn creates an indexing action. A controlled test was performed to characterize the performance of the the vane motor for a given pressure. The Sandia dynamometer test station was used to determine the performance of the motor for a given input pressure.

Main drive selection for the Windstorm Simulation Center

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lacy, J.M.; Earl, J.S.

1998-02-01

Operated by the Partnership for Natural Disaster Reduction, the Windstorm Simulation Center (WSC) will be a structural test center dedicated to studying the performance of civil structural systems subjected to hurricanes, tornadoes, and other storm winds. Within the WSC, a bank of high-power fans, the main drive, will produce the high velocity wind necessary to reproduce these storms. Several options are available for the main drive, each with advantages and liabilities. This report documents a study to identify and evaluate all candidates available, and to select the most promising system such that the best possible combination of real-world performance attributesmore » is achieved at the best value. Four broad classes of candidate were identified: electric motors, turbofan aircraft engines, turboshaft aircraft engines, and turboshaft industrial engines. Candidate systems were evaluated on a basis of technical feasibility, availability, power, installed cost, and operating cost.« less

Analysis of field-oriented controlled induction motor drives under sensor faults and an overview of sensorless schemes.

PubMed

Arun Dominic, D; Chelliah, Thanga Raj

2014-09-01

To obtain high dynamic performance on induction motor drives (IMD), variable voltage and variable frequency operation has to be performed by measuring speed of rotation and stator currents through sensors and fed back them to the controllers. When the sensors are undergone a fault, the stability of control system, may be designed for an industrial process, is disturbed. This paper studies the negative effects on a 12.5 hp induction motor drives when the field oriented control system is subjected to sensor faults. To illustrate the importance of this study mine hoist load diagram is considered as shaft load of the tested machine. The methods to recover the system from sensor faults are discussed. In addition, the various speed sensorless schemes are reviewed comprehensively. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Electronic Health Record Tools to Care for At-Risk Older Drivers: A Quality Improvement Project.

PubMed

Casey, Colleen M; Salinas, Katherine; Eckstrom, Elizabeth

2015-06-01

Evaluating driving safety of older adults is an important health topic, but primary care providers (PCP) face multiple barriers in addressing this issue. The study's objectives were to develop an electronic health record (EHR)-based Driving Clinical Support Tool, train PCPs to perform driving assessments utilizing the tool, and systematize documentation of assessment and management of driving safety issues via the tool. The intervention included development of an evidence-based Driving Clinical Support Tool within the EHR, followed by training of internal medicine providers in the tool's content and use. Pre- and postintervention provider surveys and chart review of driving-related patient visits were conducted. Surveys included self-report of preparedness and knowledge to evaluate at-risk older drivers and were analyzed using paired t-test. A chart review of driving-related office visits compared documentation pre- and postintervention including: completeness of appropriate focused history and exam, identification of deficits, patient education, and reporting to appropriate authorities when indicated. Data from 86 providers were analyzed. Pre- and postintervention surveys showed significantly increased self-assessed preparedness (p < .001) and increased driving-related knowledge (p < .001). Postintervention charts showed improved documentation of correct cognitive testing, more referrals/consults, increased patient education about community resources, and appropriate regulatory reporting when deficits were identified. Focused training and an EHR-based clinical support tool improved provider self-reported preparedness and knowledge of how to evaluate at-risk older drivers. The tool improved documentation of driving-related issues and led to improved access to interdisciplinary care coordination. Published by Oxford University Press on behalf of the Gerontological Society of America 2015.

Quiet Clean Short-haul Experimental Engine (QCSEE). Under-The-Wing (UTW) engine boilerplate nacelle test report. Volume 3: Mechanical performance

NASA Technical Reports Server (NTRS)

1977-01-01

Results of initial tests of the under the wing experimental engine and boilerplate nacelle are presented. The mechanical performance of the engine is reported with emphasis on the advanced technology components. Technology elements of the propulsion system covered include: system dynamics, composite fan blades, reduction gear, lube and accessory drive system, fan frame, inlet, core cowl cooling, fan exhaust nozzle, and digital control system.

Correspondence between Simulator and On-Road Drive Performance: Implications for Assessment of Driving Safety.

PubMed

Aksan, Nazan; Hacker, Sarah D; Sager, Lauren; Dawson, Jeffrey; Anderson, Steven; Rizzo, Matthew

2016-03-01

Forty-two younger (Mean age = 35) and 37 older drivers (Mean age = 77) completed four similar simulated drives. In addition, 32 younger and 30 older drivers completed a standard on-road drive in an instrumented vehicle. Performance in the simulated drives was evaluated using both electronic drive data and video-review of errors. Safety errors during the on-road drive were evaluated by a certified driving instructor blind to simulator performance, using state Department of Transportation criteria. We examined the degree of convergence in performance across the two platforms on various driving tasks including lane change, lane keeping, speed control, stopping, turns, and overall performance. Differences based on age group indicated a pattern of strong relative validity for simulator measures. However, relative rank-order in specific metrics of performance suggested a pattern of moderate relative validity. The findings have implications for the use of simulators in assessments of driving safety as well as its use in training and/or rehabilitation settings.

Correspondence between Simulator and On-Road Drive Performance: Implications for Assessment of Driving Safety

PubMed Central

Aksan, Nazan; Hacker, Sarah D.; Sager, Lauren; Dawson, Jeffrey; Anderson, Steven; Rizzo, Matthew

2017-01-01

Forty-two younger (Mean age = 35) and 37 older drivers (Mean age = 77) completed four similar simulated drives. In addition, 32 younger and 30 older drivers completed a standard on-road drive in an instrumented vehicle. Performance in the simulated drives was evaluated using both electronic drive data and video-review of errors. Safety errors during the on-road drive were evaluated by a certified driving instructor blind to simulator performance, using state Department of Transportation criteria. We examined the degree of convergence in performance across the two platforms on various driving tasks including lane change, lane keeping, speed control, stopping, turns, and overall performance. Differences based on age group indicated a pattern of strong relative validity for simulator measures. However, relative rank-order in specific metrics of performance suggested a pattern of moderate relative validity. The findings have implications for the use of simulators in assessments of driving safety as well as its use in training and/or rehabilitation settings. PMID:28649572

Modernization and Activation of the NASA Ames 11- by 11-Foot Transonic Wind Tunnel

NASA Technical Reports Server (NTRS)

Kmak, Frank J.

2000-01-01

The Unitary Plan Wind Tunnel (UPWT) was modernized to improve performance, capability, productivity, and reliability. Automation systems were installed in all three UPWT tunnel legs and the Auxiliaries facility. Major improvements were made to the four control rooms, model support systems, main drive motors, and main drive speed control. Pressure vessel repairs and refurbishment to the electrical distribution system were also completed. Significant changes were made to improve test section flow quality in the 11-by 11-Foot Transonic leg. After the completion of the construction phase of the project, acceptance and checkout testing was performed to demonstrate the capabilities of the modernized facility. A pneumatic test of the tunnel circuit was performed to verify the structural integrity of the pressure vessel before wind-on operations. Test section turbulence, flow angularity, and acoustic parameters were measured throughout the tunnel envelope to determine the effects of the tunnel flow quality improvements. The new control system processes were thoroughly checked during wind-off and wind-on operations. Manual subsystem modes and automated supervisory modes of tunnel operation were validated. The aerodynamic and structural performance of both the new composite compressor rotor blades and the old aluminum rotor blades was measured. The entire subsonic and supersonic envelope of the 11-by 11-Foot Transonic leg was defined up to the maximum total pressure.

Caffeine antagonism of alcohol-induced driving impairment.

PubMed

Liguori, A; Robinson, J H

2001-07-01

The extent to which caffeine antagonizes alcohol-induced impairment of simulated automobile driving at the current lowest legal American limit (0.08% BrAC) was the focus of this study. Fifteen adults swallowed a capsule (0, 200, or 400 mg caffeine) then drank a beverage (0.0 or 0.6 g/kg ethanol) in a within-subject, double-blind, randomized procedure. Forty-five minutes later, participants completed a test battery of subjective effects scales, dynamic posturography, critical flicker fusion (CFF), choice reaction time (CRT), divided attention (Stroop test), and simulated driving. Alcohol alone increased ratings of 'dizzy', 'drug effect', and 'high', slowed CRT and brake latency, and increased body sway. Caffeine alone increased ratings of 'alert' and 'jittery', but did not significantly affect body sway or psychomotor performance. Both caffeine doses comparably counteracted alcohol impairment of brake latency but not CRT or body sway. Brake latency with either alcohol-caffeine combination remained significantly longer than that with placebo. Stroop and CFF performance were unaffected by any drug condition. The results suggest that caffeine may increase alertness and improve reaction time after alcohol use but will not completely counteract alcohol impairment in a driver.

NAPLaN Test Data, ESL Bandscales and the Validity of EAL/D Teacher Judgement of Student Performance

ERIC Educational Resources Information Center

Creagh, Sue

2014-01-01

Teachers are now experiencing the age of quantitative test-driven assessment, in which there is little weight accorded to teacher-based judgement about student progress. In the Australian context, the NAPLaN test has become a driving force in school and teacher accountability. The language of NAPLaN is one of bands and numerical scores and…

Driving While Interacting With Google Glass: Investigating the Combined Effect of Head-Up Display and Hands-Free Input on Driving Safety and Multitask Performance.

PubMed

Tippey, Kathryn G; Sivaraj, Elayaraj; Ferris, Thomas K

2017-06-01

This study evaluated the individual and combined effects of voice (vs. manual) input and head-up (vs. head-down) display in a driving and device interaction task. Advances in wearable technology offer new possibilities for in-vehicle interaction but also present new challenges for managing driver attention and regulating device usage in vehicles. This research investigated how driving performance is affected by interface characteristics of devices used for concurrent secondary tasks. A positive impact on driving performance was expected when devices included voice-to-text functionality (reducing demand for visual and manual resources) and a head-up display (HUD) (supporting greater visibility of the driving environment). Driver behavior and performance was compared in a texting-while-driving task set during a driving simulation. The texting task was completed with and without voice-to-text using a smartphone and with voice-to-text using Google Glass's HUD. Driving task performance degraded with the addition of the secondary texting task. However, voice-to-text input supported relatively better performance in both driving and texting tasks compared to using manual entry. HUD functionality further improved driving performance compared to conditions using a smartphone and often was not significantly worse than performance without the texting task. This study suggests that despite the performance costs of texting-while-driving, voice input methods improve performance over manual entry, and head-up displays may further extend those performance benefits. This study can inform designers and potential users of wearable technologies as well as policymakers tasked with regulating the use of these technologies while driving.

Blind spot monitoring in light vehicles -- system performance.

DOT National Transportation Integrated Search

2014-07-01

This report summarizes findings of a small population study of blind spot monitoring systems (BSM) installed by : original vehicle manufacturers on standard production vehicles. The primary goals of these tests were to simulate real-world driving sce...

40 CFR 86.135-00 - Dynamometer procedure.

Code of Federal Regulations, 2010 CFR

2010-07-01

... see § 86.135-90. (d) Practice runs over the prescribed driving schedule may be performed at test point...; the rocking of the vehicle changes the tire rolling radius on each roll. This rocking may be minimized...

Glaucomatous retinal nerve fiber layer thickness loss is associated with slower reaction times under a divided attention task.

PubMed

Tatham, Andrew J; Boer, Erwin R; Rosen, Peter N; Della Penna, Mauro; Meira-Freitas, Daniel; Weinreb, Robert N; Zangwill, Linda M; Medeiros, Felipe A

2014-11-01

To examine the relationship between glaucomatous structural damage and ability to divide attention during simulated driving. Cross-sectional observational study. Hamilton Glaucoma Center, University of California San Diego. Total of 158 subjects from the Diagnostic Innovations in Glaucoma Study, including 82 with glaucoma and 76 similarly aged controls. Ability to divide attention was investigated by measuring reaction times to peripheral stimuli (at low, medium, or high contrast) while concomitantly performing a central driving task (car following or curve negotiation). All subjects had standard automated perimetry (SAP) and optical coherence tomography was used to measure retinal nerve fiber layer (RNFL) thickness. Cognitive ability was assessed using the Montreal Cognitive Assessment and subjects completed a driving history questionnaire. Reaction times to the driving simulator divided attention task. The mean reaction times to the low-contrast stimulus were 1.05 s and 0.64 s in glaucoma and controls, respectively, during curve negotiation (P < .001), and 1.19 s and 0.77 s (P = .025), respectively, during car following. There was a nonlinear relationship between reaction times and RNFL thickness in the better eye. RNFL thickness remained significantly associated with reaction times even after adjusting for age, SAP mean deviation in the better eye, cognitive ability, and central driving task performance. Although worse SAP sensitivity was associated with worse ability to divide attention, RNFL thickness measurements provided additional information. Information from structural tests may improve our ability to determine which patients are likely to have problems performing daily activities, such as driving. Copyright © 2014 Elsevier Inc. All rights reserved.

Concepts for Multi-Speed Rotorcraft Drive System - Status of Design and Testing at NASA GRC

NASA Technical Reports Server (NTRS)

Stevens, Mark A.; Lewicki, David G.; Handschuh, Robert F.

2015-01-01

In several studies and on-going developments for advanced rotorcraft, the need for variable multi-speed capable rotors has been raised. Speed changes of up to 50 have been proposed for future rotorcraft to improve vehicle performance. A rotor speed change during operation not only requires a rotor that can perform effectively over the operating speedload range, but also requires a propulsion system possessing these same capabilities. A study was completed investigating possible drive system arrangements that can accommodate up to a 50 speed change. Key drivers were identified from which simplicity and weight were judged as central. This paper presents the current status of two gear train concepts coupled with the first of two clutch types developed and tested thus far with focus on design lessons learned and areas requiring development. Also, a third concept is presented, a dual input planetary differential as leveraged from a simple planetary with fixed carrier.

Characterization of a pneumatic balloon actuator for use in refreshable Braille displays.

PubMed

Fan, Richard E; Feinman, Adam M; Wottawa, Christopher; King, Chih-Hung; Franco, Miguel L; Dutson, Erik P; Grundfest, Warren S; Culjat, Martin O

2009-01-01

Many existing refreshable Braille display technologies are costly or lack robust performance. A process has been developed to fabricate consistent and reliable pneumatic balloon actuators at low material cost, using a novel manufacturing process. This technique has been adapted for use in refreshable Braille displays that feature low power consumption, ease of manufacture and small form factor. A prototype refreshable cell, conforming to American Braille standards, was developed and tested. The cell was fabricated from molded PDMS to form balloon actuators with a spin-coated silicone film, and fast pneumatic driving elements and an electronic control system were developed to drive the Braille dots. Perceptual testing was performed to determine the feasibility of the approach using a single blind human subject. The subject was able to detect randomized Braille letters rapidly generated by the actuator with 100% character detection accuracy.

Novel Control Scheme of Power Assisted Wheelchair for Preventing Overturn (Part I)-Adjustment of Assisted Torque and Performance Evaluation From Field Test-

NASA Astrophysics Data System (ADS)

Seki, Hirokazu; Hata, Naoki; Koyasu, Yuichi; Hori, Yoichi

Aged people and disabled people who have difficulty in walking are increasing. As one of mobility support, significance of power assisted wheelchair which assists driving force using electric motors and spreads their living areas has been enhanced. However, the increased driving force often causes a dangerous overturn of wheelchair. In this paper, control method to prevent power assisted wheelchair from overturning is proposed. It is found the front wheels rising is caused by magnitude and rapid increase of assisted torque. Therefore, feedforward control method to limit the assisted torque by tuning its magnitude or time constant is proposed. In order to emphasize safety and feeling of security, these methods make the front wheels no rise. The effectiveness of the proposed method is verified by the practical experiments and field test based performance evaluation using many trial subjects.

VRLA Ultrabattery for high-rate partial-state-of-charge operation

NASA Astrophysics Data System (ADS)

Lam, L. T.; Louey, R.; Haigh, N. P.; Lim, O. V.; Vella, D. G.; Phyland, C. G.; Vu, L. H.; Furukawa, J.; Takada, T.; Monma, D.; Kano, T.

The objective of this study is to produce and test the hybrid valve-regulated Ultrabattery designed specifically for hybrid-electric vehicle duty, i.e., high-rate partial-state-of-charge operation. The Ultrabattery developed by CSIRO Energy Technology is a hybrid energy-storage device, which combines an asymmetric supercapacitor, and a lead-acid battery in one unit cells, taking the best from both technologies without the need for extra, expensive electronic controls. The capacitor will enhance the power and lifespan of the lead-acid battery as it acts as a buffer during high-rate discharging and charging. Consequently, this hybrid technology is able to provide and absorb charge rapidly during vehicle acceleration and braking. The work programme of this study is divided into two main parts, namely, field trial of prototype Ultrabatteries in a Honda Insight HEV and laboratory tests of prototype batteries. In this paper, the performance of prototype Ultrabatteries under different laboratory tests is reported. The evaluation of Ultrabatteries in terms of initial performance and cycling performance has been conducted at both CSIRO and Furukawa laboratories. The initial performance of prototype Ultrabatteries, such as capacity, power, cold cranking and self-discharge has been evaluated based upon the US FreedomCAR Battery Test Manual (DOE/ID-11069, October 2003). Results show that the Ultrabatteries meet, or exceed, respective targets of power, available energy, cold cranking and self-discharge set for both minimum and maximum power-assist HEVs. The cycling performance of prototype Ultrabatteries has been evaluated using: (i) simplified discharge and charge profile to simulate the driving conditions of micro-HEV; (ii) 42-V profile to simulate the driving conditions of mild-HEV and (iii) EUCAR and RHOLAB profiles to simulate the driving conditions of medium-HEV. For comparison purposes, nickel-metal-hydride (Ni-MH) cells, which are presently used in the Honda Insight HEV, have also been subjected to some of the above profiles (i.e., simplified discharge and charge profile and EUCAR profile). Although the Ultrabattery and a Ni-MH cell under EUCAR test profile are still on cycling, the outcomes to date show that the performance of these batteries and cells has been at least four times longer than that of the state-of-the art lead-acid cells or batteries. Excitingly, the performance of Ultrabatteries is proven to be comparable with that of the Ni-MH cells.

Development and interval testing of a naturalistic driving methodology to evaluate driving behavior in clinical research.

PubMed

Babulal, Ganesh M; Addison, Aaron; Ghoshal, Nupur; Stout, Sarah H; Vernon, Elizabeth K; Sellan, Mark; Roe, Catherine M

2016-01-01

Background : The number of older adults in the United States will double by 2056. Additionally, the number of licensed drivers will increase along with extended driving-life expectancy. Motor vehicle crashes are a leading cause of injury and death in older adults. Alzheimer's disease (AD) also negatively impacts driving ability and increases crash risk. Conventional methods to evaluate driving ability are limited in predicting decline among older adults. Innovations in GPS hardware and software can monitor driving behavior in the actual environments people drive in. Commercial off-the-shelf (COTS) devices are affordable, easy to install and capture large volumes of data in real-time. However, adapting these methodologies for research can be challenging. This study sought to adapt a COTS device and determine an interval that produced accurate data on the actual route driven for use in future studies involving older adults with and without AD.  Methods : Three subjects drove a single course in different vehicles at different intervals (30, 60 and 120 seconds), at different times of day, morning (9:00-11:59AM), afternoon (2:00-5:00PM) and night (7:00-10pm). The nine datasets were examined to determine the optimal collection interval. Results : Compared to the 120-second and 60-second intervals, the 30-second interval was optimal in capturing the actual route driven along with the lowest number of incorrect paths and affordability weighing considerations for data storage and curation. Discussion : Use of COTS devices offers minimal installation efforts, unobtrusive monitoring and discreet data extraction.  However, these devices require strict protocols and controlled testing for adoption into research paradigms.  After reliability and validity testing, these devices may provide valuable insight into daily driving behaviors and intraindividual change over time for populations of older adults with and without AD.  Data can be aggregated over time to look at changes or adverse events and ascertain if decline in performance is occurring.

Physical frailty and fitness of older driver

PubMed Central

Lenardt, Maria Helena; Binotto, Maria Angelica; Kolb Carneiro, Nathalia Hammerschmidt; Lourenço, Tânia Maria

2017-01-01

Abstract Aim: to analyze the association between physical frailty and the results of fitness capacity exams for driving vehicles among elder Brazilians. Methods: this is a cross sectional study, performed in traffic medicine clinics of the city of Curitiba (Brazil). The data was collected through the physical frailty tests, the use of a structured questionnaire, and searches on the records of the Brazilian National Register of Qualified Drivers.To analyze the information, the authors used descriptive statistics and non-parametrical tests. Results: One hundred seventy two elderly people, of whom 56.4% pre-fragile and 43.6% non-fragile. 25.0% were considered fit for driving, 68.6% were considered fit, but with some restrictions, and 6.4% were placed as temporarily unfit for driving. There was no association between frailty condition and the final results for driving fitness (p= 0.8934). Physical frailty was significantly associated to the restrictions observed for those who were fit under restrictions (p= 0.0313), according to the weekly amount of kilometers traveled (p= 0.0222), and to car accidents occurred after the age of 60 (p= 0.0165). Conclusion: Physical frailty was significantly associated to the restrictions related to driving, reason to which makes important to manage frailty over this group of drivers. However, no association observed between physical frailty and the final result for driving vehicles. PMID:29021637

Inertial piezoelectric linear motor driven by a single-phase harmonic wave with automatic clamping mechanism

NASA Astrophysics Data System (ADS)

He, Liangguo; Chu, Yuheng; Hao, Sai; Zhao, Xiaoyong; Dong, Yuge; Wang, Yong

2018-05-01

A novel, single-phase, harmonic-driven, inertial piezoelectric linear motor using an automatic clamping mechanism was designed, fabricated, and tested to reduce the sliding friction and simplify the drive mechanism and power supply control of the inertial motor. A piezoelectric bimorph and a flexible hinge were connected in series to form the automatic clamping mechanism. The automatic clamping mechanism was used as the driving and clamping elements. A dynamic simulation by Simulink was performed to prove the feasibility of the motor. The finite element method software COMSOL was used to design the structure of the motor. An experimental setup was built to validate the working principle and evaluate the performance of the motor. The prototype motor outputted a no-load velocity of 3.178 mm/s at a voltage of 220 Vp-p and a maximum traction force of 4.25 N under a preload force of 8 N. The minimum resolution of 1.14 μm was achieved at a driving frequency of 74 Hz, a driving voltage of 50 Vp-p, and a preload force of 0 N.

Acceptability and validity of older driver screening with the DrivingHealth Inventory.

PubMed

Edwards, Jerri D; Leonard, Kathleen M; Lunsman, Melissa; Dodson, Joan; Bradley, Stacy; Myers, Charlsie A; Hubble, Bridgette

2008-05-01

Research has indicated that technology can be effectively used to identify high-risk older drivers. However, adaptation of such technology has been limited. Researchers debate whether older drivers represent a safety problem as well as whether they should be screened for driving fitness. The present study examined how drivers feel regarding technological screening and mandatory state testing. The validity and acceptability of a new technological screening battery for identifying high-risk drivers, the DrivingHealth Inventory (DHI), was also evaluated. In a sample of 258 Alabama drivers aged 18-87, older drivers performed significantly worse than younger drivers on sensory, cognitive, and physical subtests of the DHI, and older drivers with a crash history performed worse than older drivers without crashes. Regardless of age, 90% of participants supported states requiring screening for older drivers' license renewal. The majority of the participants (72%) supported use of technological screening batteries such as the DHI as a driver screening tool. Considering the acceptability and potential efficacy of the DHI, it may be a useful tool in evaluating driving fitness among older adults.

Does Armodafinil Improve Driving Task Performance and Weight Loss in Sleep Apnea? A Randomized Trial.

PubMed

Chapman, Julia Louise; Cayanan, Elizabeth Anne; Hoyos, Camilla Miranda; Serinel, Yasmina; Comas, Maria; Yee, Brendon John; Wong, Keith Keat Huat; Grunstein, Ronald Robert; Marshall, Nathaniel Stuart

2018-05-18

RATIONALE Obstructive sleep apnea (OSA) patients unable to tolerate standard treatments have few alternatives. They may benefit from weight loss, but the major symptom of daytime performance impairment may remain during weight loss programs. OBJECTIVES We hypothesized that wakefulness-promoter armodafinil would improve driving task performance over placebo in patients undergoing weight loss. METHODS Placebo-controlled, double-blind, randomized trial of Armodafinil vs Placebo daily for 6 months in patients who were also randomized to one of two diets for six months with follow-up at one year in overweight, adult, OSA patients who had rejected standard treatment and suffered daytime sleepiness. MEASUREMENTS Primary outcome: change in steering deviation in the final 30 minutes of a 90 minute afternoon driving task (AusED) at six months. Epworth Sleepiness Scale, Functional Outcomes of Sleep Questionnaire, fat mass measured by dual-emission X-ray absorptiometry (DXA). MAIN RESULTS Armodafinil improved driving task performance over placebo at three months (12.9cm, 95%CI 4.1 to 21.7, p=0.004), but not the primary timepoint of six months (5.5cm, 95%CI -3.3 to 14.3, p=0.223). Patients on armodafinil lost 2.4kg more fat than those on placebo at six months (95%CI 0.9 to 4.0, p=0.002). Other secondary outcomes were not significantly improved. CONCLUSIONS Armodafinil did not improve driving task performance at the primary endpoint of six months. Armodafinil might be a useful adjunctive to weight loss in OSA patients rejecting conventional treatments but this needs to be directly tested in a specifically designed, properly powered clinical trial. Clinical trial registration available at www.anzctr.org.au, ID ACTRN12611000847910.

Opioids in oral fluid of Spanish drivers.

PubMed

Herrera-Gómez, Francisco; García-Mingo, Mercedes; Colás, Mónica; González-Luque, Juan Carlos; Álvarez, F Javier

2018-06-01

Driving under the influence of certain drugs is not allowed, and roadside drug testing is being considered an important tool for deterring driving under the influence of them. This study aimed to assess the presence and concentration of opioids, as well as their combined use with other drugs (laboratory confirmation after the on-road screening) in Spanish drivers between 2011 and 2016. In Spain, mandatory roadside breath alcohol and oral fluid drug testing (screening) are carried out by the Traffic Police using Dräger Alcotest ® 6810 device, and Dräger DrugTest ® 5000, DrugWipe ® , or Alere™ DDS ® 2 Mobile Test System. For positive cases in the period covered, 65,244, confirmation analysis and quantification using chromatographic techniques were performed. Opioids were confirmed in 8.6% of positive cases, being 7.2% positives to 6-acetylmorphine (6-AM), 6.5% to morphine, 5.4% to codeine, and 4.1% to methadone. The majority of the confirmed tests for morphine (96.5%), codeine (88.4%) and methadone (81.9) were also positive for 6-AM. The presence of other drugs, particularly cocaine and cannabis, was very common. Concentration values reached important levels. Positive results for morphine (0.1%), codeine (0.6%) or methadone (0.4%) alone were very infrequent. Drivers with a confirmed positive roadside test for morphine, codeine, and methadone had also consumed heroin and/or other illicit drugs, such as cocaine and/or THC, and at relevant concentrations. Improving interventions to combat the problem of driving under the influence of driving-impairing substances is a priority. Copyright © 2018 Elsevier B.V. All rights reserved.

Psychological predictors of college students' cell phone use while driving.

PubMed

Schlehofer, Michèle M; Thompson, Suzanne C; Ting, Sarah; Ostermann, Sharon; Nierman, Angela; Skenderian, Jessica

2010-07-01

Despite the known risk, many people talk on a phone while driving. This study explored psychological predictors of cell phone use while driving. College students (final N=69) completed a survey and predicted their driving performance both with and without a simultaneous phone conversation. Their actual performance on a driving simulator was then assessed. Cell phone use reduced performance on the simulation task. Further, perceiving oneself as good at compensating for driving distractions, overestimating one's performance on the driving simulator, and high illusory control predicted more frequent cell phone use while driving in everyday life. Finally, those who talked more frequently on a phone while driving had poorer real-world driving records. These findings suggest illusory control and positive illusions partly explain driver's decisions of whether to use cell phones while driving. Copyright 2010 Elsevier Ltd. All rights reserved.

TAL Performance and Mission Analysis in a CDL Capacitor Powered Direct-Drive Configuration

NASA Technical Reports Server (NTRS)

Hrbud, Ivana; Rose, M. Frank; Oleson, Steve R.; Jenkins, Rhonald M.

1999-01-01

The goals of this research are (1) to prove the concept feasibility of a direct-drive electric propulsion system, and (2) to evaluate the performance and characteristics of a Russian TAL (Thruster with Anode Layer) operating in a long-pulse mode, powered by a capacitor-based power source developed at Space Power Institute. The TAL, designated D-55, is characterized by an external acceleration zone and is powered by a unique chemical double layer (CDL) capacitor bank with a capacitance of 4 F at a charge voltage of 400 V. Performance testing of this power supply on the TAL was conducted at NASA Lewis Research Center in Cleveland, OH. Direct thrust measurements of the TAL were obtained at CDL power levels ranging from 450 to 1750 W. The specific impulse encompassed a range from 1150 s to 2200 s, yielding thruster system efficiencies between 50 and 60%. Preliminary mission analysis of the CDL direct-drive concept and other electric propulsion options was performed for the ORACLE spacecraft in 6am/6pm and 12am/12pm, 300 km sun-synchronous orbits. The direct-drive option was competitive with the other systems by increasing available net mass between 5 and 42% and reducing two-year system wet mass between 18 and 63%. Overall, the electric propulsion power requirements for the satellite solar array were reduced between 57 and 91% depending oil the orbit evaluated The direct-drive, CDL capacitor-based concept in electric propulsion thus promises to be a highly-efficient, viable alternative for satellite operations in specific near-Earth missions.

Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Engineering Test Report: METSAT A1 Signal Processor (P/N: 1331670-2, S/N: F04)

NASA Technical Reports Server (NTRS)

Lund, D.

1998-01-01

This report presents a description of the tests performed, and the test data, for the A1 METSAT Signal Processor Assembly PN: 1331679-2, S/N F04. The assembly was tested in accordance with AE-26754, "METSAT Signal Processor Scan Drive Test and Integration Procedure." The objective is to demonstrate functionality of the signal processor prior to instrument integration.

Adaptive control schemes for improving dynamic performance of efficiency-optimized induction motor drives.

PubMed

Kumar, Navneet; Raj Chelliah, Thanga; Srivastava, S P

2015-07-01

Model Based Control (MBC) is one of the energy optimal controllers used in vector-controlled Induction Motor (IM) for controlling the excitation of motor in accordance with torque and speed. MBC offers energy conservation especially at part-load operation, but it creates ripples in torque and speed during load transition, leading to poor dynamic performance of the drive. This study investigates the opportunity for improving dynamic performance of a three-phase IM operating with MBC and proposes three control schemes: (i) MBC with a low pass filter (ii) torque producing current (iqs) injection in the output of speed controller (iii) Variable Structure Speed Controller (VSSC). The pre and post operation of MBC during load transition is also analyzed. The dynamic performance of a 1-hp, three-phase squirrel-cage IM with mine-hoist load diagram is tested. Test results are provided for the conventional field-oriented (constant flux) control and MBC (adjustable excitation) with proposed schemes. The effectiveness of proposed schemes is also illustrated for parametric variations. The test results and subsequent analysis confer that the motor dynamics improves significantly with all three proposed schemes in terms of overshoot/undershoot peak amplitude of torque and DC link power in addition to energy saving during load transitions. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Integrated Advanced Microwave Sounding Unit-A(AMSU-A). Engineering Test Report: METSAT A1 Signal Processor, (P/N 1331670-2, S /N F05)

NASA Technical Reports Server (NTRS)

Lund, D.

1998-01-01

This report presents a description of the tests performed, and the test data, for the AI METSAT Signal Processor Assembly P/N 1331670-2, S/N F05. The assembly was tested in accordance with AE-26754, "METSAT Signal Processor Scan Drive and Integration Procedure." The objective is to demonstrate functionality of the signal processor prior to instrument integration.

Below-Ambient and Cryogenic Thermal Testing

NASA Technical Reports Server (NTRS)

Fesmire, James E.

2016-01-01

Thermal insulation systems operating in below-ambient temperature conditions are inherently susceptible to moisture intrusion and vapor drive toward the cold side. The subsequent effects may include condensation, icing, cracking, corrosion, and other problems. Methods and apparatus for real-world thermal performance testing of below-ambient systems have been developed based on cryogenic boiloff calorimetry. New ASTM International standards on cryogenic testing and their extension to future standards for below-ambient testing of pipe insulation are reviewed.

Blue-Enriched Light Enhances Alertness but Impairs Accurate Performance in Evening Chronotypes Driving in the Morning.

PubMed

Rodríguez-Morilla, Beatriz; Madrid, Juan A; Molina, Enrique; Pérez-Navarro, José; Correa, Ángel

2018-01-01

Attention maintenance is highly demanding and typically leads to vigilance decrement along time on task. Therefore, performance in tasks involving vigilance maintenance for long periods, such as driving, tends to deteriorate over time. Cognitive performance has been demonstrated to fluctuate over 24 h of the day (known as circadian oscillations), thus showing peaks and troughs depending on the time of day (leading to optimal and suboptimal times of day, respectively). Consequently, vigilance decrements are more pronounced along time on task when it is performed at suboptimal times of day. According to research, light exposure (especially blue-enriched white) enhances alertness. Thus, it has been proposed to prevent the vigilance decrement under such adverse circumstances. We aimed to explore the effects of blue-enriched white light (vs. dim light) on the performance of a simulated driving task at a suboptimal time of day. A group of evening-types was tested at 8 am, as this chronotype had previously shown their largest vigilance decrement at that time. In the dim light condition, vigilance decrements were expected on both subjective (as increments in the Karolinska Sleepiness Scale scores) and behavioral measures [as slower reaction times (RTs) in the auditory Psychomotor Vigilance Task, slower RTs to unexpected events during driving, and deteriorated driving accuracy along time on task]. Physiological activation was expected to decrease (as indexed by an increase of the distal-proximal temperature gradient, DPG). Under blue-enriched white light, all these trends should be attenuated. Results from the control dim light condition replicated the vigilance decrement in all measures. Most important, the blue-enriched white light attenuated this decrement, leading to both lower DPG and faster RTs. However, it impaired accuracy of driving performance, and did not have any effect on subjective sleepiness. We conclude that exposure to blue-enriched light provides an effective countermeasure to enhance vigilance performance at suboptimal times of day, according to measures such as RTs. However, it should be considered that alerting effects of light could impair accuracy in precision tasks as keeping a proper car position. The current findings provide ergonomic implications for safety and fatigue related management systems.

Evaluation of a timber column bent substructure after more than 60 years in-service

Treesearch

James P. Wacker; Xiping Wang; Douglas R. Rammer; William J. Nelson

2011-01-01

This paper describes both the field evaluation and laboratory testing of two timber-column-bent bridge substructures. These substructures served as intermediate pier supports for the East Deer Park Drive Bridge located in Gaithersburg, Maryland. A field evaluation of the bridge substructure was conducted in September 2008. Nondestructive testing was performed with a...

Initial Comparison of Single Cylinder Stirling Engine Computer Model Predictions with Test Results

NASA Technical Reports Server (NTRS)

Tew, R. C., Jr.; Thieme, L. G.; Miao, D.

1979-01-01

A Stirling engine digital computer model developed at NASA Lewis Research Center was configured to predict the performance of the GPU-3 single-cylinder rhombic drive engine. Revisions to the basic equations and assumptions are discussed. Model predictions with the early results of the Lewis Research Center GPU-3 tests are compared.

77 FR 35395 - Draft Five-Year Plan (2013-2017) for the National Toxicology Program Interagency Center for the...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-13

... innovations are driving transformative changes in toxicology and how safety testing is performed. The field of toxicology is evolving from a system based largely on animal testing toward one based on the integration of... methods that protect human and animal health and the environment while reducing, refining (enhancing...

14 CFR Appendix C to Part 27 - Criteria for Category A

Code of Federal Regulations, 2013 CFR

2013-01-01

... unless it meets the design installation and performance requirements contained in this appendix in... drive system: Design. 29.927(c)(1)—Additional tests. 29.953(a)—Fuel system independence. 29.1027(a)—Transmission and gearboxes: General. 29.1045(a)(1), (b), (c), (d), and (f)—Climb cooling test procedures. 29...

Driving performance changes of middle-aged experienced taxi drivers due to distraction tasks during unexpected situations.

PubMed

Kim, Hyung-Sik; Choi, Mi-Hyun; Choi, Jin-Seung; Kim, Hyun-Joo; Hong, Sang-Pyo; Jun, Jae-Hoon; Tack, Gye-Rae; Kim, Boseong; Min, Ung-Chan; Lim, Dae-Woon; Chung, Soon-Cheol

2013-10-01

This study investigated the effects of distraction taskssuch as sending a text message with a cellphone and searching navigation with car navigation system-on the driving performance of 29 highly experienced taxi drivers in their 50s. All participants were instructed to drive using a driving simulator for 2 min. while maintaining a constant distance from the vehicle in front and a constant speed. Participants drove without any distractions for the first minute. For an additional minute, they performed Driving Only or performed a task while driving (Driving + Sending Text Message or Driving + Searching Navigation). An unexpected situation, in which the participant had to stop abruptly due to a sudden stop of the preceding vehicle, occurred during this period. Driving performance during the unexpected situation was evaluated by car control variables, medial-lateral coefficient of variation and brake time, and by motion variables such as the jerk-cost function. Compared to Driving Only, jerk-cost function, medial-lateral coefficient of variation, and brake time increased during Driving + Sending Text Message or Driving + Searching Navigation.

ACD16-0001-021

NASA Image and Video Library

2016-01-06

Senior executives from the Renault-Nissan Alliance, including Carlos Ghosn, chairman and CEO of Nissan, and Jose Munoz, chairman of Nissan North America, visited Ames for meetings and a showcase of the technical partnership between NASA and Nissan North America. The partnership allows researchers to develop and test autonomy algorithms, concepts, and integrated prototypes for a variety of vehicular transport applications – from rovers to self-driving cars. After briefings, the group on left from left to right Kathy Sun and Liam Pedersen, Nissan and on right from front to back Carlos Ghosn, CE, Nissan chatted before taking a ride in the autonomous vehicle to observed testing of Nissan’s all-electric LEAF as it performed safe autonomous drives across the center.

Impairment due to combined sleep restriction and alcohol is not mitigated by decaying breath alcohol concentration or rest breaks.

PubMed

Manousakis, Jessica E; Anderson, Clare

2017-09-01

Epidemiological and laboratory-based driving simulator studies have shown the detrimental impact of moderate, legal levels of alcohol consumption on driving performance in sleepy drivers. As less is known about the time course of decaying alcohol alongside performance impairment, our study examined impairment and recovery of performance alongside decaying levels of alcohol, with and without sleep restriction. Sixteen healthy young males (18-27 years) underwent 4 counterbalanced conditions: Baseline, Alcohol (breath alcohol concentration [BrAC] < 0.05%), Sleep Restriction (5 hr time in bed), and Combined. Participants consumed alcohol (or control drink) ~4.5 hr post wake (12:30 p.m.). To test on the descending limb of alcohol, attention and vigilance test batteries commenced 1 hr after consumption and were completed every 30 min for 2 hr (1:30 p.m.-3:30 p.m.). The Combined condition impaired subjective and objective sleepiness. Here, performance deficits peaked 90 min after alcohol consumption or 30 min after the BrAC peak. Performance did not return to baseline levels until 2.5 hr following consumption, despite receiving rest breaks in between testing. These findings suggest that (a) falling BrACs are an inadequate guide for performance/safety and (b) rest breaks without sleep are not a safety measure for mitigating performance impairment when consuming alcohol following restricted sleep. Copyright © 2017 John Wiley & Sons, Ltd.

Signed reward prediction errors drive declarative learning

PubMed Central

Naert, Lien; Janssens, Clio; Talsma, Durk; Van Opstal, Filip; Verguts, Tom

2018-01-01

Reward prediction errors (RPEs) are thought to drive learning. This has been established in procedural learning (e.g., classical and operant conditioning). However, empirical evidence on whether RPEs drive declarative learning–a quintessentially human form of learning–remains surprisingly absent. We therefore coupled RPEs to the acquisition of Dutch-Swahili word pairs in a declarative learning paradigm. Signed RPEs (SRPEs; “better-than-expected” signals) during declarative learning improved recognition in a follow-up test, with increasingly positive RPEs leading to better recognition. In addition, classic declarative memory mechanisms such as time-on-task failed to explain recognition performance. The beneficial effect of SRPEs on recognition was subsequently affirmed in a replication study with visual stimuli. PMID:29293493

Signed reward prediction errors drive declarative learning.

PubMed

De Loof, Esther; Ergo, Kate; Naert, Lien; Janssens, Clio; Talsma, Durk; Van Opstal, Filip; Verguts, Tom

2018-01-01

Reward prediction errors (RPEs) are thought to drive learning. This has been established in procedural learning (e.g., classical and operant conditioning). However, empirical evidence on whether RPEs drive declarative learning-a quintessentially human form of learning-remains surprisingly absent. We therefore coupled RPEs to the acquisition of Dutch-Swahili word pairs in a declarative learning paradigm. Signed RPEs (SRPEs; "better-than-expected" signals) during declarative learning improved recognition in a follow-up test, with increasingly positive RPEs leading to better recognition. In addition, classic declarative memory mechanisms such as time-on-task failed to explain recognition performance. The beneficial effect of SRPEs on recognition was subsequently affirmed in a replication study with visual stimuli.

Can Driving-Simulator Training Enhance Visual Attention, Cognition, and Physical Functioning in Older Adults?

PubMed

Haeger, Mathias; Bock, Otmar; Memmert, Daniel; Hüttermann, Stefanie

2018-01-01

Virtual reality offers a good possibility for the implementation of real-life tasks in a laboratory-based training or testing scenario. Thus, a computerized training in a driving simulator offers an ecological valid training approach. Visual attention had an influence on driving performance, so we used the reverse approach to test the influence of a driving training on visual attention and executive functions. Thirty-seven healthy older participants (mean age: 71.46 ± 4.09; gender: 17 men and 20 women) took part in our controlled experimental study. We examined transfer effects from a four-week driving training (three times per week) on visual attention, executive function, and motor skill. Effects were analyzed using an analysis of variance with repeated measurements. Therefore, main factors were group and time to show training-related benefits of our intervention. Results revealed improvements for the intervention group in divided visual attention; however, there were benefits neither in the other cognitive domains nor in the additional motor task. Thus, there are no broad training-induced transfer effects from such an ecologically valid training regime. This lack of findings could be addressed to insufficient training intensities or a participant-induced bias following the cancelled randomization process.

Euro 6 Unregulated Pollutant Characterization and Statistical Analysis of After-Treatment Device and Driving-Condition Impact on Recent Passenger-Car Emissions.

PubMed

Martinet, Simon; Liu, Yao; Louis, Cédric; Tassel, Patrick; Perret, Pascal; Chaumond, Agnès; André, Michel

2017-05-16

This study aims to measure and analyze unregulated compound emissions for two Euro 6 diesel and gasoline vehicles. The vehicles were tested on a chassis dynamometer under various driving cycles: Artemis driving cycles (urban, road, and motorway), the New European Driving Cycle (NEDC) and the World Harmonized Light-Duty Test Cycle (WLTC) for Europe, and world approval cycles. The emissions of unregulated compounds (such as total particle number (PN) (over 5.6 nm); black carbon (BC); NO 2 ; benzene, toluene, ethylbenzene, and xylene (BTEX); carbonyl compounds; and polycyclic aromatic hydrocarbons (PAHs)) were measured with several online devices, and different samples were collected using cartridges and quartz filters. Furthermore, a preliminary statistical analysis was performed on eight Euro 4-6 diesel and gasoline vehicles to study the impacts of driving conditions and after-treatment and engine technologies on emissions of regulated and unregulated pollutants. The results indicate that urban conditions with cold starts induce high emissions of BTEX and carbonyl compounds. Motorway conditions are characterized by high emissions of particle numbers and CO, which mainly induced by gasoline vehicles. Compared with gasoline vehicles, diesel vehicles equipped with catalyzed or additive DPF emit fewer particles but more NO x and carbonyl compounds.

Naturalistic validation of an on-road driving test of older drivers.

PubMed

Ott, Brian R; Papandonatos, George D; Davis, Jennifer D; Barco, Peggy P

2012-08-01

The objective was to compare a standardized road test to naturalistic driving by older people who may have cognitive impairment to define improvements that could potentially enhance the validity of road testing in this population. Road testing has been widely adapted as a tool to assess driving competence of older people who may be at risk for unsafe driving because of dementia; however, the validity of this approach has not been rigorously evaluated. For 2 weeks, 80 older drivers (38 healthy elders and 42 with cognitive impairment) who passed a standardized road test were video recorded in their own vehicles. Using a standardized rating scale, 4 hr of video was rated by a driving instructor. The authors examine weighting of individual road test items to form global impressions and to compare road test and naturalistic driving using factor analyses of these two assessments. The road test score was unidimensional, reflecting a major factor related to awareness of signage and traffic behavior. Naturalistic driving reflected two factors related to lane keeping as well as traffic behavior. Maintenance of proper lane is an important dimension of driving safety that appears to be relatively underemphasized during the highly supervised procedures of the standardized road test. Road testing in this population could be improved by standardized designs that emphasize lane keeping and that include self-directed driving. Additional information should be sought from observers in the community as well as crash evidence when advising older drivers who may be cognitively impaired.

The drive-wise project: driving simulator training increases real driving performance in healthy older drivers

PubMed Central

Casutt, Gianclaudio; Theill, Nathan; Martin, Mike; Keller, Martin; Jäncke, Lutz

2014-01-01

Background: Age-related cognitive decline is often associated with unsafe driving behavior. We hypothesized that 10 active training sessions in a driving simulator increase cognitive and on-road driving performance. In addition, driving simulator training should outperform cognitive training. Methods: Ninety-one healthy active drivers (62–87 years) were randomly assigned to one of three groups: (1) a driving simulator training group, (2) an attention training group (vigilance and selective attention), or (3) a control group. The main outcome variables were on-road driving and cognitive performance. Seventy-seven participants (85%) completed the training and were included in the analyses. Training gains were analyzed using a multiple regression analysis with planned orthogonal comparisons. Results: The driving simulator-training group showed an improvement in on-road driving performance compared to the attention-training group. In addition, both training groups increased cognitive performance compared to the control group. Conclusion: Driving simulator training offers the potential to enhance driving skills in older drivers. Compared to the attention training, the simulator training seems to be a more powerful program for increasing older drivers' safety on the road. PMID:24860497

Controlled Speed Accessory Drive demonstration program

NASA Technical Reports Server (NTRS)

Hoehn, F. W.

1981-01-01

A Controlled Speed Accessory Drive System was examined in an effort to improve the fuel economy of passenger cars. Concept feasibility and the performance of a typical system during actual road driving conditions were demonstrated. The CSAD system is described as a mechanical device which limits engine accessory speeds, thereby reducing parasitic horsepower losses and improving overall vehicle fuel economy. Fuel consumption data were compiled for fleets of GSA vehicles. Various motor pool locations were selected, each representing different climatic conditions. On the basis of a total accumulated fleet usage of nearly three million miles, an overall fuel economy improvement of 6 percent to 7 percent was demonstrated. Coincident chassis dynamometer tests were accomplished on selected vehicles to establish the effect of different accessory drive systems on exhaust emissions, and to evaluate the magnitude of the mileage benefits which could be derived.

ADX: a high field, high power density, advanced divertor and RF tokamak

NASA Astrophysics Data System (ADS)

LaBombard, B.; Marmar, E.; Irby, J.; Terry, J. L.; Vieira, R.; Wallace, G.; Whyte, D. G.; Wolfe, S.; Wukitch, S.; Baek, S.; Beck, W.; Bonoli, P.; Brunner, D.; Doody, J.; Ellis, R.; Ernst, D.; Fiore, C.; Freidberg, J. P.; Golfinopoulos, T.; Granetz, R.; Greenwald, M.; Hartwig, Z. S.; Hubbard, A.; Hughes, J. W.; Hutchinson, I. H.; Kessel, C.; Kotschenreuther, M.; Leccacorvi, R.; Lin, Y.; Lipschultz, B.; Mahajan, S.; Minervini, J.; Mumgaard, R.; Nygren, R.; Parker, R.; Poli, F.; Porkolab, M.; Reinke, M. L.; Rice, J.; Rognlien, T.; Rowan, W.; Shiraiwa, S.; Terry, D.; Theiler, C.; Titus, P.; Umansky, M.; Valanju, P.; Walk, J.; White, A.; Wilson, J. R.; Wright, G.; Zweben, S. J.

2015-05-01

The MIT Plasma Science and Fusion Center and collaborators are proposing a high-performance Advanced Divertor and RF tokamak eXperiment (ADX)—a tokamak specifically designed to address critical gaps in the world fusion research programme on the pathway to next-step devices: fusion nuclear science facility (FNSF), fusion pilot plant (FPP) and/or demonstration power plant (DEMO). This high-field (⩾6.5 T, 1.5 MA), high power density facility (P/S ˜ 1.5 MW m-2) will test innovative divertor ideas, including an ‘X-point target divertor’ concept, at the required performance parameters—reactor-level boundary plasma pressures, magnetic field strengths and parallel heat flux densities entering into the divertor region—while simultaneously producing high-performance core plasma conditions that are prototypical of a reactor: equilibrated and strongly coupled electrons and ions, regimes with low or no torque, and no fuelling from external heating and current drive systems. Equally important, the experimental platform will test innovative concepts for lower hybrid current drive and ion cyclotron range of frequency actuators with the unprecedented ability to deploy launch structures both on the low-magnetic-field side and the high-magnetic-field side—the latter being a location where energetic plasma-material interactions can be controlled and favourable RF wave physics leads to efficient current drive, current profile control, heating and flow drive. This triple combination—advanced divertors, advanced RF actuators, reactor-prototypical core plasma conditions—will enable ADX to explore enhanced core confinement physics, such as made possible by reversed central shear, using only the types of external drive systems that are considered viable for a fusion power plant. Such an integrated demonstration of high-performance core-divertor operation with steady-state sustainment would pave the way towards an attractive pilot plant, as envisioned in the ARC concept (affordable, robust, compact) (Sorbom et al 2015 Fusion Eng. Des. submitted (arXiv:1409.3540)) that makes use of high-temperature superconductor technology—a high-field (9.25 T) tokamak the size of the Joint European Torus that produces 270 MW of net electricity.