Science.gov

Sample records for aircraft crash frequency

  1. Simulation of aircraft crash and its validation

    NASA Technical Reports Server (NTRS)

    Hayduk, R. J.; Thomson, R. G.

    1975-01-01

    NASA Langley Research Center is engaged in an extensive research and development task aimed at providing the general aviation industry with reliable crashworthy airframe design technology. This paper describes the full-scale crash tests of general aviation airplanes being conducted to generate data on simulated crashes and to study the nonlinear dynamic behavior of aircraft structures. Analytical techniques under development for predicting nonlinear behavior of general airframe structures under crash-loading conditions are also described. Data are presented from the full-scale crash tests as well as comparison of analytical predictions with experimental results on some simplified structures.

  2. Light aircraft crash safety program

    NASA Technical Reports Server (NTRS)

    Thomson, R. G.; Hayduk, R. J.

    1974-01-01

    NASA is embarked upon research and development tasks aimed at providing the general aviation industry with a reliable crashworthy airframe design technology. The goals of the NASA program are: reliable analytical techniques for predicting the nonlinear behavior of structures; significant design improvements of airframes; and simulated full-scale crash test data. The analytical tools will include both simplified procedures for estimating energy absorption characteristics and more complex computer programs for analysis of general airframe structures under crash loading conditions. The analytical techniques being developed both in-house and under contract are described, and a comparison of some analytical predictions with experimental results is shown.

  3. Aircraft Crash Survival Design Guide. Volume 5. Aircraft Postcrash Survival

    DTIC Science & Technology

    1980-01-01

    Crash Locator Beacons Crashworthiness Emergency Escape Postcrash Survival Aircraft Interior Materials Crashworthy Fuel Systems Ditching Postorash Fire...behavior of interip~r materials , ditching survival, emergency escape, and ~ crash loc tor beacons. ow - SECURITY CLASSIFICATION OF THIS PAGIEtfhn Pata...IGNITION SOURCE CONTROL TERMS.... . . 21 2.4 INTERIOR MATERIALS SELECTION TERMS . . . 22 2.5 DITCHING AND EMERGENCY ESCAPE TERMS. . . 23 CHAPTER 3. POSTCRASH

  4. Mechanism of Start and Development of Aircraft Crash Fires

    NASA Technical Reports Server (NTRS)

    Pinkel, I. Irving; Preston, G. Merritt; Pesman, Gerard J.

    1952-01-01

    Full-scale aircraft crashes, devised to give surge fuel spillage and a high incidence of fire, were made to investigate the mechanism of the start and development of aircraft crash fires. The results are discussed. herein. This investigation revealed the characteristics of the ignition sources, the manner in which the combustibles spread., the mechanism of the union of the combustibles and ignition sources, and the pertinent factors governing the development of a crash fire as observed in this program.

  5. Mechanism of Start and Development of Aircraft Crash Fires

    NASA Technical Reports Server (NTRS)

    Pinkel, I. Irving; Preston, G. Merritt; Pesman, Gerard J.

    1952-01-01

    Full-scale aircraft crashes were made to investigate the mechanism of the start and development of aircraft crash fires. The results are discussed herein. This investigation revealed the characteristics of the ignition sources, the manner in which the combustibles spread, the mechanism of the union of the combustibles and ignition sources, and the pertinent factors governing the development of a crash fire as observed in this program.

  6. Data development technical support document for the aircraft crash risk analysis methodology (ACRAM) standard

    SciTech Connect

    Kimura, C.Y.; Glaser, R.E.; Mensing, R.W.; Lin, T.; Haley, T.A.; Barto, A.B.; Stutzke, M.A.

    1996-08-01

    The Aircraft Crash Risk Analysis Methodology (ACRAM) Panel has been formed by the US Department of Energy Office of Defense Programs (DOE/DP) for the purpose of developing a standard methodology for determining the risk from aircraft crashes onto DOE ground facilities. In order to accomplish this goal, the ACRAM panel has been divided into four teams, the data development team, the model evaluation team, the structural analysis team, and the consequence team. Each team, consisting of at least one member of the ACRAM plus additional DOE and DOE contractor personnel, specializes in the development of the methodology assigned to that team. This report documents the work performed by the data development team and provides the technical basis for the data used by the ACRAM Standard for determining the aircraft crash frequency. This report should be used to provide the generic data needed to calculate the aircraft crash frequency into the facility under consideration as part of the process for determining the aircraft crash risk to ground facilities as given by the DOE Standard Aircraft Crash Risk Assessment Methodology (ACRAM). Some broad guidance is presented on how to obtain the needed site-specific and facility specific data but this data is not provided by this document.

  7. Estimate of air carrier and air taxi crash frequencies from high altitude en route flight operations

    SciTech Connect

    Sanzo, D.; Kimura, C.Y.; Prassinos, P.G.

    1996-06-03

    In estimating the frequency of an aircraft crashing into a facility, it has been found convenient to break the problem down into two broad categories. One category estimates the aircraft crash frequency due to air traffic from nearby airports, the so-called near-airport environment. The other category estimates the aircraft crash frequency onto facilities due to air traffic from airways, jet routes, and other traffic flying outside the near-airport environment The total aircraft crash frequency is the summation of the crash frequencies from each airport near the facility under evaluation and from all airways, jet routes, and other traffic near the facility of interest. This paper will examine the problems associated with the determining the aircraft crash frequencies onto facilities outside the near-airport environment. This paper will further concentrate on the estimating the risk of aircraft crashes to ground facilities due to high altitude air carrier and air taxi traffic. High altitude air carrier and air taxi traffic will be defined as all air carrier and air taxi flights above 18,000 feet Mean Sea Level (MSL).

  8. Evaluation of aircraft crash hazard at Los Alamos National Laboratory facilities

    SciTech Connect

    Selvage, R.D.

    1996-07-01

    This report selects a method for use in calculating the frequency of an aircraft crash occurring at selected facilities at the Los Alamos National Laboratory (the Laboratory). The Solomon method was chosen to determine these probabilities. Each variable in the Solomon method is defined and a value for each variable is selected for fourteen facilities at the Laboratory. These values and calculated probabilities are to be used in all safety analysis reports and hazards analyses for the facilities addressed in this report. This report also gives detailed directions to perform aircraft-crash frequency calculations for other facilities. This will ensure that future aircraft-crash frequency calculations are consistent with calculations in this report.

  9. Aircraft subfloor response to crash loadings

    NASA Technical Reports Server (NTRS)

    Carden, H. D.; Hayduk, R. J.

    1981-01-01

    Results are presented of an experimental and analytical study of the dynamic response to crash loadings of five different load-limiting subfloors for general aviation aircraft. These subfloors provide a high-strength structural floor platform to retain the seats and a crushable zone to absorb energy and limit vertical loads. Experimental static load-deflection data and dynamic deceleration response data for the five subfloors indicated that the high-strength floor platform performed well in that structural integrity and residual strength was maintained throughout the loading cycle. The data also indicated that some of the subfloor crush zones were more effective than others in providing nearly constant load for a range of displacement. The analytical data was generated by characterizing the nonlinear crush zones of the subfloor with static load-deflection data and using the DYCAST nonlinear finite element computer program. Comparisons between experimental and analytical data showed good correlation for the subfloors in which the static deformation mode closely approximated the dynamic deformation mode.

  10. Aircraft crash caused by stress corrosion cracking

    SciTech Connect

    Kolkman, H.J.; Kool, G.A.; Wanhill, R.J.H.

    1996-01-01

    An aircraft crash in the Netherlands was caused by disintegration of a jet engine. Fractography showed that the chain of events started with stress corrosion cracking (SCC) of a pin attached to a lever arm of the compressor variable vane system. Such a lever arm-pin assembly costs only a few dollars. Investigation of hundreds of pins from the accident and a number of identical engines revealed that this was not an isolated case. Many pins exhibited various amounts of SCC. The failed pin in the accident engine happened to be the first fractured one. SCC requires the simultaneous presence of tensile stress, a corrosive environment, and a susceptible material. In this case the stress was a residual stress arising from the production method. There was a clear correlation between the presence of salt deposits on the levers and SCC of the pins. It was shown that these deposits were able to reach the internal space between the pin and lever arm, thereby initiating SCC in this space. The corrosive environment in Western Europe explains why the problem manifested itself in the Netherlands at a relatively early stage in engine life. The main point is, however, that the manufacturer selected an SCC-prone material in the design stage. The solution has been to change the pin material.

  11. Assessment of methodologies for analysis of the dungeness B accidental aircraft crash risk.

    SciTech Connect

    LaChance, Jeffrey L.; Hansen, Clifford W.

    2010-09-01

    The Health and Safety Executive (HSE) has requested Sandia National Laboratories (SNL) to review the aircraft crash methodology for nuclear facilities that are being used in the United Kingdom (UK). The scope of the work included a review of one method utilized in the UK for assessing the potential for accidental airplane crashes into nuclear facilities (Task 1) and a comparison of the UK methodology against similar International Atomic Energy Agency (IAEA), United States (US) Department of Energy (DOE), and the US Nuclear Regulatory Commission (NRC) methods (Task 2). Based on the conclusions from Tasks 1 and 2, an additional Task 3 would provide an assessment of a site-specific crash frequency for the Dungeness B facility using one of the other methodologies. This report documents the results of Task 2. The comparison of the different methods was performed for the three primary contributors to aircraft crash risk at the Dungeness B site: airfield related crashes, crashes below airways, and background crashes. The methods and data specified in each methodology were compared for each of these risk contributors, differences in the methodologies were identified, and the importance of these differences was qualitatively and quantitatively assessed. The bases for each of the methods and the data used were considered in this assessment process. A comparison of the treatment of the consequences of the aircraft crashes was not included in this assessment because the frequency of crashes into critical structures is currently low based on the existing Dungeness B assessment. Although the comparison found substantial differences between the UK and the three alternative methodologies (IAEA, NRC, and DOE) this assessment concludes that use of any of these alternative methodologies would not change the conclusions reached for the Dungeness B site. Performance of Task 3 is thus not recommended.

  12. A multivariate spatial crash frequency model for identifying sites with promise based on crash types.

    PubMed

    Jonathan, Aguero-Valverde; Wu, Kun-Feng Ken; Donnell, Eric T

    2016-02-01

    Many studies have proposed the use of a systemic approach to identify sites with promise (SWiPs). Proponents of the systemic approach to road safety management suggest that it is more effective in reducing crash frequency than the traditional hot spot approach. The systemic approach aims to identify SWiPs by crash type(s) and, therefore, effectively connects crashes to their corresponding countermeasures. Nevertheless, a major challenge to implementing this approach is the low precision of crash frequency models, which results from the systemic approach considering subsets (crash types) of total crashes leading to higher variability in modeling outcomes. This study responds to the need for more precise statistical output and proposes a multivariate spatial model for simultaneously modeling crash frequencies for different crash types. The multivariate spatial model not only induces a multivariate correlation structure between crash types at the same site, but also spatial correlation among adjacent sites to enhance model precision. This study utilized crash, traffic, and roadway inventory data on rural two-lane highways in Pennsylvania to construct and test the multivariate spatial model. Four models with and without the multivariate and spatial correlations were tested and compared. The results show that the model that considers both multivariate and spatial correlation has the best fit. Moreover, it was found that the multivariate correlation plays a stronger role than the spatial correlation when modeling crash frequencies in terms of different crash types.

  13. A review of the analytical simulation of aircraft crash dynamics

    NASA Technical Reports Server (NTRS)

    Fasanella, Edwin L.; Carden, Huey D.; Boitnott, Richard L.; Hayduk, Robert J.

    1990-01-01

    A large number of full scale tests of general aviation aircraft, helicopters, and one unique air-to-ground controlled impact of a transport aircraft were performed. Additionally, research was also conducted on seat dynamic performance, load-limiting seats, load limiting subfloor designs, and emergency-locator-transmitters (ELTs). Computer programs were developed to provide designers with methods for predicting accelerations, velocities, and displacements of collapsing structure and for estimating the human response to crash loads. The results of full scale aircraft and component tests were used to verify and guide the development of analytical simulation tools and to demonstrate impact load attenuating concepts. Analytical simulation of metal and composite aircraft crash dynamics are addressed. Finite element models are examined to determine their degree of corroboration by experimental data and to reveal deficiencies requiring further development.

  14. Effect of Accounting for Crash Severity on the Relationship between Mass Reduction and Crash Frequency and Risk per Crash

    SciTech Connect

    Wenzel, Tom P.

    2016-05-20

    Previous analyses have indicated that mass reduction is associated with an increase in crash frequency (crashes per VMT), but a decrease in fatality or casualty risk once a crash has occurred, across all types of light-duty vehicles. These results are counter-intuitive: one would expect that lighter, and perhaps smaller, vehicles have better handling and shorter braking distances, and thus should be able to avoid crashes that heavier vehicles cannot. And one would expect that heavier vehicles would have lower risk once a crash has occurred than lighter vehicles. However, these trends occur under several alternative regression model specifications. This report tests whether these results continue to hold after accounting for crash severity, by excluding crashes that result in relatively minor damage to the vehicle(s) involved in the crash. Excluding non-severe crashes from the initial LBNL Phase 2 and simultaneous two-stage regression models for the most part has little effect on the unexpected relationships observed in the baseline regression models. This finding suggests that other subtle differences in vehicles and/or their drivers, or perhaps biases in the data reported in state crash databases, are causing the unexpected results from the regression models.

  15. Behavior Of Aircraft Components Under Crash-Type Loads

    NASA Technical Reports Server (NTRS)

    Carden, Huey D.; Boitnott, Richard L.; Fasanella, Edwin L.

    1993-01-01

    Report presents overview of research involving use of concepts of aircraft elements and substructures not necessarily designed or optimized with respect to energy-absorption or crash-loading considerations. Experimental and analytical data presented in report indicate some general trends in failure behaviors of class of composite-material structures including individual fuselage frames, skeleton subfloors with stringers and floor beams but without skin covering, and subfloors with skin added to frame/stringer arrangement.

  16. Aircraft Crash Survival Design Guide. Volume 5. Aircraft Postcrash Survival

    DTIC Science & Technology

    1989-12-01

    mine specific relationships between crash forces, structur:- failures . crao1 fires, and injuries. A series of reports covering this effort was prepared...regardless of the degree of failure of the sur- rounding structure. Success of such a system depends on proper selection of materials and design techniques...provided. 31 Another factor that can govern whether or not a fuel tank will survive a given impact is the method of failure experienced by the

  17. Vehicular crash data used to rank intersections by injury crash frequency and severity.

    PubMed

    Liu, Yi; Li, Zongzhi; Liu, Jingxian; Patel, Harshingar

    2016-09-01

    This article contains data on research conducted in "A double standard model for allocating limited emergency medical service vehicle resources ensuring service reliability" (Liu et al., 2016) [1]. The crash counts were sorted out from comprehensive crash records of over one thousand major signalized intersections in the city of Chicago from 2004 to 2010. For each intersection, vehicular crashes were counted by crash severity levels, including fatal, injury Types A, B, and C for major, moderate, and minor injury levels, property damage only (PDO), and unknown. The crash data was further used to rank intersections by equivalent injury crash frequency. The top 200 intersections with the highest number of crash occurrences identified based on crash frequency- and severity-based scenarios are shared in this brief. The provided data would be a valuable source for research in urban traffic safety analysis and could also be utilized to examine the effectiveness of traffic safety improvement planning and programming, intersection design enhancement, incident and emergency management, and law enforcement strategies.

  18. An assessment of the crash fire hazard of liquid hydrogen fueled aircraft

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The crash fire hazards of liquid hydrogen fueled aircraft relative to those of mission equivalent aircraft fueled either with conventional fuel or with liquefied methane were evaluated. The aircraft evaluated were based on Lockheed Corporation design for 400 passenger, Mach 0.85, 5500 n. mile aircraft. Four crash scenarios were considered ranging from a minor incident causing some loss of fuel system integrity to a catastrophic crash. Major tasks included a review of hazardous properties of the alternate fuels and of historic crash fire data; a comparative hazard evluation for each of the three fuels under four crash scenarios a comprehensive review and analysis and an identification of areas further development work. The conclusion was that the crash fire hazards are not significantly different when compared in general for the three fuels, although some fuels showed minor advantages in one respect or another.

  19. Aircraft Crash Survival Design Guide. Volume 3. Aircraft Structural Crash Resistance

    DTIC Science & Technology

    1989-12-01

    DESIGN CONDITIONS. 4.3.1.6 Engene !Transmisslon Mounts. Engine mounts should be designed to keep the engine attached to the basic structure, even...8217. AIRCRAFT, NASA Langley Research Center, A~tr~ujS ~ t sAgnautics, September 1983. j 235 REFERENCES (CONTD) 33. Gibbs, H. H., K- POLYMER COMPOSITE

  20. An Approach to Estimate the Localized Effects of an Aircraft Crash on a Facility

    SciTech Connect

    Kimura, C; Sanzo, D; Sharirli, M

    2004-04-19

    Aircraft crashes are an element of external events required to be analyzed and documented in facility Safety Analysis Reports (SARs) and Nuclear Explosive Safety Studies (NESSs). This paper discusses the localized effects of an aircraft crash impact into the Device Assembly Facility (DAF) located at the Nevada Test Site (NTS), given that the aircraft hits the facility. This was done to gain insight into the robustness of the DAF and to account for the special features of the DAF that enhance its ability to absorb the effects of an aircraft crash. For the purpose of this paper, localized effects are considered to be only perforation or scabbing of the facility. This paper presents an extension to the aircraft crash risk methodology of Department of Energy (DOE) Standard 3014. This extension applies to facilities that may find it necessary or desirable to estimate the localized effects of an aircraft crash hit on a facility of nonuniform construction or one that is shielded in certain directions by surrounding terrain or buildings. This extension is not proposed as a replacement to the aircraft crash risk methodology of DOE Standard 3014 but rather as an alternate method to cover situations that were not considered.

  1. Analytical modeling of transport aircraft crash scenarios to obtain floor pulses

    NASA Technical Reports Server (NTRS)

    Wittlin, G.; Lackey, D.

    1983-01-01

    The KRAS program was used to analyze transport aircraft candidate crash scenarios. Aircraft floor pulses and seat/occupant responses are presented. Results show that: (1) longitudinal only pulses can be represented by equivalent step inputs and/or static requirements; (2) the L1649 crash test floor longitudinal pulse for the aft direction (forward inertia) is less than 9g static or an equivalent 5g pulse; aft inertia accelerations are extremely small ((ch76) 3g) for representative crash scenarios; (3) a viable procedure to relate crash scenario floor pulses to standard laboratory dynamic and static test data using state of the art analysis and test procedures was demonstrated; and (4) floor pulse magnitudes are expected to be lower for wide body aircraft than for smaller narrow body aircraft.

  2. Origin and Prevention of Crash Fires in Turbojet Aircraft

    NASA Technical Reports Server (NTRS)

    Pinkel, I Irving; Weiss, Solomon; Preston, G Merritt; Pesman, Gerard J

    1957-01-01

    The manner in which the jet engine may start a crash fire was explored in test-stand and full-scale crash studies. On the basis of these studies, a method was devised for inserting and cooling the engine parts that may serve as ignition sources in crash. This method was tried successfully in full-scale crashes of jet-powered airplanes carrying engines in pod nacelles and engines buried within the airplane structure.

  3. Crash response data system for the controlled impact demonstration (CID) of a full scale transport aircraft

    NASA Technical Reports Server (NTRS)

    Calloway, Raymond S.; Knight, Vernie H., Jr.

    1986-01-01

    NASA Langley's Crash Response Data System (CRDS) which is designed to acquire aircraft structural and anthropomorphic dummy responses during the full-scale transport CID test is described. Included in the discussion are the system design approach, details on key instrumentation subsystems and operations, overall instrumentation crash performance, and data recovery results. Two autonomous high-environment digital flight instrumentation systems, DAS 1 and DAS 2, were employed to obtain research data from various strain gage, accelerometer, and tensiometric sensors installed in the B-720 test aircraft. The CRDS successfully acquired 343 out of 352 measurements of dynamic crash data.

  4. Prediction of secondary crash frequency on highway networks.

    PubMed

    Sarker, Afrid A; Paleti, Rajesh; Mishra, Sabyasachee; Golias, Mihalis M; Freeze, Philip B

    2017-01-01

    Secondary crash (SC) occurrences are major contributors to traffic delay and reduced safety, particularly in urban areas. National, state, and local agencies are investing substantial amount of resources to identify and mitigate secondary crashes to reduce congestion, related fatalities, injuries, and property damages. Though a relatively small portion of all crashes are secondary, determining the primary contributing factors for their occurrence is crucial. The non-recurring nature of SCs makes it imperative to predict their occurrences for effective incident management. In this context, the objective of this study is to develop prediction models to better understand causal factors inducing SCs. Given the count nature of secondary crash frequency data, the authors used count modeling methods including the standard Poisson and Negative Binomial (NB) models and their generalized variants to analyze secondary crash occurrences. Specifically, Generalized Ordered Response Probit (GORP) framework that subsumes standard count models as special cases and provides additional flexibility thus improving predictive accuracy were used in this study. The models developed account for possible effects of geometric design features, traffic composition and exposure, land use and other segment related attributes on frequency of SCs on freeways. The models were estimated using data from Shelby County, TN and results show that annual average daily traffic (AADT), traffic composition, land use, number of lanes, right side shoulder width, posted speed limits and ramp indicator are among key variables that effect SC occurrences. Also, the elasticity effects of these different factors were also computed to quantify their magnitude of impact.

  5. Soil analyses and evaluations at the impact dynamics research facility for two full-scale aircraft crash tests

    NASA Technical Reports Server (NTRS)

    Cheng, R. Y. K.

    1977-01-01

    The aircraft structural crash behavior and occupant survivability for aircraft crashes on a soil surface was studied. The results of placement, compaction, and maintenance of two soil test beds are presented. The crators formed by the aircraft after each test are described.

  6. Determination of crash test pulses and their application to aircraft seat analysis

    NASA Technical Reports Server (NTRS)

    Alfaro-Bou, E.; Williams, M. S.; Fasanella, E. L.

    1981-01-01

    Deceleration time histories (crash pulses) from a series of twelve light aircraft crash tests conducted at NASA Langley Research Center (LaRC) were analyzed to provide data for seat and airframe design for crashworthiness. Two vertical drop tests at 12.8 m/s (42 ft/s) and 36 G peak deceleration (simulating one of the vertical light aircraft crash pulses) were made using an energy absorbing light aircraft seat prototype. Vertical pelvis acceleration measured in a 50 percentile dummy in the energy absorbing seat were found to be 45% lower than those obtained from the same dummy in a typical light aircraft seat. A hybrid mathematical seat-occupant model was developed using the DYCAST nonlinear finite element computer code and was used to analyze a vertical drop test of the energy absorbing seat. Seat and occupant accelerations predicted by the DYCAST model compared quite favorably with experimental values.

  7. Aircraft-type crash injury investigation of a commuter train collision.

    PubMed

    Braden, G E

    1975-09-01

    Until recently, the investigation of crash injuries and their causes in railroad crashes has been relatively nonexistent. Now, however, with the trend toward a more balanced transportation system, the number of railroad passengers is increasing and there is a concurrent demand for new, rebuilt, or refurbished passenger cars. Most railroad passenger cars in service today appear to have been designed primarily for longevity and easy servicing with secondary emphasis on passenger comfort and little emphasis on passenger safety. It is unlikely that these priorities will be reversed unless crash injury investigations can demonstrate a specific need for improvements in crashworthiness. In line with this objective, techniques developed in aircraft crash investigations were used to collect and evaluate crash injury and escape data from the collision of two commuter trains.

  8. Relating crash frequency and severity: evaluating the effectiveness of shoulder rumble strips on reducing fatal and major injury crashes.

    PubMed

    Wu, Kun-Feng; Donnell, Eric T; Aguero-Valverde, Jonathan

    2014-06-01

    To approach the goal of "Toward Zero Deaths," there is a need to develop an analysis paradigm to better understand the effects of a countermeasure on reducing the number of severe crashes. One of the goals in traffic safety research is to search for an effective treatment to reduce fatal and major injury crashes, referred to as severe crashes. To achieve this goal, the selection of promising countermeasures is of utmost importance, and relies on the effectiveness of candidate countermeasures in reducing severe crashes. Although it is important to precisely evaluate the effectiveness of candidate countermeasures in reducing the number of severe crashes at a site, the current state-of-the-practice often leads to biased estimates. While there have been a few advanced statistical models developed to mitigate the problem in practice, these models are computationally difficult to estimate because severe crashes are dispersed spatially and temporally, and cannot be integrated into the Highway Safety Manual framework, which develops a series of safety performance functions and crash modification factors to predict the number of crashes. Crash severity outcomes are generally integrated into the Highway Safety Manual using deterministic distributions rather than statistical models. Accounting for the variability in crash severity as a function geometric design, traffic flow, and other roadway and roadside features is afforded by estimating statistical models. Therefore, there is a need to develop a new analysis paradigm to resolve the limitations in the current Highway Safety Manual methods. We propose an approach which decomposes the severe crash frequency into a function of the change in the total number of crashes and the probability of a crash becoming a severe crash before and after a countermeasure is implemented. We tested this approach by evaluating the effectiveness of shoulder rumble strips on reducing the number of severe crashes. A total of 310 segments that have

  9. Impact dynamics research facility for full-scale aircraft crash testing

    NASA Technical Reports Server (NTRS)

    Vaughan, V. L. J.; Alfaro-Bou, E.

    1976-01-01

    An impact dynamics research facility (IDRF) was developed to crash test full-scale general aviation aircraft under free-flight test conditions. The aircraft are crashed into the impact surface as free bodies; a pendulum swing method is used to obtain desired flight paths and velocities. Flight paths up to -60 deg and aircraft velocities along the flight paths up to about 27.0 m/s can be obtained with a combination of swing-cable lengths and release heights made available by a large gantry. Seven twin engine, 2721-kg aircraft were successfully crash tested at the facility, and all systems functioned properly. Acquisition of data from signals generated by accelerometers on board the aircraft and from external and onboard camera coverage was successful in spite of the amount of damage which occurred during each crash. Test parameters at the IDRF are controllable with flight path angles accurate within 8 percent, aircraft velocity accurate within 6 percent, pitch angles accurate to 4.25 deg, and roll and yaw angles acceptable under wind velocities up to 4.5 m/s.

  10. Structural dynamics research in a full-scale transport aircraft crash test

    NASA Technical Reports Server (NTRS)

    Mccomb, H. G., Jr.; Hayduk, R. J.; Thomson, R. G.

    1986-01-01

    A remotely piloted air-to-ground crash test of a full-scale transport aircraft was conducted for the first time for two purposes: (1) to demonstrate performance of an antimisting fuel additive in suppressing fire in a crash environment, and (2) to obtain structural dynamics data under crash conditions for comparison with analytical predictions. The test, called the Controlled Impact Demonstration (CID), was sponsored by FAA and NASA with cooperation of industry, the Department of Defense, and the British and French governments. The test aircraft was a Boeing 720 jet transport. The aircraft impacted a dry lakebed at Edwards Air Force Base, CA. The purpose of this paper is to discuss the structural aspects of the CID. The fuselage section tests and the CID itself are described. Structural response data from these tests are presented and discussed. Nonlinear analytical modeling efforts are described, and comparisons between analytical results and experimental results are presented.

  11. Experimental Photogrammetric Techniques Used on Five Full-Scale Aircraft Crash Tests

    NASA Technical Reports Server (NTRS)

    Littell, Justin D.

    2016-01-01

    Between 2013 and 2015, full-scale crash tests were conducted on five aircraft at the Landing and Impact Research Facility (LandIR) at NASA Langley Research Center (LaRC). Two tests were conducted on CH-46E airframes as part of the Transport Rotorcraft Airframe Crash Testbed (TRACT) project, and three tests were conduced on Cessna 172 aircraft as part of the Emergency Locator Transmitter Survivability and Reliability (ELTSAR) project. Each test served to evaluate a variety of crashworthy systems including: seats, occupants, restraints, composite energy absorbing structures, and Emergency Locator Transmitters. As part of each test, the aircraft were outfitted with a variety of internal and external cameras that were focused on unique aspects of the crash event. A subset of three camera was solely used in the acquisition of photogrammetric test data. Examples of this data range from simple two-dimensional marker tracking for the determination of aircraft impact conditions to entire full-scale airframe deformation to markerless tracking of Anthropomorphic Test Devices (ATDs, a.k.a. crash test dummies) during the crash event. This report describes and discusses the techniques used and implications resulting from the photogrammetric data acquired from each of the five tests.

  12. Origin and Prevention of Crash Fires in Turbojet Aircraft

    NASA Technical Reports Server (NTRS)

    Pinkel, I. Irvin; Weiss, Solomon; Preston, G. Merritt; Pesman, Gerard J.

    1958-01-01

    The tendency for the jet engine rotor to continue to rotate after crash presents the probability that crash-spilled combustibles suspended in the air or puddled on the ground at the engine inlet may be sucked into the engine. Studies with jet engines operating on a test stand and full-scale crashes of turbojet-powered airplanes showed that combustibles drawn into the engine in this way ignite explosively within the engine. Experiment showed that the gas flow through the engine is too rapid to permit the ignition of ingested combustibles on the hot metal in contact with the main gas stream. Ignition will occur on those hot surfaces not in the main gas stream. The portion of the engine airflow is diverted for cooling and ventilation to these zones where the gas moves slowly enough for ignition to occur.

  13. Assessment of crash fire hazard of LH sub 2 fueled aircraft

    NASA Technical Reports Server (NTRS)

    Brewer, G. D.; Wittlin, G.; Versaw, E. F.; Parmley, R.; Cima, R.; Walther, E. G.

    1981-01-01

    The relative safety of passengers in LH2 - fueled aircraft, as well as the safety of people in areas surrounding a crash scene, has been evaluated in an analytical study. Four representative circumstances were postulated involving a transport aircraft in which varying degrees of severity of damage were sustained. Potential hazard to the passengers and to the surroundings posed by the spilled fuel was evaluated for each circumstance. Corresponding aircraft fueled with liquid methane, Jet A, and JP-4 were also studied in order to make comparisons of the relative safety. The four scenarios which were used to provide a basis for the evaluation included: (1) a small fuel leak internal to the aircraft, (2) a survivable crash in which a significant quantity of fuel is spilled in a radial pattern as a result of impact with a stationary object while taxiing at fairly low speed, (3) a survivable crash in which a significant quantity of fuel is spilled in an axial pattern as a result of impact during landing, and (4) a non-survivable crash in which a massive fuel spill occurs instantaneously.

  14. Factors associated with pilot fatality in work-related aircraft crashes, Alaska, 1990-1999.

    PubMed

    Bensyl, D M; Moran, K; Conway, G A

    2001-12-01

    Work-related aircraft crashes are the leading cause of occupational fatality in Alaska, with civilian pilots having the highest fatality rate (410/100,000/year). To identify factors affecting survivability, the authors examined work-related aircraft crashes that occurred in Alaska in the 1990s (1990-1999), comparing crashes with pilot fatalities to crashes in which the pilot survived. Using data from National Transportation Safety Board reports, the authors carried out logistic regression analysis with the following variables: age, flight experience, use of a shoulder restraint, weather conditions (visual flight vs. instrument flight), light conditions (daylight vs. darkness), type of aircraft (airplane vs. helicopter), postcrash fire, crash location (airport vs. elsewhere), and state of residence. In the main-effects model, significant associations were found between fatality and postcrash fire (adjusted odds ratio (AOR) = 6.43, 95% confidence interval (CI): 2.38, 17.37), poor weather (AOR = 4.11, 95% CI: 2.15, 7.87), and non-Alaska resident status (AOR = 2.10, 95% CI: 1.05, 4.20). Protective effects were seen for shoulder restraint use (AOR = 0.40, 95% CI: 0.21, 0.77) and daylight versus darkness (AOR = 0.50, 95% CI: 0.25, 0.99). The finding that state of residence was associated with survivability offers new information on pilot survivability in work-related aircraft crashes in Alaska. These results may be useful in targeting safety interventions for pilots who fly occupationally in Alaska or in similar environments.

  15. Energy absorption studied to reduce aircraft crash forces

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The NASA/FAA aircraft safety reseach programs for general aviation aircraft are discussed. Energy absorption of aircraft subflooring and redesign of interior flooring are being studied. The testing of energy absorbing configurations is described. The three NASA advanced concepts performed at neary the maximum possible amount of energy absorption, and one of two minimum modifications concepts performed well. Planned full scale tests are described. Airplane seat concepts are being considered.

  16. Multivariate spatial models of excess crash frequency at area level: case of Costa Rica.

    PubMed

    Aguero-Valverde, Jonathan

    2013-10-01

    Recently, areal models of crash frequency have being used in the analysis of various area-wide factors affecting road crashes. On the other hand, disease mapping methods are commonly used in epidemiology to assess the relative risk of the population at different spatial units. A natural next step is to combine these two approaches to estimate the excess crash frequency at area level as a measure of absolute crash risk. Furthermore, multivariate spatial models of crash severity are explored in order to account for both frequency and severity of crashes and control for the spatial correlation frequently found in crash data. This paper aims to extent the concept of safety performance functions to be used in areal models of crash frequency. A multivariate spatial model is used for that purpose and compared to its univariate counterpart. Full Bayes hierarchical approach is used to estimate the models of crash frequency at canton level for Costa Rica. An intrinsic multivariate conditional autoregressive model is used for modeling spatial random effects. The results show that the multivariate spatial model performs better than its univariate counterpart in terms of the penalized goodness-of-fit measure Deviance Information Criteria. Additionally, the effects of the spatial smoothing due to the multivariate spatial random effects are evident in the estimation of excess equivalent property damage only crashes.

  17. Failure behavior of generic metallic and composite aircraft structural components under crash loads

    NASA Technical Reports Server (NTRS)

    Carden, Huey D.; Robinson, Martha P.

    1990-01-01

    Failure behavior results are presented from crash dynamics research using concepts of aircraft elements and substructure not necessarily designed or optimized for energy absorption or crash loading considerations. To achieve desired new designs incorporating improved energy absorption capabilities often requires an understanding of how more conventional designs behave under crash loadings. Experimental and analytical data are presented which indicate some general trends in the failure behavior of a class of composite structures including individual fuselage frames, skeleton subfloors with stringers and floor beams without skin covering, and subfloors with skin added to the frame-stringer arrangement. Although the behavior is complex, a strong similarity in the static/dynamic failure behavior among these structures is illustrated through photographs of the experimental results and through analytical data of generic composite structural models.

  18. Unique failure behavior of metal/composite aircraft structural components under crash type loads

    NASA Technical Reports Server (NTRS)

    Carden, Huey D.

    1990-01-01

    Failure behavior results are presented on some of the crash dynamics research conducted with concepts of aircraft elements and substructure which have not necessarily been designed or optimized for energy absorption or crash loading considerations. To achieve desired new designs which incorporate improved energy absorption capabilities often requires an understanding of how more conventional designs behave under crash type loadings. Experimental and analytical data are presented which indicate some general trends in the failure behavior of a class of composite structures which include individual fuselage frames, skeleton subfloors with stringers and floor beams but without skin covering, and subfloors with skin added to the frame-stringer arrangement. Although the behavior is complex, a strong similarity in the static/dynamic failure behavior among these structures is illustrated through photographs of the experimental results and through analytical data of generic composite structural models. It is believed that the thread of similarity in behavior is telling the designer and dynamists a great deal about what to expect in the crash behavior of these structures and can guide designs for improving the energy absorption and crash behavior of such structures.

  19. A History of Full-Scale Aircraft and Rotorcraft Crash Testing and Simulation at NASA Langley Research Center

    NASA Technical Reports Server (NTRS)

    Jackson, Karen E.; Boitnott, Richard L.; Fasanella, Edwin L.; Jones, Lisa E.; Lyle, Karen H.

    2004-01-01

    This paper summarizes 2-1/2 decades of full-scale aircraft and rotorcraft crash testing performed at the Impact Dynamics Research Facility (IDRF) located at NASA Langley Research Center in Hampton, Virginia. The IDRF is a 240-ft.-high steel gantry that was built originally as a lunar landing simulator facility in the early 1960's. It was converted into a full-scale crash test facility for light aircraft and rotorcraft in the early 1970 s. Since the first full-scale crash test was preformed in February 1974, the IDRF has been used to conduct: 41 full-scale crash tests of General Aviation (GA) aircraft including landmark studies to establish baseline crash performance data for metallic and composite GA aircraft; 11 full-scale crash tests of helicopters including crash qualification tests of the Bell and Sikorsky Advanced Composite Airframe Program (ACAP) prototypes; 48 Wire Strike Protection System (WSPS) qualification tests of Army helicopters; 3 vertical drop tests of Boeing 707 transport aircraft fuselage sections; and, 60+ crash tests of the F-111 crew escape module. For some of these tests, nonlinear transient dynamic codes were utilized to simulate the impact response of the airframe. These simulations were performed to evaluate the capabilities of the analytical tools, as well as to validate the models through test-analysis correlation. In September 2003, NASA Langley closed the IDRF facility and plans are underway to demolish it in 2007. Consequently, it is important to document the contributions made to improve the crashworthiness of light aircraft and rotorcraft achieved through full-scale crash testing and simulation at the IDRF.

  20. Aircraft Crash Survival Design Guide. Volume I. Design Criteria and Checklists. Revision

    DTIC Science & Technology

    1980-12-01

    SOURCE CONTROL TERMS ...... 37 2.12 INTERIOR MATERIALS SELECTION TERMS . . . 38 2.13 DITCH AND EMERGENCY ESCAPE TERMS . . . . 39 CHAPTER 3. AIRCRAFT CRASH...5.3.1 Seating System Orientation ...... 84 5.3.2 Litter Orientation ..... ......... . . 85 5.3.3 Materials . . . . . . . . . . . . ... 86 5.4 STRUCTURAL...88 5.4.6 Material . . . . . . . . . . . . . . . 92 5.4.7 Restraint System Anchorage . . . . ... 93 5.5 ENERGY-ABSORBING DEVICES

  1. Probabilistic model, analysis and computer code for take-off and landing related aircraft crashes into a structure

    SciTech Connect

    Glaser, R.

    1996-02-06

    A methodology is presented that allows the calculation of the probability that any of a particular collection of structures will be hit by an aircraft in a take-off or landing related accident during a specified window of time with a velocity exceeding a given critical value. A probabilistic model is developed that incorporates the location of each structure relative to airport runways in the vicinity; the size of the structure; the sizes, types, and frequency of use of commercial, military, and general aviation aircraft which take-off and land at these runways; the relative frequency of take-off and landing related accidents by aircraft type; the stochastic properties of off-runway crashes, namely impact location, impact angle, impact velocity, and the heading, deceleration, and skid distance after impact; and the stochastic properties of runway overruns and runoffs, namely the position at which the aircraft exits the runway, its exit velocity, and the heading and deceleration after exiting. Relevant probability distributions are fitted from extensive commercial, military, and general aviation accident report data bases. The computer source code for implementation of the calculation is provided.

  2. Crash Frequency Modeling Using Real-Time Environmental and Traffic Data and Unbalanced Panel Data Models

    PubMed Central

    Chen, Feng; Chen, Suren; Ma, Xiaoxiang

    2016-01-01

    Traffic and environmental conditions (e.g., weather conditions), which frequently change with time, have a significant impact on crash occurrence. Traditional crash frequency models with large temporal scales and aggregated variables are not sufficient to capture the time-varying nature of driving environmental factors, causing significant loss of critical information on crash frequency modeling. This paper aims at developing crash frequency models with refined temporal scales for complex driving environments, with such an effort providing more detailed and accurate crash risk information which can allow for more effective and proactive traffic management and law enforcement intervention. Zero-inflated, negative binomial (ZINB) models with site-specific random effects are developed with unbalanced panel data to analyze hourly crash frequency on highway segments. The real-time driving environment information, including traffic, weather and road surface condition data, sourced primarily from the Road Weather Information System, is incorporated into the models along with site-specific road characteristics. The estimation results of unbalanced panel data ZINB models suggest there are a number of factors influencing crash frequency, including time-varying factors (e.g., visibility and hourly traffic volume) and site-varying factors (e.g., speed limit). The study confirms the unique significance of the real-time weather, road surface condition and traffic data to crash frequency modeling. PMID:27322306

  3. Crash Frequency Modeling Using Real-Time Environmental and Traffic Data and Unbalanced Panel Data Models.

    PubMed

    Chen, Feng; Chen, Suren; Ma, Xiaoxiang

    2016-06-18

    Traffic and environmental conditions (e.g., weather conditions), which frequently change with time, have a significant impact on crash occurrence. Traditional crash frequency models with large temporal scales and aggregated variables are not sufficient to capture the time-varying nature of driving environmental factors, causing significant loss of critical information on crash frequency modeling. This paper aims at developing crash frequency models with refined temporal scales for complex driving environments, with such an effort providing more detailed and accurate crash risk information which can allow for more effective and proactive traffic management and law enforcement intervention. Zero-inflated, negative binomial (ZINB) models with site-specific random effects are developed with unbalanced panel data to analyze hourly crash frequency on highway segments. The real-time driving environment information, including traffic, weather and road surface condition data, sourced primarily from the Road Weather Information System, is incorporated into the models along with site-specific road characteristics. The estimation results of unbalanced panel data ZINB models suggest there are a number of factors influencing crash frequency, including time-varying factors (e.g., visibility and hourly traffic volume) and site-varying factors (e.g., speed limit). The study confirms the unique significance of the real-time weather, road surface condition and traffic data to crash frequency modeling.

  4. Finite Element Simulation of Three Full-Scale Crash Tests for Cessna 172 Aircraft

    NASA Technical Reports Server (NTRS)

    Mason, Brian H.; Warren, Jerry E., Jr.

    2017-01-01

    The NASA Emergency Locator Transmitter Survivability and Reliability (ELT-SAR) project was initiated in 2013 to assess the crash performance standards for the next generation of emergency locator transmitter (ELT) systems. Three Cessna 172 aircraft were acquired to perform crash testing at NASA Langley Research Center's Landing and Impact Research Facility. Full-scale crash tests were conducted in the summer of 2015 and each test article was subjected to severe, but survivable, impact conditions including a flare-to-stall during emergency landing, and two controlled-flight-into-terrain scenarios. Full-scale finite element analyses were performed using a commercial explicit solver, ABAQUS. The first test simulated impacting a concrete surface represented analytically by a rigid plane. Tests 2 and 3 simulated impacting a dirt surface represented analytically by an Eulerian grid of brick elements using a Mohr-Coulomb material model. The objective of this paper is to summarize the test and analysis results for the three full-scale crash tests. Simulation models of the airframe which correlate well with the tests are needed for future studies of alternate ELT mounting configurations.

  5. Frequency Analysis of Aircraft hazards for License Application

    SciTech Connect

    K. Ashley

    2006-10-24

    The preclosure safety analysis for the monitored geologic repository at Yucca Mountain must consider the hazard that aircraft may pose to surface structures. Relevant surface structures are located beneath the restricted airspace of the Nevada Test Site (NTS) on the eastern slope of Yucca Mountain, near the North Portal of the Exploratory Studies Facility Tunnel (Figure 1). The North Portal is located several miles from the Nevada Test and Training Range (NTTR), which is used extensively by the U.S. Air Force (USAF) for training and test flights (Figure 1). The NTS airspace, which is controlled by the U.S. Department of Energy (DOE) for NTS activities, is not part of the NTTR. Agreements with the DOE allow USAF aircraft specific use of the airspace above the NTS (Reference 2.1.1 [DIRS 103472], Section 3.1.1 and Appendix A, Section 2.1; and Reference 2.1.2 [DIRS 157987], Sections 1.26 through 1.29). Commercial, military, and general aviation aircraft fly within several miles to the southwest of the repository site in the Beatty Corridor, which is a broad air corridor that runs approximately parallel to U.S. Highway 95 and the Nevada-California border (Figure 2). These aircraft and other aircraft operations are identified and described in ''Identification of Aircraft Hazards'' (Reference 2.1.3, Sections 6 and 8). The purpose of this analysis is to estimate crash frequencies for aircraft hazards identified for detailed analysis in ''Identification of Aircraft Hazards'' (Reference 2.1.3, Section 8). Reference 2.1.3, Section 8, also identifies a potential hazard associated with electronic jamming, which will be addressed in this analysis. This analysis will address only the repository and not the transportation routes to the site. The analysis is intended to provide the basis for: (1) Categorizing event sequences related to aircraft hazards; (2) Identifying design or operational requirements related to aircraft hazards.

  6. Influence of horizontally curved roadway section characteristics on motorcycle-to-barrier crash frequency.

    PubMed

    Gabauer, Douglas J; Li, Xiaolong

    2015-04-01

    The purpose of this study was to investigate motorcycle-to-barrier crash frequency on horizontally curved roadway sections in Washington State using police-reported crash data linked with roadway data and augmented with barrier presence information. Data included 4915 horizontal curved roadway sections with 252 of these sections experiencing 329 motorcycle-to-barrier crashes between 2002 and 2011. Negative binomial regression was used to predict motorcycle-to-barrier crash frequency using horizontal curvature and other roadway characteristics. Based on the model results, the strongest predictor of crash frequency was found to be curve radius. This supports a motorcycle-to-barrier crash countermeasure placement criterion based, at the very least, on horizontal curve radius. With respect to the existing horizontal curve criterion of 820 feet or less, curves meeting this criterion were found to increase motorcycle-to-barrier crash frequency rate by a factor of 10 compared to curves not meeting this criterion. Other statistically significant predictors were curve length, traffic volume and the location of adjacent curves. Assuming curves of identical radius, the model results suggest that longer curves, those with higher traffic volume, and those that have no adjacent curved sections within 300 feet of either curve end would likely be better candidates for a motorcycle-to-barrier crash countermeasure.

  7. Impact Analyses and Tests of Metal Cask Considering Aircraft Engine Crash - 12308

    SciTech Connect

    Lee, Sanghoon; Choi, Woo-Seok; Kim, Ki-Young; Jeon, Je-Eon; Seo, Ki-Seog

    2012-07-01

    The structural integrity of a dual purpose metal cask currently under development by the Korea Radioactive Waste Management Cooperation (KRMC) is evaluated through analyses and tests under a high-speed missile impact considering the targeted aircraft crash conditions. The impact conditions were carefully chosen through a survey on accident cases and recommendations from the literature. The missile impact velocity was set at 150 m/s, and two impact orientations were considered. A simplified missile simulating a commercial aircraft engine is designed from an impact load history curve provided in the literature. In the analyses, the focus is on the evaluation of the containment boundary integrity of the metal cask. The analyses results are compared with the results of tests using a 1/3 scale model. The results show very good agreements, and the procedure and methodology adopted in the structural analyses are validated. While the integrity of the cask is maintained in one evaluation where the missile impacts the top side of the free standing cask, the containment boundary is breached in another case in which the missile impacts the center of the cask lid in a perpendicular orientation. A safety assessment using a numerical simulation of an aircraft engine crash into spent nuclear fuel storage systems is performed. A commercially available explicit finite element code is utilized for the dynamic simulation, and the strain rate effect is included in the modeling of the materials used in the target system and missile. The simulation results show very good agreement with the test results. It is noted that this is the first test considering an aircraft crash in Korea. (authors)

  8. Instrumentation and data acquisition for full-scale aircraft crash testing

    NASA Technical Reports Server (NTRS)

    Jones, Lisa E.; Fasanella, Edwin L.

    1993-01-01

    The Landing and Impact Dynamics Branch of the NASA Langley Research Center has been conducting full-scale aircraft crash tests since the 1970s. Using a pendulum method, aircraft are suspended by cables from a 240-ft high gantry and swung into the impact surface at various attitudes and velocities. Instrumentation for these tests include on-board high-speed cameras, strain gages, load cells, displacement transducers, and accelerometers. Transducers in the aircraft are hard-wired through a long umbilical cable to the data acquisition room. Up to 96 channels of data can be collected at a typical rate of 4000 samples per second. Data acquisition using an FM multiplexed analog system and a high-speed personal computer based digital system is described.

  9. An overview of the crash dynamics failure behavior of metal and composite aircraft structures

    NASA Technical Reports Server (NTRS)

    Carden, Huey D.; Boitnott, Richard L.; Fasanella, Edwin L.; Jones, Lisa E.

    1991-01-01

    An overview of failure behavior results is presented from some of the crash dynamics research conducted with concepts of aircraft elements and substructure not necessarily designed or optimized for energy absorption or crash loading considerations. Experimental and analytical data are presented that indicate some general trends in the failure behavior of a class of composite structures that includes fuselage panels, individual fuselage sections, fuselage frames, skeleton subfloors with stringers and floor beams without skin covering, and subfloors with skin added to the frame stringer structure. Although the behavior is complex, a strong similarity in the static/dynamic failure behavior among these structures is illustrated through photographs of the experimental results and through analytical data of generic composite structural models.

  10. Crash response data system for the controlled impact demonstration (CID) of a full-scale transport aircraft

    NASA Technical Reports Server (NTRS)

    Calloway, R. S.; Knight, V. H., Jr.

    1986-01-01

    A study involving the Controlled Impact Demonstration (CID) of a transport category aircraft was conducted with the objective to improve occupant safety during survivable crash scenarios. in connection with this study, the first remotely-piloted Full-Scale Transport aircraft was purposely crashed into the California desert. The program was initated to demonstrate the effectiveness of an imisting kerosene (AMK), a fuel additive emplyed to reduce postcrash fires. The unmanned CID flight carried 73 life-like flight research dummies, multiple experiments, high-speed interior cabin cameras, and the high-environment Crash Response Data System. Attention is given to the design approach, a block diagram of the Crash Response Data System, measurements, the digital data subsystem, signal conditioning, telemetry, on-board recording, the power subsystem, preflight checkout and calibration, and aspects of system qualification.

  11. Crash Testing and Simulation of a Cessna 172 Aircraft: Pitch Down Impact Onto Soft Soil

    NASA Technical Reports Server (NTRS)

    Fasanella, Edwin L.; Jackson, Karen E.

    2016-01-01

    During the summer of 2015, NASA Langley Research Center conducted three full-scale crash tests of Cessna 172 (C-172) aircraft at the NASA Langley Landing and Impact Research (LandIR) Facility. The first test represented a flare-to-stall emergency or hard landing onto a rigid surface. The second test, which is the focus of this paper, represented a controlled-flight-into-terrain (CFIT) with a nose-down pitch attitude of the aircraft, which impacted onto soft soil. The third test, also conducted onto soil, represented a CFIT with a nose-up pitch attitude of the aircraft, which resulted in a tail strike condition. These three crash tests were performed for the purpose of evaluating the performance of Emergency Locator Transmitters (ELTs) and to generate impact test data for model validation. LS-DYNA finite element models were generated to simulate the three test conditions. This paper describes the model development and presents test-analysis comparisons of acceleration and velocity time-histories, as well as a comparison of the time sequence of events for Test 2 onto soft soil.

  12. The annual probability of an aircraft crash on the US Department of Energy reservation in Oak Ridge, Tennessee

    SciTech Connect

    Seigler, R.S.; Luttrell, L.J.

    1992-11-01

    Aircraft hazards were evaluated to determine the total annual probability of an aircraft crash occurring at any structure located on the US Department of Energy (DOE) reservation in Oak Ridge, Tennessee. This report documents the use of an accepted methodology for calculating the probability of an aircraft crash as applied to the three Oak Ridge plant sites including the adjoining facilities. Based on the data contained herein, the evaluation concluded that the probability of an aircraft crash occurrence at a single facility is generally considered ``not credible`` as defined in DOE/OR-901. Additionally, reevaluation of probabilities would be necessary if significant changes were made to local air traffic. The probability of an aircraft crash could increase as a result of the opening of any new airport or heliport in the vicinity; a greater volume of air traffic from McGhee Tyson airport in Knoxville, should the airport status change from feeder airport to hub airport; the rerouting of commercial and/or military flights at the McGhee Tyson airport; and finally, a change in direction or the addition of a federal airway. At one time, DOE planned to establish a zone of prohibited airspace over the Y-12 plant; if the plans are enacted in the future, the probability of an aircraft crash at the Y-12 plant could decrease. Pilots since have been voluntarily requested not to fly below 3000 feet over the Y-12 plant. Also, the Federal Aviation Administration plans to reroute air traffic in the spring of 1993 on federal airway V16. However, the section of V16 which traverses the three plant sites and five adjoining facilities will not be altered. If this plan is implemented, the air traffic over the Oak Ridge facilities would not be affected significantly, and the probability of an aircraft crash as determined herein would be unchanged.

  13. Spatial Factors Affecting the Frequency of Pedestrian Traffic Crashes: A Systematic Review

    PubMed Central

    Moradi, Ali; Soori, Hamid; Kavousi, Amir; Eshghabadi, Farshid; Jamshidi, Ensiyeh

    2016-01-01

    Context Considering the importance of pedestrian traffic crashes and the role of environmental factors in the frequency of crashes, this paper aimed to review the published evidence and synthesize the results of related studies for the associations between environmental factors and distribution of pedestrian-vehicular traffic crashes. Evidence Acquisition We searched all epidemiological studies from 1966 to 2015 in electronic databases. We found 2,828 studies. Only 15 observational studies out of these studies met the inclusion criteria of the study. The quality of the included studies was assessed using the strengthening the reporting of observational studies in epidemiology (STROBE) checklist. Results A review of the studies showed significant correlations between a large number of spatial variables including student population and the number of schools, population density, traffic volume, roadway density, socio-economic status, number of intersections, and the pedestrian volume and the dependent variable of the frequency of pedestrian traffic crashes. In the studies, some spatial factors that play an important role in determining the frequency of pedestrian traffic crashes, such as facilities for increasing the pedestrians’ safety were ignored. Conclusions It is proposed that the needed research be conducted at national and regional levels in coordination and cooperation with international organizations active in the field of traffic crashes in various parts of the world, especially in Asian, African and Latin American developing countries, where a greater proportion of pedestrian traffic crashes occur. PMID:28144600

  14. Crash Frequency Analysis Using Hurdle Models with Random Effects Considering Short-Term Panel Data.

    PubMed

    Chen, Feng; Ma, Xiaoxiang; Chen, Suren; Yang, Lin

    2016-10-26

    Random effect panel data hurdle models are established to research the daily crash frequency on a mountainous section of highway I-70 in Colorado. Road Weather Information System (RWIS) real-time traffic and weather and road surface conditions are merged into the models incorporating road characteristics. The random effect hurdle negative binomial (REHNB) model is developed to study the daily crash frequency along with three other competing models. The proposed model considers the serial correlation of observations, the unbalanced panel-data structure, and dominating zeroes. Based on several statistical tests, the REHNB model is identified as the most appropriate one among four candidate models for a typical mountainous highway. The results show that: (1) the presence of over-dispersion in the short-term crash frequency data is due to both excess zeros and unobserved heterogeneity in the crash data; and (2) the REHNB model is suitable for this type of data. Moreover, time-varying variables including weather conditions, road surface conditions and traffic conditions are found to play importation roles in crash frequency. Besides the methodological advancements, the proposed technology bears great potential for engineering applications to develop short-term crash frequency models by utilizing detailed data from field monitoring data such as RWIS, which is becoming more accessible around the world.

  15. Crash Frequency Analysis Using Hurdle Models with Random Effects Considering Short-Term Panel Data

    PubMed Central

    Chen, Feng; Ma, Xiaoxiang; Chen, Suren; Yang, Lin

    2016-01-01

    Random effect panel data hurdle models are established to research the daily crash frequency on a mountainous section of highway I-70 in Colorado. Road Weather Information System (RWIS) real-time traffic and weather and road surface conditions are merged into the models incorporating road characteristics. The random effect hurdle negative binomial (REHNB) model is developed to study the daily crash frequency along with three other competing models. The proposed model considers the serial correlation of observations, the unbalanced panel-data structure, and dominating zeroes. Based on several statistical tests, the REHNB model is identified as the most appropriate one among four candidate models for a typical mountainous highway. The results show that: (1) the presence of over-dispersion in the short-term crash frequency data is due to both excess zeros and unobserved heterogeneity in the crash data; and (2) the REHNB model is suitable for this type of data. Moreover, time-varying variables including weather conditions, road surface conditions and traffic conditions are found to play importation roles in crash frequency. Besides the methodological advancements, the proposed technology bears great potential for engineering applications to develop short-term crash frequency models by utilizing detailed data from field monitoring data such as RWIS, which is becoming more accessible around the world. PMID:27792209

  16. Crash Simulation of a Vertical Drop Test of a Commuter-Class Aircraft

    NASA Technical Reports Server (NTRS)

    Jackson, Karen E.; Fasanella, Edwin L.

    2004-01-01

    A finite element model of an ATR42-300 commuter-class aircraft was developed and a crash simulation was executed. Analytical predictions were correlated with data obtained from a 30-ft/s (9.14-m/s) vertical drop test of the aircraft. The purpose of the test was to evaluate the structural response of the aircraft when subjected to a severe, but survivable, impact. The aircraft was configured with seats, dummies, luggage, and other ballast. The wings were filled with 8,700 lb. (3,946 kg) of water to represent the fuel. The finite element model, which consisted of 57,643 nodes and 62,979 elements, was developed from direct measurements of the airframe geometry. The seats, dummies, luggage, fuel, and other ballast were represented using concentrated masses. The model was executed in LS-DYNA, a commercial code for performing explicit transient dynamic simulations. Predictions of structural deformation and selected time-history responses were generated. The simulation was successfully validated through extensive test-analysis correlation.

  17. Occupant injury and fatality in general aviation aircraft for which dynamic crash testing is certification-mandated.

    PubMed

    Boyd, Douglas D

    2015-06-01

    Towards further improving general aviation aircraft crashworthiness, multi-axis dynamic tests have been required for aircraft certification (14CFR23.562) since 1985. The objective of this study was to determine if occupants in aircraft certified to these higher crashworthiness standards show a mitigated fraction of fatal accidents and/or injury severity. The NTSB aviation database was queried for accidents occurring between 2002 and 2012 involving aircraft certified to, or immune from, dynamic crash testing and manufactured after 1999. Only operations conducted under 14CFR Part 91 were considered. Statistical analysis employed proportion tests and logistic regression. Off-airport landings are associated with high decelerative forces; however for off-airport landings, the fraction of fatal accidents for aircraft subject to, or exempt from, dynamic crash testing was similar (0.53 and 0.60, respectively). Unexpectedly, for on-airport landings a higher fraction of fatalities was evident for aircraft whose certification mandated dynamic crash testing. Improved crashworthiness standards would be expected to translate into a reduced severity of accident injuries. For all accidents, as well as for those deemed survivable, the fraction of minor and serious injuries was reduced for occupants in aircraft certified to the higher crashworthiness standards. Surprisingly, the fraction of occupants fatally injured was not decreased for aircraft subject to dynamic crash tests. To shed light on this unexpected finding flight history, airman demographics and post-impact fires for aircraft for which dynamic crash testing is mandatory or exempt was examined. For the former cohort the median distance of the accident flight was nearly 44% higher. Aircraft subject to dynamic crash testing were also involved in a greater fraction (0.25 versus 0.12, respectively) of post-impact fires. Our data suggest that while the more stringent crashworthiness standards have mitigated minor and serious

  18. Safety Analysis of Dual Purpose Metal Cask Subjected to Impulsive Loads due to Aircraft Engine Crash

    NASA Astrophysics Data System (ADS)

    Shirai, Koji; Namba, Kosuke; Saegusa, Toshiari

    In Japan, the first Interim Storage Facility of spent nuclear fuel away from reactor site is being planned to start its commercial operation around 2010, in use of dual-purpose metal cask in the northern part of Main Japan Island. Business License Examination for safety design approval has started since March, 2007. To demonstrate the more scientific and rational performance of safety regulation activities on each phase for the first license procedure, CREPEI has executed demonstration tests with full scale casks, such as drop tests onto real targets without impact limiters(1) and seismic tests subjected to strong earthquake motions(2). Moreover, it is important to develop the knowledge for the inherent security of metal casks under extreme mechanical-impact conditions, especially for increasing interest since the terrorist attacks from 11th September 2001(3)-(6). This paper presents dynamic mechanical behavior of the metal cask lid closure system caused by direct aircraft engine crash and describes calculated results (especially, leak tightness based on relative dynamic displacements between metallic seals). Firstly, the local penetration damage of the interim storage facility building by a big passenger aircraft engine crash (diameter 2.7m, length 4.3m, weight 4.4ton, impact velocity 90m/s) has been examined. The reduced velocity is calculated by the local damage formula for concrete structure with its thickness of 70cm. The load vs. time function for this reduced velocity (60m/s) is estimated by the impact analysis using Finite Element code LS-DYNA with the full scale engine model onto a hypothetically rigid target. Secondly, as the most critical scenarios for the metal cask, two impact scenarios (horizontal impact hitting the cask and vertical impact onto the lid metallic seal system) are chosen. To consider the geometry of all bolts for two lids, the gasket reaction forces and the inner pressure of the cask cavity, the detailed three dimensional FEM models are

  19. Crash Testing and Simulation of a Cessna 172 Aircraft: Hard Landing Onto Concrete

    NASA Technical Reports Server (NTRS)

    Jackson, Karen E.; Fasanella, Edwin L.

    2016-01-01

    A full-scale crash test of a Cessna 172 aircraft was conducted at the Landing and Impact Research Facility at NASA Langley Research Center during the summer of 2015. The purpose of the test was to evaluate the performance of Emergency Locator Transmitters (ELTs) that were mounted at various locations in the aircraft and to generate impact test data for model validation. A finite element model of the aircraft was developed for execution in LSDYNA to simulate the test. Measured impact conditions were 722.4-in/s forward velocity and 276-in/s vertical velocity with a 1.5deg pitch (nose up) attitude. These conditions were intended to represent a survivable hard landing. The impact surface was concrete. During the test, the nose gear tire impacted the concrete, followed closely by impact of the main gear tires. The main landing gear spread outward, as the nose gear stroked vertically. The only fuselage contact with the impact surface was a slight impact of the rearmost portion of the lower tail. Thus, capturing the behavior of the nose and main landing gear was essential to accurately predict the response. This paper describes the model development and presents test-analysis comparisons in three categories: inertial properties, time sequence of events, and acceleration and velocity time-histories.

  20. Predicting expressway crash frequency using a random effect negative binomial model: A case study in China.

    PubMed

    Ma, Zhuanglin; Zhang, Honglu; Chien, Steven I-Jy; Wang, Jin; Dong, Chunjiao

    2017-01-01

    To investigate the relationship between crash frequency and potential influence factors, the accident data for events occurring on a 50km long expressway in China, including 567 crash records (2006-2008), were collected and analyzed. Both the fixed-length and the homogeneous longitudinal grade methods were applied to divide the study expressway section into segments. A negative binomial (NB) model and a random effect negative binomial (RENB) model were developed to predict crash frequency. The parameters of both models were determined using the maximum likelihood (ML) method, and the mixed stepwise procedure was applied to examine the significance of explanatory variables. Three explanatory variables, including longitudinal grade, road width, and ratio of longitudinal grade and curve radius (RGR), were found as significantly affecting crash frequency. The marginal effects of significant explanatory variables to the crash frequency were analyzed. The model performance was determined by the relative prediction error and the cumulative standardized residual. The results show that the RENB model outperforms the NB model. It was also found that the model performance with the fixed-length segment method is superior to that with the homogeneous longitudinal grade segment method.

  1. Heat shields for aircraft - A new concept to save lives in crash fires.

    NASA Technical Reports Server (NTRS)

    Neel, C. B.; Parker, J. A.; Fish, R. H.; Henshaw, J.; Newland, J. H.; Tempesta, F. L.

    1971-01-01

    A passenger compartment surrounded by a fire-retardant shell, to protect the occupants long enough for the fire to burn out or for fire-fighting equipment to reach the aircraft and extinguish it, is proposed as a new concept for saving lives in crash fires. This concept is made possible by the recent development of two new fire-retardant materials: a very lightweight foam plastic, called polyisocyanurate foam, and an intumescent paint. Exposed to heat, the intumescent paint expands to many times its original thickness and insulates the surface underneath it. Demonstration tests are illustrated, described and discussed. However, some problems, such as preventing fuselage rupture and protecting windows, must be solved before such a system can be used.

  2. Dynamics and biases of online attention: the case of aircraft crashes

    PubMed Central

    García-Gavilanes, Ruth; Tsvetkova, Milena

    2016-01-01

    The Internet not only has changed the dynamics of our collective attention but also through the transactional log of online activities, provides us with the opportunity to study attention dynamics at scale. In this paper, we particularly study attention to aircraft incidents and accidents using Wikipedia transactional data in two different language editions, English and Spanish. We study both the editorial activities on and the viewership of the articles about airline crashes. We analyse how the level of attention is influenced by different parameters such as number of deaths, airline region, and event locale and date. We find evidence that the attention given by Wikipedia editors to pre-Wikipedia aircraft incidents and accidents depends on the region of the airline for both English and Spanish editions. North American airline companies receive more prompt coverage in English Wikipedia. We also observe that the attention given by Wikipedia visitors is influenced by the airline region but only for events with a high number of deaths. Finally we show that the rate and time span of the decay of attention is independent of the number of deaths and a fast decay within about a week seems to be universal. We discuss the implications of these findings in the context of attention bias. PMID:27853560

  3. Dynamics and biases of online attention: the case of aircraft crashes.

    PubMed

    García-Gavilanes, Ruth; Tsvetkova, Milena; Yasseri, Taha

    2016-10-01

    The Internet not only has changed the dynamics of our collective attention but also through the transactional log of online activities, provides us with the opportunity to study attention dynamics at scale. In this paper, we particularly study attention to aircraft incidents and accidents using Wikipedia transactional data in two different language editions, English and Spanish. We study both the editorial activities on and the viewership of the articles about airline crashes. We analyse how the level of attention is influenced by different parameters such as number of deaths, airline region, and event locale and date. We find evidence that the attention given by Wikipedia editors to pre-Wikipedia aircraft incidents and accidents depends on the region of the airline for both English and Spanish editions. North American airline companies receive more prompt coverage in English Wikipedia. We also observe that the attention given by Wikipedia visitors is influenced by the airline region but only for events with a high number of deaths. Finally we show that the rate and time span of the decay of attention is independent of the number of deaths and a fast decay within about a week seems to be universal. We discuss the implications of these findings in the context of attention bias.

  4. Dynamics and biases of online attention: the case of aircraft crashes

    NASA Astrophysics Data System (ADS)

    García-Gavilanes, Ruth; Tsvetkova, Milena; Yasseri, Taha

    2016-10-01

    The Internet not only has changed the dynamics of our collective attention but also through the transactional log of online activities, provides us with the opportunity to study attention dynamics at scale. In this paper, we particularly study attention to aircraft incidents and accidents using Wikipedia transactional data in two different language editions, English and Spanish. We study both the editorial activities on and the viewership of the articles about airline crashes. We analyse how the level of attention is influenced by different parameters such as number of deaths, airline region, and event locale and date. We find evidence that the attention given by Wikipedia editors to pre-Wikipedia aircraft incidents and accidents depends on the region of the airline for both English and Spanish editions. North American airline companies receive more prompt coverage in English Wikipedia. We also observe that the attention given by Wikipedia visitors is influenced by the airline region but only for events with a high number of deaths. Finally we show that the rate and time span of the decay of attention is independent of the number of deaths and a fast decay within about a week seems to be universal. We discuss the implications of these findings in the context of attention bias.

  5. Behavior of composite/metal aircraft structural elements and components under crash type loads: What are they telling us

    NASA Technical Reports Server (NTRS)

    Carden, Huey D.; Boitnott, Richard L.; Fasanella, Edwin L.

    1990-01-01

    Failure behavior results are presented from crash dynamics research using concepts of aircraft elements and substructure not necessarily designed or optimized for energy absorption or crash loading considerations. To achieve desired new designs which incorporate improved energy absorption capabilities often requires an understanding of how more conventional designs behave under crash loadings. Experimental and analytical data are presented which indicate some general trends in the failure behavior of a class of composite structures which include individual fuselage frames, skeleton subfloors with stringers and floor beams but without skin covering, and subfloors with skin added to the frame-stringer arrangement. Although the behavior is complex, a strong similarity in the static and dynamic failure behavior among these structures is illustrated through photographs of the experimental results and through analytical data of generic composite structural models. It is believed that the similarity in behavior is giving the designer and dynamists much information about what to expect in the crash behavior of these structures and can guide designs for improving the energy absorption and crash behavior of such structures.

  6. Behavior of composite/metal aircraft structural elements and components under crash type loads - What are they telling us?

    NASA Technical Reports Server (NTRS)

    Carden, Huey D.; Boitnott, Richard L.; Fasanella, Edwin L.

    1990-01-01

    Failure behavior results are presented from crash dynamics research using concepts of aircraft elements and substructure not necessarily designed or optimized for energy absorption or crash loading considerations. To achieve desired new designs which incorporate improved energy absorption capabilities often requires an understanding of how more conventional designs behave under crash loadings. Experimental and analytical data are presented which indicate some general trends in the failure behavior of a class of composite structures which include individual fuselage frames, skeleton subfloors with stringers and floor beams but without skin covering, and subfloors with skin added to the frame-stringer arrangement. Although the behavior is complex, a strong similarity in the static and dynamic failure behavior among these structures is illustrated through photographs of the experimental results and through analytical data of generic composite structural models. It is believed that the similarity in behavior is giving the designer and dynamists much information about what to expect in the crash behavior of these structures and can guide designs for improving the energy absorption and crash behavior of such structures.

  7. Accident-precipitating factors for crashes in turbine-powered general aviation aircraft.

    PubMed

    Boyd, Douglas D; Stolzer, Alan

    2016-01-01

    General aviation (14CFR Part 91) accounts for 83% of civil aviation fatalities. While much research has focused on accident causes/pilot demographics in this aviation sector, studies to identify factors leading up to the crash (accident-precipitating factors) are few. Such information could inform on pre-emptive remedial action. With this in mind and considering the paucity of research on turbine-powered aircraft accidents the study objectives were to identify accident-precipitating factors and determine if the accident rate has changed over time for such aircraft operating under 14CFR Part 91. The NTSB Access database was queried for accidents in airplanes (<12,501lb) powered by 1-2 turbine engines and occurring between 1989 and 2013. We developed and utilized an accident-precipitating factor taxonomy. Statistical analyses employed logistic regression, contingency tables and a generalized linear model with Poisson distribution. The "Checklist/Flight Manual Not Followed" was the most frequent accident-precipitating factor category and carried an excess risk (OR 2.34) for an accident with a fatal and/or serious occupant injury. This elevated risk reflected an over-representation of accidents with fatal and/or serious injury outcomes (p<0.001) in the "non-adherence to V Speeds" sub-category. For accidents grouped in the "Inadequate Pre-Flight Planning/Inspection/Procedure" the "inadequate weather planning" sub-category accounted (p=0.036) for the elevated risk (OR 2.22) of an accident involving fatal and/or serious injuries. The "Violation FARs/AIM Deviation" category was also associated with a greater risk for fatal and/or serious injury (OR 2.59) with "Descent below the MDA/failure to execute the missed approach" representing the largest sub-category. Accidents in multi-engine aircraft are more frequent than their single engine counterparts and the decline (50%) in the turbine aircraft accident rate over the study period was likely due, in part, to a 6-fold

  8. A method to account for and estimate underreporting in crash frequency research.

    PubMed

    Wood, Jonathan S; Donnell, Eric T; Fariss, Christopher J

    2016-10-01

    Underreporting is a well-known issue in crash frequency research. However, statistical methods that can account for underreporting have received little attention in the published literature. This paper compares results from underreporting models to models that account for unobserved heterogeneity. The difference in the elasticities between the negative binomial underreporting model and random parameters negative binomial models, which accounts for unobserved heterogeneity in crash frequency models, are used as the basis for comparison. The paper also includes a comparison of the predicted number of unreported PDO crashes based on the negative binomial underreporting model with crashes that were reported to police but were not considered reportable to PennDOT to assess the ability of the underreporting models to predict non-reportable crashes. The data used in this study included 21,340 segments of two-lane rural highways that are owned and maintained by PennDOT. Reported accident frequencies over an eight year period (2005-2012) were included in the sample, producing a total of 170,468 segment-years of data. The results indicate that if a variable impacts both the true accident frequency and the probability of accidents being reported, statistical modeling methods that ignore underreporting produce biased regression coefficients. The magnitude of the bias in the present study (based on elasticities) ranged from 0.00-16.79%. If the variable affects the true accident frequency, but not the probability of accidents being reported, the results from the negative binomial underreporting models are consistent with analysis methods that do not account for underreporting.

  9. Crash Test of Three Cessna 172 Aircraft at NASA Langley Research Center's Landing and Impact Research Facility

    NASA Technical Reports Server (NTRS)

    Littell, Justin D.

    2015-01-01

    During the summer of 2015, three Cessna 172 aircraft were crash tested at the Landing and Impact Research Facility (LandIR) at NASA Langley Research Center (LaRC). The three tests simulated three different crash scenarios. The first simulated a flare-to-stall emergency or hard landing onto a rigid surface such as a road or runway, the second simulated a controlled flight into terrain with a nose down pitch on the aircraft, and the third simulated a controlled flight into terrain with an attempt to unsuccessfully recover the aircraft immediately prior to impact, resulting in a tail strike condition. An on-board data acquisition system captured 64 channels of airframe acceleration, along with acceleration and load in two onboard Hybrid II 50th percentile Anthropomorphic Test Devices, representing the pilot and co-pilot. Each test contained different airframe loading conditions and results show large differences in airframe performance. This paper presents test methods used to conduct the crash tests and will summarize the airframe results from the test series.

  10. Frequency of encounter of aircraft in a random horizontal field

    NASA Technical Reports Server (NTRS)

    Bird, J. D.; Smith, K. A.

    1976-01-01

    Calculations were made of the frequency of encounter as a function of azimuth of encounter of a passing aircraft with the aircraft in a random planar horizontal field. All the field aircraft moved at a constant speed but in random directions. These calculations included the total frequency of encounter with the aircraft of the field and the frequency of encounter with those aircraft of the field which were encountered in the fore quadrant, in the lateral quadrants, and in the rear quadrant; the calculations were made for various speed ratios of the field aircraft and the passing aircraft.

  11. Random parameter models of interstate crash frequencies by severity, number of vehicles involved, collision and location type.

    PubMed

    Venkataraman, Narayan; Ulfarsson, Gudmundur F; Shankar, Venky N

    2013-10-01

    A nine-year (1999-2007) continuous panel of crash histories on interstates in Washington State, USA, was used to estimate random parameter negative binomial (RPNB) models for various aggregations of crashes. A total of 21 different models were assessed in terms of four ways to aggregate crashes, by: (a) severity, (b) number of vehicles involved, (c) crash type, and by (d) location characteristics. The models within these aggregations include specifications for all severities (property damage only, possible injury, evident injury, disabling injury, and fatality), number of vehicles involved (one-vehicle to five-or-more-vehicle), crash type (sideswipe, same direction, overturn, head-on, fixed object, rear-end, and other), and location types (urban interchange, rural interchange, urban non-interchange, rural non-interchange). A total of 1153 directional road segments comprising of the seven Washington State interstates were analyzed, yielding statistical models of crash frequency based on 10,377 observations. These results suggest that in general there was a significant improvement in log-likelihood when using RPNB compared to a fixed parameter negative binomial baseline model. Heterogeneity effects are most noticeable for lighting type, road curvature, and traffic volume (ADT). Median lighting or right-side lighting are linked to increased crash frequencies in many models for more than half of the road segments compared to both-sides lighting. Both-sides lighting thereby appears to generally lead to a safety improvement. Traffic volume has a random parameter but the effect is always toward increasing crash frequencies as expected. However that the effect is random shows that the effect of traffic volume on crash frequency is complex and varies by road segment. The number of lanes has a random parameter effect only in the interchange type models. The results show that road segment-specific insights into crash frequency occurrence can lead to improved design policy and

  12. Estimation of rear-end vehicle crash frequencies in urban road tunnels.

    PubMed

    Meng, Qiang; Qu, Xiaobo

    2012-09-01

    According to The Handbook of Tunnel Fire Safety, over 90% (55 out of 61 cases) of fires in road tunnels are caused by vehicle crashes (especially rear-end crashes). It is thus important to develop a proper methodology that is able to estimate the rear-end vehicle crash frequency in road tunnels. In this paper, we first analyze the time to collision (TTC) data collected from two road tunnels of Singapore and conclude that Inverse Gaussian distribution is the best-fitted distribution to the TTC data. An Inverse Gaussian regression model is hence used to establish the relationship between the TTC and its contributing factors. We then proceed to introduce a new concept of exposure to traffic conflicts as the mean sojourn time in a given time period that vehicles are exposed to dangerous scenarios, namely, the TTC is lower than a predetermined threshold value. We further establish the relationship between the proposed exposure to traffic conflicts and crash count by using negative binomial regression models. Based on the limited data samples used in this study, the negative binomial regression models perform well although a further study using more data is needed.

  13. Technical Seminar: "Crash Safety"""

    NASA Video Gallery

    This seminar addresses the history and successful progress in predicting and improving the crash safety characteristics of vehicles, with particular emphasis on rotary wing aircraft and composite s...

  14. Non-invasive examination of a skull fragment recovered from a World War Two aircraft crash site.

    PubMed

    Gapert, René; Rieder, Kurt

    2013-09-01

    The discovery of human remains dating to the time of the Second World War is a common occurrence in Europe and the Pacific regions. This case report demonstrates the analysis of a bone fragment recovered from a Luftwaffe crash site in Austria during the summer of 2007. Eye-witness statements and official reports were used to reconstruct the historical background of the case. A recovered German military identity tag helped to identify the pilot. Aircraft parts, also discovered at the crash site in 2007, aided the identification of the aircraft type and corroborated the eye-witness reports of the final moments before and during the crash. The bone was analyzed chiefly to establish its human or non-human origin and to identify from which anatomic region the fragment could have arisen. It was identified as part of a human adult skull which exhibited peri-mortem fractures and heat damage as well as post-mortem vegetation staining. The historical background information in connection with the morphological analysis led to the presumptive identification of the cranial fragment as belonging to a downed German pilot.

  15. Effect of crash pulse shape on seat stroke requirements for limiting loads on occupants of aircraft

    NASA Technical Reports Server (NTRS)

    Carden, Huey D.

    1992-01-01

    An analytical study was made to provide comparative information on various crash pulse shapes that potentially could be used to test seats under conditions included in Federal Regulations Part 23 Paragraph 23.562(b)(1) for dynamic testing of general aviation seats, show the effects that crash pulse shape can have on the seat stroke requirements necessary to maintain a specified limit loading on the seat/occupant during crash pulse loadings, compare results from certain analytical model pulses with approximations of actual crash pulses, and compare analytical seat results with experimental airplace crash data. Structural and seat/occupant displacement equations in terms of the maximum deceleration, velocity change, limit seat pan load, and pulse time for five potentially useful pulse shapes were derived; from these, analytical seat stroke data were obtained for conditions as specified in Federal Regulations Part 23 Paragraph 23.562(b)(1) for dynamic testing of general aviation seats.

  16. Excavation of a Vietnam-era aircraft crash site: use of cross-cultural understanding and dual forensic recovery methods.

    PubMed

    Webster, A D

    1998-03-01

    The excavation of a 23 year-old aircraft crash site in the Socialist Republic of Vietnam and the transformational processes preceding its excavation in 1995-1996 are detailed. The history of the site involved an initial catastrophic event, with subsequent reclamation and disturbances. Ultimately, a recovery effort by a joint U.S. team from the Central Identification Laboratory, Hawaii (CILHI). Joint Task Force-Full Accounting (JTF-FA) and a Socialist Republic of Vietnam contingent yielded numerous human remains, personal effects, and life-support items from the crash site. This case study should be of interest to the increasing number of forensic anthropologists who carry out work in international contexts. The application of forensic anthropology in human rights abuse cases, for example in Rwanda, Argentina, and Bosnia, provide examples of such cross-cultural endeavors. Cultural factors act in the development of a site and should not be overlooked as significant taphonomic agents. The approach that an indigenous person takes to a crash site or mass grave may be quite different from our own approach, involving Western science. Holland, Anderson, and Mann (I) describe the postmortem alternation of exhumed and/or curated bone caused by indigenous South-east Asian peoples; the examples provided by these authors demonstrate how culture affects the treatment of what we would call "evidence." The international nature of an incident can add complicating "filters" to the reconstruction of events, since reclamation responses by indigenous people vary according to their interpretations of the scene. An investigating forensic anthropologist needs to understand the emic viewpoint (the insider's view), as cultural anthropologists do, when attempting to recover and reconstruct such an incident. In response to the cultural (and natural) taphonomic agents at work on such a site, the use of dual forensic recovery methods--simultaneously treating the investigation scene like an

  17. Differences in passenger car and large truck involved crash frequencies at urban signalized intersections: an exploratory analysis.

    PubMed

    Dong, Chunjiao; Clarke, David B; Richards, Stephen H; Huang, Baoshan

    2014-01-01

    The influence of intersection features on safety has been examined extensively because intersections experience a relatively large proportion of motor vehicle conflicts and crashes. Although there are distinct differences between passenger cars and large trucks-size, operating characteristics, dimensions, and weight-modeling crash counts across vehicle types is rarely addressed. This paper develops and presents a multivariate regression model of crash frequencies by collision vehicle type using crash data for urban signalized intersections in Tennessee. In addition, the performance of univariate Poisson-lognormal (UVPLN), multivariate Poisson (MVP), and multivariate Poisson-lognormal (MVPLN) regression models in establishing the relationship between crashes, traffic factors, and geometric design of roadway intersections is investigated. Bayesian methods are used to estimate the unknown parameters of these models. The evaluation results suggest that the MVPLN model possesses most of the desirable statistical properties in developing the relationships. Compared to the UVPLN and MVP models, the MVPLN model better identifies significant factors and predicts crash frequencies. The findings suggest that traffic volume, truck percentage, lighting condition, and intersection angle significantly affect intersection safety. Important differences in car, car-truck, and truck crash frequencies with respect to various risk factors were found to exist between models. The paper provides some new or more comprehensive observations that have not been covered in previous studies.

  18. Exploring the effects of roadway characteristics on the frequency and severity of head-on crashes: case studies from Malaysian federal roads.

    PubMed

    Hosseinpour, Mehdi; Yahaya, Ahmad Shukri; Sadullah, Ahmad Farhan

    2014-01-01

    Head-on crashes are among the most severe collision types and of great concern to road safety authorities. Therefore, it justifies more efforts to reduce both the frequency and severity of this collision type. To this end, it is necessary to first identify factors associating with the crash occurrence. This can be done by developing crash prediction models that relate crash outcomes to a set of contributing factors. This study intends to identify the factors affecting both the frequency and severity of head-on crashes that occurred on 448 segments of five federal roads in Malaysia. Data on road characteristics and crash history were collected on the study segments during a 4-year period between 2007 and 2010. The frequency of head-on crashes were fitted by developing and comparing seven count-data models including Poisson, standard negative binomial (NB), random-effect negative binomial, hurdle Poisson, hurdle negative binomial, zero-inflated Poisson, and zero-inflated negative binomial models. To model crash severity, a random-effect generalized ordered probit model (REGOPM) was used given a head-on crash had occurred. With respect to the crash frequency, the random-effect negative binomial (RENB) model was found to outperform the other models according to goodness of fit measures. Based on the results of the model, the variables horizontal curvature, terrain type, heavy-vehicle traffic, and access points were found to be positively related to the frequency of head-on crashes, while posted speed limit and shoulder width decreased the crash frequency. With regard to the crash severity, the results of REGOPM showed that horizontal curvature, paved shoulder width, terrain type, and side friction were associated with more severe crashes, whereas land use, access points, and presence of median reduced the probability of severe crashes. Based on the results of this study, some potential countermeasures were proposed to minimize the risk of head-on crashes.

  19. Decomposing the association between the amount of exposure and the frequency of self-reported involvement in a road crash

    PubMed Central

    Jiménez-Mejías, Eladio; Lardelli-Claret, Pablo; Jiménez-Moleón, José Juan; Amezcua-Prieto, Carmen; Pulido Manzanero, José; Luna-del-Castillo, Juan de Dios

    2013-01-01

    We tried to obtain preliminary evidence to test the hypothesis that the association between driving exposure and the frequency of reporting a road crash can be decomposed into two paths: direct and indirect (mediated by risky driving patterns). In a cross-sectional study carried out between 2007 and 2010, a sample of 1114 car drivers who were students at the University of Granada completed a questionnaire with items about driving exposure during the previous year, risk-related driving circumstances and involvement in road crashes. We applied the decomposition procedure proposed by Buis for logit models. The indirect path showed a strong dose-response relationship with the frequency of reporting a road crash, whereas the direct path did not. The decomposition procedure was able to identify the indirect path as the main explanatory mechanism for the association between exposure and the frequency of reporting a road crash. PMID:23129719

  20. Multivariate random-parameters zero-inflated negative binomial regression model: an application to estimate crash frequencies at intersections.

    PubMed

    Dong, Chunjiao; Clarke, David B; Yan, Xuedong; Khattak, Asad; Huang, Baoshan

    2014-09-01

    Crash data are collected through police reports and integrated with road inventory data for further analysis. Integrated police reports and inventory data yield correlated multivariate data for roadway entities (e.g., segments or intersections). Analysis of such data reveals important relationships that can help focus on high-risk situations and coming up with safety countermeasures. To understand relationships between crash frequencies and associated variables, while taking full advantage of the available data, multivariate random-parameters models are appropriate since they can simultaneously consider the correlation among the specific crash types and account for unobserved heterogeneity. However, a key issue that arises with correlated multivariate data is the number of crash-free samples increases, as crash counts have many categories. In this paper, we describe a multivariate random-parameters zero-inflated negative binomial (MRZINB) regression model for jointly modeling crash counts. The full Bayesian method is employed to estimate the model parameters. Crash frequencies at urban signalized intersections in Tennessee are analyzed. The paper investigates the performance of MZINB and MRZINB regression models in establishing the relationship between crash frequencies, pavement conditions, traffic factors, and geometric design features of roadway intersections. Compared to the MZINB model, the MRZINB model identifies additional statistically significant factors and provides better goodness of fit in developing the relationships. The empirical results show that MRZINB model possesses most of the desirable statistical properties in terms of its ability to accommodate unobserved heterogeneity and excess zero counts in correlated data. Notably, in the random-parameters MZINB model, the estimated parameters vary significantly across intersections for different crash types.

  1. Test-Analysis Correlation of a Crash Simulation of a Vertical Drop Test of a Commuter-Category Aircraft

    NASA Technical Reports Server (NTRS)

    Jackson, Karen E.; Fasanella, Edwin L.

    2004-01-01

    A finite element model of an ATR42-300 commuter-class aircraft was developed and a crash simulation was executed. Analytical predictions were correlated with data obtained from a 30-feet per second (9.14-meters per second) vertical drop test of the aircraft. The purpose of the test was to evaluate the structural response of the aircraft when subjected to a severe, but survivable, impact. The aircraft was configured with seats, dummies, luggage, and other ballast. The wings were filled with 8,700 lb. (3,946 kilograms) of water to represent the fuel. The finite element model, which consisted of 57,643 nodes and 62,979 elements, was developed from direct measurements of the airframe geometry. The seats, dummies, luggage, simulated engines and fuel, and other ballast were represented using concentrated masses. The model was executed in LS-DYNA, a commercial finite element code for performing explicit transient dynamic simulations. Analytical predictions of structural deformation and selected time-history responses were correlated with experimental data from the drop test to validate the simulation.

  2. Full Bayes Poisson gamma, Poisson lognormal, and zero inflated random effects models: Comparing the precision of crash frequency estimates.

    PubMed

    Aguero-Valverde, Jonathan

    2013-01-01

    In recent years, complex statistical modeling approaches have being proposed to handle the unobserved heterogeneity and the excess of zeros frequently found in crash data, including random effects and zero inflated models. This research compares random effects, zero inflated, and zero inflated random effects models using a full Bayes hierarchical approach. The models are compared not just in terms of goodness-of-fit measures but also in terms of precision of posterior crash frequency estimates since the precision of these estimates is vital for ranking of sites for engineering improvement. Fixed-over-time random effects models are also compared to independent-over-time random effects models. For the crash dataset being analyzed, it was found that once the random effects are included in the zero inflated models, the probability of being in the zero state is drastically reduced, and the zero inflated models degenerate to their non zero inflated counterparts. Also by fixing the random effects over time the fit of the models and the precision of the crash frequency estimates are significantly increased. It was found that the rankings of the fixed-over-time random effects models are very consistent among them. In addition, the results show that by fixing the random effects over time, the standard errors of the crash frequency estimates are significantly reduced for the majority of the segments on the top of the ranking.

  3. Modeling work zone crash frequency by quantifying measurement errors in work zone length.

    PubMed

    Yang, Hong; Ozbay, Kaan; Ozturk, Ozgur; Yildirimoglu, Mehmet

    2013-06-01

    Work zones are temporary traffic control zones that can potentially cause safety problems. Maintaining safety, while implementing necessary changes on roadways, is an important challenge traffic engineers and researchers have to confront. In this study, the risk factors in work zone safety evaluation were identified through the estimation of a crash frequency (CF) model. Measurement errors in explanatory variables of a CF model can lead to unreliable estimates of certain parameters. Among these, work zone length raises a major concern in this analysis because it may change as the construction schedule progresses generally without being properly documented. This paper proposes an improved modeling and estimation approach that involves the use of a measurement error (ME) model integrated with the traditional negative binomial (NB) model. The proposed approach was compared with the traditional NB approach. Both models were estimated using a large dataset that consists of 60 work zones in New Jersey. Results showed that the proposed improved approach outperformed the traditional approach in terms of goodness-of-fit statistics. Moreover it is shown that the use of the traditional NB approach in this context can lead to the overestimation of the effect of work zone length on the crash occurrence.

  4. Advanced Techniques in Crash Impact Protection and Emergency Egress from Air Transport Aircraft

    DTIC Science & Technology

    1976-06-01

    research programs related to the development of more fire resistant cabin interior and cabin insulation materials [Kourtides & Parker, 1972 (526)], which...Corporation’s trade name for polyvinylidene fluoride plastic material, and Nomex is the duPont trade name for its high-temperature- resistant nylon, formed...Boeing 727 crash evacuation on 11 Novem- ber, 1965, McFadden constructed several working models of polyethylene (non-flame resistant ) hoods to test

  5. Computer Simulation of an Aircraft Seat and Occupant in a Crash Environment. Volume 1. Technical Report

    DTIC Science & Technology

    1983-03-01

    is the moment N’* which drops to zero after a small angular displacement from the * : initial position, provided that the crash deceleration is suffi...position of the element 55 coordinate system. After the rigid body motion is removed, it is possible to use the classical small deformation finite element... after comple- tion of the solution. 4.1. PROGRAM INPUT Input data are read by the program in the following seven blocks: 1. Simulation and output control

  6. Measurement of the frequency stability of responders in aircraft

    NASA Technical Reports Server (NTRS)

    Liu, Xiaofan

    1994-01-01

    Measurement on an aircraft orbit, such as a satellite launching orbit, is made by the responder in the aircraft along with several remote track stations on the ground. During the launching, the system is required to have precise time synchronization and frequency accuracy. At the same time, accurate measurement of aircraft velocity requires high frequency stability of the system. However, atomic frequency standards in the ground stations supply time and frequency reference standard with excellent long term and short term frequency stability for the above-mentioned goals. The stability of responder is also an important factor affecting the performance of the system and there are more requirements for the corresponding time/frequency measurements. In the system, the responders do not use continuous wave (CW) but narrow pulse modulated wave; consequently, the characterization theory of their stability is more complicated and the measurement technique is more difficult for pulsed wave than that for CW. A systematic characterization theory of the frequency stability for pulsed wave is demonstrated and the measuring methods are discussed. The measurement systems, which have been set up in Beijing Institute of Radio Metrology and Measurement (BIRMM) and can be used to test the frequency stability of pulse coherent responders in time domain and frequency domain with high sensitivity and accuracy, are described. Using these measurement systems, successful measurements for the responders were made with which the satellite launching orbits were precisely obtained and tracked.

  7. AP1000{sup R} design robustness against extreme external events - Seismic, flooding, and aircraft crash

    SciTech Connect

    Pfister, A.; Goossen, C.; Coogler, K.; Gorgemans, J.

    2012-07-01

    Both the International Atomic Energy Agency (IAEA) and the U.S. Nuclear Regulatory Commission (NRC) require existing and new nuclear power plants to conduct plant assessments to demonstrate the unit's ability to withstand external hazards. The events that occurred at the Fukushima-Dai-ichi nuclear power station demonstrated the importance of designing a nuclear power plant with the ability to protect the plant against extreme external hazards. The innovative design of the AP1000{sup R} nuclear power plant provides unparalleled protection against catastrophic external events which can lead to extensive infrastructure damage and place the plant in an extended abnormal situation. The AP1000 plant is an 1100-MWe pressurized water reactor with passive safety features and extensive plant simplifications that enhance construction, operation, maintenance and safety. The plant's compact safety related footprint and protection provided by its robust nuclear island structures prevent significant damage to systems, structures, and components required to safely shutdown the plant and maintain core and spent fuel pool cooling and containment integrity following extreme external events. The AP1000 nuclear power plant has been extensively analyzed and reviewed to demonstrate that it's nuclear island design and plant layout provide protection against both design basis and extreme beyond design basis external hazards such as extreme seismic events, external flooding that exceeds the maximum probable flood limit, and malicious aircraft impact. The AP1000 nuclear power plant uses fail safe passive features to mitigate design basis accidents. The passive safety systems are designed to function without safety-grade support systems (such as AC power, component cooling water, service water, compressed air or HVAC). The plant has been designed to protect systems, structures, and components critical to placing the reactor in a safe shutdown condition within the steel containment vessel

  8. Application of a random effects negative binomial model to examine tram-involved crash frequency on route sections in Melbourne, Australia.

    PubMed

    Naznin, Farhana; Currie, Graham; Logan, David; Sarvi, Majid

    2016-07-01

    Safety is a key concern in the design, operation and development of light rail systems including trams or streetcars as they impose crash risks on road users in terms of crash frequency and severity. The aim of this study is to identify key traffic, transit and route factors that influence tram-involved crash frequencies along tram route sections in Melbourne. A random effects negative binomial (RENB) regression model was developed to analyze crash frequency data obtained from Yarra Trams, the tram operator in Melbourne. The RENB modelling approach can account for spatial and temporal variations within observation groups in panel count data structures by assuming that group specific effects are randomly distributed across locations. The results identify many significant factors effecting tram-involved crash frequency including tram service frequency (2.71), tram stop spacing (-0.42), tram route section length (0.31), tram signal priority (-0.25), general traffic volume (0.18), tram lane priority (-0.15) and ratio of platform tram stops (-0.09). Findings provide useful insights on route section level tram-involved crashes in an urban tram or streetcar operating environment. The method described represents a useful planning tool for transit agencies hoping to improve safety performance.

  9. Frequency Spectrum for Integration of Unmanned Aircraft

    NASA Technical Reports Server (NTRS)

    Kerczewski, Robert J.; Wilson, Jeffrey D.; Bishop, William D.

    2013-01-01

    The goal of enabling the integration of unmanned aircraft systems (UAS) into the National Airspace System (NAS) in terms of UAS achieving routine access to the NAS has been established as a national goal in the United States. Among a number of technical barriers that must be overcome to meet this goal is the absence of standard, certifiable communications links supplying the control and non-payload communications (CNPC) function, essentially providing the link over which a pilot on the ground can control the unmanned aircraft (UA). The International Civil Aviation Organization (ICAO) has determined that the CNPC link must operate over protected aviation spectrum. Therefore protected aviation spectrum must be allocated for this function, approved through the processes of the International Telecommunications Union Radiocommunication Sector (ITU-R). Work has progressed in the definition of spectrum requirements for CNPC, and a portion of these requirements has been satisfied through new allocations approved at the ITU-R 2012 World Radiocommunication Conference (WRC-12). Additional work is ongoing or planned to satisfy the remaining spectrum requirements and define the specifications for the usage of CNPC spectrum allocations and develop supporting standards. This paper provides an overview of the status of RF spectrum for UAS CNPC. Issues that have been identified and ongoing analysis and research that will be necessary to fulfill spectrum requirements for UAS CNPC will be discussed. The results of this work will provide for the safe integration of UA into the NAS in both the LOS (Line of Sight) and BLOS (Beyond Line of Sight) realms.

  10. Death and injury in aerial spraying: pre-crash, crash, and post-crash prevention strategies.

    PubMed

    Richter, E D; Gordon, M; Halamish, M; Gribetz, B

    1981-01-01

    To prevent crash-related death and injury among spray pilots, a program including pre-crash, crash and post-crash stages of intervention for aircraft, physical environment, and pilots and ground crews was proposed in accordance with a matrix of options derived from road crash epidemiology. In addition to the dangers of fixed obstacles, low-altitude runs, and heavy work schedules, work hazards included combined exposures to noise, vibration, G forces, heat stress, pesticides, and dehydration. Together, these exposures were believed to have produced slight, but crucial decreases in pilot performance, alertness and skill. For aircraft, the major pre-crash measure was cockpit air cooling, with filter technologies to prevent in-flight pesticide exposure. Crash and post-crash design changes to reduce energy transfers to the pilot's body (thermal, kinetic) were the most important recommendations, because absolute prevention of the crash event was unlikely. For the environment, pre-crash recommendations included marking fixed obstacles, such as power and telephone lines, but preferably their elimination. Other measures included drainage pits with sodium hydroxide points to neutralize parathion and prevent dispersion of parathion-containing mists. Pilot pre-crash measures (more fluid intake, biological monitoring--EMG, urinary alkyl phosphate, cholinesterase testing) required special organizational arrangements. Systematic application of options from the foregoing matrix suggest that the high risk of death and injury from aerial spraying is unnecessary.

  11. Aircraft Fault Detection Using Real-Time Frequency Response Estimation

    NASA Technical Reports Server (NTRS)

    Grauer, Jared A.

    2016-01-01

    A real-time method for estimating time-varying aircraft frequency responses from input and output measurements was demonstrated. The Bat-4 subscale airplane was used with NASA Langley Research Center's AirSTAR unmanned aerial flight test facility to conduct flight tests and collect data for dynamic modeling. Orthogonal phase-optimized multisine inputs, summed with pilot stick and pedal inputs, were used to excite the responses. The aircraft was tested in its normal configuration and with emulated failures, which included a stuck left ruddervator and an increased command path latency. No prior knowledge of a dynamic model was used or available for the estimation. The longitudinal short period dynamics were investigated in this work. Time-varying frequency responses and stability margins were tracked well using a 20 second sliding window of data, as compared to a post-flight analysis using output error parameter estimation and a low-order equivalent system model. This method could be used in a real-time fault detection system, or for other applications of dynamic modeling such as real-time verification of stability margins during envelope expansion tests.

  12. General Models for Assessing Hazards Aircraft Pose to Surface Facilities

    SciTech Connect

    G.E. Ragan

    2002-11-18

    This paper derives formulas for estimating the frequency of accidental aircraft crashes into surface facilities. Objects unintentionally dropped from aircraft are also considered. The approach allows the facility to be well within the flight area; inside the flight area, but close to the edge; or completely outside the flight area.

  13. The application of EOQ and lead time crashing cost models in material with limited life time (Case study: CN-235 Aircraft at PT Dirgantara Indonesia)

    NASA Astrophysics Data System (ADS)

    Agustina Hidayat, Yosi; Ria Kasanah, Aprilia; Yudhistira, Titah

    2016-02-01

    PT. Dirgantara Indonesia, one of State Owned Enterprises engaging in the aerospace industry, targets to control 30% of world market for light and medium sized aircraft. One type of the aircrafts produced by PT. DI every year is CN-235. Currently, the cost of material procurement reaches 50% of the total cost of production. Material has a variety of characteristics, one of which is having a lifetime. The demand characteristic of the material with expiration for the CN-235 aircraft is deterministic. PT DI does not have any scientific background for its procurement of raw material policy. In addition, there are two methods of transportation used for delivering materials, i.e. by land and air. Each method has different lead time. Inventory policies used in this research are deterministic and probabilistic. Both deterministic and probabilistic single and multi-item inventory policies have order quantity, time to order, reorder point, and lead time as decision variables. The performance indicator for this research is total inventory cost. Inventory policy using the single item EOQ and considering expiration factor inventory results in a reduction in total costs up to 69.58% and multi item results in a decrease in total costs amounted to 71.16%. Inventory policy proposal using the model of a single item by considering expiration factor and lead time crashing cost results in a decrease in total costs amounted to 71.5% and multi item results in a decrease in total costs amounted to 71.62%. Subsequently, wasted expired materials, with the proposed models have been successfully decreased to 95%.

  14. Frequencies and Flutter Speed Estimation for Damaged Aircraft Wing Using Scaled Equivalent Plate Analysis

    NASA Technical Reports Server (NTRS)

    Krishnamurthy, Thiagarajan

    2010-01-01

    Equivalent plate analysis is often used to replace the computationally expensive finite element analysis in initial design stages or in conceptual design of aircraft wing structures. The equivalent plate model can also be used to design a wind tunnel model to match the stiffness characteristics of the wing box of a full-scale aircraft wing model while satisfying strength-based requirements An equivalent plate analysis technique is presented to predict the static and dynamic response of an aircraft wing with or without damage. First, a geometric scale factor and a dynamic pressure scale factor are defined to relate the stiffness, load and deformation of the equivalent plate to the aircraft wing. A procedure using an optimization technique is presented to create scaled equivalent plate models from the full scale aircraft wing using geometric and dynamic pressure scale factors. The scaled models are constructed by matching the stiffness of the scaled equivalent plate with the scaled aircraft wing stiffness. It is demonstrated that the scaled equivalent plate model can be used to predict the deformation of the aircraft wing accurately. Once the full equivalent plate geometry is obtained, any other scaled equivalent plate geometry can be obtained using the geometric scale factor. Next, an average frequency scale factor is defined as the average ratio of the frequencies of the aircraft wing to the frequencies of the full-scaled equivalent plate. The average frequency scale factor combined with the geometric scale factor is used to predict the frequency response of the aircraft wing from the scaled equivalent plate analysis. A procedure is outlined to estimate the frequency response and the flutter speed of an aircraft wing from the equivalent plate analysis using the frequency scale factor and geometric scale factor. The equivalent plate analysis is demonstrated using an aircraft wing without damage and another with damage. Both of the problems show that the scaled

  15. Development of an LS-DYNA Model of an ATR42-300 Aircraft for Crash Simulation

    NASA Technical Reports Server (NTRS)

    Jackson, Karen E.; Fasanella, Edwin L.

    2004-01-01

    This paper describes the development of an LS-DYNA simulation of a vertical drop test of an ATR42-300 twin-turboprop high-wing commuter-class airplane. A 30-ft/s drop test of this aircraft was performed onto a concrete impact surface at the FAA Technical Center on July 30, 2003. The purpose of the test was to evaluate the structural response of a commuter-class aircraft when subjected to a severe, but survivable, impact. The aircraft was configured with crew and passenger seats, anthropomorphic test dummies, forward and aft luggage, instrumentation, and onboard data acquisition systems. The wings were filled with approximately 8,700 lb. of water to represent the fuel and the aircraft weighed a total of 33,200 lb. The model, which consisted of 57,643 nodes and 62,979 elements, was developed from direct measurements of the airframe geometry, over a period of approximately 8 months. The seats, dummies, luggage, fuel, and other ballast were represented using concentrated masses. Comparisons were made of the structural deformation and failure behavior of the airframe, as well as selected acceleration time history responses.

  16. Aircraft Detection from VHR Images Based on Circle-Frequency Filter and Multilevel Features

    PubMed Central

    Gao, Feng; Li, Bo

    2013-01-01

    Aircraft automatic detection from very high-resolution (VHR) images plays an important role in a wide variety of applications. This paper proposes a novel detector for aircraft detection from very high-resolution (VHR) remote sensing images. To accurately distinguish aircrafts from background, a circle-frequency filter (CF-filter) is used to extract the candidate locations of aircrafts from a large size image. A multi-level feature model is then employed to represent both local appearance and spatial layout of aircrafts by means of Robust Hue Descriptor and Histogram of Oriented Gradients. The experimental results demonstrate the superior performance of the proposed method. PMID:24163637

  17. Nonlinear transient analysis by energy minimization: A theoretical basis for the ACTION computer code. [predicting the response of a lightweight aircraft during a crash

    NASA Technical Reports Server (NTRS)

    Kamat, M. P.

    1980-01-01

    The formulation basis for establishing the static or dynamic equilibrium configurations of finite element models of structures which may behave in the nonlinear range are provided. With both geometric and time independent material nonlinearities included, the development is restricted to simple one and two dimensional finite elements which are regarded as being the basic elements for modeling full aircraft-like structures under crash conditions. Representations of a rigid link and an impenetrable contact plane are added to the deformation model so that any number of nodes of the finite element model may be connected by a rigid link or may contact the plane. Equilibrium configurations are derived as the stationary conditions of a potential function of the generalized nodal variables of the model. Minimization of the nonlinear potential function is achieved by using the best current variable metric update formula for use in unconstrained minimization. Powell's conjugate gradient algorithm, which offers very low storage requirements at some slight increase in the total number of calculations, is the other alternative algorithm to be used for extremely large scale problems.

  18. Aircraft

    DTIC Science & Technology

    2002-01-01

    Company, Washington, DC Boeing Commercial Aircraft Division, Seattle, WA and Long Beach, CA Boeing Military Aircraft and Missile Division, St. Louis, MO and... aircraft ; military fixed-wing aircraft ; rotorcraft (helicopters and tiltrotor aircraft ); and aircraft jet engines. Two companies dominate the commercial... aircraft business, Boeing and Airbus. Four companies dominate the military fixed-wing market, Boeing, Lockheed Martin, BAE Systems, and European

  19. The search and rescue satellite mission - A basis for international cooperation. [in aircraft crash and marine distress

    NASA Technical Reports Server (NTRS)

    Redisch, W. N.; Trudell, B. J.

    1978-01-01

    The use of geostationary and polar-orbiting satellites to monitor and locate signals of the Emergency Locator Transmitter (ELT) and Emergency Position Indicating Radio Beacon (EPIB) of general aviation aircraft and inspected marine vessels respectively is described. The joint U.S. Canada/France SARSAT demonstration program will require a minimum of four minutes of mutual visibility of distress transmitter, local user terminal and satellite to obtain a location by Doppler tracking. The program consisting of placing instrumentation on-board three of the Tiros-N series of NOAA operational satellites is attracting interest also from other countries including the USSR, Norway, Australia, and Japan.

  20. Critical market crashes

    NASA Astrophysics Data System (ADS)

    Sornette, D.

    2003-04-01

    This review presents a general theory of financial crashes and of stock market instabilities that his co-workers and the author have developed over the past seven years. We start by discussing the limitation of standard analyses for characterizing how crashes are special. The study of the frequency distribution of drawdowns, or runs of successive losses shows that large financial crashes are “outliers”: they form a class of their own as can be seen from their statistical signatures. If large financial crashes are “outliers”, they are special and thus require a special explanation, a specific model, a theory of their own. In addition, their special properties may perhaps be used for their prediction. The main mechanisms leading to positive feedbacks, i.e., self-reinforcement, such as imitative behavior and herding between investors are reviewed with many references provided to the relevant literature outside the narrow confine of Physics. Positive feedbacks provide the fuel for the development of speculative bubbles, preparing the instability for a major crash. We demonstrate several detailed mathematical models of speculative bubbles and crashes. A first model posits that the crash hazard drives the market price. The crash hazard may sky-rocket at some times due to the collective behavior of “noise traders”, those who act on little information, even if they think they “know”. A second version inverses the logic and posits that prices drive the crash hazard. Prices may skyrocket at some times again due to the speculative or imitative behavior of investors. According the rational expectation model, this entails automatically a corresponding increase of the probability for a crash. We also review two other models including the competition between imitation and contrarian behavior and between value investors and technical analysts. The most important message is the discovery of robust and universal signatures of the approach to crashes. These precursory

  1. Characterization of the frequency and nature of bleed air contamination events in commercial aircraft.

    PubMed

    Shehadi, M; Jones, B; Hosni, M

    2016-06-01

    Contamination of the bleed air used to pressurize and ventilate aircraft cabins is of concern due to the potential health and safety hazards for passengers and crew. Databases from the Federal Aviation Administration, NASA, and other sources were examined in detail to determine the frequency of bleed air contamination incidents. The frequency was examined on an aircraft model basis with the intent of identifying aircraft make and models with elevated frequencies of contamination events. The reported results herein may help investigators to focus future studies of bleed air contamination incidents on smaller number of aircrafts. Incident frequency was normalized by the number of aircraft, number of flights, and flight hours for each model to account for the large variations in the number of aircraft of different models. The focus of the study was on aircraft models that are currently in service and are used by major airlines in the United States. Incidents examined in this study include those related to smoke, oil odors, fumes, and any symptom that might be related to exposure to such contamination, reported by crew members, between 2007 and 2012, for US-based carriers for domestic flights and all international flights that either originated or terminated in the US. In addition to the reported frequency of incidents for different aircraft models, the analysis attempted to identify propulsion engines and auxiliary power units associated with aircrafts that had higher frequencies of incidents. While substantial variations were found in frequency of incidents, it was found that the contamination events were widely distributed across nearly all common models of aircraft.

  2. Throughput and delay characteristics for a slow-frequency hopped aircraft-to-aircraft packet radio network

    NASA Astrophysics Data System (ADS)

    Harrison, Scott Russell

    1990-03-01

    Current lack of data transfer capability between tactical aircraft results in decreased mission effectiveness or the need to equip every aircraft with all the sensors and data processing equipment to perform each task expected of them. In the Air Force, these developments established the need for aircraft-to-aircraft data communications so that navigation, threat and targeting information could be shared within a flight and so that digital voice communications could also be maintained. Data rates within a flight of fighter aircraft to support these requirements will need to be between 100 and 250 kilobits/second (KBPS) and between 2.4 KBPS and 16 KBPS between the flight and a command and control aircraft. Other sources place the former figure as high as 512 KBPS. To increase the security of these radio channels, against both jamming and intrusion, anti-jam and low probability of interception (LPI) techniques must be used. One method of achieving these capabilities is to use spread spectrum techniques such as frequency hopping. The Air Force is currently concentrating its efforts around the Joint Tactical Information Distribution System (JTIDS).

  3. Aggregate crash prediction models: introducing crash generation concept.

    PubMed

    Naderan, Ali; Shahi, Jalil

    2010-01-01

    Safety conscious planning is a new proactive approach towards understanding crashes. It requires a planning-level decision-support tool to facilitate proactive approach to assessing safety effects of alternative urban planning scenarios. The objective of this research study is to develop a series of aggregate crash prediction models (ACPM) that are consistent with the trip generation step of the conventional four-step demand models. The concept of crash generation models (CGMs) is introduced utilizing trip generation data in a generalized linear regression with the assumption of a negative binomial error structure. The relationship of crash frequencies in traffic analysis zones (TAZ) and number of trips generated by purpose is investigated. This translates into immediate checking of the impact of future trip generations on crash frequencies in comprehensive transportation-planning studies (i.e. ability to forecast crashes at each time-step trips are being forecasted). A good relation was seen between crash frequency and number of trips produced/attracted by purpose per TAZ.

  4. Assessment of aircraft impact possibilities at the Idaho Chemical Processing Plant on the INEL Site

    SciTech Connect

    Lee, L.G.; Mines, J.M.; Webb, B.B.

    1993-08-01

    The concern of this study was the possibility of an aircraft collision with facilities at the Idaho Chemical Processing Plant (ICPP). Two sets of data were combined in calculating the probability of this event. The first was from the Nuclear Regulatory Commission. The Nuclear Regulatory Commission data is used to check the adequacy of nuclear power plant location relative to aircraft crashes. For neighboring airport scenarios, the accepted rate unit is fatal crashes per square mile. For in-flight crash scenarios, a total loss of control crash rate (where the pilot was completely out of control) is used for evaluating nuclear reactors. Numbers were given per linear mile of flight. The other set of data was obtained from the National Transportation Safety Board`s annual review. These data points show higher crash frequencies because crashes in which the pilot maintained some control have not been excluded. By including this data set, the evaluation gained two advantages. First, the data are separated by type of aircraft, which makes frequencies for specific flight paths more meaningful. Second, the data are given year by year over a ten-year time span. Therefore, it is possible to gain a sense of the variability in crash frequencies from one year to another.

  5. DC-link approach to constant-frequency aircraft power

    NASA Technical Reports Server (NTRS)

    Yorksi, D. S.

    1983-01-01

    This paper discusses a hybrid high-power aircraft electrical system that has very difficult and complex operating requirements. Many issues raised in selecting an approach for this application are similar to those that must eventually be addressed for a large all-electric aircraft. The requirements for this specific system are reviewed, a solution for those requirements is proposed, and some explanation is provided for the choice. Because the system requires a substantial amount of 400-Hz power, a dc-link system was selected to provide that power.

  6. DC-link approach to constant-frequency aircraft power

    NASA Astrophysics Data System (ADS)

    Yorksi, D. S.

    1983-06-01

    This paper discusses a hybrid high-power aircraft electrical system that has very difficult and complex operating requirements. Many issues raised in selecting an approach for this application are similar to those that must eventually be addressed for a large all-electric aircraft. The requirements for this specific system are reviewed, a solution for those requirements is proposed, and some explanation is provided for the choice. Because the system requires a substantial amount of 400-Hz power, a dc-link system was selected to provide that power.

  7. Re-visiting crash-speed relationships: A new perspective in crash modelling.

    PubMed

    Imprialou, Maria-Ioanna M; Quddus, Mohammed; Pitfield, David E; Lord, Dominique

    2016-01-01

    Although speed is considered to be one of the main crash contributory factors, research findings are inconsistent. Independent of the robustness of their statistical approaches, crash frequency models typically employ crash data that are aggregated using spatial criteria (e.g., crash counts by link termed as a link-based approach). In this approach, the variability in crashes between links is explained by highly aggregated average measures that may be inappropriate, especially for time-varying variables such as speed and volume. This paper re-examines crash-speed relationships by creating a new crash data aggregation approach that enables improved representation of the road conditions just before crash occurrences. Crashes are aggregated according to the similarity of their pre-crash traffic and geometric conditions, forming an alternative crash count dataset termed as a condition-based approach. Crash-speed relationships are separately developed and compared for both approaches by employing the annual crashes that occurred on the Strategic Road Network of England in 2012. The datasets are modelled by injury severity using multivariate Poisson lognormal regression, with multivariate spatial effects for the link-based model, using a full Bayesian inference approach. The results of the condition-based approach show that high speeds trigger crash frequency. The outcome of the link-based model is the opposite; suggesting that the speed-crash relationship is negative regardless of crash severity. The differences between the results imply that data aggregation is a crucial, yet so far overlooked, methodological element of crash data analyses that may have direct impact on the modelling outcomes.

  8. RFID Transponders' Radio Frequency Emissions in Aircraft Communication and Navigation Radio Bands

    NASA Technical Reports Server (NTRS)

    Nguyen, Truong X.; Ely, Jay J.; Williams, Reuben A.; Koppen, Sandra V.; Salud, Maria Theresa P.

    2006-01-01

    Radiated emissions in aircraft communication and navigation bands are measured from several active radio frequency identification (RFID) tags. The individual tags are different in design and operations. They may also operate in different frequency bands. The process for measuring the emissions is discussed, and includes tag interrogation, reverberation chamber testing, and instrument settings selection. The measurement results are described and compared against aircraft emission limits. In addition, interference path loss for the cargo bays of passenger aircraft is measured. Cargo bay path loss is more appropriate for RFID tags than passenger cabin path loss. The path loss data are reported for several aircraft radio systems on a Boeing 747 and an Airbus A320.

  9. Impact of pavement conditions on crash severity.

    PubMed

    Li, Yingfeng; Liu, Chunxiao; Ding, Liang

    2013-10-01

    Pavement condition has been known as a key factor related to ride quality, but it is less clear how exactly pavement conditions are related to traffic crashes. The researchers used Geographic Information System (GIS) to link Texas Department of Transportation (TxDOT) Crash Record Information System (CRIS) data and Pavement Management Information System (PMIS) data, which provided an opportunity to examine the impact of pavement conditions on traffic crashes in depth. The study analyzed the correlation between several key pavement condition ratings or scores and crash severity based on a large number of crashes in Texas between 2008 and 2009. The results in general suggested that poor pavement condition scores and ratings were associated with proportionally more severe crashes, but very poor pavement conditions were actually associated with less severe crashes. Very good pavement conditions might induce speeding behaviors and therefore could have caused more severe crashes, especially on non-freeway arterials and during favorable driving conditions. In addition, the results showed that the effects of pavement conditions on crash severity were more evident for passenger vehicles than for commercial vehicles. These results provide insights on how pavement conditions may have contributed to crashes, which may be valuable for safety improvement during pavement design and maintenance. Readers should notice that, although the study found statistically significant effects of pavement variables on crash severity, the effects were rather minor in reality as suggested by frequency analyses.

  10. Financial Services Advertising before and after the Crash of 1987.

    ERIC Educational Resources Information Center

    Everett, Stephen E.

    1988-01-01

    Examines institutional changes in advertising before and after the stock market "crash" of 1987 as represented in the "Wall Street Journal." Finds that financial institutions increased the frequency and size of ads after the crash. (RS)

  11. Best Practices for Crash Modeling and Simulation

    NASA Technical Reports Server (NTRS)

    Fasanella, Edwin L.; Jackson, Karen E.

    2002-01-01

    Aviation safety can be greatly enhanced by the expeditious use of computer simulations of crash impact. Unlike automotive impact testing, which is now routine, experimental crash tests of even small aircraft are expensive and complex due to the high cost of the aircraft and the myriad of crash impact conditions that must be considered. Ultimately, the goal is to utilize full-scale crash simulations of aircraft for design evaluation and certification. The objective of this publication is to describe "best practices" for modeling aircraft impact using explicit nonlinear dynamic finite element codes such as LS-DYNA, DYNA3D, and MSC.Dytran. Although "best practices" is somewhat relative, it is hoped that the authors' experience will help others to avoid some of the common pitfalls in modeling that are not documented in one single publication. In addition, a discussion of experimental data analysis, digital filtering, and test-analysis correlation is provided. Finally, some examples of aircraft crash simulations are described in several appendices following the main report.

  12. Crash Types: Markers of Increased Risk of Alcohol-Involved Crashes Among Teen Drivers*

    PubMed Central

    Bingham, C. Raymond; Shope, Jean T.; Parow, Julie E.; Raghunathan, Trivellore E.

    2009-01-01

    Objective: Teens drink/drive less often than adults but are more likely to crash when they do drink/drive. This study identified alcohol-related crash types for which teen drivers were at greater risk compared with adults. Method: Michigan State Police crash records for drivers ages 16-19 (teens) and 45-65 years (adults) who experienced at least one crash from 1989 to 1996 were used to create alcohol crash types consisting of alcohol-related crashes that included specific combinations of other crash characteristics, such as drinking and driving at night (i.e., alcohol/nighttime). These data were combined with data from the 1990 and 1995 National Personal Travel Surveys and the 2001 National Household Travel Survey to estimate rates and rate ratios of alcohol-related crash types based on person-miles driven. Results: Teens were relatively less likely than adults to be involved in alcohol-related crashes but were significantly more likely to be in alcohol-related crashes that included other crash characteristics. Teen males' crash risk was highest when drinking and driving with a passenger, at night, at night with a passenger, and at night on the weekend, and casualties were more likely to result from alcohol-related nighttime crashes. All the highest risk alcohol-related crash types for teen female drinking drivers involved casualties and were most likely to include speeding, passenger presence, and nighttime driving. Conclusions: The frequency with which passengers, nighttime or weekend driving, and speeding occurred in the highest risk alcohol-related crash types for teens suggests that these characteristics should be targeted by policies, programs, and enforcement to reduce teen alcohol-related crash rates. PMID:19515292

  13. Crash Tests of Protective Airplane Floors

    NASA Technical Reports Server (NTRS)

    Carden, H. D.

    1986-01-01

    Energy-absorbing floors reduce structural buckling and impact forces on occupants. 56-page report discusses crash tests of energy-absorbing aircraft floors. Describes test facility and procedures; airplanes, structural modifications, and seats; crash dynamics; floor and seat behavior; and responses of anthropometric dummies seated in airplanes. Also presents plots of accelerations, photographs and diagrams of test facility, and photographs and drawings of airplanes before, during, and after testing.

  14. The optimal control frequency response problem in manual control. [of manned aircraft systems

    NASA Technical Reports Server (NTRS)

    Harrington, W. W.

    1977-01-01

    An optimal control frequency response problem is defined within the context of the optimal pilot model. The problem is designed to specify pilot model control frequencies reflective of important aircraft system properties, such as control feel system dynamics, airframe dynamics, and gust environment, as well as man machine properties, such as task and attention allocation. This is accomplished by determining a bounded set of control frequencies which minimize the total control cost. The bounds are given by zero and the neuromuscular control frequency response for each control actuator. This approach is fully adaptive, i.e., does not depend upon user entered estimates. An algorithm is developed to solve this optimal control frequency response problem. The algorithm is then applied to an attitude hold task for a bare airframe fighter aircraft case with interesting dynamic properties.

  15. Aircraft Survivability. Spring 2009

    DTIC Science & Technology

    2009-01-01

    Surviving an Aircraft Crash with Airbag Restraintsby Thomas Barth Inflatable restraint solutions have improved the survivability of commercial...Surviving an Aircraft Crash with Airbag Restraints by Thomas Barth Transport Aircraft Interiors The AmSafe Aviation Airbag entered service on commercial...all night.” Keithley also noted that, in his early days at BRL, Walt teamed up with a group of like-minded innovators, including Jim Foulk, Roland

  16. Frequency-response identification of XV-15 tilt-rotor aircraft dynamics

    NASA Technical Reports Server (NTRS)

    Tischler, Mark B.

    1987-01-01

    The timely design and development of the next generation of tilt-rotor aircraft (JVX) depend heavily on the in-depth understanding of existing XV-15 dynamics and the availability of fully validated simulation models. Previous studies have considered aircraft and simulation trim characteristics, but analyses of basic flight vehicle dynamics were limited to qualitative pilot evaluation. The present study has the following objectives: documentation and evaluation of XV-15 bare-airframe dynamics; comparison of aircraft and simulation responses; and development of a validated transfer-function description of the XV-15 needed for future studies. A nonparametric frequency-response approach is used which does not depend on assumed model order or structure. Transfer-function representations are subsequently derived which fit the frequency responses in the bandwidth of greatest concern for piloted handling-qualities and control-system applications.

  17. Crash Impact Demonstration. (pt 3/10)

    NASA Technical Reports Server (NTRS)

    1984-01-01

    This clip: Extreme Long shot of impact showing the huge fireball surrounding the airplane. With narration. Background: On December 1st, 1984, a remote controlled 4 engined transport jet took off from Edwards AFB, CA and crashed into a barren patch of nearby desert. This Controlled Impact Demonstration was a joint R&D program by the FAA and NASA. The FAA designed the C.I.D. to underscore results of exhaustive research in two areas of aircraft safety: improved crash protection and reduced post-crash fire hazards.Despite the fact the crash did not go exactly as designed C.I.D.did achieve its primary objectives.The analysis of C.I.D. data continues. The CID's crash wothiness tests were as important to the FAA as the fire safety tests. The crash protection objectives were: 1st: To obtain data on impact forces and their transmission thru the structure to the seats and occupants. 2nd: To evaluate the performance of existing and advanced energy absorbing seats. 3rd :To compare tests used to predict structural behaviour with an actual crash. AMK (anti-misting kerosene) fuel was employed in the test. The FAA has examined AMK's potential for protecting commercial transports from ignition of misted fuels. All research indicated that AMK would be effective in preventing this problem. The C.I.D. was an opportunity to use AMK in a realistic, impact-survivable crash.

  18. Crash Impact Demonstration. (pt 5/10)

    NASA Technical Reports Server (NTRS)

    1984-01-01

    This clip: Wide shot of impact, front/port side showing a large volume of AMK flowing over the fuselage, and the effects on the occupants. With narration. Background: On December 1st, 1984, a remote controlled 4 engined transport jet took off from Edwards AFB, CA and crashed into a barren patch of nearby desert. This Controlled Impact Demonstration was a joint R&D program by the FAA and NASA. The FAA designed the C.I.D. to underscore results of exhaustive research in two areas of aircraft safety: improved crash protection and reduced post-crash fire hazards.Despite the fact the crash did not go exactly as designed C.I.D.did achieve its primary objectives.The analysis of C.I.D. data continues. The CID's crash wothiness tests were as important to the FAA as the fire safety tests. The crash protection objectives were: 1st: To obtain data on impact forces and their transmission thru the structure to the seats and occupants. 2nd: To evaluate the performance of existing and advanced energy absorbing seats. 3rd :To compare tests used to predict structural behaviour with an actual crash. AMK (anti-misting kerosene) fuel was employed in the test. The FAA has examined AMK's potential for protecting commercial transports from ignition of misted fuels. All research indicated that AMK would be effective in preventing this problem. The C.I.D. was an opportunity to use AMK in a realistic, impact-survivable crash.

  19. Crash Impact Demonstration. (pt 6/10)

    NASA Technical Reports Server (NTRS)

    1984-01-01

    This clip: Cockpit interior. Showing the pilot during impact, view forward. With narration. Background: On December 1st, 1984, a remote controlled 4 engined transport jet took off from Edwards AFB, CA and crashed into a barren patch of nearby desert. This Controlled Impact Demonstration was a joint R&D program by the FAA and NASA. The FAA designed the C.I.D. to underscore results of exhaustive research in two areas of aircraft safety: improved crash protection and reduced post-crash fire hazards.Despite the fact the crash did not go exactly as designed C.I.D.did achieve its primary objectives.The analysis of C.I.D. data continues. The CID's crash wothiness tests were as important to the FAA as the fire safety tests. The crash protection objectives were: 1st: To obtain data on impact forces and their transmission thru the structure to the seats and occupants. 2nd: To evaluate the performance of existing and advanced energy absorbing seats. 3rd :To compare tests used to predict structural behaviour with an actual crash. AMK (anti-misting kerosene) fuel was employed in the test. The FAA has examined AMK's potential for protecting commercial transports from ignition of misted fuels. All research indicated that AMK would be effective in preventing this problem. The C.I.D. was an opportunity to use AMK in a realistic, impact-survivable crash.

  20. Crash Impact Demonstration. (pt 4/10)

    NASA Technical Reports Server (NTRS)

    1984-01-01

    This clip: Demonstrates and explains how AMK can 'fail' and then burn. Explains how the 'unlikely' scenario at impact occured. With narration. Background: On December 1st, 1984, a remote controlled 4 engined transport jet took off from Edwards AFB, CA and crashed into a barren patch of nearby desert. This Controlled Impact Demonstration was a joint R&D program by the FAA and NASA. The FAA designed the C.I.D. to underscore results of exhaustive research in two areas of aircraft safety: improved crash protection and reduced post-crash fire hazards.Despite the fact the crash did not go exactly as designed C.I.D.did achieve its primary objectives.The analysis of C.I.D. data continues. The CID's crash wothiness tests were as important to the FAA as the fire safety tests. The crash protection objectives were: 1st: To obtain data on impact forces and their transmission thru the structre to the seats and occupants. 2nd: To evaluate the performance of existing and advanced energy absorbing seats. 3rd :To compare tests used to predict structural behaviour with an actual crash. AMK (anti-misting kerosene) fuel was employed in the test. The FAA has examined AMK's potential for protecting commercial transports from ignition of misted fuels. All research indicated that AMK would be effective in preventing this problem. The C.I.D. was an opportunity to use AMK in a realistic, impact-survivable crash.

  1. Crash Impact Demonstration. (pt 7/10)

    NASA Technical Reports Server (NTRS)

    1984-01-01

    This clip: Montage of several different views thru the duration of impact. With narration. Background: On December 1st, 1984, a remote controlled 4 engined transport jet took off from Edwards AFB, CA and crashed into a barren patch of nearby desert. This Controlled Impact Demonstration was a joint R&D program by the FAA and NASA. The FAA designed the C.I.D. to underscore results of exhaustive research in two areas of aircraft safety: improved crash protection and reduced post-crash fire hazards.Despite the fact the crash did not go exactly as designed C.I.D.did achieve its primary objectives.The analysis of C.I.D. data continues. The CID's crash wothiness tests were as important to the FAA as the fire safety tests. The crash protection objectives were: 1st: To obtain data on impact forces and their transmission thru the structure to the seats and occupants. 2nd: To evaluate the performance of existing and advanced energy absorbing seats. 3rd :To compare tests used to predict structural behaviour with an actual crash. AMK (anti-misting kerosene) fuel was employed in the test. The FAA has examined AMK's potential for protecting commercial transports from ignition of misted fuels. All research indicated that AMK would be effective in preventing this problem. The C.I.D. was an opportunity to use AMK in a realistic, impact-survivable crash.

  2. Crash Impact Demonstration. (pt 10/10)

    NASA Technical Reports Server (NTRS)

    1984-01-01

    This clip: Looking down the length of the plane from high on the tail. The AMK flows over the fuselage toward the camera No narration. Background: On December 1st, 1984, a remote controlled 4 engined transport jet took off from Edwards AFB, CA and crashed into a barren patch of nearby desert. This Controlled Impact Demonstration was a joint R&D program by the FAA and NASA. The FAA designed the C.I.D. to underscore results of exhaustive research in two areas of aircraft safety: improved crash protection and reduced post-crash fire hazards.Despite the fact the crash did not go exactly as designed C.I.D.did achieve its primary objectives.The analysis of C.I.D. data continues. The CID's crash wothiness tests were as important to the FAA as the fire safety tests. The crash protection objectives were: 1st: To obtain data on impact forces and their transmission thru the structure to the seats and occupants. 2nd: To evaluate the performance of existing and advanced energy absorbing seats. 3rd :To compare tests used to predict structural behaviour with an actual crash. AMK (anti-misting kerosene) fuel was employed in the test. The FAA has examined AMK's potential for protecting commercial transports from ignition of misted fuels. All research indicated that AMK would be effective in preventing this problem. The C.I.D. was an opportunity to use AMK in a realistic, impact-survivable crash.

  3. Crash Impact Demonstration. (pt 9/10)

    NASA Technical Reports Server (NTRS)

    1984-01-01

    This clip: Long shot, wide, showing entire impact and fireball in realtime No narration. Background: On December 1st, 1984, a remote controlled 4 engined transport jet took off from Edwards AFB, CA and crashed into a barren patch of nearby desert. This Controlled Impact Demonstration was a joint R&D program by the FAA and NASA. The FAA designed the C.I.D. to underscore results of exhaustive research in two areas of aircraft safety: improved crash protection and reduced post-crash fire hazards.Despite the fact the crash did not go exactly as designed C.I.D.did achieve its primary objectives.The analysis of C.I.D. data continues. The CID's crash wothiness tests were as important to the FAA as the fire safety tests. The crash protection objectives were: 1st: To obtain data on impact forces and their transmission thru the structure to the seats and occupants. 2nd: To evaluate the performance of existing and advanced energy absorbing seats. 3rd :To compare tests used to predict structural behaviour with an actual crash. AMK (anti-misting kerosene) fuel was employed in the test. The FAA has examined AMK's potential for protecting commercial transports from ignition of misted fuels. All research indicated that AMK would be effective in preventing this problem. The C.I.D. was an opportunity to use AMK in a realistic, impact-survivable crash.

  4. Crash Impact Demonstration. (pt 8/10)

    NASA Technical Reports Server (NTRS)

    1984-01-01

    This clip: Montage of high-speed (slow-motion) footage. Various med/wide angles. No narration. Background: On December 1st, 1984, a remote controlled 4 engined transport jet took off from Edwards AFB, CA and crashed into a barren patch of nearby desert. This Controlled Impact Demonstration was a joint R&D program by the FAA and NASA. The FAA designed the C.I.D. to underscore results of exhaustive research in two areas of aircraft safety: improved crash protection and reduced post-crash fire hazards.Despite the fact the crash did not go exactly as designed C.I.D.did achieve its primary objectives.The analysis of C.I.D. data continues. The CID's crash wothiness tests were as important to the FAA as the fire safety tests. The crash protection objectives were: 1st: To obtain data on impact forces and their transmission thru the structure to the seats and occupants. 2nd: To evaluate the performance of existing and advanced energy absorbing seats. 3rd :To compare tests used to predict structural behaviour with an actual crash. AMK (anti-misting kerosene) fuel was employed in the test. The FAA has examined AMK's potential for protecting commercial transports from ignition of misted fuels. All research indicated that AMK would be effective in preventing this problem. The C.I.D. was an opportunity to use AMK in a realistic, impact-survivable crash.

  5. High frequency drive mechanism for an active controls systems aircraft control surface

    NASA Technical Reports Server (NTRS)

    Smith, H. E.

    1981-01-01

    The mechanism was successfully utilized on a wind tunnel model tested in the transonic blow down tunnel. The mechanism is also applicable to a flying aircraft. Several interrelated mechanical subsystems were utilized, including a low inertia antibacklash drive mechanism for high frequency oscillation and a compact antibacklash drive mechanism for conversion of rotary motion to linear motion.

  6. Aircraft on-board SAR processing using a frequency-domain fast correlation technique

    NASA Technical Reports Server (NTRS)

    Liu, Kuang Y.

    1988-01-01

    The design of a frequency-domain fast correlation processor for aircraft onboard synthetic-aperture radar (SAR) applications is described. The design uses the fast Fourier transform (FFT) fast correlation technique to perform both range and azimuth pulse compression functions for the NASA/JPL L-band, quad-polarization airborne SAR. The subject processor is computationally efficient and requires a simple control unit. It is capable of producing single-look, 8-m (slant range) by 10-m (azimuth) resolution, SAR images of a selected polarization over a swath width of up to 15 km in real time onboard the aircraft.

  7. Flight test validation of a frequency-based system identification method on an F-15 aircraft

    NASA Technical Reports Server (NTRS)

    Schkolnik, Gerard S.; Orme, John S.; Hreha, Mark A.

    1995-01-01

    A frequency-based performance identification approach was evaluated using flight data from the NASA F-15 Highly Integrated Digital Electronic Control aircraft. The approach used frequency separation to identify the effectiveness of multiple controls simultaneously as an alternative to independent control identification methods. Fourier transformations converted measured control and response data into frequency domain representations. Performance gradients were formed using multiterm frequency matching of control and response frequency domain models. An objective function was generated using these performance gradients. This function was formally optimized to produce a coordinated control trim set. This algorithm was applied to longitudinal acceleration and evaluated using two control effectors: nozzle throat area and inlet first ramp. Three criteria were investigated to validate the approach: simultaneous gradient identification, gradient frequency dependency, and repeatability. This report describes the flight test results. These data demonstrate that the approach can accurately identify performance gradients during simultaneous control excitation independent of excitation frequency.

  8. Comparison of teen and adult driver crash scenarios in a nationally representative sample of serious crashes.

    PubMed

    McDonald, Catherine C; Curry, Allison E; Kandadai, Venk; Sommers, Marilyn S; Winston, Flaura K

    2014-11-01

    Motor vehicle crashes are the leading cause of death and acquired disability during the first four decades of life. While teen drivers have the highest crash risk, few studies examine the similarities and differences in teen and adult driver crashes. We aimed to: (1) identify and compare the most frequent crash scenarios-integrated information on a vehicle's movement prior to crash, immediate pre-crash event, and crash configuration-for teen and adult drivers involved in serious crashes, and (2) for the most frequent scenarios, explore whether the distribution of driver critical errors differed for teens and adult drivers. We analyzed data from the National Motor Vehicle Crash Causation Survey, a nationally representative study of serious crashes conducted by the U.S. National Highway Traffic Safety Administration from 2005 to 2007. Our sample included 642 16- to 19-year-old and 1167 35- to 54-year-old crash-involved drivers (weighted n=296,482 and 439,356, respectively) who made a critical error that led to their crash's critical pre-crash event (i.e., event that made the crash inevitable). We estimated prevalence ratios (PR) and 95% confidence intervals (CI) to compare the relative frequency of crash scenarios and driver critical errors. The top five crash scenarios among teen drivers, accounting for 37.3% of their crashes, included: (1) going straight, other vehicle stopped, rear end; (2) stopped in traffic lane, turning left at intersection, turn into path of other vehicle; (3) negotiating curve, off right edge of road, right roadside departure; (4) going straight, off right edge of road, right roadside departure; and (5) stopped in lane, turning left at intersection, turn across path of other vehicle. The top five crash scenarios among adult drivers, accounting for 33.9% of their crashes, included the same scenarios as the teen drivers with the exception of scenario (3) and the addition of going straight, crossing over an intersection, and continuing on a

  9. Aircraft

    DOEpatents

    Hibbs, B.D.; Lissaman, P.B.S.; Morgan, W.R.; Radkey, R.L.

    1998-09-22

    This disclosure provides a solar rechargeable aircraft that is inexpensive to produce, is steerable, and can remain airborne almost indefinitely. The preferred aircraft is a span-loaded flying wing, having no fuselage or rudder. Travelling at relatively slow speeds, and having a two-hundred foot wingspan that mounts photovoltaic cells on most all of the wing`s top surface, the aircraft uses only differential thrust of its eight propellers to turn. Each of five sections of the wing has one or more engines and photovoltaic arrays, and produces its own lift independent of the other sections, to avoid loading them. Five two-sided photovoltaic arrays, in all, are mounted on the wing, and receive photovoltaic energy both incident on top of the wing, and which is incident also from below, through a bottom, transparent surface. The aircraft is capable of a top speed of about ninety miles per hour, which enables the aircraft to attain and can continuously maintain altitudes of up to sixty-five thousand feet. Regenerative fuel cells in the wing store excess electricity for use at night, such that the aircraft can sustain its elevation indefinitely. A main spar of the wing doubles as a pressure vessel that houses hydrogen and oxygen gases for use in the regenerative fuel cell. The aircraft has a wide variety of applications, which include weather monitoring and atmospheric testing, communications, surveillance, and other applications as well. 31 figs.

  10. Aircraft

    DOEpatents

    Hibbs, Bart D.; Lissaman, Peter B. S.; Morgan, Walter R.; Radkey, Robert L.

    1998-01-01

    This disclosure provides a solar rechargeable aircraft that is inexpensive to produce, is steerable, and can remain airborne almost indefinitely. The preferred aircraft is a span-loaded flying wing, having no fuselage or rudder. Travelling at relatively slow speeds, and having a two-hundred foot wingspan that mounts photovoltaic cells on most all of the wing's top surface, the aircraft uses only differential thrust of its eight propellers to turn. Each of five sections of the wing has one or more engines and photovoltaic arrays, and produces its own lift independent of the other sections, to avoid loading them. Five two-sided photovoltaic arrays, in all, are mounted on the wing, and receive photovoltaic energy both incident on top of the wing, and which is incident also from below, through a bottom, transparent surface. The aircraft is capable of a top speed of about ninety miles per hour, which enables the aircraft to attain and can continuously maintain altitudes of up to sixty-five thousand feet. Regenerative fuel cells in the wing store excess electricity for use at night, such that the aircraft can sustain its elevation indefinitely. A main spar of the wing doubles as a pressure vessel that houses hydrogen and oxygen gasses for use in the regenerative fuel cell. The aircraft has a wide variety of applications, which include weather monitoring and atmospheric testing, communications, surveillance, and other applications as well.

  11. Effect of motion frequency spectrum on subjective comfort response. [modeling passenger reactions to commercial aircraft flights

    NASA Technical Reports Server (NTRS)

    Jacobson, I. D.; Schoultz, M. B.; Blake, J. C.

    1973-01-01

    In order to model passenger reaction to present and future aircraft environments, it is necessary to obtain data in several ways. First, of course, is the gathering of environmental and passenger reaction data on commercial aircraft flights. In addition, detailed analyses of particular aspects of human reaction to the environment are best studied in a controllable experimental situation. Thus the use of simulators, both flight and ground based, is suggested. It is shown that there is a reasonably high probability that the low frequency end of the spectrum will not be necessary for simulation purposes. That is, the fidelity of any simulation which omits the very low frequency content will not yield results which differ significantly from the real environment. In addition, there does not appear to be significant differences between the responses obtained in the airborne simulator environment versus those obtained on commercial flights.

  12. Overview Of Structural Behavior and Occupant Responses from Crash Test of a Composite Airplane

    NASA Technical Reports Server (NTRS)

    Jones, Lisa E.; Carden, Huey D.

    1995-01-01

    As part of NASA's composite structures crash dynamics research, a general aviation aircraft with composite wing, fuselage and empennage (but with metal subfloor structure) was crash tested at the NASA Langley Research Center Impact Research Facility. The test was conducted to determine composite aircraft structural behavior for crash loading conditions and to provide a baseline for a similar aircraft test with a modified subfloor. Structural integrity and cabin volume were maintained. Lumbar loads for dummy occupants in energy absorbing seats wer substantially lower than those in standard aircraft seats; however, loads in the standard seats were much higher that those recorded under similar conditions for an all-metallic aircraft.

  13. Nonlinear structural crash dynamics analyses

    NASA Technical Reports Server (NTRS)

    Hayduk, R. J.; Thomson, R. G.; Wittlin, G.; Kamat, M. P.

    1979-01-01

    Presented in this paper are the results of three nonlinear computer programs, KRASH, ACTION and DYCAST used to analyze the dynamic response of a twin-engine, low-wing airplane section subjected to a 8.38 m/s (27.5 ft/s) vertical impact velocity crash condition. This impact condition simulates the vertical sink rate in a shallow aircraft landing or takeoff accident. The three distinct analysis techniques for nonlinear dynamic response of aircraft structures are briefly examined and compared versus each other and the experimental data. The report contains brief descriptions of the three computer programs, the respective aircraft section mathematical models, pertinent data from the experimental test performed at NASA Langley, and a comparison of the analyses versus test results. Cost and accuracy comparisons between the three analyses are made to illustrate the possible uses of the different nonlinear programs and their future potential.

  14. Relationship between low-frequency aircraft noise and annoyance due to rattle and vibration.

    PubMed

    Fidell, Sanford; Pearsons, Karl; Silvati, Laura; Sneddon, Matthew

    2002-04-01

    A near-replication of a study of the annoyance of rattle and vibration attributable to aircraft noise [Fidell et al., J. Acoust. Soc. Am. 106, 1408-1415 (1999)] was conducted in the vicinity of Minneapolis-St. Paul International Airport (MSP). The findings of the current study were similar to those reported earlier with respect to the types of objects cited as sources of rattle in homes, frequencies of notice of rattle, and the prevalence of annoyance due to aircraft noise-induced rattle. A reliably lower prevalence rate of annoyance (but not of complaints) with rattle and vibration was noted among respondents living in homes that had been treated to achieve a 5-dB improvement in A-weighted noise reduction than among respondents living in untreated homes. This difference is not due to any substantive increase in low-frequency noise reduction of acoustically treated homes, but may be associated with installation of nonrattling windows. Common interpretations of the prevalence of a consequential degree of annoyance attributable to low-frequency aircraft noise may be developed from the combined results of the present and prior studies.

  15. Sonic IR crack detection of aircraft turbine engine blades with multi-frequency ultrasound excitations

    SciTech Connect

    Zhang, Ding; Han, Xiaoyan; Newaz, Golam

    2014-02-18

    Effectively and accurately detecting cracks or defects in critical engine components, such as turbine engine blades, is very important for aircraft safety. Sonic Infrared (IR) Imaging is such a technology with great potential for these applications. This technology combines ultrasound excitation and IR imaging to identify cracks and flaws in targets. In general, failure of engine components, such as blades, begins with tiny cracks. Since the attenuation of the ultrasound wave propagation in turbine engine blades is small, the efficiency of crack detection in turbine engine blades can be quite high. The authors at Wayne State University have been developing the technology as a reliable tool for the future field use in aircraft engines and engine parts. One part of the development is to use finite element modeling to assist our understanding of effects of different parameters on crack heating while experimentally hard to achieve. The development has been focused with single frequency ultrasound excitation and some results have been presented in a previous conference. We are currently working on multi-frequency excitation models. The study will provide results and insights of the efficiency of different frequency excitation sources to foster the development of the technology for crack detection in aircraft engine components.

  16. Frequency Response of an Aircraft Wing with Discrete Source Damage Using Equivalent Plate Analysis

    NASA Technical Reports Server (NTRS)

    Krishnamurthy, T.; Eldred, Lloyd B.

    2007-01-01

    An equivalent plate procedure is developed to provide a computationally efficient means of matching the stiffness and frequencies of flight vehicle wing structures for prescribed loading conditions. Several new approaches are proposed and studied to match the stiffness and first five natural frequencies of the two reference models with and without damage. One approach divides the candidate reference plate into multiple zones in which stiffness and mass can be varied using a variety of materials including aluminum, graphite-epoxy, and foam-core graphite-epoxy sandwiches. Another approach places point masses along the edge of the stiffness-matched plate to tune the natural frequencies. Both approaches are successful at matching the stiffness and natural frequencies of the reference plates and provide useful insight into determination of crucial features in equivalent plate models of aircraft wing structures.

  17. The expected frequency of collisions of smallmeteorites with cars and aircraft

    NASA Astrophysics Data System (ADS)

    Poveda, A.; Herrera, M. a.; García, J. L.; Hernández-Alcántara, A.; Curioca, K.

    1999-05-01

    The cumulative distribution cf2>Ncf1>(cf2>dcf1>) of diameters of Earth-CrossingAsteroids (ECAs) derived by Poveda et al. ([Poveda et al., 1998], submitted) is used to estimatethe frequency of collisions of meteoroids with cars and with aircraft. The expected frequency ofcollisions of a car with a meteorite larger than 10 cm in diameter turns out to be one impact every16 years. This frequency is consistent with the known incidence of such events ([Lewis, 1996]).The expected frequency of collisions of a cruising airplane with a meteorite larger than 1 cm indiameter turns out to be one impact every 30 years. Such an impactor hitting an airplane at avelocity of several hundreds of meters per second could cause a serious accident. 1999 ElsevierScience Ltd.

  18. New methods to identify and rank high pedestrian crash zones: an illustration.

    PubMed

    Pulugurtha, Srinivas S; Krishnakumar, Vanjeeswaran K; Nambisan, Shashi S

    2007-07-01

    Identifying and ranking high pedestrian crash zones plays a key role in developing efficient and effective strategies to enhance pedestrian safety. This paper presents (1) a Geographical Information Systems (GIS) methodology to study the spatial patterns of pedestrian crashes in order to identify high pedestrian crash zones, and (2) an evaluation of methods to rank these high pedestrian crash zones. The GIS based methodology to identify high pedestrian crash zones includes geocoding crash data, creating crash concentration maps, and then identifying high pedestrian crash zones. Two methods generally used to create crash concentration maps based on density values are the Simple Method and the Kernel Method. Ranking methods such as crash frequency, crash density, and crash rate, as well as composite methods such as the sum-of-the-ranks and the crash score methods are used to rank the selected high pedestrian crash zones. The use of this methodology and ranking methods for high pedestrian crash zones are illustrated using the Las Vegas metropolitan area as the study area. Crash data collected for a 5-year period (1998-2002) were address matched using the street name/reference street name intersection location reference system. A crash concentration map was then created using the Kernel Method as it facilitates the creation of a smooth density surface when compared to the Simple Method. Twenty-two linear high crash zones and seven circular high crash zones were then identified. The GIS based methodology reduced the subjectivity in the analysis process. Results obtained from the evaluation of methods to rank high pedestrian crash zones show a significant variation in ranking when individual methods were considered. However, rankings of high pedestrian crash zones were relatively consistent with little to no variation when the sum-of-the-ranks method and the crash score method were used. Thus, these composite methods are recommended for use in ranking high pedestrian

  19. Aircraft

    DTIC Science & Technology

    2003-01-01

    national power. But with the recent events such as the war with Iraq, the Severe Acute Respiratory Syndrome (SARS) outbreak, some major carriers... TITLE AND SUBTITLE 2003 Industry Studies: Aircraft 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER

  20. Icing Frequencies Experienced During Climb and Descent by Fighter-Interceptor Aircraft

    NASA Technical Reports Server (NTRS)

    Perkins, Porter J.

    1958-01-01

    Data and analyses are presented on the relative frequencies of occurrence and severity of icing cloud layers encountered by jet aircraft in the climb and descent phases of flights to high altitudes. Fighter-interceptor aircraft operated by the Air Defense Command (USAF) at bases in the Duluth and Seattle areas collected the data with icing meters installed for a l-year period. The project was part of an extensive program conducted by the NACA to collect Icing cloud data for evaluating the icing problem relevant to routine operations. The average frequency of occurrence of icing was found to be about 5 percent of the number of climbs and descents during 1 year of operations The icing encounters were predominantly in the low and middle cloud layers, decreasing above 15,000 feet to practically none above 25,000 feet. The greatest thickness of ice that would accumulate on any aircraft component (as indicated by the accretion on a small object) was measured with the icing meters. The ice thicknesses on a small sensing probe averaged less than 1/32 inch and did not exceed 1/2 inch. Such accumulations are relatively small when compared with those that can form during horizontal flight in icing clouds. The light accretions resulted from relatively steep angles of flight through generally thin cloud layers. Because of the limited statistical reliability of the results, an analysis was made using previous statistics on icing clouds below an altitude of 20,000 feet to determine the general icing severity probabilities. The calculations were made using adiabatic lifting as a basis to establish the liquid-water content. Probabilities of over-all ice accretions on a small object as a function of airspeed and rate of climb were computed from the derived water contents. These results were then combined with the probability of occurrence of icing in order to give the icing severity that can be expected for routine aircraft operations.

  1. Optimizing an Actuator Array for the Control of Multi-Frequency Noise in Aircraft Interiors

    NASA Technical Reports Server (NTRS)

    Palumbo, D. L.; Padula, S. L.

    1997-01-01

    Techniques developed for selecting an optimized actuator array for interior noise reduction at a single frequency are extended to the multi-frequency case. Transfer functions for 64 actuators were obtained at 5 frequencies from ground testing the rear section of a fully trimmed DC-9 fuselage. A single loudspeaker facing the left side of the aircraft was the primary source. A combinatorial search procedure (tabu search) was employed to find optimum actuator subsets of from 2 to 16 actuators. Noise reduction predictions derived from the transfer functions were used as a basis for evaluating actuator subsets during optimization. Results indicate that it is necessary to constrain actuator forces during optimization. Unconstrained optimizations selected actuators which require unrealistically large forces. Two methods of constraint are evaluated. It is shown that a fast, but approximate, method yields results equivalent to an accurate, but computationally expensive, method.

  2. Two-frequency /Delta k/ microwave scatterometer measurements of ocean wave spectra from an aircraft

    NASA Technical Reports Server (NTRS)

    Johnson, J. W.; Jones, W. L.; Weissman, D. E.

    1981-01-01

    A technique for remotely sensing the large-scale gravity wave spectrum on the ocean surface using a two frequency (Delta k) microwave scatterometer has been demonstrated from stationary platforms and proposed from moving platforms. This measurement takes advantage of Bragg type resonance matching between the electromagnetic wavelength at the difference frequency and the length of the large-scale surface waves. A prominent resonance appears in the cross product power spectral density (PSD) of the two backscattered signals. Ku-Band aircraft scatterometer measurements were conducted by NASA in the North Sea during the 1979 Maritime Remote Sensing (MARSEN) experiment. Typical examples of cross product PSD's computed from the MARSEN data are presented. They demonstrate strong resonances whose frequency and bandwidth agree with the surface characteristics and the theory. Directional modulation spectra of the surface reflectivity are compared to the gravity wave spectrum derived from surface truth measurements.

  3. Crash Impact Demonstration. (pt 2/10)

    NASA Technical Reports Server (NTRS)

    1984-01-01

    This clip: One of the 'wing cutters' rips through the starboard inboard engine, rupturing fuel lines before tearing open the wing tanks and releasing huge quantities of fuel. The very unlikely then happens With narration. Background: On December 1st, 1984, a remote controlled 4 engined transport jet took off from Edwards AFB, CA and crashed into a barren patch of nearby desert. This Controlled Impact Demonstration was a joint R&D program by the FAA and NASA. The FAA designed the C.I.D. to underscore results of exhaustive research in two areas of aircraft safety: improved crash protection and reduced post-crash fire hazards.Despite the fact the crash did not go exactly as designed C.I.D.did achieve its primary objectives.The analysis of C.I.D. data continues. The CID's crash wothiness tests were as important to the FAA as the fire safety tests. The crash protection objectives were: 1st: To obtain data on impact forces and their transmission thru the structure to the seats and occupants. 2nd: To evaluate the performance of existing and advanced energy absorbing seats. 3rd :To compare tests used to predict structural behaviour with an actual crash. AMK (anti-misting kerosene) fuel was employed in the test. The FAA has examined AMK's potential for protecting commercial transports from ignition of misted fuels. All research indicated that AMK would be effective in preventing this problem. The C.I.D. was an opportunity to use AMK in a realistic, impact-survivable crash.

  4. Crash Impact Demonstration. (pt 1/10)

    NASA Technical Reports Server (NTRS)

    1984-01-01

    This clip: Front view, long shot. The model scenario is gone, as the plane impacts short of the target area and port wing first, skidding to the left. With narration. Background: On December 1st, 1984, a remote controlled 4 engined transport jet took off from Edwards AFB, CA and crashed into a barren patch of nearby desert. This Controlled Impact Demonstration was a joint R&D program by the FAA and NASA. The FAA designed the C.I.D. to underscore results of exhaustive research in two areas of aircraft safety: improved crash protection and reduced post-crash fire hazards.Despite the fact the crash did not go exactly as designed C.I.D.did achieve its primary objectives.The analysis of C.I.D. data continues. The CID's crash wothiness tests were as important to the FAA as the fire safety tests. The crash protection objectives were: 1st: To obtain data on impact forces and their transmission thru the structure to the seats and occupants. 2nd: To evaluate the performance of existing and advanced energy absorbing seats. 3rd :To compare tests used to predict structural behaviour with an actual crash. AMK (anti-misting kerosene) fuel was employed in the test. The FAA has examined AMK's potential for protecting commercial transports from ignition of misted fuels. All research indicated that AMK would be effective in preventing this problem. The C.I.D. was an opportunity to use AMK in a realistic, impact-survivable crash.

  5. Injury Prevention in Aircraft Crashes: Investigative Techniques and Applications (la Prevention des lesions lors des accidents d’ avions: les techniques d’investigation et leurs applications)

    DTIC Science & Technology

    1998-02-01

    approximately parallel to the long axis of the spine. Similarly, a typical finding in light-aircraft accidents involves blunt trauma applied to...produce minor superficial trauma such as bruises and abrasions which do not incapacitate, injurious forces result in moderate to severe trauma ...spleen can occur from blunt trauma to any part of the abdomen. Studies to delineate tolerance levels to non-penetrating abdominal trauma are limited

  6. Crash Rates of Scheduled Commuter and Air Carrier Flights Before and After a Regulatory Change

    PubMed Central

    Baker, Susan P.; Groff, Loren; Haaland, Wren; Qiang, Yandong; Rebok, George W.; Li, Guohua

    2010-01-01

    Introduction In 1997, in an effort to reduce the crash rate of scheduled commuter flights, the FAA required aircraft with 10–30 passenger seats to operate under stricter rules. Training and other requirements of 14 CFR Part 121 rules were applied to these midsize commuters, which previously had operated under the less strict Part 135 rules. Published crash rates obscured changes related to aircraft size. This research was undertaken to determine whether the rule change affected crash rates of aircraft with 10–30 passenger seats. Method We determined the number of passenger seats on each Part 135 or Part 121 aircraft that crashed between 1983 and 2007. For aircraft with < 10, 10–30, and > 30 seats, we estimated the numbers of departures and crash rates, adjusting for changes in total departures and numbers of in-service aircraft. Results The Part 135 crash rate tripled in 1997 when commuters with 10–30 seats were excluded, reflecting the administrative change. However, the crash rate of aircraft with 10–30 passenger seats began to decline 4 yr before the rule change; thereafter, their rate was lower than for larger aircraft. The fleet size of aircraft with 10–30 passenger seats increased from 1983 to 1997, then declined as they were replaced with larger aircraft in response to the rule change. Discussion No effect of the rule change on crash rates of 10–30-seat aircraft was apparent. The decline in their crash rates began before the rule change and may have been related to the 1992 requirement for ground proximity warning devices. PMID:19378909

  7. The Rockne crash. American commercial air crash investigation in the early years.

    PubMed

    Eckert, W G

    1982-03-01

    In midmorning on March 31, 1931, at Bazaar, Kansas (between Kansas City and Wichita), an F-10A air transport of the Transcontinental and Western Airline crashed in bad weather, resulting in the loss of the two crew members and six passengers. This crash brought the sensational news to the American public of the death of Knute Rockne, the lengendary football coach of Notre Dame University. It also focused the public's attention on the hazards of airline travel in America 50 years ago. The response of the Department of Commerce's Committee on aviation Safety, developing since 1926, helped assure the public that a proper investigation into questions of safety of airline transports was made. The response to the crash of the F-10A transport that killed Rockne was to ground all the planes and carefully examine the wings for defects. This resulted in the eventual removal of all wooden wings from air transports and effectively demonstrated the need for advanced aircraft design. This led to the introduction of several new concepts in aircraft design, including the Boeing Transport and the DC series of the Douglas Aircraft company, which has been a mainstay for commercial and military transportation since the early 1930s. A general review of the development of aviation is given as well as the details of the development of aircraft accident investigation by the federal government. This includes the investigation of the Rockne crash.

  8. Application of several methods for determining transfer functions and frequency response of aircraft from flight data

    NASA Technical Reports Server (NTRS)

    Eggleston, John M; Mathews, Charles W

    1954-01-01

    In the process of analyzing the longitudinal frequency-response characteristics of aircraft, information on some of the methods of analysis has been obtained by the Langley Aeronautical Laboratory of the National Advisory Committee for Aeronautics. In the investigation of these methods, the practical applications and limitations were stressed. In general, the methods considered may be classed as: (1) analysis of sinusoidal response, (2) analysis of transient response as to harmonic content through determination of the Fourier integral by manual or machine methods, and (3) analysis of the transient through the use of least-squares solutions of the coefficients of an assumed equation for either the transient time response or frequency response (sometimes referred to as curve-fitting methods). (author)

  9. Modeling XV-15 tilt-rotor aircraft dynamics by frequency and time-domain identification techniques

    NASA Technical Reports Server (NTRS)

    Tischler, Mark B.; Kaletka, Juergen

    1987-01-01

    Models of the open-loop hover dynamics of the XV-15 Tilt-Rotor Aircraft are extracted from flight data using two approaches: frequency domain and time-domain identification. Both approaches are reviewed and the identification results are presented and compared in detail. The extracted models are compared favorably, with the differences associated mostly with the inherent weighing of each technique. Step responses are used to show that the predictive capability of the models from both techniques is excellent. Based on the results of this study, the relative strengths and weaknesses of the frequency and time-domain techniques are summarized and a proposal for a coordinated parameter identification approach is presented.

  10. Modeling XV-15 tilt-rotor aircraft dynamics by frequency and time-domain identification techniques

    NASA Technical Reports Server (NTRS)

    Tischler, Mark B.; Kaletka, Juergen

    1986-01-01

    Models of the open-loop hover dynamics of the XV-15 Tilt-Rotor Aircraft are extracted from flight data using two approaches: frequency-domain and time-domain identification. Both approaches are reviewed and the identification results are presented and compared in detail. The extracted models compare favorable, with the differences associated mostly with the inherent weighting of each technique. Step responses are used to show that the predictive capability of the models from both techniques is excellent. Based on the results of this study, the relative strengths and weaknesses of the frequency- and time-domain techniques are summarized, and a proposal for a coordinated parameter identification approach is presented.

  11. Time and frequency response of a resistance-wire aircraft atmospheric temperature sensor

    NASA Astrophysics Data System (ADS)

    Payne, G. A.; Friehe, C. A.; Edwards, D. K.

    1994-04-01

    The heat transfer characteristics of an aircraft-mounted resistance-wire atmospheric temperature sensor are modeled to determine the time and frequency responses. The sensor element (Rosemount 102E4AL) consists of a 25-micron-diameter platinum wire wound around a cruciform mica support with approximately 143 diameters of wire between contacts with the mica. A longitudinally distributed, radially lumped capacitance model provided for the convective heat transfer to the wire and the transient heat conduction along it. Similarly, the temperature gradient across the thin dimension of the mica support was neglected, and a radially distributed model provided for the convective heat transfer to the mica and the transient conduction within it. The two solutions are coupled by the boundary conditions at the wire-mica contact. The equations were solved to produce the temperature distribution along the wire and in the mica support as a function of the frequency of a free-stream sinusoidal temperature fluctuation. The frequency response transfer function was determined and fit to a two-time-constant transfer function by regression analysis. The two-time-constant model fits the general solution very well. The small (fast response) time constant is essentially determined by the wire itself. The larger (slow response) time constant is due to conduction into and out of the mica supports. The model predicts that the effects of the mica supports are important for frequencies greater than about 0.1 Hz. The responses to five different temperature waveform inputs (sinusoid, step, pulse, ramp, and ramp level) are derived using the two-time-constant model with Laplace transform techniques for both infinite-length wire (no mica support effects) and the finite-length wire of the 102 probe. The actual temperature signals are distorted by the larger time constant of the mica supports, especially for the pulse and ramp inputs that are typical of aircraft measurements of thermals and

  12. Finite Difference Time Marching in the Frequency Domain: A Parabolic Formulation for Aircraft Acoustic Nacelle Design

    NASA Technical Reports Server (NTRS)

    Baumeister, Kenneth J.; Kreider, Kevin L.

    1996-01-01

    An explicit finite difference iteration scheme is developed to study harmonic sound propagation in aircraft engine nacelles. To reduce storage requirements for large 3D problems, the time dependent potential form of the acoustic wave equation is used. To insure that the finite difference scheme is both explicit and stable, time is introduced into the Fourier transformed (steady-state) acoustic potential field as a parameter. Under a suitable transformation, the time dependent governing equation in frequency space is simplified to yield a parabolic partial differential equation, which is then marched through time to attain the steady-state solution. The input to the system is the amplitude of an incident harmonic sound source entering a quiescent duct at the input boundary, with standard impedance boundary conditions on the duct walls and duct exit. The introduction of the time parameter eliminates the large matrix storage requirements normally associated with frequency domain solutions, and time marching attains the steady-state quickly enough to make the method favorable when compared to frequency domain methods. For validation, this transient-frequency domain method is applied to sound propagation in a 2D hard wall duct with plug flow.

  13. Crash risk: How cycling flow can help explain crash data.

    PubMed

    Dozza, Marco

    2016-05-12

    Crash databases are commonly queried to infer crash causation, prioritize countermeasures to prevent crashes, and evaluate safety systems. However, crash databases, which may be compiled from police and hospital records, alone cannot provide estimates of crash risk. Moreover, they fail to capture road user behavior before the crash. In Sweden, as in many other countries, crash databases are particularly sterile when it comes to bicycle crashes. In fact, not only are bicycle crashes underreported in police reports, they are also poorly documented in hospital reports. Nevertheless, these reports are irreplaceable sources of information, clearly highlighting the surprising prevalence of single-bicycle crashes and hinting at some cyclist behaviors, such as alcohol consumption, that may increase crash risk. In this study, we used exposure data from 11 roadside stations measuring cyclist flow in Gothenburg to help explain crash data and estimate risk. For instance, our results show that crash risk is greatest at night on weekends, and that this risk is larger for single-bicycle crashes than for crashes between a cyclist and another motorist. This result suggests that the population of night-cyclists on weekend nights is particularly prone to specific crash types, which may be influenced by specific contributing factors (such as alcohol), and may require specific countermeasures. Most importantly, our results demonstrate that detailed exposure data can help select, filter, aggregate, highlight, and normalize crash data to obtain a sharper view of the cycling safety problem, to achieve a more fine-tuned intervention.

  14. Evaluation of analysis techniques for low frequency interior noise and vibration of commercial aircraft

    NASA Technical Reports Server (NTRS)

    Landmann, A. E.; Tillema, H. F.; Marshall, S. E.

    1989-01-01

    The application of selected analysis techniques to low frequency cabin noise associated with advanced propeller engine installations is evaluated. Three design analysis techniques were chosen for evaluation including finite element analysis, statistical energy analysis (SEA), and a power flow method using element of SEA (computer program Propeller Aircraft Interior Noise). An overview of the three procedures is provided. Data from tests of a 727 airplane (modified to accept a propeller engine) were used to compare with predictions. Comparisons of predicted and measured levels at the end of the first year's effort showed reasonable agreement leading to the conclusion that each technique had value for propeller engine noise predictions on large commercial transports. However, variations in agreement were large enough to remain cautious and to lead to recommendations for further work with each technique. Assessment of the second year's results leads to the conclusion that the selected techniques can accurately predict trends and can be useful to a designer, but that absolute level predictions remain unreliable due to complexity of the aircraft structure and low modal densities.

  15. A joint-probability approach to crash prediction models.

    PubMed

    Pei, Xin; Wong, S C; Sze, N N

    2011-05-01

    Many road safety researchers have used crash prediction models, such as Poisson and negative binomial regression models, to investigate the associations between crash occurrence and explanatory factors. Typically, they have attempted to separately model the crash frequencies of different severity levels. However, this method may suffer from serious correlations between the model estimates among different levels of crash severity. Despite efforts to improve the statistical fit of crash prediction models by modifying the data structure and model estimation method, little work has addressed the appropriate interpretation of the effects of explanatory factors on crash occurrence among different levels of crash severity. In this paper, a joint probability model is developed to integrate the predictions of both crash occurrence and crash severity into a single framework. For instance, the Markov chain Monte Carlo (MCMC) approach full Bayesian method is applied to estimate the effects of explanatory factors. As an illustration of the appropriateness of the proposed joint probability model, a case study is conducted on crash risk at signalized intersections in Hong Kong. The results of the case study indicate that the proposed model demonstrates a good statistical fit and provides an appropriate analysis of the influences of explanatory factors.

  16. NASA/FAA general aviation crash dynamics program

    NASA Technical Reports Server (NTRS)

    Thomson, R. G.; Hayduk, R. J.; Carden, H. D.

    1981-01-01

    The program involves controlled full scale crash testing, nonlinear structural analyses to predict large deflection elastoplastic response, and load attenuating concepts for use in improved seat and subfloor structure. Both analytical and experimental methods are used to develop expertise in these areas. Analyses include simplified procedures for estimating energy dissipating capabilities and comprehensive computerized procedures for predicting airframe response. These analyses are developed to provide designers with methods for predicting accelerations, loads, and displacements on collapsing structure. Tests on typical full scale aircraft and on full and subscale structural components are performed to verify the analyses and to demonstrate load attenuating concepts. A special apparatus was built to test emergency locator transmitters when attached to representative aircraft structure. The apparatus is shown to provide a good simulation of the longitudinal crash pulse observed in full scale aircraft crash tests.

  17. NASA/FAA general aviation crash dynamics program - An update

    NASA Technical Reports Server (NTRS)

    Hayduk, R. J.; Thomson, R. G.; Carden, H. D.

    1979-01-01

    Work in progress in the NASA/FAA General Aviation Crash Dynamics Program for the development of technology for increased crash-worthiness and occupant survivability of general aviation aircraft is presented. Full-scale crash testing facilities and procedures are outlined, and a chronological summary of full-scale tests conducted and planned is presented. The Plastic and Large Deflection Analysis of Nonlinear Structures and Modified Seat Occupant Model for Light Aircraft computer programs which form part of the effort to predict nonlinear geometric and material behavior of sheet-stringer aircraft structures subjected to large deformations are described, and excellent agreement between simulations and experiments is noted. The development of structural concepts to attenuate the load transmitted to the passenger through the seats and subfloor structure is discussed, and an apparatus built to test emergency locator transmitters in a realistic environment is presented.

  18. Non-Maximally Decimated Filter Banks Enable Adaptive Frequency Hopping for Unmanned Aircraft Vehicles

    NASA Technical Reports Server (NTRS)

    Venosa, Elettra; Vermeire, Bert; Alakija, Cameron; Harris, Fred; Strobel, David; Sheehe, Charles J.; Krunz, Marwan

    2017-01-01

    In the last few years, radio technologies for unmanned aircraft vehicle (UAV) have advanced very rapidly. The increasing need to fly unmanned aircraft systems (UAS) in the national airspace system (NAS) to perform missions of vital importance to national security, defense, and science has pushed ahead the design and implementation of new radio platforms. However, a lot still has to be done to improve those radios in terms of performance and capabilities. In addition, an important aspect to account for is hardware cost and the feasibility to implement these radios using commercial off-the-shelf (COTS) components. UAV radios come with numerous technical challenges and their development involves contributions at different levels of the design. Cognitive algorithms need to be developed in order to perform agile communications using appropriate frequency allocation while maintaining safe and efficient operations in the NAS and, digital reconfigurable architectures have to be designed in order to ensure a prompt response to environmental changes. Command and control (C2) communications have to be preserved during "standard" operations while crew operations have to be minimized. It is clear that UAV radios have to be software-defined systems, where size, weight and power consumption (SWaP) are critical parameters. This paper provides preliminary results of the efforts performed to design a fully digital radio architecture as part of a NASA Phase I STTR. In this paper, we will explain the basic idea and technical principles behind our dynamic/adaptive frequency hopping radio for UAVs. We will present our Simulink model of the dynamic FH radio transmitter design for UAV communications and show simulation results and FPGA system analysis.

  19. Marijuana Use and Motor Vehicle Crashes

    PubMed Central

    Li, Mu-Chen; Brady, Joanne E.; DiMaggio, Charles J.; Lusardi, Arielle R.; Tzong, Keane Y.; Li, Guohua

    2012-01-01

    Since 1996, 16 states and the District of Columbia in the United States have enacted legislation to decriminalize marijuana for medical use. Although marijuana is the most commonly detected nonalcohol drug in drivers, its role in crash causation remains unsettled. To assess the association between marijuana use and crash risk, the authors performed a meta-analysis of 9 epidemiologic studies published in English in the past 2 decades identified through a systematic search of bibliographic databases. Estimated odds ratios relating marijuana use to crash risk reported in these studies ranged from 0.85 to 7.16. Pooled analysis based on the random-effects model yielded a summary odds ratio of 2.66 (95% confidence interval: 2.07, 3.41). Analysis of individual studies indicated that the heightened risk of crash involvement associated with marijuana use persisted after adjustment for confounding variables and that the risk of crash involvement increased in a dose-response fashion with the concentration of 11-nor-9-carboxy-delta-9-tetrahydrocannabinol detected in the urine and the frequency of self-reported marijuana use. The results of this meta-analysis suggest that marijuana use by drivers is associated with a significantly increased risk of being involved in motor vehicle crashes. PMID:21976636

  20. Fatality rate of pedestrians and fatal crash involvement rate of drivers in pedestrian crashes: a case study of Iran.

    PubMed

    Kashani, Ali Tavakoli; Besharati, Mohammad Mehdi

    2016-04-20

    The aim of this study was to uncover patterns of pedestrian crashes. In the first stage, 34,178 pedestrian-involved crashes occurred in Iran during a four-year period were grouped into homogeneous clusters using a clustering analysis. Next, some in-cluster and inter-cluster crash patterns were analysed. The clustering analysis yielded six pedestrian crash groups. Car/van/pickup crashes on rural roads as well as heavy vehicle crashes were found to be less frequent but more likely to be fatal compared to other crash clusters. In addition, after controlling for crash frequency in each cluster, it was found that the fatality rate of each pedestrian age group as well as the fatal crash involvement rate of each driver age group varies across the six clusters. Results of present study has some policy implications including, promoting pedestrian safety training sessions for heavy vehicle drivers, imposing limitations over elderly heavy vehicle drivers, reinforcing penalties toward under 19 drivers and motorcyclists. In addition, road safety campaigns in rural areas may be promoted to inform people about the higher fatality rate of pedestrians on rural roads. The crash patterns uncovered in this study might also be useful for prioritizing future pedestrian safety research areas.

  1. Aircraft Survivability. Summer 2011

    DTIC Science & Technology

    2011-01-01

    Survivability Program Office SUMMER 2011 craShworthineSS & personnel casualties Report Documentation Page Form ApprovedOMB No. 0704-0188 Public...unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 Aircraft Survivability is published three times a year by the Joint...and stroking seats. The knowledge gained from studying Vietnam crash data was consolidated into the Crash Survival Design Guide (CSDG), which

  2. Post-crash fuel dispersal

    SciTech Connect

    Tieszen, S.R.

    1997-03-01

    This paper is a brief overview of work over the last several decades in understanding what occurs to jet fuel stored in aircraft fuel tanks on impact with the ground. Fuel dispersal is discussed in terms of the overall crash dynamics process and impact regimes are identified. In a generic sense, the types of flow regimes which can occur are identified and general descriptions of the processes are given. Examples of engineering level tools, both computational and experimental, which have applicability to analyzing the complex environments are presented. Finally, risk based decision is discussed as a quick means of identifying requirements for development of preventative or mitigation strategies, such as further work on the development of an anti-misting agent.

  3. Adaptive Optimal Control Using Frequency Selective Information of the System Uncertainty With Application to Unmanned Aircraft.

    PubMed

    Maity, Arnab; Hocht, Leonhard; Heise, Christian; Holzapfel, Florian

    2016-11-28

    A new efficient adaptive optimal control approach is presented in this paper based on the indirect model reference adaptive control (MRAC) architecture for improvement of adaptation and tracking performance of the uncertain system. The system accounts here for both matched and unmatched unknown uncertainties that can act as plant as well as input effectiveness failures or damages. For adaptation of the unknown parameters of these uncertainties, the frequency selective learning approach is used. Its idea is to compute a filtered expression of the system uncertainty using multiple filters based on online instantaneous information, which is used for augmentation of the update law. It is capable of adjusting a sudden change in system dynamics without depending on high adaptation gains and can satisfy exponential parameter error convergence under certain conditions in the presence of structured matched and unmatched uncertainties as well. Additionally, the controller of the MRAC system is designed using a new optimal control method. This method is a new linear quadratic regulator-based optimal control formulation for both output regulation and command tracking problems. It provides a closed-form control solution. The proposed overall approach is applied in a control of lateral dynamics of an unmanned aircraft problem to show its effectiveness.

  4. Effect of bus size and operation to crash occurrences.

    PubMed

    Chimba, Deo; Sando, Thobias; Kwigizile, Valerian

    2010-11-01

    This paper evaluates roadway and operational factors considered to influence crashes involving buses. Factors evaluated included those related to bus sizes and operation services. Negative binomial (NB) and multinomial logit (MNL) models were used in linearizing and quantifying these factors with respect to crash frequency and injury severities, respectively. The results showed that position of the bus travel lane, presence or absence of on-street shoulder parking, posted speed limit, lane width, median width, number of lanes per direction and number of vehicles per lane has a higher influence on bus crashes compared to other roadway and traffic factors. Wider lanes and medians were found to reduce probability of bus crashes while more lanes and higher volume per lane were found to increase the likelihood of occurrences of bus-related crashes. Roadways with higher posted speed limits excluding freeways were found to have high probability of crashes compared to low speed limit roadways. Buses traveling on the inner lanes and making left turns were found to have higher probability of crashes compared to those traveling on the right most lanes. The same factors were found to influence injury severity though with varying magnitudes compared to crash frequency.

  5. Reductions in Injury Crashes Associated With Red Light Camera Enforcement in Oxnard, California

    PubMed Central

    Retting, Richard A.; Kyrychenko, Sergey Y.

    2002-01-01

    Objectives. This study estimated the impact of red light camera enforcement on motor vehicle crashes in one of the first US communities to employ such cameras—Oxnard, California. Methods. Crash data were analyzed for Oxnard and for 3 comparison cities. Changes in crash frequencies were compared for Oxnard and control cities and for signalized and nonsignalized intersections by means of a generalized linear regression model. Results. Overall, crashes at signalized intersections throughout Oxnard were reduced by 7% and injury crashes were reduced by 29%. Right-angle crashes, those most associated with red light violations, were reduced by 32%; right-angle crashes involving injuries were reduced by 68%. Conclusions. Because red light cameras can be a permanent component of the transportation infrastructure, crash reductions attributed to camera enforcement should be sustainable. (Am J Public Health. 2002;92:1822–1825) PMID:12406815

  6. Survey of NASA research on crash dynamics

    NASA Technical Reports Server (NTRS)

    Thomson, R. G.; Carden, H. D.; Hayduk, R. J.

    1984-01-01

    Ten years of structural crash dynamics research activities conducted on general aviation aircraft by the National Aeronautics and Space Administration (NASA) are described. Thirty-two full-scale crash tests were performed at Langley Research Center, and pertinent data on airframe and seat behavior were obtained. Concurrent with the experimental program, analytical methods were developed to help predict structural behavior during impact. The effects of flight parameters at impact on cabin deceleration pulses at the seat/occupant interface, experimental and analytical correlation of data on load-limiting subfloor and seat configurations, airplane section test results for computer modeling validation, and data from emergency-locator-transmitter (ELT) investigations to determine probable cause of false alarms and nonactivations are assessed. Computer programs which provide designers with analytical methods for predicting accelerations, velocities, and displacements of collapsing structures are also discussed.

  7. Seat Design for Crash Worthiness

    NASA Technical Reports Server (NTRS)

    Pinkel, I Irving; Rosenberg, Edmund G

    1957-01-01

    A study of many crash deceleration records suggested a simplified model of a crash deceleration pulse, which incorporates the essential properties of the pulse. The model pulse is considered to be composed of a base pulse on which are superimposed one or more secondary pulses of shorter duration. The results of a mathematical analysis of the seat-passenger deceleration in response to the airplane deceleration pulse are provided. On the basis of this information, presented as working charts, the maximum deceleration loads experienced by the seat and passenger in response to the airplane deceleration pulse can be computed. This maximum seat-passenger deceleration is found to depend on the natural frequency of the seat containing the passenger, considered as a mass-spring system. A method is presented that shows how to arrive at a combination of seat strength, natural frequency, and ability to absorb energy in deformation beyond the elastic limit that will allow the seat to serve without failure during an airplane deceleration pulse taken as the design requirement.

  8. Matrix method of determining the longitudinal-stability coefficients and frequency response of an aircraft from transient flight data

    NASA Technical Reports Server (NTRS)

    Donegan, James J; Pearson, Henry A

    1952-01-01

    A matrix method is presented for determining the longitudinal-stability coefficients and frequency response of an aircraft from arbitrary maneuvers. The method is devised so that it can be applied to time-history measurements of combinations of such simple quantities as angle of attack, pitching velocity, load factor, elevator angle, and hinge moment to obtain the over-all coefficients. Although the method has been devised primarily for the evaluation of stability coefficients which are of primary interest in most aircraft loads and stability studies, it can be used also, with a simple additional computation, to determine the frequency-response characteristics. The entire procedure can be applied or extended to other problems which can be expressed by linear differential equations.

  9. Review of Aircraft Crash Structural Response Research.

    DTIC Science & Technology

    1982-08-01

    Con:z:..~~ie C strurtIr’~s ZIL or:Es’. . :o: e ~ c: if proper r2 SiC __L nwcrtn; :e crashwortn: r25s estr : , -tn 0._. es," General~-~-- design...11Ilk LAS VEGAS A-CIDE NT CABIN FLOOR CONTROLLED TESI CABIN FLOOP Fig 6 Damage comparison between controlled test and Las %egas acc¢ident. P IL •I

  10. Multivariate poisson lognormal modeling of crashes by type and severity on rural two lane highways.

    PubMed

    Wang, Kai; Ivan, John N; Ravishanker, Nalini; Jackson, Eric

    2017-02-01

    In an effort to improve traffic safety, there has been considerable interest in estimating crash prediction models and identifying factors contributing to crashes. To account for crash frequency variations among crash types and severities, crash prediction models have been estimated by type and severity. The univariate crash count models have been used by researchers to estimate crashes by crash type or severity, in which the crash counts by type or severity are assumed to be independent of one another and modelled separately. When considering crash types and severities simultaneously, this may neglect the potential correlations between crash counts due to the presence of shared unobserved factors across crash types or severities for a specific roadway intersection or segment, and might lead to biased parameter estimation and reduce model accuracy. The focus on this study is to estimate crashes by both crash type and crash severity using the Integrated Nested Laplace Approximation (INLA) Multivariate Poisson Lognormal (MVPLN) model, and identify the different effects of contributing factors on different crash type and severity counts on rural two-lane highways. The INLA MVPLN model can simultaneously model crash counts by crash type and crash severity by accounting for the potential correlations among them and significantly decreases the computational time compared with a fully Bayesian fitting of the MVPLN model using Markov Chain Monte Carlo (MCMC) method. This paper describes estimation of MVPLN models for three-way stop controlled (3ST) intersections, four-way stop controlled (4ST) intersections, four-way signalized (4SG) intersections, and roadway segments on rural two-lane highways. Annual Average Daily traffic (AADT) and variables describing roadway conditions (including presence of lighting, presence of left-turn/right-turn lane, lane width and shoulder width) were used as predictors. A Univariate Poisson Lognormal (UPLN) was estimated by crash type and

  11. Crack detection on HC-130H aircraft using low frequency eddy current

    SciTech Connect

    Moore, D.G.; Mihelic, J.E.; Barnes, J.D.

    1998-02-01

    An eddy current inspection method was developed at the Federal Aviation Administration`s Airworthiness Assurance NDI Validation Center (AANC) to easily and rapidly detect subsurface fatigue cracks in the wheel well fairing on the US Coast Guard (USCG) HC-130H aircraft caused by fatigue. The inspection procedure locates cracks as small as 10.2 millimeters in length at 2.54 mm below the skin surface at raised fastener sites. The test procedure developed baseline three USCG aircraft. Inspection results on the three aircraft reveals good correlation with results made during subsequent structural disassembly.

  12. Geographic Region, Weather, Pilot Age and Air Carrier Crashes: a Case-Control Study

    PubMed Central

    Li, Guohua; Pressley, Joyce C.; Qiang, Yandong; Grabowski, Jurek G.; Baker, Susan P.; Rebok, George W.

    2009-01-01

    Background Information about risk factors of aviation crashes is crucial for developing effective intervention programs. Previous studies assessing factors associated with crash risk were conducted primarily in general aviation, air taxis and commuter air carriers. Methods A matched case-control design was used to examine the associations of geographic region, basic weather condition, and pilot age with the risk of air carrier (14 CFR Part 121) crash involvement. Cases (n=373) were air carrier crashes involving aircraft made by Boeing, McDonnell Douglas, and Airbus, recorded in the National Transportation Safety Board’s aviation crash database during 1983 through 2002, and controls (n=746) were air carrier incidents involving aircraft of the same three makes selected at random from the Federal Aviation Administration’s aviation incident database. Each case was matched with two controls on the calendar year when the index crash occurred. Conditional logistic regression was used for statistical analysis. Results With adjustment for basic weather condition, pilot age, and total flight time, the risk of air carrier crashes in Alaska was more than three times the risk for other regions [adjusted odds ratio (OR) 3.18, 95% confidence interval (CI) 1.35 – 7.49]. Instrument meteorological conditions were associated with an increased risk for air carrier crashes involving pilot error (adjusted OR 2.26, 95% CI 1.15 – 4.44) and a decreased risk for air carrier crashes without pilot error (adjusted OR 0.57, 95% CI 0.40 – 0.87). Neither pilot age nor total flight time was significantly associated with the risk of air carrier crashes. Conclusions The excess risk of air carrier crashes in Alaska and the effect of adverse weather on pilot-error crashes underscore the importance of environmental hazards in flight safety. PMID:19378910

  13. Development of a Comprehensive Neck Injury Criterion for Aircraft-Related Incidences

    DTIC Science & Technology

    1995-02-15

    Naval helicopter and fixed- wing aircraft crashes and from U.S. Army helicopter crashes were identified in the literature. Together, these statistics...Cervical Spine 3.7 Adapted from Coltman et al., 1989 (Reference 5) Fixed- wing aircraft mishaps produce the same general injury trends as do...helicopter crashes: head and extremity injuries are the most prevalent. Injuries to the thorax occur less often in fixed- wing aircraft than in helicopter

  14. Pilot Age and Error in Air-Taxi Crashes

    PubMed Central

    Rebok, George W.; Qiang, Yandong; Baker, Susan P.; Li, Guohua

    2010-01-01

    Introduction The associations of pilot error with the type of flight operations and basic weather conditions are well documented. The correlation between pilot characteristics and error is less clear. This study aims to examine whether pilot age is associated with the prevalence and patterns of pilot error in air-taxi crashes. Methods Investigation reports from the National Transportation Safety Board for crashes involving non-scheduled Part 135 operations (i.e., air taxis) in the United States between 1983 and 2002 were reviewed to identify pilot error and other contributing factors. Crash circumstances and the presence and type of pilot error were analyzed in relation to pilot age using Chi-square tests. Results Of the 1751 air-taxi crashes studied, 28% resulted from mechanical failure, 25% from loss of control at landing or takeoff, 7% from visual flight rule conditions into instrument meteorological conditions, 7% from fuel starvation, 5% from taxiing, and 28% from other causes. Crashes among older pilots were more likely to occur during the daytime rather than at night and off airport than on airport. The patterns of pilot error in air-taxi crashes were similar across age groups. Of the errors identified, 27% were flawed decisions, 26% were inattentiveness, 23% mishandled aircraft kinetics, 15% mishandled wind and/or runway conditions, and 11% were others. Conclusions Pilot age is associated with crash circumstances but not with the prevalence and patterns of pilot error in air-taxi crashes. Lack of age-related differences in pilot error may be attributable to the “safe worker effect.” PMID:19601508

  15. Bicycling crash characteristics: An in-depth crash investigation study.

    PubMed

    Beck, Ben; Stevenson, Mark; Newstead, Stuart; Cameron, Peter; Judson, Rodney; Edwards, Elton R; Bucknill, Andrew; Johnson, Marilyn; Gabbe, Belinda

    2016-11-01

    The aim of this study was to describe the crash characteristics and patient outcomes of a sample of patients admitted to hospital following bicycle crashes. Injured cyclists were recruited from the two major trauma services for the state of Victoria, Australia. Enrolled cyclists completed a structured interview, and injury details and patient outcomes were extracted from the Victorian State Trauma Registry (VSTR) and the Victorian Orthopaedic Trauma Outcomes Registry (VOTOR). 186 cyclists consented to participate in the study. Crashes commonly occurred during daylight hours and in clear weather conditions. Two-thirds of crashes occurred on-road (69%) and were a combination of single cyclist-only events (56%) and multi-vehicle crashes (44%). Of the multi-vehicle crashes, a motor vehicle was the most common impact partner (72%) and distinct pre-crash directional interactions were observed between the cyclist and motor vehicle. Nearly a quarter of on-road crashes occurred when the cyclist was in a marked bicycle lane. Of the 31% of crashes that were not on-road, 28 (15%) occurred on bicycle paths and 29 (16%) occurred in other locations. Crashes on bicycle paths commonly occurred on shared bicycle and pedestrian paths (83%) and did not involve another person or vehicle. Other crash locations included mountain bike trails (39%), BMX parks (21%) and footpaths (18%). While differences in impact partners and crash characteristics were observed between crashes occurring on-road, on bicycle paths and in other locations, injury patterns and severity were similar. Most cyclists had returned to work at 6 months post-injury, however only a third of participants reported a complete functional recovery. Further research is required to develop targeted countermeasures to address the risk factors identified in this study.

  16. Annoyance by aircraft noise and fear of overflying aircraft in relation to attitudes toward the environment and community

    NASA Technical Reports Server (NTRS)

    Loeb, M.; Moran, S. V.

    1977-01-01

    It has been suggested that expressions of annoyance attributable to aircraft noise may reflect in part fear of aircraft overflights and possible crashes. If this is true, then residents of areas where crashes have occurred should express more annoyance. To test this hypothesis, 50 residents of an Albany, New York area where an aircraft crash producing fatalities recently occurred and 50 residents of a comparable nearby area without such a history, were asked to respond to a 'Quality of Life Questionnaire.' Among the items were some designed to test annoyance by noise and fear of aircraft overflights. It was predicted that those in the crash area would express more fear and would more often identify aircraft as a noise source. These hypotheses were sustained. A near-replication was carried out in Louisville, Kentucky; results were much the same. Analyses indicated that for the crash-area groups, there was associating of aircraft fear and noise annoyance responses; this was true to an apparently lesser extent for non-crash groups. The greater annoyance of crash groups by aircraft community noise apparently does not carry over to situations in which aircraft noise is assessed in the laboratory.

  17. Identifying repeat DUI crash factors using state crash records.

    PubMed

    Fu, Haoqiang

    2008-11-01

    The objective of this study is to identify high risk factors that are closely related to repeat DUI crashes using readily available information from the state crash records. Survival analysis was used and a Cox proportional hazards model was developed using the police-reported crash records in the state of Louisiana. A variety of variables were found to be significant in predicting repeat DUI crashes. The factors included the characteristics of the drivers (gender, race, and age), the types of the vehicle (light truck/pick up truck or other), the characteristics of the crash (hit-and-run, driver violations, and whether the driver is arrested), the type of location (residential area or other), and the characteristics of the roadway (highway type and roadway type). This study provides a comprehensive picture of the repeat DUI crashes. The model can quantitatively predict the relative hazards of repeat DUI crashes. It can be used to identify the characteristics of the crash-involved DUI drivers who are at greatest risk of being involved in a subsequent DUI crash, allowing to apply appropriate remedial measures to reduce the risk.

  18. Indexing crash worthiness and crash aggressivity by vehicle type.

    PubMed

    Huang, Helai; Siddiqui, Chowdhury; Abdel-Aty, Mohamed

    2011-07-01

    Crash aggressivity (CA), along with conventional crash worthiness (CW), has been recently studied to deal with the crash incompatibility between vehicles on roads. Clearly, injury severity depends on the attacking ability of striking vehicle as well as the protective ability of struck vehicle. This study proposes a systematic crash-based approach to index CA and CW of various vehicles. The approach deviates from existing methods in three aspects: (a) an explicit definition and specification in the model for CW and CA; (b) Bayesian hierarchical analysis to account for the crash-vehicle two-level data structure; (c) a five-level ordinal model to explicitly consider all levels of crash severity. The case study on major vehicle types illustrated the method and confirmed the consistency of results with previous studies. Both crash worthiness and crash aggressivity significantly vary by vehicle types, in which we identified the dominating effect of vehicle mass, and also highlighted the extraordinary aggressivity of Light Trucks and Vans (LTVs). While it was not surprising to identify least CA and CW of motorcycles, buses were unconventionally found to be less aggressive than other motor vehicles. The method proposed in this research is applicable to detailed crash-based vehicle inspection and evaluation.

  19. Aircraft Crash Survival Design Guide. Volume III. Aircraft Structural Crashworthiness

    DTIC Science & Technology

    1980-08-01

    acceleration of the head can produce concussion . Further, skull fracture can result from localized impact with surrounding struc- ture. Therefore... NfL -STD-12IO or l10" in- (door depth of 2 in. Jinverted or vrted or hatches eta. an side). Load uniformly an inter- ammumed to distributed over forward

  20. An air photo analysis of an airplane crash.

    PubMed

    Rinker, J N; Garstang, J H; Edwards, D; Del Vecchio, J J

    1989-07-01

    Crash patterns-such as cut and damaged vegetation, gouges, debris scatter, burn areas, etc.,-and their spatial relations can be very effectively evaluated by the analysis of stereo aerial photographs. Results from the Canadian Aviation Safety Board's use of aerial photography in the Gander, Nfld., crash of Dec. 12, 1985, show that the technique can lend direct support to an investigation in several ways. It provides an overall perspective view of the regional relations of the crash patterns. It helps direct ground activities. In three-covered areas, it can help establish aircraft attitude and orientation. When combined with debris plots and attitude determinations, it can help establish the breakup sequence. And, when coupled to photogrammetric procedures, it can assign dimensional values to attitude, descent path, areas, lengths, etc.

  1. General aviation crash safety program at Langley Research Center

    NASA Technical Reports Server (NTRS)

    Thomson, R. G.

    1976-01-01

    The purpose of the crash safety program is to support development of the technology to define and demonstrate new structural concepts for improved crash safety and occupant survivability in general aviation aircraft. The program involves three basic areas of research: full-scale crash simulation testing, nonlinear structural analyses necessary to predict failure modes and collapse mechanisms of the vehicle, and evaluation of energy absorption concepts for specific component design. Both analytical and experimental methods are being used to develop expertise in these areas. Analyses include both simplified procedures for estimating energy absorption capabilities and more complex computer programs for analysis of general airframe response. Full-scale tests of typical structures as well as tests on structural components are being used to verify the analyses and to demonstrate improved design concepts.

  2. Monitoring of hidden fatigue crack growth in multi-layer aircraft structures using high frequency guided waves

    NASA Astrophysics Data System (ADS)

    Chan, H.; Masserey, B.; Fromme, P.

    2015-03-01

    Varying loading conditions of aircraft structures result in stress concentration at fastener holes, where multi-layered components are connected, potentially leading to the development of hidden fatigue cracks in inaccessible layers. High frequency guided waves propagating along the structure allow for the structural health monitoring (SHM) of such components, e.g., aircraft wings. Experimentally the required guided wave modes can be easily excited using standard ultrasonic wedge transducers. However, the sensitivity for the detection of small, potentially hidden, fatigue cracks has to be ascertained. The type of multi-layered model structure investigated consists of two adhesively bonded aluminum plate-strips with a sealant layer. Fatigue experiments were carried out and the growth of fatigue cracks at the fastener hole in one of the metallic layers was monitored optically during cyclic loading. The influence of the fatigue cracks of increasing size on the scattered guided wave field was evaluated. The sensitivity and repeatability of the high frequency guided wave modes to detect and monitor the fatigue crack growth was investigated, using both standard pulse-echo equipment and a laser interferometer. The potential for hidden fatigue crack growth monitoring at critical and difficult to access fastener locations from a stand-off distance was ascertained. The robustness of the methodology for practical in situ ultrasonic monitoring of fatigue crack growth is discussed.

  3. Delamination Modeling of Composites for Improved Crash Analysis

    NASA Technical Reports Server (NTRS)

    Fleming, David C.

    1999-01-01

    Finite element crash modeling of composite structures is limited by the inability of current commercial crash codes to accurately model delamination growth. Efforts are made to implement and assess delamination modeling techniques using a current finite element crash code, MSC/DYTRAN. Three methods are evaluated, including a straightforward method based on monitoring forces in elements or constraints representing an interface; a cohesive fracture model proposed in the literature; and the virtual crack closure technique commonly used in fracture mechanics. Results are compared with dynamic double cantilever beam test data from the literature. Examples show that it is possible to accurately model delamination propagation in this case. However, the computational demands required for accurate solution are great and reliable property data may not be available to support general crash modeling efforts. Additional examples are modeled including an impact-loaded beam, damage initiation in laminated crushing specimens, and a scaled aircraft subfloor structures in which composite sandwich structures are used as energy-absorbing elements. These examples illustrate some of the difficulties in modeling delamination as part of a finite element crash analysis.

  4. Compressible magnetohydrodynamic sawtooth crash

    NASA Astrophysics Data System (ADS)

    Sugiyama, Linda E.

    2014-02-01

    In a toroidal magnetically confined plasma at low resistivity, compressible magnetohydrodynamic (MHD) predicts that an m = 1/n = 1 sawtooth has a fast, explosive crash phase with abrupt onset, rate nearly independent of resistivity, and localized temperature redistribution similar to experimental observations. Large scale numerical simulations show that the 1/1 MHD internal kink grows exponentially at a resistive rate until a critical amplitude, when the plasma motion accelerates rapidly, culminating in fast loss of the temperature and magnetic structure inside q < 1, with somewhat slower density redistribution. Nonlinearly, for small effective growth rate the perpendicular momentum rate of change remains small compared to its individual terms ∇p and J × B until the fast crash, so that the compressible growth rate is determined by higher order terms in a large aspect ratio expansion, as in the linear eigenmode. Reduced MHD fails completely to describe the toroidal mode; no Sweet-Parker-like reconnection layer develops. Important differences result from toroidal mode coupling effects. A set of large aspect ratio compressible MHD equations shows that the large aspect ratio expansion also breaks down in typical tokamaks with rq =1/Ro≃1/10 and a /Ro≃1/3. In the large aspect ratio limit, failure extends down to much smaller inverse aspect ratio, at growth rate scalings γ =O(ɛ2). Higher order aspect ratio terms, including B˜ϕ, become important. Nonlinearly, higher toroidal harmonics develop faster and to a greater degree than for large aspect ratio and help to accelerate the fast crash. The perpendicular momentum property applies to other transverse MHD instabilities, including m ≥ 2 magnetic islands and the plasma edge.

  5. Resisting "Crash Diet" Staff Development

    ERIC Educational Resources Information Center

    Dana, Nancy Fichtman; Yendol-Hoppey, Diane

    2008-01-01

    People often respond to the pressure of attending a high school reunion or their child's wedding by going on a crash diet to get quick results. In response, friends may marvel about how good they look on the outside. But what folks don't acknowledge is that, in the name of getting results, crash dieters have done some very unhealthy things to…

  6. Refuse-to-crash: NASA tackles loss of control.

    PubMed

    Croft, John W

    2003-03-01

    The article reviews technologies under study at NASA that will alert pilots of loss of control in time to take action or be able to take necessary action to avoid crashing. Topics discussed include efforts to understand factors behind loss of control, how flight simulator data has been reviewed to develop a new understanding of aircraft aerodynamics, use of models to simulate accidents, and design changes resulting from the data collected.

  7. Aircraft Crash Survival Design Guide. Volume 2. Aircraft Crash Environment and Human Tolerance

    DTIC Science & Technology

    1980-01-01

    spine can produce spinal fracture through flex- ure that results from jackknife bending over a lap- belt-only restraint. The lap belt might inflict...injuries to the internal organs if it is not re- tained on the pelvic girdle but is allowed to exert its force above the iliac crests in the soft...exerted by deceleration of the thighs and lower legs accom- panied by lap belt slippage up and over the iliac crests. Lap belt slippage up and over the

  8. Aircraft Crash Survival Design Guide. Volume 2. Aircraft Design Crash Impact Conditions and Human Tolerance

    DTIC Science & Technology

    1989-12-01

    0.6 Waist circumference at minimum girth L 32.0 + 0.6 Hip width M 14.7 + 0.7 Popliteal height N* (17.3 + 0.2) Shoulder-elbow length Q* (14.1 ± 0.3...SQnencluding the time for reviewing insttructions,. searching existing data Source,.7 gallheing and nanrtaining the date needed. nd completing and r"evweorg...depth review of research in human tolerance before 1970 can be found in Reference 9. 5.2 FACTORS AFFECTING HUMAN TOLERANCE 5.2.1 Body Characteristics The

  9. Frequency Allocations for Unmanned Aircraft Systems in the National Airspace. Access 5 White Paper to the WRC Advisory Committee

    NASA Technical Reports Server (NTRS)

    2006-01-01

    A critical aspect of the Access 5 program is identifying appropriate spectrum for civil and commercial purposes. However, currently, there is no spectrum allocated for the command/control link between the aircraft control station and the unmanned aircraft. Until such frequency spectrum is allocated and approved, it will be difficult for the UAS community to obtain civil airworthiness certification and operate in the NAS on a routine basis. This document provides a perspective from the UAS community on Agenda Items being considered for the upcoming World Radiocommunication Conference 2007 (WRC 07). Primarily, it supports the proposal to add Aeronautical Mobile (Route) Services (AM(R)S) to existing bands that could be used for UAS Line-of-Sight operations. It also recommends the need to identify spectrum that could be used for an Aeronautical Mobile Satellite (Route) Service (AMS(R)S) that would allow UAS to operate Beyond Line-of-Sight. If spectrum is made available to provide these services, it will then be incumbent upon the UAS community to justify their use of this spectrum as well as the assurance that they will not interfere with other users of this newly allocated spectrum.

  10. Right-turn-on-red laws and motor vehicle crashes: a review of the literature

    SciTech Connect

    Zador, P.L.

    1984-01-01

    Alternative analyses of data previously published by Zador et al. confirm that adoption of right-turn-on-red laws increased by about 18% the frequency of all right-turning crashes at all signalized intersections in the jurisdictions that adopted such laws. From a view of the available literature it is estimated that at the approximately 80% of all signalized intersections where motorists are allowed to turn right on red all right-turning crashes increased by about 23%, pedestrian crashes by about 60%, and bicyclist crashes by about 100%. 11 references, 1 table.

  11. Exploring spatial autocorrelation of traffic crashes based on severity.

    PubMed

    Soltani, Ali; Askari, Sajad

    2017-01-19

    As a developing country, Iran has one of the highest crash-related deaths, with a typical rate of 15.6 cases in every 100 thousand people. This paper is aimed to find the potential temporal and spatial patterns of road crashes aggregated at traffic analysis zonal (TAZ) level in urban environments. Localization pattern and hotspot distribution were examined using geo-information approach to find out the impact of spatial/temporal dimensions on the emergence of such patterns. The spatial clustering of crashes and hotspots were assessed using spatial autocorrelation methods such as the Moran's I and Getis-Ord Gi* index. Comap was used for comparing clusters in three attributes: the time of occurrence, severity, and location. The analysis of the annually crash frequencies aggregated in 156 TAZ in Shiraz; from 2010 to 2014, Iran showed that both Moran's I method and Getis-Ord Gi* statistics produced significant clustering of crash patterns. While crashes emerged a clustered pattern, comparison of the spatio-temporal separations showed an accidental spread in distinct categories. The local governmental agencies can use the outcomes to adopt more effective strategies for traffic safety planning and management.

  12. Crash involvement of large trucks by configuration: a case-control study.

    PubMed Central

    Stein, H S; Jones, I S

    1988-01-01

    For a two-year period, large truck crashes on the interstate system in Washington State were investigated using a case-control method. For each large truck involved in a crash, three trucks were randomly selected for inspection from the traffic stream at the same time and place as the crash but one week later. The effects of truck and driver characteristics on crashes were assessed by comparing their relative frequency among the crash-involved and comparison sample trucks. Double trailer trucks were consistently overinvolved in crashes by a factor of two to three in both single and multiple vehicle crashes. Single unit trucks pulling trailers also were overinvolved. Doubles also had a higher frequency of jackknifing compared to tractor-trailers. The substantial overinvolvement of doubles in crashes was found regardless of driver age, hours of driving, cargo weight, or type of fleet. Younger drivers, long hours of driving, and operating empty trucks were also associated with higher crash involvement. PMID:3354729

  13. EMS response to an airliner crash.

    PubMed

    Dasgupta, Shuvra; French, Simone; Williams-Johnson, Jean; Hutson, Rhonda; Hart, Nicole; Wong, Mark; Williams, Eric; Espinosa, Kurdell; Maycock, Celeste; Edwards, Romayne; McCartney, Trevor; Cawich, Shamir; Crandon, Ivor

    2012-06-01

    This report of an aircraft crash at a major airport in Kingston, Jamaica examines the response of the local Emergency Medical Services (EMS). Factors that impacted the response are discussed, and the need for more disaster simulation exercises is highlighted. The objective of this case report was to document the response of EMS personnel to the crash of American Airlines Flight 331, and to utilize the information to examine and improve the present protocol. While multiple errors can occur during a mass-casualty event, these can be reduced by frequent simulation exercises during which various personnel practice and learn designated roles. Efficient triage, proper communication, and knowledge of the roles are important in ensuring the best possible outcome. While the triage system and response of the EMS personnel were effective for this magnitude of catastrophe, more work is needed in order to meet predetermined standards. Ways in which this can be overcome include: (1) hosting more disaster simulation exercises; (2) encouraging more involvement with first responders; and (3) strengthening the links in the local EMS system. Vigorous public education must be instituted and maintained.

  14. Consideration of some factors affecting low-frequency fuselage noise transmission for propeller aircraft

    NASA Technical Reports Server (NTRS)

    Mixson, J. S.; Roussos, L. A.

    1986-01-01

    Possible reasons for disagreement between measured and predicted trends of sidewall noise transmission at low frequency are investigated using simplified analysis methods. An analytical model combining incident plane acoustic waves with an infinite flat panel is used to study the effects of sound incidence angle, plate structural properties, frequency, absorption, and the difference between noise reduction and transmission loss. Analysis shows that these factors have significant effects on noise transmission but they do not account for the differences between measured and predicted trends at low frequencies. An analytical model combining an infinite flat plate with a normally incident acoustic wave having exponentially decaying magnitude along one coordinate is used to study the effect of a localized source distribution such as is associated with propeller noise. Results show that the localization brings the predicted low-frequency trend of noise transmission into better agreement with measured propeller results. This effect is independent of low-frequency stiffness effects that have been previously reported to be associated with boundary conditions.

  15. Spatial regression analysis of traffic crashes in Seoul.

    PubMed

    Rhee, Kyoung-Ah; Kim, Joon-Ki; Lee, Young-ihn; Ulfarsson, Gudmundur F

    2016-06-01

    Traffic crashes can be spatially correlated events and the analysis of the distribution of traffic crash frequency requires evaluation of parameters that reflect spatial properties and correlation. Typically this spatial aspect of crash data is not used in everyday practice by planning agencies and this contributes to a gap between research and practice. A database of traffic crashes in Seoul, Korea, in 2010 was developed at the traffic analysis zone (TAZ) level with a number of GIS developed spatial variables. Practical spatial models using available software were estimated. The spatial error model was determined to be better than the spatial lag model and an ordinary least squares baseline regression. A geographically weighted regression model provided useful insights about localization of effects. The results found that an increased length of roads with speed limit below 30 km/h and a higher ratio of residents below age of 15 were correlated with lower traffic crash frequency, while a higher ratio of residents who moved to the TAZ, more vehicle-kilometers traveled, and a greater number of access points with speed limit difference between side roads and mainline above 30 km/h all increased the number of traffic crashes. This suggests, for example, that better control or design for merging lower speed roads with higher speed roads is important. A key result is that the length of bus-only center lanes had the largest effect on increasing traffic crashes. This is important as bus-only center lanes with bus stop islands have been increasingly used to improve transit times. Hence the potential negative safety impacts of such systems need to be studied further and mitigated through improved design of pedestrian access to center bus stop islands.

  16. The Cleveland Aircraft Fire Tests

    NASA Technical Reports Server (NTRS)

    Brenneman, James J.; Heine, Donald A.

    1968-01-01

    On June 30 and July 1, 1966, tests were conducted to evaluate high expansion foam's ability to extend the time for which an aircraft passenger cabin environment would remain survivable during a post-crash fire. While some results tend to confirm those of similar tests, others may shed new light on the problem.

  17. Active Control of High Frequency Combustion Instability in Aircraft Gas-Turbine Engines

    NASA Technical Reports Server (NTRS)

    Corrigan, Bob (Technical Monitor); DeLaat, John C.; Chang, Clarence T.

    2003-01-01

    Active control of high-frequency (greater than 500 Hz) combustion instability has been demonstrated in the NASA single-nozzle combustor rig at United Technologies Research Center. The combustor rig emulates an actual engine instability and has many of the complexities of a real engine combustor (i.e. actual fuel nozzle and swirler, dilution cooling, etc.) In order to demonstrate control, a high-frequency fuel valve capable of modulating the fuel flow at up to 1kHz was developed. Characterization of the fuel delivery system was accomplished in a custom dynamic flow rig developed for that purpose. Two instability control methods, one model-based and one based on adaptive phase-shifting, were developed and evaluated against reduced order models and a Sectored-1-dimensional model of the combustor rig. Open-loop fuel modulation testing in the rig demonstrated sufficient fuel modulation authority to proceed with closed-loop testing. During closed-loop testing, both control methods were able to identify the instability from the background noise and were shown to reduce the pressure oscillations at the instability frequency by 30%. This is the first known successful demonstration of high-frequency combustion instability suppression in a realistic aero-engine environment. Future plans are to carry these technologies forward to demonstration on an advanced low-emission combustor.

  18. Intelligent geocoding system to locate traffic crashes.

    PubMed

    Qin, Xiao; Parker, Steven; Liu, Yi; Graettinger, Andrew J; Forde, Susie

    2013-01-01

    State agencies continue to face many challenges associated with new federal crash safety and highway performance monitoring requirements that use data from multiple and disparate systems across different platforms and locations. On a national level, the federal government has a long-term vision for State Departments of Transportation (DOTs) to report state route and off-state route crash data in a single network. In general, crashes occurring on state-owned or state maintained highways are a priority at the Federal and State level; therefore, state-route crashes are being geocoded by state DOTs. On the other hand, crashes occurring on off-state highway system do not always get geocoded due to limited resources and techniques. Creating and maintaining a statewide crash geographic information systems (GIS) map with state route and non-state route crashes is a complicated and expensive task. This study introduces an automatic crash mapping process, Crash-Mapping Automation Tool (C-MAT), where an algorithm translates location information from a police report crash record to a geospatial map and creates a pinpoint map for all crashes. The algorithm has approximate 83 percent mapping rate. An important application of this work is the ability to associate the mapped crash records to underlying business data, such as roadway inventory and traffic volumes. The integrated crash map is the foundation for effective and efficient crash analyzes to prevent highway crashes.

  19. High-frequency guided ultrasonic waves for hidden defect detection in multi-layer aircraft structures

    NASA Astrophysics Data System (ADS)

    Masserey, B.; Raemy, C.; Fromme, P.

    2012-05-01

    Aerospace structures contain multi-layer components subjected to cyclic loading conditions; fatigue cracks and disbonds can develop, often at fastener holes. High-frequency guided waves have the potential for non-destructive damage detection at critical and difficult to access locations from a stand-off distance. Using commercially available ultrasonic transducers, high frequency guided waves were generated that penetrate through the complete thickness of a model structure, consisting of two adhesively bonded aluminum plates. The wave propagation along the specimen was measured and quantified using a laser interferometer. The wave propagation and scattering at internal defects was simulated using Finite Element (FE) models and good agreement with the measurement results found. The detection sensitivity using standard pulse-echo measurements was verified and the influence of the stand-off distance predicted from the FE simulation results.

  20. Application of analysis techniques for low frequency interior noise and vibration of commercial aircraft

    NASA Technical Reports Server (NTRS)

    Landmann, A. E.; Tillema, H. F.; Macgregor, G. R.

    1992-01-01

    Finite element analysis (FEA), statistical energy analysis (SEA), and a power flow method (computer program PAIN) were used to assess low frequency interior noise associated with advanced propeller installations. FEA and SEA models were used to predict cabin noise and vibration and evaluate suppression concepts for structure-borne noise associated with the shaft rotational frequency and harmonics (less than 100 Hz). SEA and PAIN models were used to predict cabin noise and vibration and evaluate suppression concepts for airborne noise associated with engine radiated propeller tones. Both aft-mounted and wing-mounted propeller configurations were evaluated. Ground vibration test data from a 727 airplane modified to accept a propeller engine were used to compare with predictions for the aft-mounted propeller. Similar data from the 767 airplane was used for the wing-mounted comparisons.

  1. Rotorcraft Crash Mishap Analysis (Revised)

    DTIC Science & Technology

    2014-07-01

    Velocities The nature of the crash velocity data is such that it covers a very wide range of values. Consequently, when the means or medians are...analyzed. Sixty-six percent of the crashes where the surface was reported occurred onto sod which is a term for a broad range of unprepared, natural...thirty percent range , far short of the percentages that one would hope for the model to explain to be considered truly predictive. These results mean

  2. Spatial analysis to identify high risk areas for traffic crashes resulting in death of pedestrians in Tehran.

    PubMed

    Moradi, Ali; Soori, Hamid; Kavousi, Amir; Eshghabadi, Farshid; Jamshidi, Ensiyeh; Zeini, Salahdien

    2016-01-01

    Background: More than 20% of deaths from traffic crashes are related to pedestrians. This figure in Tehran, the capital of Iran, reaches to 40%. This study aimed to determine the high-risk areas and spatially analyze the traffic crashes, causing death to pedestrians in Tehran. Methods: Mapping was used to display the distribution of the crashes. Determining the distribution pattern of crashes and the hot spots/ low-risk areas were done, using Moran's I index and Getis-Ord G, respectively. Results: A total of 198 crashes were studied; 92 of which, (46.4%) occurred in 2013 to 2014 and other 106 cases (63.6%) occurred in 2014 to 2015. The highest and the lowest frequency of crashes was related to January (26 cases) and June (10 cases), respectively. One hundred fifty- eight cases (79.8%) of crashes occurred in Tehran highways. Moran's index showed that the studied traffic crashes had a cluster distribution (p<0.001). Getis- Ord General G index indicated that the distribution of hot and cold spots of the studied crashes was statistically significant (p<0.001). Conclusion: The majority of traffic crashes causing death to pedestrians occurred in highways located in the main entrances and exits of Tehran. Given the important role of environmental factors in the occurrence of traffic crashes related to pedestrians, identification of these factors requires more studies with casual inferences.

  3. Spatial analysis to identify high risk areas for traffic crashes resulting in death of pedestrians in Tehran

    PubMed Central

    Moradi, Ali; Soori, Hamid; Kavousi, Amir; Eshghabadi, Farshid; Jamshidi, Ensiyeh; Zeini, Salahdien

    2016-01-01

    Background: More than 20% of deaths from traffic crashes are related to pedestrians. This figure in Tehran, the capital of Iran, reaches to 40%. This study aimed to determine the high-risk areas and spatially analyze the traffic crashes, causing death to pedestrians in Tehran. Methods: Mapping was used to display the distribution of the crashes. Determining the distribution pattern of crashes and the hot spots/ low-risk areas were done, using Moran’s I index and Getis-Ord G, respectively. Results: A total of 198 crashes were studied; 92 of which, (46.4%) occurred in 2013 to 2014 and other 106 cases (63.6%) occurred in 2014 to 2015. The highest and the lowest frequency of crashes was related to January (26 cases) and June (10 cases), respectively. One hundred fifty- eight cases (79.8%) of crashes occurred in Tehran highways. Moran’s index showed that the studied traffic crashes had a cluster distribution (p<0.001). Getis- Ord General G index indicated that the distribution of hot and cold spots of the studied crashes was statistically significant (p<0.001). Conclusion: The majority of traffic crashes causing death to pedestrians occurred in highways located in the main entrances and exits of Tehran. Given the important role of environmental factors in the occurrence of traffic crashes related to pedestrians, identification of these factors requires more studies with casual inferences. PMID:28210615

  4. Development and use of computational techniques in Army Aviation research and development programs for crash resistant helicopter technology

    NASA Technical Reports Server (NTRS)

    Burrows, Leroy T.

    1993-01-01

    During the 1960's over 30 full-scale aircraft crash tests were conducted by the Flight Safety Foundation under contract to the Aviation Applied Technology Directorate (AATD) of the U.S. Army Aviation Systems Command (AVSCOM). The purpose of these tests were to conduct crash injury investigations that would provide a basis for the formulation of sound crash resistance design criteria for light fixed-wing and rotary wing aircraft. This resulted in the Crash Survival Design Criteria Designer's Guide which was first published in 1967 and has been revised numerous times, the last being in 1989. Full-scale aircraft crash testing is an expensive way to investigate structural deformations of occupied spaces and to determine the decelerative loadings experienced by occupants in a crash. This gave initial impetus to the U.S. Army to develop analytical methods to predict the dynamic response of aircraft structures in a crash. It was believed that such analytical tools could be very useful in the preliminary design stage of a new helicopter system which is required to demonstrate a level of crash resistance and had to be more cost effective than full-scale crash tests or numerous component design support tests. From an economic point of view, it is more efficient to optimize for the incorporation of crash resistance features early in the design stage. However, during preliminary design it is doubtful if sufficient design details, which influence the exact plastic deformation shape of structural elements, will be available. The availability of simple procedures to predict energy absorption and load-deformation characteristics will allow the designer to initiate valuable cost, weight, and geometry tradeoff studies. The development of these procedures will require some testing of typical specimens. This testing should, as a minimum, verify the validity of proposed procedures for providing pertinent nonlinear load-deformation data. It was hoped that through the use of these

  5. Safety performance functions for crash severity on undivided rural roads.

    PubMed

    Russo, Francesca; Busiello, Mariarosaria; Dell'Acqua, Gianluca

    2016-08-01

    The objective of this paper is to explore the effect of the road features of two-lane rural road networks on crash severity. One of the main goals is to calibrate Safety Performance Functions (SPFs) that can predict the frequency per year of injuries and fatalities on homogeneous road segments. It was found that on more than 2000km of study-road network that annual average daily traffic, lane width, curvature change rate, length, and vertical grade are important variables in explaining the severity of crashes. A crash database covering a 5-year period was examined to achieve the goals (1295 injurious crashes that included 2089 injuries and 235 fatalities). A total of 1000km were used to calibrate SPFs and the remaining 1000km reflecting the traffic, geometric, functional features of the preceding one were used to validate their effectiveness. A negative binomial regression model was used. Reflecting the crash configurations of the dataset and maximizing the validation outcomes, four main sets of SPFs were developed as follows: (a) one equation to predict only injury frequency per year for the subset where only non-fatal injuries occurred, (b) two different equations to predict injury frequency and fatality frequency per year per sub-set where at least one fa tality occurred together with one injury, and (c) only one equation to predict the total frequency per year of total casualties correlating accurate percentages to obtain the final expected frequency of injuries and fatalities per year on homogeneous road segments. Residual analysis confirms the effectiveness of the SPFs.

  6. How Common are Noise Sources on the Crash Arc of Malaysian Flight 370

    SciTech Connect

    Fenimore, Edward E.; Kunkle, Thomas David; Stead, Richard J.

    2014-10-21

    Malaysian Flight 370 disappeared nearly without a trace. Besides some communication handshakes to the INMASAT satellite, the Comprehensive Test Ban Treaty monitoring system could have heard the aircraft crash into the southern Indian Ocean. One noise event from Cape Leeuwin has been suggested by Stead as the crash and occurs within the crash location suggested by Kunkle at el. We analyze the hydrophone data from Cape Leeuwin to understand how common such noise events are on the arc of possible locations where Malaysian Flight 370 might have crashed. Few other noise sources were found on the arc. The noise event found by Stead is the strongest. No noise events are seen within the Australian Transportation Safety Board (ATSB) new search location until the 10th strongest event, an event which is very close to the noise level.

  7. Full-Scale Crash Tests and Analyses of Three High-Wing Single

    NASA Technical Reports Server (NTRS)

    Annett, Martin S.; Littell, Justin D.; Stimson, Chad M.; Jackson, Karen E.; Mason, Brian H.

    2015-01-01

    The NASA Emergency Locator Transmitter Survivability and Reliability (ELTSAR) project was initiated in 2014 to assess the crash performance standards for the next generation of ELT systems. Three Cessna 172 aircraft have been acquired to conduct crash testing at NASA Langley Research Center's Landing and Impact Research Facility. Testing is scheduled for the summer of 2015 and will simulate three crash conditions; a flare to stall while emergency landing, and two controlled flight into terrain scenarios. Instrumentation and video coverage, both onboard and external, will also provide valuable data of airframe response. Full-scale finite element analyses will be performed using two separate commercial explicit solvers. Calibration and validation of the models will be based on the airframe response under these varying crash conditions.

  8. Crash Lethality Model

    DTIC Science & Technology

    2014-02-05

    Systems Command (Code 4.3.1), 48110 Shaw Road, Patuxent River, Maryland 20670-1906. DESTRUCTION NOTICE - Destroy by any method that will prevent...GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR( S ) John A. Ball Michael Knott David Burke 5d. PROJECT NUMBER 5e. TASK NUMBER 5f...WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME( S ) AND ADDRESS(ES) Naval Air Warfare Center Aircraft Division 48110 Shaw Road Patuxent

  9. Crash-Resistant Shield

    NASA Technical Reports Server (NTRS)

    Bixler, Charles H.

    1990-01-01

    Impact-resistant shield designed to consist of aluminum honeycomb structure sandwiched between inner and outer aluminum skins. Intended to protect radioisotope thermoelectric generator of spacecraft from impact with ground or water after free fall from upper atmosphere. Designed to absorb impact energy by buckling, while inner and outer skins designed to protect against shrapnel, overpressure, and impact loads. Concept of shield applicable to crashproof compartments for ground vehicles and aircraft.

  10. Aircraft Control Strategies by Game Theoretic Approach against Wind Shear

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Masahiro; Umemura, Akira

    The safety problem of aircraft that encounters wind shear during the final approach flight phase is addressed using a game theoretic approach. The game consists of two players, an aircraft and wind shear. The control scheme is composed of non-cooperative game between players. In the game, aircraft tries to fly to avoid crashing to ground and down burst attempts to force the aircraft to crash. A new control strategy based on nonlinear receding horizon control is applied to the game. It is shown by simulation that this control strategy is effective against wind shear.

  11. Propensity scores-potential outcomes framework to incorporate severity probabilities in the highway safety manual crash prediction algorithm.

    PubMed

    Sasidharan, Lekshmi; Donnell, Eric T

    2014-10-01

    Accurate estimation of the expected number of crashes at different severity levels for entities with and without countermeasures plays a vital role in selecting countermeasures in the framework of the safety management process. The current practice is to use the American Association of State Highway and Transportation Officials' Highway Safety Manual crash prediction algorithms, which combine safety performance functions and crash modification factors, to estimate the effects of safety countermeasures on different highway and street facility types. Many of these crash prediction algorithms are based solely on crash frequency, or assume that severity outcomes are unchanged when planning for, or implementing, safety countermeasures. Failing to account for the uncertainty associated with crash severity outcomes, and assuming crash severity distributions remain unchanged in safety performance evaluations, limits the utility of the Highway Safety Manual crash prediction algorithms in assessing the effect of safety countermeasures on crash severity. This study demonstrates the application of a propensity scores-potential outcomes framework to estimate the probability distribution for the occurrence of different crash severity levels by accounting for the uncertainties associated with them. The probability of fatal and severe injury crash occurrence at lighted and unlighted intersections is estimated in this paper using data from Minnesota. The results show that the expected probability of occurrence of fatal and severe injury crashes at a lighted intersection was 1 in 35 crashes and the estimated risk ratio indicates that the respective probabilities at an unlighted intersection was 1.14 times higher compared to lighted intersections. The results from the potential outcomes-propensity scores framework are compared to results obtained from traditional binary logit models, without application of propensity scores matching. Traditional binary logit analysis suggests that

  12. "Crashing the gates" - selection criteria for television news reporting of traffic crashes.

    PubMed

    De Ceunynck, Tim; De Smedt, Julie; Daniels, Stijn; Wouters, Ruud; Baets, Michèle

    2015-07-01

    This study investigates which crash characteristics influence the probability that the crash is reported in the television news. To this purpose, all news items from the period 2006-2012 about traffic crashes from the prime time news of two Belgian television channels are linked to the official injury crash database. Logistic regression models are built for the database of all injury crashes and for the subset of fatal crashes to identify crash characteristics that correlate with a lower or higher probability of being reported in the news. A number of significant biases in terms of crash severity, time, place, types of involved road users and victims' personal characteristics are found in the media reporting of crashes. More severe crashes are reported in the media more easily than less severe crashes. Significant fluctuations in media reporting probability through time are found in terms of the year and month in which the crash took place. Crashes during week days are generally less reported in the news. The geographical area (province) in which the crash takes place also has a significant impact on the probability of being reported in the news. Crashes on motorways are significantly more represented in the news. Regarding the age of the involved victims, a clear trend of higher media reporting rates of crashes involving young victims or young fatalities is observed. Crashes involving female fatalities are also more frequently reported in the news. Furthermore, crashes involving a bus have a significantly higher probability of being reported in the news, while crashes involving a motorcycle have a significantly lower probability. Some models also indicate a lower reporting rate of crashes involving a moped, and a higher reporting rate of crashes involving heavy goods vehicles. These biases in media reporting can create skewed perceptions in the general public about the prevalence of traffic crashes and eventually may influence people's behaviour.

  13. Application of Probability Methods to Assess Crash Modeling Uncertainty

    NASA Technical Reports Server (NTRS)

    Lyle, Karen H.; Stockwell, Alan E.; Hardy, Robin C.

    2003-01-01

    Full-scale aircraft crash simulations performed with nonlinear, transient dynamic, finite element codes can incorporate structural complexities such as: geometrically accurate models; human occupant models; and advanced material models to include nonlinear stress-strain behaviors, and material failure. Validation of these crash simulations is difficult due to a lack of sufficient information to adequately determine the uncertainty in the experimental data and the appropriateness of modeling assumptions. This paper evaluates probabilistic approaches to quantify the effects of finite element modeling assumptions on the predicted responses. The vertical drop test of a Fokker F28 fuselage section will be the focus of this paper. The results of a probabilistic analysis using finite element simulations will be compared with experimental data.

  14. Application of Probability Methods to Assess Crash Modeling Uncertainty

    NASA Technical Reports Server (NTRS)

    Lyle, Karen H.; Stockwell, Alan E.; Hardy, Robin C.

    2007-01-01

    Full-scale aircraft crash simulations performed with nonlinear, transient dynamic, finite element codes can incorporate structural complexities such as: geometrically accurate models; human occupant models; and advanced material models to include nonlinear stress-strain behaviors, and material failure. Validation of these crash simulations is difficult due to a lack of sufficient information to adequately determine the uncertainty in the experimental data and the appropriateness of modeling assumptions. This paper evaluates probabilistic approaches to quantify the effects of finite element modeling assumptions on the predicted responses. The vertical drop test of a Fokker F28 fuselage section will be the focus of this paper. The results of a probabilistic analysis using finite element simulations will be compared with experimental data.

  15. Visual assessment of pedestrian crashes.

    PubMed

    Griswold, Julia; Fishbain, Barak; Washington, Simon; Ragland, David R

    2011-01-01

    Of the numerous factors that play a role in fatal pedestrian collisions, the time of day, day of the week, and time of year can be significant determinants. More than 60% of all pedestrian collisions in 2007 occurred at night, despite the presumed decrease in both pedestrian and automobile exposure during the night. Although this trend is partially explained by factors such as fatigue and alcohol consumption, prior analysis of the Fatality Analysis Reporting System database suggests that pedestrian fatalities increase as light decreases after controlling for other factors. This study applies graphical cross-tabulation, a novel visual assessment approach, to explore the relationships among collision variables. The results reveal that twilight and the first hour of darkness typically observe the greatest frequency of pedestrian fatal collisions. These hours are not necessarily the most risky on a per mile travelled basis, however, because pedestrian volumes are often still high. Additional analysis is needed to quantify the extent to which pedestrian exposure (walking/crossing activity) in these time periods plays a role in pedestrian crash involvement. Weekly patterns of pedestrian fatal collisions vary by time of year due to the seasonal changes in sunset time. In December, collisions are concentrated around twilight and the first hour of darkness throughout the week while, in June, collisions are most heavily concentrated around twilight and the first hours of darkness on Friday and Saturday. Friday and Saturday nights in June may be the most dangerous times for pedestrians. Knowing when pedestrian risk is highest is critically important for formulating effective mitigation strategies and for efficiently investing safety funds. This applied visual approach is a helpful tool for researchers intending to communicate with policy-makers and to identify relationships that can then be tested with more sophisticated statistical tools.

  16. Watch for those fragments of evidence: the use of an automatic timepiece to help correlate a helicopter crash site from the Vietnam War.

    PubMed

    Tuller, Hugh; Paolello, Josephine M

    2012-01-01

    This case study illustrates the use of the date function on an automatic wristwatch to help identify a Vietnam War helicopter crash site. The location of a crash incident can sometimes be uncertain because of inadequate or inaccurate wartime records and the passage of time. Artifacts recovered from a prospective crash scene are regularly used to correlate the loss incident. In this case study, a recovered automatic watch displayed a date 2 days later than the reported loss incident. Although the date conflicts with the aircraft crash incident report, it is observed that a fully wound automatic watch continues to work for c. 2 days after movement of the watch ceases. Thus, the watch's date in fact correlates with the aircraft crash incident report. It is noted that automatic watches may also be used to date scenes of crime.

  17. Modeling left-turn crash occurrence at signalized intersections by conflicting patterns.

    PubMed

    Wang, Xuesong; Abdel-Aty, Mohamed

    2008-01-01

    In order to better understand the underlying crash mechanisms, left-turn crashes occurring at 197 four-legged signalized intersections over 6 years were classified into nine patterns based on vehicle maneuvers and then were assigned to intersection approaches. Crash frequency of each pattern was modeled at the approach level by mainly using Generalized Estimating Equations (GEE) with the Negative Binomial as the link function to account for the correlation among the crash data. GEE with a binomial logit link function was also applied for patterns with fewer crashes. The Cumulative Residuals test shows that, for correlated left-turn crashes, GEE models usually outperformed basic Negative Binomial models. The estimation results show that there are obvious differences in the factors that cause the occurrence of different left-turn collision patterns. For example, for each pattern, the traffic flows to which the colliding vehicles belong are identified to be significant. The width of the crossing distance (represented by the number of through lanes on the opposing approach of the left-turning traffic) is associated with more left-turn traffic colliding with opposing through traffic (Pattern 5), but with less left-turning traffic colliding with near-side crossing through traffic (Pattern 8). The safety effectiveness of the left-turning signal is not consistent for different crash patterns; "protected" phasing is correlated with fewer Pattern 5 crashes, but with more Pattern 8 crashes. The study indicates that in order to develop efficient countermeasures for left-turn crashes and improve safety at signalized intersections, left-turn crashes should be considered in different patterns.

  18. CDC Vital Signs: Motor Vehicle Crash Deaths

    MedlinePlus

    ... Press Kit Read the MMWR Science Clips Motor Vehicle Crash Deaths How is the US doing? Language: ... Sweden, Switzerland, and the United Kingdom. Problem Motor vehicle crash deaths in the US are still too ...

  19. Characteristics of Older Motorcyclist Crashes

    PubMed Central

    Stutts, Jane; Foss, Robert; Svoboda, Colleen

    2004-01-01

    In the U.S. as well as other countries, the number of motorcyclists killed in traffic crashes has risen sharply over the past five years, due in part to the increased popularity of motorcycling among older riders. This paper examines trends in motorcyclist casualties and vehicle registrations from 1990–2002, based on national and state (North Carolina) motor vehicle crash and vehicle registration data. The data show similar patterns of increased fatalities that parallel a growth in motorcycle registrations. Whereas the number of motorcyclists ages 16–24 declined over the 13–year study period, the number of riders ages 35 and older increased. Three years of recent (2000–2002) NC data are examined to identify salient characteristics of the crashes of these older riders. Results are discussed with respect to approaches for mitigating the increase in motorcyclist deaths and injuries. PMID:15319126

  20. A random parameters probit model of urban and rural intersection crashes.

    PubMed

    Tay, Richard

    2015-11-01

    Intersections are hazardous locations and many studies have been conducted to identify the factors contributing to the frequency and severity of intersection crashes. However, little attention has been devoted to investigating the differences between crashes at urban and rural intersections, which have different road, traffic and environmental characteristics. By applying a random parameters probit model to the data from the Canadian Province of Alberta between 2008 and 2012, we find that urban intersection crashes are more likely to be associated with hit and run behaviours, roads with higher traffic volume, wet surfaces, four lanes and skewed intersections, and crashes on weekdays and off-peak hours, whereas rural crashes are likely to be associated with increases in fatalities and injuries, roads with higher speed limits, special road features, exit and entrance terminals, gravel, curvature and two lanes, crashes during weekends, peak hours and night-time, run-off-road crashes, and police visit to crash scene. Hence, road safety professionals in urban and rural areas should consider these differences when designing and implementing counter-measures to improve intersection safety, especially their safety audits and reviews, enforcement activities and education campaigns, to target the more vulnerable times and locations in the different areas.

  1. Adolescent Predictors of Traffic Crash Patterns from Licensure into Early Young Adulthood

    PubMed Central

    Bingham, C. Raymond; Shope, Jean T.

    2005-01-01

    This paper examines differences in the adolescent psychosocial and problem behavior characteristics of individuals who have stable-low, increasing, stable-high and decreasing frequencies of motor vehicle crashes from licensure into early young adulthood. Problem Behavior Theory was used as the guiding theoretical framework. Study data were collected when the participants were in 10th and 12th grades, and during a young adulthood follow-up telephone survey conducted five to six years later (n = 1,936). For men, stable high crash rates were associated with less parental monitoring and more substance use, and a stable low crash rates were associated with better marks in school. For women, stable high crash rates were associated with poorer marks in school and more substance use, and patterns of both decreasing and stable high crash rates were associated with less parental monitoring and less parental orientation. It is concluded that patterns of motor vehicle crashes are associated with adolescent psychosocial and problem behavior characteristics. Interventions targeting these factors may have broad positive effects on problem behaviors, including problem driving and motor vehicle crashes. In addition, the results of this study may be useful in designing traffic safety policies that target individuals whose psychosocial characteristics indicate that they are at high risk of being involved in a crash.

  2. NASA technical advances in aircraft occupant safety. [clear air turbulence detectors, fire resistant materials, and crashworthiness

    NASA Technical Reports Server (NTRS)

    Enders, J. H.

    1978-01-01

    NASA's aviation safety technology program examines specific safety problems associated with atmospheric hazards, crash-fire survival, control of aircraft on runways, human factors, terminal area operations hazards, and accident factors simulation. While aircraft occupants are ultimately affected by any of these hazards, their well-being is immediately impacted by three specific events: unexpected turbulence encounters, fire and its effects, and crash impact. NASA research in the application of laser technology to the problem of clear air turbulence detection, the development of fire resistant materials for aircraft construction, and to the improvement of seats and restraint systems to reduce crash injuries are reviewed.

  3. Can-Filled Crash Barrier

    NASA Technical Reports Server (NTRS)

    Wilson, A. H.

    1983-01-01

    Crash barrier composed largely of used aluminum beverage cans protects occupants of cars in collisions with poles or trees. Lightweight, can-filled barrier very effective in softening impact of an automobile in head-on and off-angle collisions. Preliminary results indicate barrier is effective in collisions up to 40 mi/h (64 km/h).

  4. Technostress: Surviving a Database Crash.

    ERIC Educational Resources Information Center

    Dobb, Linda S.

    1990-01-01

    Discussion of technostress in libraries focuses on a database crash at California Polytechnic State University, San Luis Obispo. Steps taken to restore the data are explained, strategies for handling technological accidents are suggested, the impact on library staff is discussed, and a 10-item annotated bibliography on technostress is provided.…

  5. Full-scale crash test of a CH-47C helicopter

    NASA Technical Reports Server (NTRS)

    Castle, C. B.

    1976-01-01

    A full-scale crash test of a large troop/cargo carrying CH-47C helicopter was conducted at the Langley impact dynamics research facility. The crash test of this large helicopter was performed as part of a joint U.S. Army-NASA helicopter test program to provide dynamic structural and seat response data. The test, the procedures employed, the instrumentation, a general assessment of the resulting damage, and typical levels of accelerations experienced during the crash are reported. Various energy-absorbing seating systems for crew and troops were installed and instrumented to provide data for use in the development of design criteria for future aircraft. The crash conditions were selected to simulate known crash conditions and are representative of the 95th percentile accident environment for an autorotating helicopter. Visual examination of the crashed test specimen indicated irreparable damage to many of the structural components. The highest accelerations were recorded by the accelerometers located on the cabin floor in the aft section of the helicopter, directly above the primary impact location and on the floor of the cockpit above the secondary impact location(s).

  6. Investigations of Crashes Involving Pregnant Occupants

    PubMed Central

    Klinich, Kathleen DeSantis; Schneider, Lawrence W.; Moore, Jamie L.; Pearlman, Mark D.

    2000-01-01

    Case reports of 16 crashes involving pregnant occupants are presented that illustrate the main conclusions of a crash-investigation program that includes 42 crashes investigated to date. Some unusual cases that are exceptions to the overall trends are also described. The study indicates a strong association between adverse fetal outcome and both crash severity and maternal injury. Proper restraint use, with and without airbag deployment, generally leads to acceptable fetal outcomes in lower severity crashes, while it does not affect fetal outcome in high-severity crashes. Compared to properly restrained pregnant occupants, improperly restrained occupants have a higher risk of adverse fetal outcome in lower severity crashes, which comprise the majority of all motor-vehicle collisions. PMID:11558095

  7. Modeling the effect of operator and passenger characteristics on the fatality risk of motorcycle crashes

    PubMed Central

    Tavakoli Kashani, Ali; Rabieyan, Rahim; Besharati, Mohammad Mehdi

    2016-01-01

    Abstract: Background: In Iran more than 25% of crash fatalities belong to motorcycle operators and passengers in the recent years, from which about 20% are related to passenger fatalities. Methods: The aim of this study was to investigate the motorcycle operator and passenger characteristics as well as other contributory factors that may affect the fatality risk of motorcyclists involved in traffic crashes. To this end, motorcycle crash data between 2009 and 2012 was extracted from Iran traffic crash database and a logistic regression analysis was performed to obtain odds ratio estimates for each of the study variables. Results: The fatality risk of motorcyclists has a direct relationship with the number of pillion passengers carried. Results also indicate that the amount of increase in the likelihood of having a fatality in a motorcycles crash is considerably higher when the operator is accompanied by a male passenger of the same age. Furthermore, results showed that if the crash is occurred in the darkness, on curves, in rural areas and on highways, then the crash would be more likely to be fatal. Moreover, the head-on collisions, older operators, unlicensed operators and not using a safety helmet were found to increase the likelihood of a fatality in a motorcycle crash. Conclusions: Preventative measures such as, imposing stricter rules regarding safety helmet usage and confining the number of pillion passengers to one, might be implemented to reduce the fatality risk in motorcycle crashes. In addition, more appropriate infrastructures for penalizing offending motorcyclists could also reduce the frequency of law violations such as not wearing helmet or riding without motorcycle license, which in turn, would result into a reduction in the fatality risk of motorcycle crashes. PMID:26420217

  8. Observed and unobserved correlation between crash avoidance manoeuvers and crash severity.

    PubMed

    Kaplan, Sigal; Prato, Carlo Giacomo

    2016-12-01

    Understanding drivers' responses to critical events, analyzing drivers' abilities to perform corrective manoeuvers, and investigating the correlation between these manoeuvers and crash severity provide the opportunity of increasing the knowledge about how to avoid crash occurrence or at least mitigate crash severity. We extend existing research on the determinants of engaging in crash avoidance manoeuvers by considering that observable and unobservable factors relate to both the selection of corrective manoeuvers and the severity outcome. Accordingly, we propose a joint multinomial-logit ordered-probit model of single-vehicle crashes extracted from the NASS GES database for the years 2005-2009. Results show (1) the existence of unobserved correlation between crash avoidance manoeuvers and crash severity, and (2) the link between drivers' attributes, risky driving behaviour, road characteristics, and environmental conditions, with the propensity to engage in crash avoidance manoeuvers and experience severe crash outcomes.

  9. Full-Scale Crash Test of an MD-500 Helicopter

    NASA Technical Reports Server (NTRS)

    Littell, Justin

    2011-01-01

    A full-scale crash test was successfully conducted in March 2010 of an MD-500 helicopter at NASA Langley Research Center s Landing and Impact Research Facility. The reasons for conducting this test were threefold: 1 To generate data to be used with finite element computer modeling efforts, 2 To study the crashworthiness features typically associated with a small representative helicopter, and 3 To compare aircraft response to data collected from a previously conducted MD-500 crash test, which included an externally deployable energy absorbing (DEA) concept. Instrumentation on the airframe included accelerometers on various structural components of the airframe; and strain gages on keel beams, skid gear and portions of the skin. Three Anthropomorphic Test Devices and a specialized Human Surrogate Torso Model were also onboard to collect occupant loads for evaluation with common injury risk criteria. This paper presents background and results from this crash test conducted without the DEA concept. These results showed accelerations of approximately 30 to 50 g on the airframe at various locations, little energy attenuation through the airframe, and moderate to high probability of occupant injury for a variety of injury criteria.

  10. A Study of Transport Airplane Crash-Resistant Fuel Systems

    NASA Technical Reports Server (NTRS)

    Jones, Lisa (Technical Monitor); Robertson, S. H.; Johnson, N. B.; Hall, D. S.; Rimson, I. J.

    2002-01-01

    This report presents the results of a study, funded by the Federal Aviation Administration (FAA), of transport airplane crash-resistant fuel system (CRFS). The report covers the historical studies related to aircraft crash fires and fuel containment concepts undertaken by the FAA, NASA, and the U.S. Army, which ultimately led to the current state of the art in CRFS technology. It describes the basic research, testing, field investigations and production efforts which have led to the highly successful military CRFS, which has saved many lives and reduced costs of accidents. Current CRFS technology used in transport category airplanes is defined and compared to the available state-of-the-art technology. The report provides information to the FAA and other government organizations which can help them plan their efforts to improve the state of crash fire protection in the transport airplane fleet. The report provides guidance to designers looking for information about CRFS design problems, analysis tools to use for product improvement, and a summary of current and proposed regulations for transport category airplane fuel systems.

  11. Naturalistic Assessment of Novice Teenage Crash Experience

    PubMed Central

    Lee, Suzanne E.; Simons-Morton, Bruce G.; Klauer, Sheila E.; Ouimet, Marie Claude; Dingus, Thomas A.

    2011-01-01

    Background Crash risk is highest during the first months after licensure. Current knowledge about teenagers’ driving exposure and the factors increasing their crash risk is based on self-reported data and crash database analyses. While these research tools are useful, new developments in naturalistic technologies have allowed researchers to examine newly-licensed teenagers’ exposure and crash risk factors in greater detail. The Naturalistic Teenage Driving Study (NTDS) described in this paper is the first study to follow a group of newly-licensed teenagers continuously for 18 months after licensure. The goals of this paper are to compare the crash and near-crash experience of drivers in the NTDS to national trends, to describe the methods and lessons learned in the NTDS, and to provide initial data on driving exposure for these drivers. Methods A data acquisition system was installed in the vehicles of 42 newly-licensed teenage drivers 16 years of age during their first 18 months of independent driving. It consisted of cameras, sensors (accelerometers, GPS, yaw, front radar, lane position, and various sensors obtained via the vehicle network), and a computer with removable hard drive. Data on the driving of participating parents was also collected when they drove the instrumented vehicle. Findings The primary findings after 18 months included the following: (1) crash and near-crash rates among teenage participants were significantly higher during the first six months of the study than the final 12 months, mirroring the national trends; (2) crash and near-crash rates were significantly higher for teenage than adult (parent) participants, also reflecting national trends; (3) teenaged driving exposure averaged between 507-710 kilometers (315-441 miles) per month over the study period, but varied substantially between participants with standard errors representing 8-14 percent of the mean; and (4) crash and near-crash types were very similar for male and female

  12. 77 FR 52205 - Airworthiness Directives; Univair Aircraft Corporation Airplanes

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-29

    ... Corporation Airplanes AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: We are superseding an existing airworthiness directive (AD) for certain Univair Aircraft Corporation Models (ERCO... of a Univair Aircraft Corporation Model ERCO 415-D Ercoupe that crashed after an in-flight ]...

  13. Sleep-related crash characteristics: Implications for applying a fatigue definition to crash reports.

    PubMed

    Filtness, A J; Armstrong, K A; Watson, A; Smith, S S

    2017-02-01

    Sleep-related (SR) crashes are an endemic problem the world over. However, police officers report difficulties in identifying sleepiness as a crash contributing factor. One approach to improving the sensitivity of SR crash identification is by applying a proxy definition post hoc to crash reports. To identify the prominent characteristics of SR crashes and highlight the influence of proxy definitions, ten years of Queensland (Australia) police reports of crashes occurring in ≥100km/h speed zones were analysed. In Queensland, two approaches are routinely taken to identifying SR crashes. First, attending police officers identify crash causal factors; one possible option is 'fatigue/fell asleep'. Second, a proxy definition is applied to all crash reports. Those meeting the definition are considered SR and added to the police-reported SR crashes. Of the 65,204 vehicle operators involved in crashes 3449 were police-reported as SR. Analyses of these data found that male drivers aged 16-24 years within the first two years of unsupervised driving were most likely to have a SR crash. Collision with a stationary object was more likely in SR than in not-SR crashes. Using the proxy definition 9739 (14.9%) crashes were classified as SR. Using the proxy definition removes the findings that SR crashes are more likely to involve males and be of high severity. Additionally, proxy defined SR crashes are no less likely at intersections than not-SR crashes. When interpreting crash data it is important to understand the implications of SR identification because strategies aimed at reducing the road toll are informed by such data. Without the correct interpretation, funding could be misdirected. Improving sleepiness identification should be a priority in terms of both improvement to police and proxy reporting.

  14. Deployable System for Crash-Load Attenuation

    NASA Technical Reports Server (NTRS)

    Kellas, Sotiris; Jackson, Karen E.

    2007-01-01

    An externally deployable honeycomb structure is investigated with respect to crash energy management for light aircraft. The new concept utilizes an expandable honeycomb-like structure to absorb impact energy by crushing. Distinguished by flexible hinges between cell wall junctions that enable effortless deployment, the new energy absorber offers most of the desirable features of an external airbag system without the limitations of poor shear stability, system complexity, and timing sensitivity. Like conventional honeycomb, once expanded, the energy absorber is transformed into a crush efficient and stable cellular structure. Other advantages, afforded by the flexible hinge feature, include a variety of deployment options such as linear, radial, and/or hybrid deployment methods. Radial deployment is utilized when omnidirectional cushioning is required. Linear deployment offers better efficiency, which is preferred when the impact orientation is known in advance. Several energy absorbers utilizing different deployment modes could also be combined to optimize overall performance and/or improve system reliability as outlined in the paper. Results from a series of component and full scale demonstration tests are presented as well as typical deployment techniques and mechanisms. LS-DYNA analytical simulations of selected tests are also presented.

  15. Effect of electronic stability control on automobile crash risk.

    PubMed

    Farmer, Charles

    2004-12-01

    Per vehicle crash involvement rates were compared for otherwise identical vehicle models with and without electronic stability control (ESC) systems. ESC was found to affect single-vehicle crashes to a greater extent than multiple-vehicle crashes, and crashes with fatal injuries to a greater extent than less severe crashes. Based on all police-reported crashes in 7 states over 2 years, ESC reduced single-vehicle crash involvement risk by approximately 41 percent (95 percent confidence limits 3348) and single-vehicle injury crash involvement risk by 41 percent (2752). This translates to an estimated 7 percent reduction in overall crash involvement risk (310) and a 9 percent reduction in overall injury crash involvement risk (314). Based on all fatal crashes in the United States over 3 years, ESC was found to have reduced single-vehicle fatal crash involvement risk by 56 percent (3968). This translates to an estimated 34 percent reduction in overall fatal crash involvement risk (2145).

  16. Low frequency cabin noise reduction based on the intrinsic structural tuning concept: The theory and the experimental results, phase 2. [jet aircraft noise

    NASA Technical Reports Server (NTRS)

    Sengupta, G.

    1978-01-01

    Low frequency cabin noise and sonically induced stresses in an aircraft fuselage may be reduced by intrinsic tuning of the various structural members such as the skin, stringers, and frames and then applying damping treatments on these members. The concept is also useful in identifying the key structural resonance mechanisms controlling the fuselage response to broadband random excitation and in developing suitable damping treatments for reducing the structural response in various frequency ranges. The mathematical proof of the concept and the results of some laboratory and field tests on a group of skin-stringer panels are described. In the so-called stiffness-controlled region, the noise transmission may actually be controlled by stiffener resonances, depending upon the relationship between the natural frequencies of the skin bay and the stiffeners. Therefore, cabin noise in the stiffness-controlled region may be effectively reduced by applying damping treatments on the stiffeners.

  17. Comprehensive analysis of vehicle-pedestrian crashes at intersections in Florida.

    PubMed

    Lee, Chris; Abdel-Aty, Mohamed

    2005-07-01

    This study analyzes vehicle-pedestrian crashes at intersections in Florida over 4 years, 1999-2002. The study identifies the group of drivers and pedestrians, and traffic and environmental characteristics that are correlated with high pedestrian crashes using log-linear models. The study also estimates the likelihood of pedestrian injury severity when pedestrians are involved in crashes using an ordered probit model. To better reflect pedestrian crash risk, a logical measure of exposure is developed using the information on individual walking trips in the household travel survey. Lastly, the impact of average traffic volume on pedestrian crashes is examined. As a result of the analysis, it was found that pedestrian and driver demographic factors, and road geometric, traffic and environment conditions are closely related to the frequency and injury severity of pedestrian crashes. Higher average traffic volume at intersections increases the number of pedestrian crashes; however, the rate of increase is steeper at lower values of average traffic volume. Based on the findings in the analysis, some countermeasures are recommended to improve pedestrian safety.

  18. Potential Crash Location (PCL) Model

    DTIC Science & Technology

    2014-02-05

    UNCLASSIFIED AD NUMBER LIMITATION CHANGES TO: FROM: AUTHORITY THIS PAGE IS UNCLASSIFIED ADB383242 Approved for public release; distribution is...model; Sensis model 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF PAGES 19a. NAME OF RESPONSIBLE PERSON...approach to defining the outer limits . This report also discusses two different approaches to modeling rotor craft UAS crash locations. NAWCADPAX/TR

  19. Structureborne noise in aircraft

    NASA Technical Reports Server (NTRS)

    Clevenson, S. A.; Metcalf, V. L.

    1987-01-01

    The amount of noise reaching an aircraft's interior by structureborne paths, when high levels of other noises are present, involves the measurement of transfer functions between vibrating levels on the wing and interior noise. The magnitude of the structureborne noise transfer function is established by exciting the aircraft with an electrodynamic shaker; a second transfer function is measured using the same sensor locations with the aircraft engines operating. Attention is given to the case of a twin-turboprop OV-10A aircraft; the resulting transfer function values at the discrete frequencies corresponding to the propeller blade passage frequency and its first four harmonics are tabulated and illustrated.

  20. Identification of Aircraft Hazards

    SciTech Connect

    K. Ashley

    2006-12-08

    Aircraft hazards were determined to be potentially applicable to a repository at Yucca Mountain in ''Monitored Geological Repository External Events Hazards Screening Analysis'' (BSC 2005 [DIRS 174235], Section 6.4.1). That determination was conservatively based upon limited knowledge of flight data in the area of concern and upon crash data for aircraft of the type flying near Yucca Mountain. The purpose of this report is to identify specific aircraft hazards that may be applicable to a monitored geologic repository (MGR) at Yucca Mountain, using NUREG-0800, ''Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants'' (NRC 1987 [DIRS 103124], Section 3.5.1.6), as guidance for the inclusion or exclusion of identified aircraft hazards. The intended use of this report is to provide inputs for further screening and analysis of identified aircraft hazards based upon the criteria that apply to Category 1 and Category 2 event sequence analyses as defined in 10 CFR 63.2 [DIRS 176544] (Section 4). The scope of this report includes the evaluation of military, private, and commercial use of airspace in the 100-mile regional setting of the repository at Yucca Mountain with the potential for reducing the regional setting to a more manageable size after consideration of applicable screening criteria (Section 7).

  1. IDENTIFICATION OF AIRCRAFT HAZARDS

    SciTech Connect

    K.L. Ashley

    2005-03-23

    Aircraft hazards were determined to be potentially applicable to a repository at Yucca Mountain in the ''Monitored Geological Repository External Events Hazards Screening Analysis'' (BSC 2004, Section 6.4.1). That determination was conservatively based on limited knowledge of flight data in the area of concern and on crash data for aircraft of the type flying near Yucca Mountain. The purpose of this report is to identify specific aircraft hazards that may be applicable to a Monitored Geologic Repository (MGR) at Yucca Mountain using NUREG-0800, ''Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants'' (NRC 1987, Section 3.5.1.6), as guidance for the inclusion or exclusion of identified aircraft hazards. NUREG-0800 is being used here as a reference because some of the same considerations apply. The intended use of this report is to provide inputs for further screening and analysis of the identified aircraft hazards based on the criteria that apply to Category 1 and 2 event sequence analyses as defined in 10 CFR 63.2 (see Section 4). The scope of this technical report includes the evaluation of military, private, and commercial use of airspace in the 100-mile regional setting of the MGR at Yucca Mountain with the potential for reducing the regional setting to a more manageable size after consideration of applicable screening criteria (see Section 7).

  2. Road crashes involving animals in Australia.

    PubMed

    Rowden, Peter; Steinhardt, Dale; Sheehan, Mary

    2008-11-01

    Each year in Australia many thousands of collisions occur between motor vehicles and animals, resulting in considerable vehicle repair costs, injury to persons, and loss of animal life. This paper reviews animal-related road crashes in Australia and presents data from the in-depth Rural and Remote Road Safety Study in North Queensland for serious casualties (n=33) resulting from direct impact with an animal or swerving to avoid an animal on public roads. These crash types accounted for 5.5% of all eligible on-road serious casualties in the study and, hence, are considered to be an important issue that requires particular attention within rural and remote areas. Kangaroos and wallabies were the predominant species involved in these crashes (44.8%). Consistent with international studies, night-time travel was found to be a significant risk factor when comparing animal-related crashes to other serious injury crashes in the study. There were also a significantly higher proportion of motorcyclists (51.7%) than other vehicle occupants involved in animal-related serious crashes compared to all other serious injury crashes. Data matching to official Government records found underreporting of animal-related crashes to be an issue of concern. These findings are discussed in terms of countermeasures suitable for the Australian context and the need for consistent crash reporting across jurisdictions.

  3. Motorcycle-related spinal injury: crash characteristics.

    PubMed

    Zulkipli, Zarir Hafiz; Abdul Rahmat, Abdul Manap; Mohd Faudzi, Siti Atiqah; Paiman, Noor Faradila; Wong, Shaw Voon; Hassan, Ahamedali

    2012-11-01

    This study presents an analysis of crash characteristics of motorcyclists who sustained spinal injuries in motorcycle crashes. The aim of the study is to identify the salient crash characteristics that would help explain spinal injury risks for motorcyclists. Data were retrospectively collected from police case reports that were archived at MIROS from year 2005 to 2007. The data were categorized into two subcategories; the first group was motorcycle crashes with spinal injury (case) and the second group was motorcycle crashes without spinal injury (control). A total of 363 motorcyclists with spinal injury and 873 motorcyclists without spinal injury were identified and analyzed. Descriptive analysis and multivariate analysis were performed in order to determine the odds of each characteristic in contributing to spinal injury. Single vehicle crash, collision with fixed objects and crash configuration were found to have significant influence on motorcyclists in sustaining spinal injury (p<0.05). Although relatively few than other impact configurations, the rear-end impacted motorcyclist shows the highest risk of spinal injury. Helmets have helped to reduce head injury but they did not seem to offer corresponding protection for the spine in the study. With a growing number of young motorcyclists, further efforts are needed to find effective measures to help reduce the crash incidents and severity of spinal injury. In sum, the study provides some insights on some vital crash characteristics associated with spinal injury that can be further investigated to determine the appropriate counter-measures and prevention strategies to reduce spinal injury.

  4. Multifractal analysis of stock exchange crashes

    NASA Astrophysics Data System (ADS)

    Siokis, Fotios M.

    2013-03-01

    We analyze the complexity of rare events of the DJIA Index. We reveal that the returns of the time series exhibit strong multifractal properties meaning that temporal correlations play a substantial role. The effect of major stock market crashes can be best illustrated by the comparison of the multifractal spectra of the time series before and after the crash. Aftershock periods compared to foreshock periods exhibit richer and more complex dynamics. Compared to an average crash, calculated by taking into account the larger 5 crashes of the DJIA Index, the 1929 event exhibits significantly more increase in multifractality than the 1987 crisis.

  5. CDC Vital Signs: Motor Vehicle Crash Injuries: Costly but Preventable

    MedlinePlus

    ... Press Kit Read the MMWR Science Clips Motor Vehicle Crash Injuries Costly but Preventable Language: English Español ( ... and how to prevent future crashes. Problem Motor vehicle crashes are a leading cause of injury in ...

  6. Adoption of right turn on red: effects on crashes at signalized intersections

    SciTech Connect

    Zador, P.; Moshman, J.; Marcus, L.

    1980-01-01

    By the end of the 1970's, all states in the US had modified their laws to permit drivers to turn right on steady red at signalized intersections. Police-reported crash data from six states (New Jersey, Oklahoma, South Carolina, Tennessee, Virginia, and Wisconsin) where permissive right-turn-on-red laws were adopted during 1974 to 1977, as well as data from three states where the law in effect was unchanged throughout the period, were used to determine the effect of adopting such laws on the frequency of crashes involving right turning maneuvers at signalized intersections. It was found that the increase in the overall frequency of such crashes in states that adopted permissive right-turn-on-red laws exceeded by more than 20% the comparable change in states that retained the same laws. Larger than average increases were found for crashes in urban areas (25%) and for crashes involving a single vehicle and a pedestrian (57%) especially in urban areas (79%). An increase of over 30% was found for child pedestrians. A 100% increase was found for adults, and 110% increase in pedestrian crashes was found for the elderly after adoption of RTOR. It was concluded that the widespread and indiscriminate adoption of permissive right-turn-on-red laws was in conflict with the Congressional intent of adopting such laws only to the maximum extent practicable consistent with safety.

  7. Effects of Enforcement Intensity on Alcohol Impaired Driving Crashes

    PubMed Central

    Fell, James C.; Waehrer, Geetha; Voas, Robert B.; Auld-Owens, Amy; Carr, Katie; Pell, Karen

    2014-01-01

    Background Research measuring levels of enforcement has investigated whether increases in police activities (e.g., checkpoints, driving-while-intoxicated [DWI] special patrols) above some baseline level are associated with reduced crashes and fatalities. Little research, however, has attempted to quantitatively measure enforcement efforts and relate different enforcement levels to specific levels of the prevalence of alcohol-impaired driving. Objective The objective of this study was to investigate the effects of law-enforcement intensity in a sample of communities on the rate of crashes involving a drinking driver. We analyzed the influence of different enforcement strategies and measures: (1) specific deterrence -annual number of driving-under-the-influence (DUI) arrests per capita; (2) general deterrence -frequency of sobriety checkpoint operations; (3) highly visible traffic enforcement -annual number of traffic stops per capita; (4) enforcement presence - number of sworn officers per capita; and (5) overall traffic enforcement - the number of other traffic enforcement citations per capita (i.e., seat belt citations, speeding tickets, and other moving violations and warnings) in each community. Methods We took advantage of nationwide data on the local prevalence of impaired driving from the 2007 National Roadside Survey (NRS), measures of DUI enforcement activity provided by the police departments that participated in the 2007 NRS, and crashes from the General Estimates System (GES) in the same locations as the 2007 NRS. We analyzed the relationship between the intensity of enforcement and the prevalence of impaired driving crashes in 22 to 26 communities with complete data. Log-linear regressions were used throughout the study. Results A higher number of DUI arrests per 10,000 driving-aged population was associated with a lower ratio of drinking-driver crashes to non-drinking-driver crashes (p=0.035) when controlling for the percentage of legally intoxicated

  8. Injury in U.S. Army helicopter crashes October 1979-September 1985.

    PubMed

    Shanahan, D F; Shanahan, M O

    1989-04-01

    All U.S. Army class A and B mishaps of four types of helicopters occurring from 1 October 1979 through 30 September 1985 were reviewed. During this 6-year period, there were 298 crashes involving 303 aircraft. There were 1,060 individuals aboard the crashed aircraft and 611 were injured, 136 fatally. The most common cause of injury was the "secondary impact" caused by collapse of structure into occupied areas, by inadequate restraint of the occupants which allowed them to flail into structure, or by a combination of both mechanisms. Injury solely related to acceleration occurred infrequently. The most frequently injured body regions in survivable crashes were the head (28%) and extremities (43%). Injury patterns are compared for different helicopter types and related to differences in design. Basic principles of crash injury protection, including individual protection by helmets, seatbelts, and airbags, and structural modifications to minimize injury potential, as well as crashworthy fuel systems, are reviewed, and recommendations are made to increase the crashworthiness of helicopters, such as adapting designs and standards on the basis of active field investigations.

  9. Patient Litter System Response in a Full-Scale CH-46 Crash Test.

    PubMed

    Weisenbach, Charles A; Rooks, Tyler; Bowman, Troy; Fralish, Vince; McEntire, B Joseph

    2017-03-01

    U.S. Military aeromedical patient litter systems are currently required to meet minimal static strength performance requirements at the component level. Operationally, these components must function as a system and are subjected to the dynamics of turbulent flight and potentially crash events. The first of two full-scale CH-46 crash tests was conducted at NASA's Langley Research Center and included an experiment to assess patient and litter system response during a severe but survivable crash event. A three-tiered strap and pole litter system was mounted into the airframe and occupied by three anthropomorphic test devices (ATDs). During the crash event, the litter system failed to maintain structural integrity and collapsed. Component structural failures were recorded from the litter support system and the litters. The upper ATD was displaced laterally into the cabin, while the middle ATD was displaced longitudinally into the cabin. Acceleration, force, and bending moment data from the instrumented middle ATD were analyzed using available injury criteria. Results indicated that a patient might sustain a neck injury. The current test illustrates that a litter system, with components designed and tested to static requirements only, experiences multiple component structural failures during a dynamic crash event and does not maintain restraint control of its patients. It is unknown if a modern litter system, with components tested to the same static criteria, would perform differently. A systems level dynamic performance requirement needs to be developed so that patients can be provided with protection levels equivalent to that provided to seated aircraft occupants.

  10. Occupant injury in rollover crashes - Contribution of planar impacts with objects and other vehicles.

    PubMed

    Ivarsson, Johan; Poplin, Gerald; McMurry, Tim; Crandall, Jeff; Kerrigan, Jason

    2015-12-01

    Planar impacts with objects and other vehicles may increase the risk and severity of injury in rollover crashes. The current study compares the frequency of injury measures (MAIS 2+, 3+, and 4+; fatal; AIS 2+ head and cervical spine; and AIS 3+ head and thorax) as well as vehicle type distribution (passenger car, SUV, van, and light truck), crash kinematics, and occupant demographics between single vehicle single event rollovers (SV Pure) and multiple event rollovers to determine which types of multiple event rollovers can be pooled with SV Pure to study rollover induced occupant injury. Four different types of multiple event rollovers were defined: single and multi-vehicle crashes for which the rollover is the most severe event (SV Prim and MV Prim) and single and multi-vehicle crashes for which the rollover is not the most severe event (SV Non-Prim and MV Non-Prim). Information from real world crashes was obtained from the National Automotive Sampling System - Crashworthiness Data System (NASS-CDS) for the period from 1995 through 2011. Belted, contained or partially ejected, adult occupants in vehicles that completed 1-16 lateral quarter turns were assigned to one of the five rollover categories. The results showed that the frequency of injury in non-primary rollovers (SV Non-Prim and MV Non-Prim) involving no more than one roof inversion is substantially greater than in SV Pure, but that this disparity diminishes for crashes involving multiple inversions. It can further be concluded that for a given number of roof inversions, the distribution of injuries and crash characteristics in SV Pure and SV Prim crashes are sufficiently similar for these categories to be considered collectively for purposes of understanding etiologies and developing strategies for prevention.

  11. Modeling fault among motorcyclists involved in crashes.

    PubMed

    Haque, Md Mazharul; Chin, Hoong Chor; Huang, Helai

    2009-03-01

    Singapore crash statistics from 2001 to 2006 show that the motorcyclist fatality and injury rates per registered vehicle are higher than those of other motor vehicles by 13 and 7 times, respectively. The crash involvement rate of motorcyclists as victims of other road users is also about 43%. The objective of this study is to identify the factors that contribute to the fault of motorcyclists involved in crashes. This is done by using the binary logit model to differentiate between at-fault and not-at-fault cases and the analysis is further categorized by the location of the crashes, i.e., at intersections, on expressways and at non-intersections. A number of explanatory variables representing roadway characteristics, environmental factors, motorcycle descriptions, and rider demographics have been evaluated. Time trend effect shows that not-at-fault crash involvement of motorcyclists has increased with time. The likelihood of night time crashes has also increased for not-at-fault crashes at intersections and expressways. The presence of surveillance cameras is effective in reducing not-at-fault crashes at intersections. Wet-road surfaces increase at-fault crash involvement at non-intersections. At intersections, not-at-fault crash involvement is more likely on single-lane roads or on median lane of multi-lane roads, while on expressways at-fault crash involvement is more likely on the median lane. Roads with higher speed limit have higher at-fault crash involvement and this is also true on expressways. Motorcycles with pillion passengers or with higher engine capacity have higher likelihood of being at-fault in crashes on expressways. Motorcyclists are more likely to be at-fault in collisions involving pedestrians and this effect is higher at night. In multi-vehicle crashes, motorcyclists are more likely to be victims than at-fault. Young and older riders are more likely to be at-fault in crashes than middle-aged group of riders. The findings of this study will help

  12. Simulation of Aircraft Landing Gears with a Nonlinear Dynamic Finite Element Code

    NASA Technical Reports Server (NTRS)

    Lyle, Karen H.; Jackson, Karen E.; Fasanella, Edwin L.

    2000-01-01

    Recent advances in computational speed have made aircraft and spacecraft crash simulations using an explicit, nonlinear, transient-dynamic, finite element analysis code more feasible. This paper describes the development of a simple landing gear model, which accurately simulates the energy absorbed by the gear without adding substantial complexity to the model. For a crash model, the landing gear response is approximated with a spring where the force applied to the fuselage is computed in a user-written subroutine. Helicopter crash simulations using this approach are compared with previously acquired experimental data from a full-scale crash test of a composite helicopter.

  13. Sympathetic crashing acute pulmonary edema

    PubMed Central

    Agrawal, Naman; Kumar, Akshay; Aggarwal, Praveen; Jamshed, Nayer

    2016-01-01

    Sympathetic crashing acute pulmonary edema (SCAPE) is the extreme end of the spectrum of acute pulmonary edema. It is important to understand this disease as it is relatively common in the emergency department (ED) and has better outcomes when managed appropriately. The patients have an abrupt redistribution of fluid in the lungs, and when treated promptly and effectively, these patients will rapidly recover. Noninvasive ventilation and intravenous nitrates are the mainstay of treatment which should be started within minutes of the patient's arrival to the ED. Use of morphine and intravenous loop diuretics, although popular, has poor scientific evidence. PMID:28149030

  14. Sympathetic crashing acute pulmonary edema.

    PubMed

    Agrawal, Naman; Kumar, Akshay; Aggarwal, Praveen; Jamshed, Nayer

    2016-12-01

    Sympathetic crashing acute pulmonary edema (SCAPE) is the extreme end of the spectrum of acute pulmonary edema. It is important to understand this disease as it is relatively common in the emergency department (ED) and has better outcomes when managed appropriately. The patients have an abrupt redistribution of fluid in the lungs, and when treated promptly and effectively, these patients will rapidly recover. Noninvasive ventilation and intravenous nitrates are the mainstay of treatment which should be started within minutes of the patient's arrival to the ED. Use of morphine and intravenous loop diuretics, although popular, has poor scientific evidence.

  15. Pedestrian crashes in Washington, DC and Baltimore.

    PubMed

    Preusser, David F; Wells, JoAnn K; Williams, Allan F; Weinstein, Helen B

    2002-09-01

    Police crash reports were obtained for pedestrian-motor vehicle crashes in Washington, DC (N = 852) and Baltimore (N = 1234) for the year 1998. Reports were coded using procedures developed and applied in these two cities during the 1970s, including the determination of pedestrian crash type, primary precipitating factor, and culpability. Results indicated substantial differences between crash patterns observed during the 1970s and those observed during 1998. Midblock dart-dash crashes, which typically involve a precipitating factor or critical error by a child pedestrian, decreased (from 37% to 15% in Washington). Across all crashes in both cities, the number of drivers who made a critical error leading to the crash was nearly equivalent to the number of pedestrians who made a critical error. Overall, pedestrians were slightly more likely to be judged culpable (50% vs. 39%). Turning vehicle crashes, which typically involve a driver's failure to grant a pedestrian the right of way at a signalized intersection, increased (from 9% to 25% in Washington). Countermeasures to reduce the number of pedestrians hit by turning vehicles are discussed.

  16. Bibliography on aircraft fire hazards and safety. Volume 2: Safety. Part 1: Key numbers 1 to 524

    NASA Technical Reports Server (NTRS)

    Pelouch, J. J., Jr. (Compiler); Hacker, P. T. (Compiler)

    1974-01-01

    Bibliographic citations are presented to describe and define aircraft safety methods, equipment, and criteria. Some of the subjects discussed are: (1) fire and explosion suppression using whiffle balls, (2) ultraviolet flame detecting sensors, (3) evaluation of flame arrestor materials for aircraft fuel systems, (4) crash fire prevention system for supersonic commercial aircraft, and (5) fire suppression for aerospace vehicles.

  17. Methods to rank traffic rule violations resulting in crashes for allocation of funds.

    PubMed

    Penmetsa, Praveena; Pulugurtha, Srinivas S

    2017-02-01

    Education, enforcement and engineering countermeasures are implemented to make road users comply with the traffic rules. Not all the traffic rule violations can be addressed nor countermeasures be implemented at all unsafe locations, at once, due to limited funds. Therefore, this study aims at ranking the traffic rule violations resulting in crashes based on individual ranks, such as 1) frequency (expressed as a function of the number of drivers violating a traffic rule and involved in crashes), 2) crash severity, 3) total crash cost, and, 4) cost severity index, to assist transportation system managers in prioritizing the allocation of funds and improving safety on roads. Crash data gathered for the state of North Carolina was processed and used in this study. Variations in the ranks of traffic rule violations were observed when individual ranking methods are used. As an example, exceeding authorized speed limit and driving under the influence of alcohol are ranked 1st and 2nd based on crash severity while failure to reduce speed and failure to yield the right-of-way are ranked 1st and 2nd based on frequency. To minimize the variations and capture the merits of individual ranking methods, four different composite ranks were computed by combining selected individual ranks. The computed averages and standard deviations of absolute rank differences between composite ranks is lower than those obtained from individual ranks. The weights to combine the selected individual ranks have a marginal effect on the computed averages and standard deviations of absolute rank differences. Combining frequency and crash severity or cost severity index, using equal weights, is recommended for prioritization and allocation of funds.

  18. Peacetime Replacement and Crash Damage Factors for Army Aircraft

    DTIC Science & Technology

    1989-05-01

    3 .- ~4 -- 4-PI - % c - CI -C 0 m 1 12 l i1 f- Ci Vs I % 4 44 V4c - C) ) *. 40 w, - %D 4m...0c caI cnz wt OZm U) *50 LL4 U1. co* Cq I If LLi t4 .4 .C4 Ul Ul . 44 M- ci coJ v! CflU! m) 0 rs ca a.a Lt w t.t. -1 LI10 LL 0.~ .4q 0q- 3 C4 cLaL (1 P...14 IL . 4C4 .| aJIL ’-4 C0 C Iu IJ I I - -N c z:~ C, C9 t~~ 4 .. . 6"" w1 ILI 00 - ED c~Lc. WA.o. 0% 0 . 3 P - Up t NQ4 0 1. MiN 44 :

  19. Advanced Concept in Aircraft Crash Firefighting Using Carbon Tetrafluoride.

    DTIC Science & Technology

    1980-03-01

    tetrafluoromethane (carbon tetrafluoride) CF4 (Halon 1400), hexafluoroethane C2F6 (Halon 2600), and octafluoropropane C3 F8 (Halon 3800). The agents are...above when measured within the fire-hardened section. Determination Of Smoke Density. Two methods were employed to assess the relative visual...collection solution could be accurately measured . The other sampling device (figure 12) consisted of two evacuated test tubes held in place by a wooden bracket

  20. A Study of Aircraft Post-Crash Fuel Fire Mitigation

    DTIC Science & Technology

    1994-06-01

    Center-Belvoir N Fort Belvoir, Virginia Oma ___ Contract No. DAAK70-92-C-0059 Approved for public release; distribution unlimited June 1994 19 19 2 2...Road, Suits 230 Ft. Belvoir, Virginia 22060-5843 11. SUPPLEMENTARY NOTES 12L. DISTRIBUTIOWAVAILABIUITY STATEMENT 12b. DISTRIBUTION CODE Approved fior...manufactuin as specified by fth Environmental. Protection Agency. Effectiveness of agents has beeni determined udra Variety of laboratory test conditions. Mass

  1. A preliminary investigation of the relationships between historical crash and naturalistic driving.

    PubMed

    Pande, Anurag; Chand, Sai; Saxena, Neeraj; Dixit, Vinayak; Loy, James; Wolshon, Brian; Kent, Joshua D

    2017-04-01

    This paper describes a project that was undertaken using naturalistic driving data collected via Global Positioning System (GPS) devices to demonstrate a proof-of-concept for proactive safety assessments of crash-prone locations. The main hypothesis for the study is that the segments where drivers have to apply hard braking (higher jerks) more frequently might be the "unsafe" segments with more crashes over a long-term. The linear referencing methodology in ArcMap was used to link the GPS data with roadway characteristic data of US Highway 101 northbound (NB) and southbound (SB) in San Luis Obispo, California. The process used to merge GPS data with quarter-mile freeway segments for traditional crash frequency analysis is also discussed in the paper. A negative binomial regression analyses showed that proportion of high magnitude jerks while decelerating on freeway segments (from the driving data) was significantly related with the long-term crash frequency of those segments. A random parameter negative binomial model with uniformly distributed parameter for ADT and a fixed parameter for jerk provided a statistically significant estimate for quarter-mile segments. The results also indicated that roadway curvature and the presence of auxiliary lane are not significantly related with crash frequency for the highway segments under consideration. The results from this exploration are promising since the data used to derive the explanatory variable(s) can be collected using most off-the-shelf GPS devices, including many smartphones.

  2. [Deep sea trip of the ship crash Northern Force fleet].

    PubMed

    Ushakov, I B; Bubeev, Iu A; Mazaĭkin, D N; Pisarev, A A

    2008-07-01

    A long-termed navy march of crash shupborn group of Northern Navy became a sign-oriented event in the life of the Armed Forces. After more then 10 years cessation this march signed recommencement of permanent Russia navy attendance in strategically important areas of the World Ocean. The authors highlight work of military-navy specialists in conditions of this march. The most important peculiarity of this march was participation of a hard aircraft carrier "Navy Admiral of the Soviet Union N.G.Kuznetsov". Activity of aircraft staff in carrying out the boardings and the deck starts requires the highest mobilization of all psycho-physiological resources. There was effectuated a complex medical-psychophysiological research of functional condition of aircraft and engineer staff of the group during the service. Also there was effectuated an operative recovery of functional condition among sailors and officers of the ship staff. Method of neuronsemantic diagnostics of psychological disadaptation and suicide risk was used during the analyze of groups of risk. The results of the analyze permitted to educe main psychotraumatizing factors, to form recommendations on psycho-correction, organization-educative measures taking into account individual peculiarities of motivation sphere and cognitive sensitivity. There were effectuated different trainings of moralities, communicativeness, strategy of negotiation and stress-managment in cooperation with the psychologist of the ship.

  3. 49 CFR 238.403 - Crash energy management.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Crash energy management. 238.403 Section 238.403... Equipment § 238.403 Crash energy management. (a) Each power car and trailer car shall be designed with a crash energy management system to dissipate kinetic energy during a collision. The crash...

  4. 49 CFR 238.403 - Crash energy management.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Crash energy management. 238.403 Section 238.403... Equipment § 238.403 Crash energy management. (a) Each power car and trailer car shall be designed with a crash energy management system to dissipate kinetic energy during a collision. The crash...

  5. 49 CFR 238.403 - Crash energy management.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Crash energy management. 238.403 Section 238.403... Equipment § 238.403 Crash energy management. (a) Each power car and trailer car shall be designed with a crash energy management system to dissipate kinetic energy during a collision. The crash...

  6. 49 CFR 238.403 - Crash energy management.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Crash energy management. 238.403 Section 238.403... Equipment § 238.403 Crash energy management. (a) Each power car and trailer car shall be designed with a crash energy management system to dissipate kinetic energy during a collision. The crash...

  7. 49 CFR 238.403 - Crash energy management.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Crash energy management. 238.403 Section 238.403... Equipment § 238.403 Crash energy management. (a) Each power car and trailer car shall be designed with a crash energy management system to dissipate kinetic energy during a collision. The crash...

  8. Car Crashes and Central Disorders of Hypersomnolence: A French Study

    PubMed Central

    Lopez, Regis; Pesenti, Carole; Plazzi, Giuseppe; Drouot, Xavier; Leu-Semenescu, Smaranda; Beziat, Severine; Arnulf, Isabelle; Dauvilliers, Yves

    2015-01-01

    Background Drowsiness compromises driving ability by reducing alertness and attentiveness, and delayed reaction times. Sleep-related car crashes account for a considerable proportion of accident at the wheel. Narcolepsy type 1 (NT1), narcolepsy type 2 (NT2) and idiopathic hypersomnia (IH) are rare central disorders of hypersomnolence, the most severe causes of sleepiness thus being potential dangerous conditions for both personal and public safety with increasing scientific, social, and political attention. Our main objective was to assess the frequency of recent car crashes in a large cohort of patients affected with well-defined central disorders of hypersomnolence versus subjects from the general population. Methods We performed a cross-sectional study in French reference centres for rare hypersomnia diseases and included 527 patients and 781 healthy subjects. All participants included needed to have a driving license, information available on potential accident events during the last 5 years, and on potential confounders; thus analyses were performed on 282 cases (71 IH, 82 NT2, 129 NT1) and 470 healthy subjects. Results Patients reported more frequently than healthy subjects the occurrence of recent car crashes (in the previous five years), a risk that was confirmed in both treated and untreated subjects at study inclusion (Untreated, OR = 2.21 95%CI = [1.30–3.76], Treated OR = 2.04 95%CI = [1.26–3.30]), as well as in all disease categories, and was modulated by subjective sleepiness level (Epworth scale and naps). Conversely, the risk of car accidents of patients treated for at least 5 years was not different to healthy subjects (OR = 1.23 95%CI = [0.56–2.69]). Main risk factors were analogous in patients and healthy subjects. Conclusion Patients affected with central disorders of hypersomnolence had increased risk of recent car crashes compared to subjects from the general population, a finding potentially reversed by long-term treatment. PMID:26052938

  9. Acoustic-seismic coupling for a wide range of angles of incidence and frequencies using signals of jet-aircraft overflights

    NASA Astrophysics Data System (ADS)

    Liebsch, Mattes; Altmann, Jürgen

    2016-12-01

    We present the excitation of soil vibration at the surface and at depths to 0.6 m caused by the sound of jet-aircraft overflights. By evaluating a multitude of overflight events we show that the coupling coefficient between soil velocity and sound pressure is only dependent on the angle of incidence of the acoustic wave and the frequency and thus can be averaged over the events. While previous publications presented only pointwise measurements we present signals for a wide range of angles of incidence and frequencies. In the seismic signal we found frequency bands of increased and decreased soil velocity caused by interference of the directly excited seismic wave with waves propagating in the ground and reflected at an underground boundary and at the surface. We use this seismic response to the broadband acoustic excitation to estimate soil characteristics e.g. P-wave velocity and depth of the boundary. The behaviour at depths > 0 m can be explained by an additional reflection at the surface. Here the reflection coefficient from theory was used successfully. The reflection coefficient of the P wave at that boundary - where insufficient information is available for its derivation from theory - was estimated from amplitude ratios at the surface.

  10. Risk, randomness, crashes and quants

    NASA Astrophysics Data System (ADS)

    Farhadi, Alessio; Vvedensky, Dimitri

    2003-03-01

    Market movements, whether short-term fluctuations, long-term trends, or sudden surges or crashes, have an immense and widespread economic impact. These movements are suggestive of the complex behaviour seen in many non-equilibrium physical systems. Not surprisingly, therefore, the characterization of market behaviour presents an inviting challenge to the physical sciences and, indeed, many concepts and methods developed for modelling non-equilibrium natural phenomena have found fertile ground in financial settings. In this review, we begin with the simplest random process, the random walk, and, assuming no prior knowledge of markets, build up to the conceptual and computational machinery used to analyse and model the behaviour of financial systems. We then consider the evidence that calls into question several aspects of the random walk model of markets and discuss some ideas that have been put forward to account for the observed discrepancies. The application of all of these methods is illustrated with examples of actual market data.

  11. Ocular injuries in automobile crashes.

    PubMed

    Huelke, D F; O'Day, J; Barhydt, W H

    1982-01-01

    Tempered windshields commonly used in Europe have been shown to be related to the relatively high incidence of ocular injuries. Although windshields of the High Penetration Resistant (HPR) type in cars in North America are not at all significantly involved in ocular injuries, still about 50 % of the injuries of the eye area are caused by glass. The HPR windshield probably is the main reason for the relatively low occurrence of ocular injuries in United States crashes compared to these injuries reported from countries with tempered windshields. No ocular injuries were observed among belted occupants in this study. It appears that the increased use of lap-shoulder belts would decrease the likelihood of occupant contact with the windshield, mirrors, roof support, steering wheel, and instrument panel- about two thirds of the occupant contacts related to ocular injury- and thus reduce the incidence of ocular injuries leading to decreased vision.

  12. Factors Contributing to Crashes among Young Drivers

    PubMed Central

    Bates, Lyndel J.; Davey, Jeremy; Watson, Barry; King, Mark J.; Armstrong, Kerry

    2014-01-01

    Young drivers are the group of drivers most likely to crash. There are a number of factors that contribute to the high crash risk experienced by these drivers. While some of these factors are intrinsic to the young driver, such as their age, gender or driving skill, others relate to social factors and when and how often they drive. This article reviews the factors that affect the risk of young drivers crashing to enable a fuller understanding of why this risk is so high in order to assist in developing effective countermeasures. PMID:25097763

  13. Air Cushion Crash Rescue Vehicle (ACCRV)

    DTIC Science & Technology

    1987-10-01

    x 13.3 x 5.7 Battery Incl. Monitors 1 DC Defibril- 11.90 3.8 x 13.3 x 9.2 Battery Inc\\. lator 106 -) 0) ho cd o +-> w c cd 3...reverse if necessary and identify by block number) Current USAF crash rescue vehicles have been designed to operate on the roads, ramps, taxiways...Cushion Crash Rescue Vehicle (ACCRV) has been designed by integrating a retractable air cushion system with a crash rescue vehicle. This report

  14. A probabilistic quantitative risk assessment model for the long-term work zone crashes.

    PubMed

    Meng, Qiang; Weng, Jinxian; Qu, Xiaobo

    2010-11-01

    Work zones especially long-term work zones increase traffic conflicts and cause safety problems. Proper casualty risk assessment for a work zone is of importance for both traffic safety engineers and travelers. This paper develops a novel probabilistic quantitative risk assessment (QRA) model to evaluate the casualty risk combining frequency and consequence of all accident scenarios triggered by long-term work zone crashes. The casualty risk is measured by the individual risk and societal risk. The individual risk can be interpreted as the frequency of a driver/passenger being killed or injured, and the societal risk describes the relation between frequency and the number of casualties. The proposed probabilistic QRA model consists of the estimation of work zone crash frequency, an event tree and consequence estimation models. There are seven intermediate events--age (A), crash unit (CU), vehicle type (VT), alcohol (AL), light condition (LC), crash type (CT) and severity (S)--in the event tree. Since the estimated value of probability for some intermediate event may have large uncertainty, the uncertainty can thus be characterized by a random variable. The consequence estimation model takes into account the combination effects of speed and emergency medical service response time (ERT) on the consequence of work zone crash. Finally, a numerical example based on the Southeast Michigan work zone crash data is carried out. The numerical results show that there will be a 62% decrease of individual fatality risk and 44% reduction of individual injury risk if the mean travel speed is slowed down by 20%. In addition, there will be a 5% reduction of individual fatality risk and 0.05% reduction of individual injury risk if ERT is reduced by 20%. In other words, slowing down speed is more effective than reducing ERT in the casualty risk mitigation.

  15. "I am flying to the stars"--suicide by aircraft in Germany.

    PubMed

    Schwark, Thorsten; Severin, Karsten; Grellner, Wolfgang

    2008-08-06

    In 2006, 67 persons were killed in aircraft accidents in Germany and involving German aircrafts abroad. In spite of extensive investigation of each aircraft accident, there are no reliable data as to the number of suicides by aircraft. We report on a 50-year-old man who committed suicide by willfully crashing his Beech "Sierra" aircraft minutes after take off from an airport close to the town of Rendsburg, Germany. Before killing himself, the intoxicated pilot had sent an SMS announcing his suicide plans to a friend. The findings of the medico-legal investigation and the results of a review of aircraft accident reports by the German Federal Bureau of Aircraft Accidents Investigation (BFU) regarding suicidal plane crashes are presented.

  16. Cost of Crashes Related to Road Conditions, United States, 2006

    PubMed Central

    Zaloshnja, Eduard; Miller, Ted R.

    2009-01-01

    This is the first study to estimate the cost of crashes related to road conditions in the U.S. To model the probability that road conditions contributed to the involvement of a vehicle in the crash, we used 2000–03 Large Truck Crash Causation Study (LTCCS) data, the only dataset that provides detailed information whether road conditions contributed to crash occurrence. We applied the logistic regression results to a costed national crash dataset in order to calculate the probability that road conditions contributed to the involvement of a vehicle in each crash. In crashes where someone was moderately to seriously injured (AIS-2-6) in a vehicle that harmfully impacted a large tree or medium or large non-breakaway pole, or if the first harmful event was collision with a bridge, we changed the calculated probability of being road-related to 1. We used the state distribution of costs of fatal crashes where road conditions contributed to crash occurrence or severity to estimate the respective state distribution of non-fatal crash costs. The estimated comprehensive cost of traffic crashes where road conditions contributed to crash occurrence or severity was $217.5 billion in 2006. This represented 43.6% of the total comprehensive crash cost. The large share of crash costs related to road design and conditions underlines the importance of these factors in highway safety. Road conditions are largely controllable. Road maintenance and upgrading can prevent crashes and reduce injury severity. PMID:20184840

  17. GEMACS (General EM Model for the Analysis of Computer Systems) Frequency-Domain Analysis to Determine the Lightning Induced Electromagnetic Skin Current Distributions on an Aircraft.

    DTIC Science & Technology

    1986-12-01

    Static Electricity. Paper No 17: 1-9. Fort Worth TX, June 21- 23, 1983. 40. Rustan, P.L. and J. Moreau . "Aircraft Lightning Attach- ment at Low Altitudes...John F. and Gustave L. Weinstock. Aircraft Related Lightning Mechanisms: Technical Report. Contract F33615-71-C-1581. McDonnell Aircraft Company, St

  18. Occupant Responses in a Full-Scale Crash Test of the Sikorsky ACAP Helicopter

    NASA Technical Reports Server (NTRS)

    Jackson, Karen E.; Fasanella, Edwin L.; Boitnott, Richard L.; McEntire, Joseph; Lewis, Alan

    2002-01-01

    A full-scale crash test of the Sikorsky Advanced Composite Airframe Program (ACAP) helicopter was performed in 1999 to generate experimental data for correlation with a crash simulation developed using an explicit nonlinear, transient dynamic finite element code. The airframe was the residual flight test hardware from the ACAP program. For the test, the aircraft was outfitted with two crew and two troop seats, and four anthropomorphic test dummies. While the results of the impact test and crash simulation have been documented fairly extensively in the literature, the focus of this paper is to present the detailed occupant response data obtained from the crash test and to correlate the results with injury prediction models. These injury models include the Dynamic Response Index (DRI), the Head Injury Criteria (HIC), the spinal load requirement defined in FAR Part 27.562(c), and a comparison of the duration and magnitude of the occupant vertical acceleration responses with the Eiband whole-body acceleration tolerance curve.

  19. Full-Scale Crash Test and Finite Element Simulation of a Composite Prototype Helicopter

    NASA Technical Reports Server (NTRS)

    Jackson, Karen E.; Fasanella, Edwin L.; Boitnott, Richard L.; Lyle, Karen H.

    2003-01-01

    A full-scale crash test of a prototype composite helicopter was performed at the Impact Dynamics Research Facility at NASA Langley Research Center in 1999 to obtain data for validation of a finite element crash simulation. The helicopter was the flight test article built by Sikorsky Aircraft during the Advanced Composite Airframe Program (ACAP). The composite helicopter was designed to meet the stringent Military Standard (MIL-STD-1290A) crashworthiness criteria and was outfitted with two crew and two troop seats and four anthropomorphic dummies. The test was performed at 38-ft/s vertical and 32.5-ft/s horizontal velocity onto a rigid surface. An existing modal-vibration model of the Sikorsky ACAP helicopter was converted into a model suitable for crash simulation. A two-stage modeling approach was implemented and an external user-defined subroutine was developed to represent the complex landing gear response. The crash simulation was executed with a nonlinear, explicit transient dynamic finite element code. Predictions of structural deformation and failure, the sequence of events, and the dynamic response of the airframe structure were generated and the numerical results were correlated with the experimental data to validate the simulation. The test results, the model development, and the test-analysis correlation are described.

  20. Optical communications for transport aircraft

    NASA Technical Reports Server (NTRS)

    Stengel, Robert

    1994-01-01

    Optical communications for transport aircraft are discussed. The problem involves: increasing demand for radio-frequency bands from an enlarging pool of users (aircraft, ground and sea vehicles, fleet operators, traffic control centers, and commercial radio and television); desirability of providing high-bandwidth dedicated communications to and from every aircraft in the National Airspace System; need to support communications, navigation, and surveillance for a growing number of aircraft; and improved meteorological observations by use of probe aircraft. The solution involves: optical signal transmission support very high data rates; optical transmission of signals between aircraft, orbiting satellites, and ground stations, where unobstructed line-of-sight is available; conventional radio transmissions of signals between aircraft and ground stations, where optical line-of-sight is unavailable; and radio priority given to aircraft in weather.

  1. Statistical Detection of Atypical Aircraft Flights

    NASA Technical Reports Server (NTRS)

    Statler, Irving; Chidester, Thomas; Shafto, Michael; Ferryman, Thomas; Amidan, Brett; Whitney, Paul; White, Amanda; Willse, Alan; Cooley, Scott; Jay, Joseph; Rosenthal, Loren; Swickard, Andrea; Bates, Derrick; Scherrer, Chad; Webb, Bobbie-Jo; Lawrence, Robert; Mosbrucker, Chris; Prothero, Gary; Andrei, Adi; Romanowski, Tim; Robin, Daniel; Prothero, Jason; Lynch, Robert; Lowe, Michael

    2006-01-01

    A computational method and software to implement the method have been developed to sift through vast quantities of digital flight data to alert human analysts to aircraft flights that are statistically atypical in ways that signify that safety may be adversely affected. On a typical day, there are tens of thousands of flights in the United States and several times that number throughout the world. Depending on the specific aircraft design, the volume of data collected by sensors and flight recorders can range from a few dozen to several thousand parameters per second during a flight. Whereas these data have long been utilized in investigating crashes, the present method is oriented toward helping to prevent crashes by enabling routine monitoring of flight operations to identify portions of flights that may be of interest with respect to safety issues.

  2. Patterns of Drug Use in Fatal Crashes

    PubMed Central

    Romano, Eduardo; Pollini, Robin A.

    2013-01-01

    Aims To characterize drug prevalence among fatally injured drivers, identify significant associations (i.e., day of week, time of day, age, gender), and compare findings with those for alcohol. Design Descriptive and logistic mixed-model regression analyses of Fatality Analysis Reporting System data. Setting U.S. states with drug test results for >80% of fatally injured drivers, 1998-2010. Participants Drivers killed in single-vehicle crashes on public roads who died at the scene of the crash (N=16,942). Measurements Drug test results, blood alcohol concentration (BAC), gender, age, and day and time of crash. Findings Overall, 45.1% of fatally injured drivers tested positive for alcohol (39.9% BAC>0.08) and 25.9% for drugs. The most common drugs present were stimulants (7.2%) and cannabinols (7.1%), followed by “other” drugs (4.1%), multiple drugs (4.1%), narcotics (2.1%), and depressants (1.5%). Drug-involved crashes occurred with relative uniformity throughout the day while alcohol-involved crashes were more common at night (p<.01). The odds of testing positive for drugs varied depending upon drug class, driver characteristics, time of day, and the presence of alcohol. Conclusions Fatal single vehicle crashes involving drugs are less common than those involving alcohol and the characteristics of drug-involved crashes differ depending upon drug class and whether alcohol is present. Concerns about drug-impaired driving should not detract from the current law enforcement focus on alcohol-impaired driving. PMID:23600629

  3. Macroscopic modeling of pedestrian and bicycle crashes: A cross-comparison of estimation methods.

    PubMed

    Amoh-Gyimah, Richard; Saberi, Meead; Sarvi, Majid

    2016-08-01

    The paper presents a cross-comparison of different estimation methods to model pedestrian and bicycle crashes. The study contributes to macro level safety studies by providing further methodological and empirical evidence on the various factors that influence the frequency of pedestrian and bicycle crashes at the planning level. Random parameter negative binomial (RPNB) models are estimated to explore the effects of various planning factors associated with total, serious injury and minor injury crashes while accounting for unobserved heterogeneity. Results of the RPNB models were compared with the results of a non-spatial negative binomial (NB) model and a Poisson-Gamma-CAR model. Key findings are, (1) the RPNB model performed best with the lowest mean absolute deviation, mean squared predicted error and Akaiki information criterion measures and (2) signs of estimated parameters are consistent if these variables are significant in models with the same response variables. We found that vehicle kilometers traveled (VKT), population, percentage of commuters cycling or walking to work, and percentage of households without motor vehicles have a significant and positive correlation with the number of pedestrian and bicycle crashes. Mixed land use is also found to have a positive association with the number of pedestrian and bicycle crashes. Results have planning and policy implications aimed at encouraging the use of sustainable modes of transportation while ensuring the safety of pedestrians and cyclist.

  4. Robust human body model injury prediction in simulated side impact crashes.

    PubMed

    Golman, Adam J; Danelson, Kerry A; Stitzel, Joel D

    2016-01-01

    This study developed a parametric methodology to robustly predict occupant injuries sustained in real-world crashes using a finite element (FE) human body model (HBM). One hundred and twenty near-side impact motor vehicle crashes were simulated over a range of parameters using a Toyota RAV4 (bullet vehicle), Ford Taurus (struck vehicle) FE models and a validated human body model (HBM) Total HUman Model for Safety (THUMS). Three bullet vehicle crash parameters (speed, location and angle) and two occupant parameters (seat position and age) were varied using a Latin hypercube design of Experiments. Four injury metrics (head injury criterion, half deflection, thoracic trauma index and pelvic force) were used to calculate injury risk. Rib fracture prediction and lung strain metrics were also analysed. As hypothesized, bullet speed had the greatest effect on each injury measure. Injury risk was reduced when bullet location was further from the B-pillar or when the bullet angle was more oblique. Age had strong correlation to rib fractures frequency and lung strain severity. The injuries from a real-world crash were predicted using two different methods by (1) subsampling the injury predictors from the 12 best crush profile matching simulations and (2) using regression models. Both injury prediction methods successfully predicted the case occupant's low risk for pelvic injury, high risk for thoracic injury, rib fractures and high lung strains with tight confidence intervals. This parametric methodology was successfully used to explore crash parameter interactions and to robustly predict real-world injuries.

  5. An exploratory study of the relationship between road rage and crash experience in a representative sample of US drivers.

    PubMed

    Wells-Parker, Elisabeth; Ceminsky, Jennifer; Hallberg, Victoria; Snow, Ronald W; Dunaway, Gregory; Guiling, Shawn; Williams, Marsha; Anderson, Bradley

    2002-05-01

    The phenomenon of road rage has been frequently discussed but infrequently examined. Using a representative sample of 1382 US adult drivers, who were interviewed in a 1998 telephone survey, exploratory analyses examined the relationship between self-reported measures of road rage, generally hazardous driving behaviors, and crash experience. Regarding specific road rage behaviors, most respondents reported having engaged in verbal expressions of annoyance; however only 2.45% reported ever having been involved in direct confrontation with another car or driver. After controlling for gender, age. driving frequency, annual miles driven and verbal expression, an angry/threatening driving subscale of road rage was significantly associated with hazardous driving behaviors that included frequency of driving over the legal blood alcohol limit, receipt of tickets in the past year. and habitually exceeding the speed limit as well as crash experience. However, the verbal/frustration expression subscale was not associated with crash experience or hazardous driving indicators, except for number of tickets, after controlling for other crash-related factors such as gender and age. Direct confrontation by deliberately hitting another car or leaving the car to argue with and/or injure another driver was rarely reported. Results suggest that angry/threatening driving is related to crash involvement; however, after controlling for exposure and angry/threatening and hazardous driving the relationship of milder expressions of frustration while driving and crash involvement was not significant.

  6. Modeling the effects of AADT on predicting multiple-vehicle crashes at urban and suburban signalized intersections.

    PubMed

    Chen, Chen; Xie, Yuanchang

    2016-06-01

    Annual Average Daily Traffic (AADT) is often considered as a main covariate for predicting crash frequencies at urban and suburban intersections. A linear functional form is typically assumed for the Safety Performance Function (SPF) to describe the relationship between the natural logarithm of expected crash frequency and covariates derived from AADTs. Such a linearity assumption has been questioned by many researchers. This study applies Generalized Additive Models (GAMs) and Piecewise Linear Negative Binomial (PLNB) regression models to fit intersection crash data. Various covariates derived from minor-and major-approach AADTs are considered. Three different dependent variables are modeled, which are total multiple-vehicle crashes, rear-end crashes, and angle crashes. The modeling results suggest that a nonlinear functional form may be more appropriate. Also, the results show that it is important to take into consideration the joint safety effects of multiple covariates. Additionally, it is found that the ratio of minor to major-approach AADT has a varying impact on intersection safety and deserves further investigations.

  7. [Medico-legal study on crashes of fighter planes of the National People's Army].

    PubMed

    Lignitz, Eberhard; Kopetz, Bernd; Wirth, Ingo

    2009-01-01

    In the years 1974 to 1990, 39 pilots died in 34 crashes of fighter planes of the National People's Army; 32 victims were examined forensically. For the present study all autopsy protocols and examination reports available in the German Federal Military Archives in Freiburg could be evaluated. Both officer cadets and experienced pilots of high military ranks were among the victims. The majority of the crashes (24 out of 34) was caused by human failure. Health problems or the use of alcohol and medications did not play a role in the aircraft accidents. All killed pilots were identified. The injury patterns after fatal ejection are different from the patterns seen after impact with a plane. Such patterns of findings are meaningful in the reconstruction of unknown sequences of events leading to the accidents and for the assessment of the pilots' capacity to act at the moment of the incident

  8. Gasoline prices and their relationship to drunk-driving crashes.

    PubMed

    Chi, Guangqing; Zhou, Xuan; McClure, Timothy E; Gilbert, Paul A; Cosby, Arthur G; Zhang, Li; Robertson, Angela A; Levinson, David

    2011-01-01

    This study investigates the relationship between changing gasoline prices and drunk-driving crashes. Specifically, we examine the effects of gasoline prices on drunk-driving crashes in Mississippi by several crash types and demographic groups at the monthly level from 2004 to 2008, a period experiencing great fluctuation in gasoline prices. An exploratory visualization by graphs shows that higher gasoline prices are generally associated with fewer drunk-driving crashes. Higher gasoline prices depress drunk-driving crashes among young and adult drivers, among male and female drivers, and among white and black drivers. Results from negative binomial regression models show that when gas prices are higher, there are fewer drunk-driving crashes, particularly among property-damage-only crashes. When alcohol consumption levels are higher, there are more drunk-driving crashes, particularly fatal and injury crashes. The effects of gasoline prices and alcohol consumption are stronger on drunk-driving crashes than on all crashes. The findings do not vary much across different demographic groups. Overall, gasoline prices have greater effects on less severe crashes and alcohol consumption has greater effects on more severe crashes.

  9. From rational bubbles to crashes

    NASA Astrophysics Data System (ADS)

    Sornette, D.; Malevergne, Y.

    2001-10-01

    We study and generalize in various ways the model of rational expectation (RE) bubbles introduced by Blanchard and Watson in the economic literature. Bubbles are argued to be the equivalent of Goldstone modes of the fundamental rational pricing equation, associated with the symmetry-breaking introduced by non-vanishing dividends. Generalizing bubbles in terms of multiplicative stochastic maps, we summarize the result of Lux and Sornette that the no-arbitrage condition imposes that the tail of the return distribution is hyperbolic with an exponent μ<1. We then outline the main results of Malevergne and Sornette, who extend the RE bubble model to arbitrary dimensions d: a number d of market time series are made linearly interdependent via d× d stochastic coupling coefficients. We derive the no-arbitrage condition in this context and, with the renewal theory for products of random matrices applied to stochastic recurrence equations, we extend the theorem of Lux and Sornette to demonstrate that the tails of the unconditional distributions associated with such d-dimensional bubble processes follow power laws, with the same asymptotic tail exponent μ<1 for all assets. The distribution of price differences and of returns is dominated by the same power-law over an extended range of large returns. Although power-law tails are a pervasive feature of empirical data, the numerical value μ<1 is in disagreement with the usual empirical estimates μ≈3. We then discuss two extensions (the crash hazard rate model and the non-stationary growth rate model) of the RE bubble model that provide two ways of reconciliation with the stylized facts of financial data.

  10. Emergency Locator Transmitter System Performance During Three Full-Scale General Aviation Crash Tests

    NASA Technical Reports Server (NTRS)

    Littell, Justin D.; Stimson, Chad M.

    2016-01-01

    Full-scale crash tests were conducted on three Cessna 172 aircraft at NASA Langley Research Center's Landing and Impact Research facility during the summer of 2015. The purpose of the three tests was to evaluate the performance of commercially available Emergency Locator Transmitter (ELT) systems and support development of enhanced installation guidance. ELTs are used to provide location information to Search and Rescue (SAR) organizations in the event of an aviation distress situation, such as a crash. The crash tests simulated three differing severe but survivable crash conditions, in which it is expected that the onboard occupants have a reasonable chance of surviving the accident and would require assistance from SAR personnel. The first simulated an emergency landing onto a rigid surface, while the second and third simulated controlled flight into terrain. Multiple ELT systems were installed on each airplane according to federal regulations. The majority of the ELT systems performed nominally. In the systems which did not activate, post-test disassembly and inspection offered guidance for non-activation cause in some cases, while in others, no specific cause could be found. In a subset of installations purposely disregarding best practice guidelines, failure of the ELT-to-antenna cabling connections were found. Recommendations for enhanced installation guidance of ELT systems will be made to the Radio Technical Commission for Aeronautics (RTCA) Special Committee 229 for consideration for adoption in a future release of ELT minimum operational performance specifications. These recommendations will be based on the data gathered during this test series as well as a larger series of crash simulations using computer models that will be calibrated based on these data

  11. Side Impact Regulatory Trends, Crash Environment and Injury Risk in the USA.

    PubMed

    Prasad, Priya; Dalmotas, Dainius; Chouinard, Aline

    2015-11-01

    Light duty vehicles in the US are designed to meet and exceed regulatory standards, self-imposed industry agreements and safety rating tests conducted by NHTSA and IIHS. The evolution of side impact regulation in the US from 1973 to 2015 is discussed in the paper along with two key industry agreements in 2003 affecting design of restraint systems and structures for side impact protection. A combination of all the above influences shows that vehicles in the US are being designed to more demanding and comprehensive requirements than in any other region of the world. The crash environment in the US related to side impacts was defined based on data in the nationally representative crash database NASS. Crash environment factors, including the distribution of cars, light trucks and vans (LTV's), and medium-to-heavy vehicles (MHV's) in the fleet, and the frequency of their interactions with one another in side impacts, were considered. Other factors like, crash severity in terms of closing velocity between two vehicles involved in crash, gender and age of involved drivers in two-vehicle and single vehicle crashes, were also examined. Injury risks in side impacts to drivers and passengers were determined in various circumstances such as near-side, far-side, and single vehicle crashes as a function of crash severity, in terms of estimated closing speed or lateral delta-V. Also injury risks in different pairs of striking and struck cars and LTV's, were estimated. A logistic regression model for studying injury risks in two vehicle crashes was developed. The risk factors included in the model include case and striking vehicles, consisting of cars, SUV's, vans, and pickup trucks, delta-V, damage extent, occupant proximity to the impact side, age and gender of the occupant, and belt use. Results show that car occupants make up the vast majority of serious-to-fatally injured occupants. Injury rates of car occupants in two-vehicle collision are highest when the car is struck by a

  12. Predicting crash risk and identifying crash precursors on Korean expressways using loop detector data.

    PubMed

    Kwak, Ho-Chan; Kho, Seungyoung

    2016-03-01

    In order to improve traffic safety on expressways, it is important to develop proactive safety management strategies with consideration for segment types and traffic flow states because crash mechanisms have some differences by each condition. The primary objective of this study is to develop real-time crash risk prediction models for different segment types and traffic flow states on expressways. The mainline of expressways is divided into basic segment and ramp vicinity, and the traffic flow states are classified into uncongested and congested conditions. Also, Korean expressways have irregular intervals between loop detector stations. Therefore, we investigated on the effect and application of the detector stations at irregular intervals for the crash risk prediction on expressways. The most significant traffic variables were selected by conditional logistic regression analysis which could control confounding factors. Based on the selected traffic variables, separate models to predict crash risk were developed using genetic programming technique. The model estimation results showed that the traffic flow characteristics leading to crashes are differed by segment type and traffic flow state. Especially, the variables related to the intervals between detector stations had a significant influence on crash risk prediction under the uncongested condition. Finally, compared with the single model for all crashes and the logistic models used in previous studies, the proposed models showed higher prediction performance. The results of this study can be applied to develop more effective proactive safety management strategies for different segment types and traffic flow states on expressways with loop detector stations at irregular intervals.

  13. Commuter motorcycle crashes in Malaysia: An understanding of contributing factors

    PubMed Central

    Oxley, Jennifer; Yuen, Jeremy; Ravi, Mano Deepa; Hoareau, Effie; Mohammed, Mohammed Azman Aziz; Bakar, Harun; Venkataraman, Saraswathy; Nair, Prame Kumar

    2013-01-01

    In Malaysia, two-thirds of reported workplace-related fatal and serious injury incidents are the result of commuting crashes (especially those involving motorcyclists), however, little is known about the contributing factors to these collisions. A telephone survey of 1,750 motorcyclists (1,004 adults who had been involved in a motorcycle commuting crash in the last 2 years and 746 adult motorcyclists who had not been involved in a motorcycle crash in the last 2 years) was undertaken. The contributions of a range of behavioural, attitudinal, employment and travel pattern factors to collision involvement were examined. The findings revealed that the majority of participants were licensed riders, rode substantial distances (most often for work purposes), and reported adopting safe riding practices (helmet wearing and buckling). However, there were some concerning findings regarding speeding behaviour, use of mobile phones while riding, and engaging in other risky behaviours. Participants who had been involved in a collision were younger (aged 25–29 years), had higher exposure (measured by distances travelled, frequency of riding, and riding on high volume and higher speed roads), reported higher rates of riding for work purposes, worked more shift hours and had a higher likelihood of riding at relatively high speeds compared with participants who had not been involved in a collision. Collisions generally occurred during morning and early evening hours, striking another vehicles, and during normal traffic flow. The implications of these findings for policy decisions and development of evidence-based behavioural/training interventions addressing key contributing factors are discussed. PMID:24406945

  14. Factors Affecting Ejection Risk in Rollover Crashes

    PubMed Central

    Funk, James R.; Cormier, Joseph M.; Bain, Charles E.; Wirth, Jeffrey L.; Bonugli, Enrique B.; Watson, Richard A.

    2012-01-01

    Ejection greatly increases the risk of injury and fatality in a rollover crash. The purpose of this study was to determine the crash, vehicle, and occupant characteristics that affect the risk of ejection in rollovers. Information from real world rollover crashes occurring from 2000 – 2010 was obtained from the National Automotive Sampling System (NASS) in order to analyze the effect of the following parameters on ejection risk: seatbelt use, rollover severity, vehicle type, seating position, roof crush, side curtain airbag deployment, glazing type, and occupant age, gender, and size. Seatbelt use was found to reduce the risk of partial ejection and virtually eliminate the risk of complete ejection. For belted occupants, the risk of partial ejection risk was significantly increased in rollover crashes involving more roof inversions, light trucks and vans (LTVs), and larger occupants. For unbelted occupants, the risk of complete ejection was significantly increased in rollover crashes involving more roof inversions, LTVs, far side occupants, and higher levels of roof crush. Roof crush was not a significant predictor of ejection after normalizing for rollover severity. Curtain airbag deployment was associated with reduced rates of partial and complete ejection, but the effect was not statistically significant, perhaps due to the small sample size (n = 89 raw cases with curtain deployments). A much greater proportion of occupants who were ejected in spite of curtain airbag deployment passed through the sunroof and other portals as opposed to the adjacent side window compared to occupants who were ejected in rollovers without a curtain airbag deployment. The primary factors that reduce ejection risk in rollover crashes are, in generally decreasing order of importance: seatbelt use, fewer roof inversions, passenger car body type, curtain airbag deployment, near side seating position, and small occupant size. PMID:23169130

  15. ATD Occupant Responses from Three Full-Scale General Aviation Crash Tests

    NASA Technical Reports Server (NTRS)

    Littell, Justin D.; Annett, Martin S.

    2016-01-01

    During the summer of 2015, three Cessna 172 General Aviation (GA) aircraft were crash tested at the Landing and Impact Research (LandIR) Facility at NASA Langley Research Center (LaRC). Three different crash scenarios were represented. The first test simulated a flare-to-stall emergency or hard landing onto a rigid surface such as a road or runway. The second test simulated a controlled flight into terrain with a nose down pitch of the aircraft, and the third test simulated a controlled flight into terrain with an attempt to unsuccessfully recover the aircraft immediately prior to impact, resulting in a tail strike condition. An on-board data acquisition system (DAS) captured 64 channels of airframe acceleration, along with accelerations and loads in two onboard Hybrid II 50th percentile Anthropomorphic Test Devices (ATDs) representing the pilot and copilot. Each of the three tests contained different airframe loading conditions and different types of restraints for both the pilot and co-pilot ATDs. The results show large differences in occupant response and restraint performance with varying likelihoods of occupant injury.

  16. Kinematics of U.S. Army helicopter crashes: 1979-85.

    PubMed

    Shanahan, D F; Shanahan, M O

    1989-02-01

    All records of U.S. Army Class A and B mishaps of four types of helicopters occurring from Oct. 1, 1979, through Sept. 30, 1985, were reviewed for terrain impact kinematic parameters. During this 6-year period, there were 298 mishaps involving 303 aircraft. Approximately 88% of these crashes were considered survivable. Mean and 95th percentile vertical velocity changes at the most severe terrain impact were similar for all aircraft types except the UH-60, which experienced significantly higher impact velocities (p less than 0.001). Overall 95th percentile vertical and horizontal velocity changes at the most severe terrain impact were 11.2 m.s-1 and 25.5 m.s-1, respectively. Both these values are substantially different from values cited in current design standards. Roll, pitch, and yaw attitudes at impact were similar for all aircraft and agreed with the values in current design standards, except that the distribution of roll angles was considerably wider. The importance of using current kinematic parameters for crashworthiness design standards and crash injury prevention is stressed. Recommendations are made to improve crashworthiness design standards.

  17. 14 CFR 27.952 - Fuel system crash resistance.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fuel system crash resistance. 27.952... crash resistance. Unless other means acceptable to the Administrator are employed to minimize the hazard...) Separation of fuel and ignition sources. To provide maximum crash resistance, fuel must be located as far...

  18. 14 CFR 29.952 - Fuel system crash resistance.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fuel system crash resistance. 29.952... crash resistance. Unless other means acceptable to the Administrator are employed to minimize the hazard...) Separation of fuel and ignition sources. To provide maximum crash resistance, fuel must be located as far...

  19. 14 CFR 29.952 - Fuel system crash resistance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Fuel system crash resistance. 29.952... crash resistance. Unless other means acceptable to the Administrator are employed to minimize the hazard...) Separation of fuel and ignition sources. To provide maximum crash resistance, fuel must be located as far...

  20. 14 CFR 27.952 - Fuel system crash resistance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Fuel system crash resistance. 27.952... crash resistance. Unless other means acceptable to the Administrator are employed to minimize the hazard...) Separation of fuel and ignition sources. To provide maximum crash resistance, fuel must be located as far...

  1. Aircraft electromagnetic compatibility

    NASA Technical Reports Server (NTRS)

    Clarke, Clifton A.; Larsen, William E.

    1987-01-01

    Illustrated are aircraft architecture, electromagnetic interference environments, electromagnetic compatibility protection techniques, program specifications, tasks, and verification and validation procedures. The environment of 400 Hz power, electrical transients, and radio frequency fields are portrayed and related to thresholds of avionics electronics. Five layers of protection for avionics are defined. Recognition is given to some present day electromagnetic compatibility weaknesses and issues which serve to reemphasize the importance of EMC verification of equipment and parts, and their ultimate EMC validation on the aircraft. Proven standards of grounding, bonding, shielding, wiring, and packaging are laid out to help provide a foundation for a comprehensive approach to successful future aircraft design and an understanding of cost effective EMC in an aircraft setting.

  2. Statistical implications of using moving violations to determine crash responsibility in young driver crashes.

    PubMed

    Curry, Allison E; Pfeiffer, Melissa R; Myers, Rachel K; Durbin, Dennis R; Elliott, Michael R

    2014-04-01

    Traditional methods for determining crash responsibility - most commonly moving violation citations - may not accurately characterize at-fault status among crash-involved drivers given that: (1) issuance may vary by factors that are independent of fault (e.g., driver age, gender), and (2) these methods do not capture driver behaviors that are not illegal but still indicative of fault. We examined the statistical implications of using moving violations to determine crash responsibility in young driver crashes by comparing it with a method based on crash-contributing driver actions. We selected all drivers in police-reported passenger-vehicle crashes (2010-2011) that involved a New Jersey driver <21 years old (79,485 driverscrash responsibility was determined from the crash report using two alternative methods: (1) issuance of a moving violation citation; and (2) presence of a driver action (e.g., failure to yield, inattention). Overall, 18% of crash-involved drivers were issued a moving violation while 50% had a driver action. Only 32.2% of drivers with a driver action were cited for a moving violation. Further, the likelihood of being cited given the presence of a driver action was higher among certain driver subgroups-younger drivers, male drivers, and drivers in single-vehicle and more severe crashes. Specifically among young drivers, those driving at night, carrying peer passengers, and having a suspended or no license were more often cited. Conversely, fatally-injured drivers were almost never cited. We also demonstrated that using citation data may lead to statistical bias in the characterization of at-fault drivers and of quasi-induced exposure measures. Studies seeking to accurately determine crash responsibility should thoughtfully consider the potential sources of bias that may result from using legal culpability methods. For many studies, determining driver responsibility via the identification of

  3. Statistical implications of using moving violations to determine crash responsibility in young driver crashes

    PubMed Central

    Curry, Allison E.; Pfeiffer, Melissa R.; Myers, Rachel K.; Durbin, Dennis R.; Elliott, Michael R.

    2014-01-01

    Traditional methods for determining crash responsibility—most commonly moving violation citations—may not accurately characterize at-fault status among crash-involved drivers given that: (1) issuance may vary by factors that are independent of fault (e.g., driver age, gender), and (2) these methods do not capture driver behaviors that are not illegal but still indicative of fault. We examined the statistical implications of using moving violations to determine crash responsibility in young driver crashes by comparing it with a method based on crash-contributing driver actions. We selected all drivers in police-reported passenger-vehicle crashes (2010–2011) that involved a New Jersey driver <21 years old (79,485 drivers < age 21, 61,355 drivers ≥ age 21.) For each driver, crash responsibility was determined from the crash report using two alternative methods: (1) issuance of a moving violation citation; and (2) presence of a driver action (e.g., failure to yield, inattention). Overall, 18% of crash-involved drivers were issued a moving violation while 50% had a driver action. Only 32.2% of drivers with a driver action were cited for a moving violation. Further, the likelihood of being cited given the presence of a driver action was higher among certain driver subgroups—younger drivers, male drivers, and drivers in single-vehicle and more severe crashes. Specifically among young drivers, those driving at night, carrying peer passengers, and having a suspended or no license were more often cited. Conversely, fatally-injured drivers were almost never cited. We also demonstrated that using citation data may lead to statistical bias in the characterization of at-fault drivers and of quasi-induced exposure measures. Studies seeking to accurately determine crash responsibility should thoughtfully consider the potential sources of bias that may result from using legal culpability methods. For many studies, determining driver responsibility via the identification

  4. Crash Position Indicator/Crash Survivable Flight Data Recorder Ejectable versus Nonejectable

    DTIC Science & Technology

    1983-07-27

    I. REPORT NUMWER 2. GOVT ACCESSION NO. 3. RECIPIENT’S CATALOG NUMBER TM 83-1 SY ski - _ __ __ _ 4. TITLE (end Subtitle) S. TYPE OF REPORT & PERIOD...excellent except for the Mortar type (personal hazard if inadvertently ejected on the ground). The acquisition cost of ejectable systems are...States and foreign military air forces and air carriers use both ejectable and nonejectable type Crash Position Indicator/Crash Survivable Flight Data

  5. Role of a MHD mode crash in triggering H-mode at marginal heating power on the HL-2A tokamak

    NASA Astrophysics Data System (ADS)

    Cheng, J.; Xu, Y.; Hidalgo, C.; Yan, L. W.; Liu, Yi; Jiang, M.; Li, Y. G.; Yu, L. M.; Dong, Y. B.; Li, D.; Liu, L.; Zhong, W. L.; Xu, J. Q.; Huang, Z. H.; Ji, X. Q.; Song, S. D.; Yu, D. L.; Xu, M.; Shi, Z. B.; Pan, O.; Yang, Q. W.; Ding, X. T.; Duan, X. R.; Liu, Yong

    2016-12-01

    The impact of a low frequency MHD mode crash on triggering the H-mode has been studied in detail on the HL-2A tokamak. The mode manifests fishbone characteristics with a precession frequency f ≈ 14- 19 kHz. The abrupt mode crash evokes substantial energy release from the core to the plasma boundary and hence increases the edge pressure gradient and Er × B flow shear, which further suppresses turbulence and leads to confinement improvement into the H-mode. Under the same NBI heating (∼1 MW), the I-phase plasma transits into H-mode with a rapid MHD mode crash while it returns to the L-mode without the presence of the mode in the I-phase. With increasing heating power by the ECRH added to the NBI, the MHD mode disappears. The statistical result shows that with the MHD mode crash the heating power for accessing the H-mode is significantly lower than that without the mode crash. All these facts reveal that the MHD mode crash in the I-phase plays a critical role in trigging the I → H transition at marginal heating power. In addition, it has been found that with the same NBI power heating, the magnitude of the mode (crash) increases with increasing plasma density, implying larger energy release being needed to access the H-mode for higher density plasmas.

  6. Renormalization Group Analysis of October Market Crashes

    NASA Astrophysics Data System (ADS)

    Gluzman, S.; Yukalov, V. I.

    The self-similar analysis of time series, suggested earlier by the authors, is applied to the description of market crises. The main attention is payed to the October 1929, 1987 and 1997 stock market crises, which can be successfully treated by the suggested approach. The analogy between market crashes and critical phenomena is emphasized.

  7. Pedestrian crash estimation models for signalized intersections.

    PubMed

    Pulugurtha, Srinivas S; Sambhara, Venkata R

    2011-01-01

    The focus of this paper is twofold: (1) to examine the non-linear relationship between pedestrian crashes and predictor variables such as demographic characteristics (population and household units), socio-economic characteristics (mean income and total employment), land use characteristics, road network characteristics (the number of lanes, speed limit, presence of median, and pedestrian and vehicular volume) and accessibility to public transit systems, and (2) to develop generalized linear pedestrian crash estimation models (based on negative binomial distribution to accommodate for over-dispersion of data) by the level of pedestrian activity and spatial proximity to extract site specific data at signalized intersections. Data for 176 randomly selected signalized intersections in the City of Charlotte, North Carolina were used to examine the non-linear relationships and develop pedestrian crash estimation models. The average number of pedestrian crashes per year within 200 feet of each intersection was considered as the dependent variable whereas the demographic characteristics, socio-economic characteristics, land use characteristics, road network characteristics and the number of transit stops were considered as the predictor variables. The Pearson correlation coefficient was used to eliminate predictor variables that were correlated to each other. Models were then developed separately for all signalized intersections, high pedestrian activity signalized intersections and low pedestrian activity signalized intersections. The use of 0.25mile, 0.5mile and 1mile buffer widths to extract data and develop models was also evaluated.

  8. Modal analysis of the human neck in vivo as a criterion for crash test dummy evaluation

    NASA Astrophysics Data System (ADS)

    Willinger, R.; Bourdet, N.; Fischer, R.; Le Gall, F.

    2005-10-01

    Low speed rear impact remains an acute automative safety problem because of a lack of knowledge of the mechanical behaviour of the human neck early after impact. Poorly validated mathematical models of the human neck or crash test dummy necks make it difficult to optimize automotive seats and head rests. In this study we have constructed an experimental and theoretical modal analysis of the human head-neck system in the sagittal plane. The method has allowed us to identify the mechanical properties of the neck and to validate a mathematical model in the frequency domain. The extracted modal characteristics consist of a first natural frequency at 1.3±0.1 Hz associated with head flexion-extension motion and a second mode at 8±0.7 Hz associated with antero-posterior translation of the head, also called retraction motion. Based on this new validation parameters we have been able to compare the human and crash test dummy frequency response functions and to evaluate their biofidelity. Three head-neck systems of current test dummies dedicated for use in rear-end car crash accident investigations have been evaluated in the frequency domain. We did not consider any to be acceptable, either because of excessive rigidity of their flexion-extension mode or because they poorly reproduce the head translation mode. In addition to dummy evaluation, this study provides new insight into injury mechanisms when a given natural frequency can be linked to a specific neck deformation.

  9. The Pattern of Road Traffic Crashes in South East Iran

    PubMed Central

    Rad, Mahdieh; Martiniuk, Alexandra LC.; Ansari-Moghaddam, Alireza; Mohammadi, Mahdi; Rashedi, Fariborz; Ghasemi, Ardavan

    2016-01-01

    Background: In the present study, the epidemiologic aspects of road traffic crashes in South East of Iran are described. Methods: This cross-sectional study included the profile of 2398 motor vehicle crashes recorded in the police office in one Year in South East of Iran. Data collected included: demographics, the type of crash, type of involved vehicle, location of crash and factors contributing to the crash. Descriptive statistics were used for data analysis. Results: Collisions with other vehicles or objects contributed the highest proportion (62.4%) of motor vehicle crashes. Human factors including careless driving, violating traffic laws, speeding, and sleep deprivation/fatigue were the most important causal factors accounting for 90% of road crashes. Data shows that 41% of drivers were not using a seat belt at the time of crash. One- third of the crashes resulted in injury (25%) or death (5%). Conclusions: Reckless driving such as speeding and violation of traffic laws are major risk factors for crashes in the South East of Iran. This highlights the need for education along with traffic law enforcement to reduce motor vehicle crashes in future. PMID:27157159

  10. Defining and screening crash surrogate events using naturalistic driving data.

    PubMed

    Wu, Kun-Feng; Jovanis, Paul P

    2013-12-01

    Naturalistic driving studies provide an excellent opportunity to better understand crash causality and to supplement crash observations with a much larger number of near crash events. The goal of this research is the development of a set of diagnostic procedures to define, screen, and identify crash and near crash events that can be used in enhanced safety analyses. A way to better understand crash occurrence and identify potential countermeasures to improve safety is to learn from and use near crash events, particularly those near crashes that have a common etiology to crash outcomes. This paper demonstrates that a multi-stage modeling framework can be used to search through naturalistic driving data, extracting statistically similar crashes and near crashes. The procedure is tested using data from the VTTI 100-car study for road departure events. A total of 63 events are included in this application. While the sample size is limited in this empirical study, the authors believe the procedure is ready for testing in other applications.

  11. Under-reporting of road traffic crash data in Ghana.

    PubMed

    Salifu, Mohammed; Ackaah, Williams

    2012-01-01

    Having reliable estimates of the shortfalls in road traffic crash data is an important prerequisite for setting more realistic targets for crash/casualty reduction programmes and for a better appreciation of the socio-economic significance of road traffic crashes. This study was carried out to establish realistic estimates of the overall shortfall (under-reporting) in the official crash statistics in Ghana over an eight-year period (1997-2004). Surveys were conducted at hospitals and among drivers to generate relevant alternative data which were then matched against records in police crash data files and the official database. Overall shortfalls came from two sources, namely, 'non-reporting' and 'under-recording'. The results show that the level of non-reporting varied significantly with the severity of the crash from about 57% for property damage crashes through 8% for serious injury crashes to 0% for fatal crashes. Crashes involving cyclists and motorcyclists were also substantially non-reported. Under-recording on the other hand declined significantly over the period from an average of 37% in 1997-1998 to 27% in 2003-2004. Thus, the official statistics of road traffic crashes in Ghana are subject to significant shortfalls that need to be accounted for. Correction factors have therefore been suggested for adjusting the official data.

  12. How similar are two-unit bicycle and motorcycle crashes?

    PubMed

    Haworth, Narelle; Debnath, Ashim Kumar

    2013-09-01

    This paper explores the similarities and differences between bicycle and motorcycle crashes with other motor vehicles. If similar treatments can be effective for both bicycle and motorcycle crashes, then greater benefits in terms of crash costs saved may be possible for the same investment in treatments. To reduce the biases associated with under-reporting of these crashes to police, property damage and minor injury crashes were excluded. The most common crash type for both bicycles (31.1%) and motorcycles (24.5%) was intersection from adjacent approaches. Drivers of other vehicles were coded most at fault in the majority of two-unit bicycle (57.0%) and motorcycle crashes (62.7%). The crash types, patterns of fault and factors affecting fault were generally similar for bicycle and motorcycle crashes. This confirms the need to combat the factors contributing to failure of other drivers to yield right of way to two-wheelers, and suggest that some of these actions should prove beneficial to the safety of both motorized and non-motorized two-wheelers. In contrast, child bicyclists were more often at fault, particularly in crashes involving a vehicle leaving the driveway or footpath. The greater reporting of violations by riders and drivers in motorcycle crashes also deserves further investigation.

  13. Survivors’ experiences from a train crash

    PubMed Central

    Saveman, Britt-Inger

    2011-01-01

    Rarely described are people's lived experiences from severe injury events such as train crashes. The number of train crashes named disasters with ≥10 killed and/or ≥100 nonfatally injured grows globally and the trend shows that more people survive these disasters today than did so in the past. This results in an increased number of survivors needing care. The aim of the study was to explore survivors’ experiences from a train crash. Narrative interviews were performed with 14 passengers 4 years after a train crash event. Qualitative content analysis was used to analyse the interviews. Experiences were captured in three main themes: (1) Living in the mode of existential threat describes how the survivors first lost control, then were thrown into a state of unimaginable chaos as they faced death. (2) Dealing with the unthinkable described how survivors restored control, the central role of others, and the importance of reconstructing the event to move forward in their processing. (3) Having cheated death shows how some became shackled by their history, whereas others overcame the haunting of unforgettable memories. Furthermore, the result shows how all experienced a second chance in life. Experiencing a train crash meant that the passengers experienced severe vulnerability and a threat to life and interdependence turned out to play a crucial role. Focusing on helping other passengers on site was one way to regain the loss of control and kept the chaos at bay. Family, friends, and fellow passengers turned out to be extremely important during the recovery process why such closeness should be promoted and facilitated. PMID:22125573

  14. Modelling crash propensity of carshare members.

    PubMed

    Dixit, Vinayak; Rashidi, Taha Hossein

    2014-09-01

    Carshare systems are considered a promising solution for sustainable development of cities. To promote carsharing it is imperative to make them cost effective, which includes reduction in costs associated to crashes and insurance. To achieve this goal, it is important to characterize carshare users involved in crashes and understand factors that can explain at-fault and not-at fault drivers. This study utilizes data from GoGet carshare users in Sydney, Australia. Based on this study it was found that carshare users who utilize cars less frequently, own one or more cars, have less number of accidents in the past ten years, have chosen a higher insurance excess and have had a license for a longer period of time are less likely to be involved in a crash. However, if a crash occurs, carshare users not needing a car on the weekend, driving less than 1000km in the last year, rarely using a car and having an Australian license increases the likelihood to be at-fault. Since the dataset contained information about all members as well as not-at-fault drivers, it provided a unique opportunity to explore some aspects of quasi-induced exposure. The results indicate systematic differences in the distribution between the not-at-fault drivers and the carshare members based on the kilometres driven last year, main mode of travel, car ownership status and how often the car is needed. Finally, based on this study it is recommended that creating an incentive structure based on training and experience (based on kilometres driven), possibly tagged to the insurance excess could improve safety, and reduce costs associated to crashes for carshare systems.

  15. Real world crash evaluation of vehicle stability control (VSC) technology.

    PubMed

    Bahouth, G

    2005-01-01

    This study quantifies the effect of Vehicle Stability Control (VSC) in reducing crash involvement rates for a subset of vehicles in the US fleet. Crash rates for a variety of impact types before and after VSC technology was implemented are compared. Police-reported crashes from six available US state files from 1998-2002 were analyzed including 13,987 crash-involved study vehicles not equipped with the technology and 5,671 crashes of vehicles equipped with VSC as a standard feature. Overall, an 11.2% (95% CI: 2.4%, 21.1%) reduction in multi-vehicle frontal crash involvement was identified for VSC-equipped vehicles. A 52.6% (95% CI: 42.5%, 62.7%) reduction in single-vehicle crash rates was found.

  16. Application of Probabilistic Analysis to Aircraft Impact Dynamics

    NASA Technical Reports Server (NTRS)

    Lyle, Karen H.; Padula, Sharon L.; Stockwell, Alan E.

    2003-01-01

    Full-scale aircraft crash simulations performed with nonlinear, transient dynamic, finite element codes can incorporate structural complexities such as: geometrically accurate models; human occupant models; and advanced material models to include nonlinear stressstrain behaviors, laminated composites, and material failure. Validation of these crash simulations is difficult due to a lack of sufficient information to adequately determine the uncertainty in the experimental data and the appropriateness of modeling assumptions. This paper evaluates probabilistic approaches to quantify the uncertainty in the simulated responses. Several criteria are used to determine that a response surface method is the most appropriate probabilistic approach. The work is extended to compare optimization results with and without probabilistic constraints.

  17. Aircraft fires, smoke toxicity, and survival.

    PubMed

    Chaturvedi, A K; Sanders, D C

    1996-03-01

    In-flight fires in modern aircraft are rare, but post-crash fires do occur. Cabin occupants frequently survive initial forces of such crashes but are incapacitated from smoke inhalation. According to an international study, there were 95 fire-related civil passenger aircraft accidents worldwide over a 26-yr period, claiming approximately 2400 lives. Between 1985 and 1991, about 16% (32 accidents) of all U.S. transport aircraft accidents involved fire and 22% (140 fatalities) of the deaths in these accidents resulted from fire/smoke toxicity. Our laboratory analyses of postmortem blood samples (1967-93) indicate that 360 individuals in 134 fatal fire-related civil aircraft (air carrier and general aviation) accidents had carboxyhemoglobin saturation levels (> or = 20%), with or without blood cyanide, high enough to impair performance. Combustion toxicology is now moving from a descriptive to a mechanistic phase. Methods for gas analyses have been developed and combustion/animal-exposure assemblies have been constructed. Material/fire-retardant toxicity and interactions between smoke gases are being studied. Relationships between gas exposure concentrations, blood levels, and incapacitation onset are being established in animal models. Continuing basic research in smoke toxicity will be necessary to understand its complexities, and thus enhance aviation safety and fire survival chances.

  18. Aircraft Crash Survival Design Guide. Volume 4. Aircraft Seats, Restraints. Litters, and Padding

    DTIC Science & Technology

    1980-06-01

    to load the sheet normal to the surface, a diaphragming action will occur. The equilibrium and stress- strain (e)astic- plastic ) relations for the...polyethylene sheet and plank . . . . . . . . . . . . 0 a 0 * , 223 84 Recommended stress- strain properties for padding material for head contact...polystyrene . . . . . 238 90 Typical response of plastic foam tocompression test ............ 239 91 Specific energy absorbed to maximum strain versus

  19. Aircraft Crash Survival Design Guide. Volume 4. Aircraft Seats, Restraints, Litters, and Cockpit/Cabin Delethalization

    DTIC Science & Technology

    1989-12-01

    to include inforirmation and changes *Now the Aviation Applied Technology Directorate, U.S. Army Aviation Rese•,c,-i and Technoilogy Activity, U.S...in) a length of metal tubing The concept was developed by an American auto- mobile manufacturing company for incorporation into steering columns to...Technical Report 75-59A, Eustis Directorate, U.S. Army Air Mobility Research and Development Laboratory, Fort Eustis, Virginia, May 1976, AD A026246. 8

  20. Ball lightning risk to aircraft

    NASA Astrophysics Data System (ADS)

    Doe, R.; Keul, A.

    2009-04-01

    Lightning is a rare but regular phenomenon for air traffic. Aircraft are designed to withstand lightning strikes. Research on lightning and aircraft can be called detailed and effective. In the last 57 years, 18 reported lightning aviation disasters with a fatality figure of at least 714 persons occurred. For comparison, the last JACDEC ten-year average fatality figure was 857. The majority encountered lightning in the climb, descent, approach and/or landing phase. Ball lightning, a metastable, rare lightning type, is also seen from and even within aircraft, but former research only reported individual incidents and did not generate a more detailed picture to ascertain whether it constitutes a significant threat to passenger and aircraft safety. Lacking established incident report channels, observations were often only passed on as "air-travel lore". In an effort to change this unsatisfactory condition, the authors have collected a first international dataset of 38 documented ball lightning aircraft incidents from 1938 to 2001 involving 13 reports over Europe, 13 over USA/Canada, and 7 over Russia. 18 (47%) reported ball lightning outside the aircraft, 18 (47%) inside, 2 cases lacked data. 8 objects caused minor damage, 8 major damage (total: 42%), only one a crash. No damage was reported in 18 cases. 3 objects caused minor crew injury. In most cases, ball lightning lasted several seconds. 11 (29%) incidents ended with an explosion of the object. A cloud-aircraft lightning flash was seen in only 9 cases (24%) of the data set. From the detailed accounts of air personnel in the last 70 years, it is evident that ball lightning is rarely, but consistently observed in connection with aircraft and can also occur inside the airframe. Reports often came from multiple professional witnesses and in several cases, damages were investigated by civil or military authorities. Although ball lightning is no main air traffic risk, the authors suggest that incident and accident

  1. Method and apparatus for monitoring aircraft components

    DOEpatents

    Dickens, Larry M.; Haynes, Howard D.; Ayers, Curtis W.

    1996-01-01

    Operability of aircraft mechanical components is monitored by analyzing the voltage output of an electrical generator of the aircraft. Alternative generators, for a turbine-driven rotor aircraft, include the gas producer turbine tachometer generator, the power turbine tachometer generator, and the aircraft systems power producing starter/generator. Changes in the peak amplitudes of the fundamental frequency and its harmonics are correlated to changes in condition of the mechanical components.

  2. Method and apparatus for monitoring aircraft components

    DOEpatents

    Dickens, L.M.; Haynes, H.D.; Ayers, C.W.

    1996-01-16

    Operability of aircraft mechanical components is monitored by analyzing the voltage output of an electrical generator of the aircraft. Alternative generators, for a turbine-driven rotor aircraft, include the gas producer turbine tachometer generator, the power turbine tachometer generator, and the aircraft systems power producing starter/generator. Changes in the peak amplitudes of the fundamental frequency and its harmonics are correlated to changes in condition of the mechanical components. 14 figs.

  3. Database improvements for motor vehicle/bicycle crash analysis

    PubMed Central

    Lusk, Anne C; Asgarzadeh, Morteza; Farvid, Maryam S

    2015-01-01

    Background Bicycling is healthy but needs to be safer for more to bike. Police crash templates are designed for reporting crashes between motor vehicles, but not between vehicles/bicycles. If written/drawn bicycle-crash-scene details exist, these are not entered into spreadsheets. Objective To assess which bicycle-crash-scene data might be added to spreadsheets for analysis. Methods Police crash templates from 50 states were analysed. Reports for 3350 motor vehicle/bicycle crashes (2011) were obtained for the New York City area and 300 cases selected (with drawings and on roads with sharrows, bike lanes, cycle tracks and no bike provisions). Crashes were redrawn and new bicycle-crash-scene details were coded and entered into the existing spreadsheet. The association between severity of injuries and bicycle-crash-scene codes was evaluated using multiple logistic regression. Results Police templates only consistently include pedal-cyclist and helmet. Bicycle-crash-scene coded variables for templates could include: 4 bicycle environments, 18 vehicle impact-points (opened-doors and mirrors), 4 bicycle impact-points, motor vehicle/bicycle crash patterns, in/out of the bicycle environment and bike/relevant motor vehicle categories. A test of including these variables suggested that, with bicyclists who had minor injuries as the control group, bicyclists on roads with bike lanes riding outside the lane had lower likelihood of severe injuries (OR, 0.40, 95% CI 0.16 to 0.98) compared with bicyclists riding on roads without bicycle facilities. Conclusions Police templates should include additional bicycle-crash-scene codes for entry into spreadsheets. Crash analysis, including with big data, could then be conducted on bicycle environments, motor vehicle potential impact points/doors/mirrors, bicycle potential impact points, motor vehicle characteristics, location and injury. PMID:25835304

  4. The seismography of crashes in financial markets

    NASA Astrophysics Data System (ADS)

    Araújo, Tanya; Louçã, Francisco

    2008-01-01

    This Letter investigates the dynamics of stocks in the S&P500 for the last 33 years, considering the population of all companies present in the index for the whole period. Using a stochastic geometry technique and defining a robust index of the dynamics of the market structure, which is able to provide information about the intensity of the crises, the Letter proposes a seismographic classification of the crashes that occurred during the period. The index is used in order to investigate and to classify the impact of the thirteen crashes between July 1973 and March 2006 and to discuss the available evidence of change of structure after the fin de siècle.

  5. The Stock Market Crashes of 1929 and 1987: Linking History and Personal Finance Education

    ERIC Educational Resources Information Center

    Lopus, Jane S.

    2005-01-01

    This article discusses two twentieth-century stock market crashes: the crash of 1929 and the crash of 1987. When this material is presented to students, they see important parallels between the two historical events. But despite remarkable similarities in the severity and many other aspects of the two crashes, the crash of 1929 was followed by the…

  6. Psychiatric response to the Clapham rail crash.

    PubMed Central

    Burns, T P; Hollins, S C

    1991-01-01

    The psychiatric response to the Clapham rail crash is described. The psychiatric input was short term, dealing with the 38 inpatients and over 200 hospital staff involved in the response. The need to evolve a compact, responsive team structure is noted. The value of a proactive approach and provision of psychological debriefing is defended. Incorporation of components of the psychiatric response into the Hospital's major incident plan is reported. PMID:1994007

  7. Classification of Rollovers According to Crash Severity

    PubMed Central

    Digges, K.; Eigen, A.

    2006-01-01

    NASS/CDS 1995–2004 was used to classify rollovers according to severity. The rollovers were partitioned into two classes – rollover as the first event and rollover preceded by an impact with a fixed or non-fixed object. The populations of belted and unbelted were examined separately and combined. The average injury rate for the unbelted was five times that for the belted. Approximately 21% of the severe injuries suffered by belted occupants were in crashes with harmful events prior to the rollover that produced severe damage to the vehicle. This group carried a much higher injury risk than the average. A planar damage measure in addition to the rollover measure was required to adequately capture the crash severity of this population. For rollovers as the first event, approximately 1% of the serious injuries to belted occupants occurred during the first quarter-turn. Rollovers that were arrested during the 1st quarter-turn carried a higher injury rate than average. The number of quarter-turns were grouped in various ways including the number of times the vehicle roof faces the ground (number of vehicle inversions). The number of vehicle inversions was found to be a statistically significant injury predictor for 78% of the belted and unbelted populations with MAIS 3+F injuries in rollovers. The remaining 22% required crash severity metrics in addition to the number of vehicle inversions. PMID:16968634

  8. Dynamic model for automotive side impact crashes

    NASA Astrophysics Data System (ADS)

    Sun, Ludong; Taghvaeeyan, Saber; Rajamani, Rajesh

    2014-07-01

    A rigid body model to represent a side impact crash is constructed using five degrees-of-freedom (dof) for the vehicle and three dof for each occupant in the vehicle. Nonlinear stiffness and damping elements and the presence of physical gaps between several components make the model highly nonlinear. The model is validated using experimental crash test data from a National Highway Traffic Safety Administration (NHTSA) database. To simplify the parameter identification process and reduce the number of parameters to be identified at each stage, a two-step process is adopted in which the vehicle is first assumed to be unaffected by the presence of the occupants, and its model parameters are identified. Subsequently, the parameters in the occupant models are identified. The active set method with a performance index that includes both the L2 and L∞ norms is used for parameter identification. A challenge is posed by the fact that the optimisation problem involved is non-convex. To overcome this challenge, a large set of random initial values of parameter estimates is generated and the optimisation method is applied with all these initial conditions. The values of parameters that provide the minimal performance index from the entire set of initial conditions are then chosen as the best parameter values. The optimal parameters values thus identified are shown to significantly improve the match between the model responses and the experimentally measured sensor signals from the NHTSA crash test.

  9. Modeling Situation Awareness and Crash Risk

    PubMed Central

    Fisher, Donald L.; Strayer, David. L.

    2014-01-01

    In this article we develop a model of the relationship between crash risk and a driver’s situation awareness. We consider a driver’s situation awareness to reflect the dynamic mental model of the driving environment and to be dependent upon several psychological processes including Scanning the driving environment, Predicting and anticipating hazards, Identifying potential hazards in the driving scene as they occur, Deciding on an action, and Executing an appropriate Response (SPIDER). Together, SPIDER is important for establishing and maintaining good situation awareness of the driving environment and good situation awareness is important for coordinating and scheduling the SPIDER-relevant processes necessary for safe driving. An Order-of-Processing (OP) model makes explicit the SPIDER-relevant processes and how they predict the likelihood of a crash when the driver is or is not distracted by a secondary task. For example, the OP model shows how a small decrease in the likelihood of any particular SPIDER activity being completed successfully (because of a concurrent secondary task performance) would lead to a large increase in the relative risk of a crash. PMID:24776225

  10. Safer Roadside Crash Walls Would Limit Deceleration

    NASA Technical Reports Server (NTRS)

    Schneider, William C.; Locke, James P.

    2003-01-01

    The figure depicts the aspects of a proposed deceleration-limiting design for crash walls at the sides of racetracks and highways. The proposal is intended to overcome the disadvantages of both rigid barriers and kinetic-energy-absorbing barriers of prior design. Rigid barriers can keep high-speed crashing motor vehicles from leaving roadways and thereby prevent injury to nearby persons and objects, but they can also subject the occupants of the vehicles to deceleration levels high enough to cause injury or death. Kinetic-energy-absorbing barriers of prior design reduce deceleration levels somewhat, but are not designed to soften impacts optimally; moreover, some of them allow debris to bounce back onto roadways or onto roadside areas, and, in cases of glancingly incident vehicles, some of them can trap the vehicles in such a manner as to cause more injury than would occur if the vehicles were allowed to skid along the rigid barriers. The proposed crash walls would (1) allow tangentially impacting vehicles to continue sliding along the racetrack without catching them, (2) catch directly impacting vehicles to prevent them from injuring nearby persons and objects, and (3) absorb kinetic energy in a more nearly optimum way to limit decelerations to levels that human occupants could survive.

  11. Aircraft Design

    NASA Technical Reports Server (NTRS)

    Bowers, Albion H. (Inventor); Uden, Edward (Inventor)

    2016-01-01

    The present invention is an aircraft wing design that creates a bell shaped span load, which results in a negative induced drag (induced thrust) on the outer portion of the wing; such a design obviates the need for rudder control of an aircraft.

  12. Identifying Critical Road Geometry Parameters Affecting Crash Rate and Crash Type

    PubMed Central

    Othman, Sarbaz; Thomson, Robert; Lannér, Gunnar

    2009-01-01

    The objective of this traffic safety investigation was to find critical road parameters affecting crash rate (CR). The study was based on crash and road maintenance data from Western Sweden. More than 3000 crashes, reported from 2000 to 2005 on median-separated roads, were collected and combined with road geometric and surface data. The statistical analysis showed variations in CR when road elements changed confirming that road characteristics affect CR. The findings indicated that large radii right-turn curves were more dangerous than left curves, in particular, during lane changing manoeuvres. However sharper curves are more dangerous in both left and right curves. Moreover, motorway carriageways with no or limited shoulders have the highest CR when compared to other carriageway widths, while one lane carriageway sections on 2+1 roads were the safest. Road surface results showed that both wheel rut depth and road roughness have negative impacts on traffic safety. PMID:20184841

  13. Macro-level safety analysis of pedestrian crashes in Shanghai, China.

    PubMed

    Wang, Xuesong; Yang, Junguang; Lee, Chris; Ji, Zhuoran; You, Shikai

    2016-11-01

    Pedestrian safety has become one of the most important issues in the field of traffic safety. This study aims at investigating the association between pedestrian crash frequency and various predictor variables including roadway, socio-economic, and land-use features. The relationships were modeled using the data from 263 Traffic Analysis Zones (TAZs) within the urban area of Shanghai - the largest city in China. Since spatial correlation exists among the zonal-level data, Bayesian Conditional Autoregressive (CAR) models with seven different spatial weight features (i.e. (a) 0-1 first order, adjacency-based, (b) common boundary-length-based, (c) geometric centroid-distance-based, (d) crash-weighted centroid-distance-based, (e) land use type, adjacency-based, (f) land use intensity, adjacency-based, and (g) geometric centroid-distance-order) were developed to characterize the spatial correlations among TAZs. Model results indicated that the geometric centroid-distance-order spatial weight feature, which was introduced in macro-level safety analysis for the first time, outperformed all the other spatial weight features. Population was used as the surrogate for pedestrian exposure, and had a positive effect on pedestrian crashes. Other significant factors included length of major arterials, length of minor arterials, road density, average intersection spacing, percentage of 3-legged intersections, and area of TAZ. Pedestrian crashes were higher in TAZs with medium land use intensity than in TAZs with low and high land use intensity. Thus, higher priority should be given to TAZs with medium land use intensity to improve pedestrian safety. Overall, these findings can help transportation planners and managers understand the characteristics of pedestrian crashes and improve pedestrian safety.

  14. Costs of crashes to government, United States, 2008.

    PubMed

    Miller, Ted R; Bhattacharya, Soma; Zaloshnja, Eduard; Taylor, Dexter; Bahar, Geni; David, Iuliana

    2011-01-01

    We estimated how much the Federal government and state/local government pay for different kinds of crashes in the United States. Government costs include reductions in an array of public services (emergency, incident management, vocational rehabilitation, coroner court processing of liability litigation), medical payments, social safety net assistance to the injured and their families, and taxes foregone because victims miss work. Government also pays when its employees crash while working and covers fringe benefits for crash-involved employees and their benefit-eligible dependents in non-work hours. We estimated government shares of crash costs by component. We applied those estimates to existing US Department of Transportation estimates of crash costs to society and employers. Government pays an estimated $35 billion annually because of crashes, an estimated 12.6% of the economic cost of crashes (Federal 7.1%, State/local 5.5%). Government bears a higher percentage of the monetary costs of injury crashes than fatal crashes or crashes involving property damage only. Government is increasingly recovering the medical cost of crashes from auto insurers. Nevertheless, medical costs and income and sales tax losses account for 75% of government's crash costs. For State/local government to break even on a 100%-State funded investment in road safety, the intervention would need to have an unrealistically high benefit-cost ratio of 34. Government invests in medical treatment of illness to save lives and improve quality of life. Curing a child's leukemia, for example, is not less costly than leaving that leukemia untreated. Safety should not be held to a different standard.

  15. Older driver population and crash involvement trends, 1974-1988.

    PubMed

    Stutts, J C; Martell, C

    1992-08-01

    North Carolina motor vehicle crash data for even-numbered years 1974-1988, inclusive, are analyzed in conjunction with North Carolina population, licensed driver, and mileage data to examine trends in motor vehicle crash involvement by driver age, sex, and race. Crash rates per licensed driver are presented along with crash rates per estimated vehicle miles travelled calculated on the basis of induced exposure. Results focus particularly on older drivers. They show that older drivers' representation in the licensed driver population has increased at a greater rate than their representation in either the census or crash involvement populations. These trends are particularly strong for females and for nonwhites. Furthermore, crash rates have declined more for drivers aged 55 and older than for younger drivers. The greatest declines, both in terms of crashes per licensed driver and crashes per estimated miles travelled, have been experienced by drivers age 65 and older, particularly nonwhites. Males show higher overall crash rates per miles travelled than females, but this effect decreases with age and disappears entirely in the oldest age categories. Results are discussed in light of the changing nature of the overall driving population and the cohort of older drivers in particular.

  16. Crash Culpability and the Role of Driver Blood Alcohol Levels

    PubMed Central

    Kufera, Joseph A.; Soderstrom, Carl A.; Dischinger, Patricia C.; Ho, Shiu M.; Shepard, Angela

    2006-01-01

    Twenty years ago the American Medical Association reported the relationship between blood alcohol concentration (BAC) and crash causation. This study addresses culpability, age, gender and BAC in a population of drivers injured in motor vehicle crashes. Five years of hospital and crash data were linked, using probabilistic techniques. Trends in culpability were analyzed by BAC category. Given BAC level, the youngest and oldest drivers were more likely to have caused their crash. Women drivers had significantly higher odds of culpability at the highest BAC levels. Seatbelt use was also associated with culpability, perhaps as a marker for risk-taking among drinkers. PMID:16968631

  17. Transport aircraft accident dynamics

    NASA Technical Reports Server (NTRS)

    Cominsky, A.

    1982-01-01

    A study was carried out of 112 impact survivable jet transport aircraft accidents (world wide) of 27,700 kg (60,000 lb.) aircraft and up extending over the last 20 years. This study centered on the effect of impact and the follow-on events on aircraft structures and was confined to the approach, landing and takeoff segments of the flight. The significant characteristics, frequency of occurrence and the effect on the occupants of the above data base were studied and categorized with a view to establishing typical impact scenarios for use as a basis of verifying the effectiveness of potential safety concepts. Studies were also carried out of related subjects such as: (1) assessment of advanced materials; (2) human tolerance to impact; (3) merit functions for safety concepts; and (4) impact analysis and test methods.

  18. An investigation of the speeding-related crash designation through crash narrative reviews sampled via logistic regression.

    PubMed

    Fitzpatrick, Cole D; Rakasi, Saritha; Knodler, Michael A

    2017-01-01

    Speed is one of the most important factors in traffic safety as higher speeds are linked to increased crash risk and higher injury severities. Nearly a third of fatal crashes in the United States are designated as "speeding-related", which is defined as either "the driver behavior of exceeding the posted speed limit or driving too fast for conditions." While many studies have utilized the speeding-related designation in safety analyses, no studies have examined the underlying accuracy of this designation. Herein, we investigate the speeding-related crash designation through the development of a series of logistic regression models that were derived from the established speeding-related crash typologies and validated using a blind review, by multiple researchers, of 604 crash narratives. The developed logistic regression model accurately identified crashes which were not originally designated as speeding-related but had crash narratives that suggested speeding as a causative factor. Only 53.4% of crashes designated as speeding-related contained narratives which described speeding as a causative factor. Further investigation of these crashes revealed that the driver contributing code (DCC) of "driving too fast for conditions" was being used in three separate situations. Additionally, this DCC was also incorrectly used when "exceeding the posted speed limit" would likely have been a more appropriate designation. Finally, it was determined that the responding officer only utilized one DCC in 82% of crashes not designated as speeding-related but contained a narrative indicating speed as a contributing causal factor. The use of logistic regression models based upon speeding-related crash typologies offers a promising method by which all possible speeding-related crashes could be identified.

  19. 150 Passenger Commercial Aircraft

    NASA Technical Reports Server (NTRS)

    Bucovsky, Adrian; Romli, Fairuz I.; Rupp, Jessica

    2002-01-01

    It has been projected that the need for a short-range mid-sized, aircraft is increasing. The future strategy to decrease long-haul flights will increase the demand for short-haul flights. Since passengers prefer to meet their destinations quickly, airlines will increase the frequency of flights, which will reduce the passenger load on the aircraft. If a point-to-point flight is not possible, passengers will prefer only a one-stop short connecting flight to their final destination. A 150-passenger aircraft is an ideal vehicle for these situations. It is mid-sized aircraft and has a range of 3000 nautical miles. This type of aircraft would market U.S. domestic flights or inter-European flight routes. The objective of the design of the 150-passenger aircraft is to minimize fuel consumption. The configuration of the aircraft must be optimized. This aircraft must meet CO2 and NOx emissions standards with minimal acquisition price and operating costs. This report contains all the work that has been performed for the completion of the design of a 150 passenger commercial aircraft. The methodology used is the Technology Identification, Evaluation, and Selection (TIES) developed at Georgia Tech Aerospace Systems Design laboratory (ASDL). This is an eight-step conceptual design process to evaluate the probability of meeting the design constraints. This methodology also allows for the evaluation of new technologies to be implemented into the design. The TIES process begins with defining the problem with a need established and a market targeted. With the customer requirements set and the target values established, a baseline concept is created. Next, the design space is explored to determine the feasibility and viability of the baseline aircraft configuration. If the design is neither feasible nor viable, new technologies can be implemented to open up the feasible design space and allow for a plausible solution. After the new technologies are identified, they must be evaluated

  20. Aircraft Operations Classification System

    NASA Technical Reports Server (NTRS)

    Harlow, Charles; Zhu, Weihong

    2001-01-01

    Accurate data is important in the aviation planning process. In this project we consider systems for measuring aircraft activity at airports. This would include determining the type of aircraft such as jet, helicopter, single engine, and multiengine propeller. Some of the issues involved in deploying technologies for monitoring aircraft operations are cost, reliability, and accuracy. In addition, the system must be field portable and acceptable at airports. A comparison of technologies was conducted and it was decided that an aircraft monitoring system should be based upon acoustic technology. A multimedia relational database was established for the study. The information contained in the database consists of airport information, runway information, acoustic records, photographic records, a description of the event (takeoff, landing), aircraft type, and environmental information. We extracted features from the time signal and the frequency content of the signal. A multi-layer feed-forward neural network was chosen as the classifier. Training and testing results were obtained. We were able to obtain classification results of over 90 percent for training and testing for takeoff events.

  1. Crash protection of stock car racing drivers--application of biomechanical analysis of Indy car crash research.

    PubMed

    Melvin, John W; Begeman, Paul C; Faller, Ronald K; Sicking, Dean L; McClellan, Scott B; Maynard, Edwin; Donegan, Michael W; Mallott, Annette M; Gideon, Thomas W

    2006-11-01

    Biomechanical analysis of Indy car crashes using on-board impact recorders (Melvin et al. 1998, Melvin et al. 2001) indicates that Indy car driver protection in high-energy crashes can be achieved in frontal, side, and rear crashes with severities in the range of 100 to 135 G peak deceleration and velocity changes in the range of 50 to 70 mph. These crashes were predominantly single-car impacts with the rigid concrete walls of oval tracks. This impressive level of protection was found to be due to the unique combination of a very supportive and tight-fitting cockpit-seating package, a six-point belt restraint system, and effective head padding with an extremely strong chassis that defines the seat and cockpit of a modern Indy car. In 2000 and 2001, a series of fatal crashes in stock car racing created great concern for improving the crash protection for drivers in those racecars. Unlike the Indy car, the typical racing stock car features a more spacious driver cockpit due to its resemblance to the shape of a passenger car. The typical racing seat used in stock cars did not have the same configuration or support characteristics of the Indy car seat, and five-point belt restraints were used. The tubular steel space frame chassis of a stock car also differs from an Indy car's composite chassis structure in both form and mechanical behavior. This paper describes the application of results of the biomechanical analysis of the Indy car crash studies to the unique requirements of stock car racing driver crash protection. Sled test and full-scale crash test data using both Hybrid III frontal crash anthropomorphic test devices (ATDs) and BioSID side crash ATDs for the purpose of evaluating countermeasures involving restraint systems, seats and head/neck restraints has been instrumental in guiding these developments. In addition, the development of deformable walls for oval tracks (the SAFER Barrier) is described as an adjunct to improved occupant restraint through control

  2. Using hierarchical tree-based regression model to predict train-vehicle crashes at passive highway-rail grade crossings.

    PubMed

    Yan, Xuedong; Richards, Stephen; Su, Xiaogang

    2010-01-01

    This paper applies a nonparametric statistical method, hierarchical tree-based regression (HTBR), to explore train-vehicle crash prediction and analysis at passive highway-rail grade crossings. Using the Federal Railroad Administration (FRA) database, the research focuses on 27 years of train-vehicle accident history in the United States from 1980 through 2006. A cross-sectional statistical analysis based on HTBR is conducted for public highway-rail grade crossings that were upgraded from crossbuck-only to stop signs without involvement of other traffic-control devices or automatic countermeasures. In this study, HTBR models are developed to predict train-vehicle crash frequencies for passive grade crossings controlled by crossbucks only and crossbucks combined with stop signs respectively, and assess how the crash frequencies change after the stop-sign treatment is applied at the crossbuck-only-controlled crossings. The study results indicate that stop-sign treatment is an effective engineering countermeasure to improve safety at the passive grade crossings. Decision makers and traffic engineers can use the HTBR models to examine train-vehicle crash frequency at passive crossings and assess the potential effectiveness of stop-sign treatment based on specific attributes of the given crossings.

  3. Development of an energy-absorbing passenger seat for a transport aircraft

    NASA Technical Reports Server (NTRS)

    Eichelberger, C. P.; Alfaro-Bou, E.; Fasanella, E. L.

    1985-01-01

    Commercial air transport passenger safety and survivability, in the event of an impact-survivable crash, are subjects receiving increased technical focus/study by the aviation community. A B-720 aircraft, highly instrumented, and remotely controlled from the ground by a pilot in a simulated cockpit, was crashed on a specially prepared gravel covered impact site. The aircraft was impacted under controlled conditions in an air-to-ground gear-up mode, at a nominal speed of 150 knots and 4-1/2 deg glide slope. Data from a number of on board, crash worthiness experiments provided valuable information related to structural loads/failure modes, antimisting kerosene fuel, passenger and attendant restraint systems and energy absorbing seats. The development of an energy absorbing (EA) seat accomplished through innovative modification of a typical modern standard commercial aviation transport, three passenger seat is described.

  4. Aircraft Steels

    DTIC Science & Technology

    2009-02-19

    NAWCADPAX/TR-2009/ 12 AIRCRAFT STEELS by E. U. Lee R. Taylor C. Lei H. C. Sanders 19 February 2009...MARYLAND NAWCADPAX/TR-2009/ 12 19 February 2009 AIRCRAFT STEELS by E. U. Lee R. Taylor C. Lei H. C. Sanders...Prescribed by ANSI Std. Z39-18 NAWCADPAX/TR-2009/ 12 ii SUMMARY Five high strength and four stainless steels have been studied, identifying their

  5. Comparison of Multivariate Poisson lognormal spatial and temporal crash models to identify hot spots of intersections based on crash types.

    PubMed

    Cheng, Wen; Gill, Gurdiljot Singh; Dasu, Ravi; Xie, Meiquan; Jia, Xudong; Zhou, Jiao

    2017-02-01

    Most of the studies are focused on the general crashes or total crash counts with considerably less research dedicated to different crash types. This study employs the Systemic approach for detection of hotspots and comprehensively cross-validates five multivariate models of crash type-based HSID methods which incorporate spatial and temporal random effects. It is anticipated that comparison of the crash estimation results of the five models would identify the impact of varied random effects on the HSID. The data over a ten year time period (2003-2012) were selected for analysis of a total 137 intersections in the City of Corona, California. The crash types collected in this study include: Rear-end, Head-on, Side-swipe, Broad-side, Hit object, and Others. Statistically significant correlations among crash outcomes for the heterogeneity error term were observed which clearly demonstrated their multivariate nature. Additionally, the spatial random effects revealed the correlations among neighboring intersections across crash types. Five cross-validation criteria which contains, Residual Sum of Squares, Kappa, Mean Absolute Deviation, Method Consistency Test, and Total Rank Difference, were applied to assess the performance of the five HSID methods at crash estimation. In terms of accumulated results which combined all crash types, the model with spatial random effects consistently outperformed the other competing models with a significant margin. However, the inclusion of spatial random effect in temporal models fell short of attaining the expected results. The overall observation from the model fitness and validation results failed to highlight any correlation among better model fitness and superior crash estimation.

  6. Crash characteristics and injury patterns among commercial motorcycle users attending Kitale level IV district hospital, Kenya

    PubMed Central

    Sisimwo, Peter Kiteywo; Mwaniki, Peter Kabanya; Bii, Christine

    2014-01-01

    Introduction Motorcycle users involved in crashes are likely to die or be severely injured due to high frequency of head, chest and leg injuries. We carried out a descriptive cross sectional study to determine crash characteristics and injury patterns among motorcycle users attending Kitale district hospital, Kenya. Methods Motorcycle trauma patients were recruited between 1st August 2013 and 31stOctober 2013. Data collection was done using a pre-tested, coded questionnaire. Frequencies mean (SD) and chi-square was employed in the analysis. Analysis was done using SPSS V.20. Results were considered significant at α = 0.05. Results Motorcycle trauma patients formed 39.4% of all road traffic injuries. Males constituted 69.8%, females 30.2% and mean age was 30(±13) years. Riders accounted for majority of injury patients (45%), passengers (38.8%) and pedestrians (15.9%). Mechanism of motorcycle crash was involving motorcycle versus vehicle (45.6%). Riders suffered severe injuries compared to passengers (χ2=129.936, p < 0.001). Head injury patients were assessed as having Glasgow coma scale (GCS) of 70% 9-12, 26% GCS of 13-15 and 7% GCS of 3-8. Injuries sustained by victims included head and neck injury 40%, lower extremity injury 39.9% and chest injury 8.2%. Riders without helmets during the crash sustained head injuries (χ2=111.352, p < 0.001). Conclusion Head injuries and lower extremity injuries accounted for the major proportion of injuries sustained by motorcycle users. Non helmet use was associated with increased risk of head injuries. Morbidity can be mitigated by encouraging use of protective gear like helmets. PMID:25883724

  7. Toll road crashes of commercial and passenger motor vehicles.

    PubMed

    Braver, Elisa R; Solomon, Mark G; Preusser, David F

    2002-05-01

    Revenue-collection data from toll roads allow for accurate estimates of miles driven by vehicle type and, when combined with crash data, valid estimates of crash involvements per mile driven. Data on vehicle-miles traveled and collisions were obtained from toll road authorities in Florida. Kansas, and New York. In addition, state crash files and published vehicle-miles of travel were obtained for toll roads in Illinois. Indiana, Ohio, and Pennsylvania. Large commercial motor vehicles were significantly underinvolved in single-vehicle crashes on all state toll roads. In five states, commercial motor vehicles were significantly overinvolved in multiple-vehicle crashes relative to passenger vehicles; the exceptions were Kansas, where they had significantly lower multiple-vehicle involvement rates, and Indiana. where there were no significant differences in multiple-vehicle involvements by vehicle type. The risk of commercial motor vehicle involvement in multiple-vehicle crashes resulting in deaths or serious injuries was double that of passenger vehicles in the two states (Ohio and Pennsylvania) that identified serious injuries. Whether crash rates, on toll roads of commercial motor vehicles are higher or lower than those of passenger vehicles appears to depend on the type of crash, specific toll road. and traffic density.

  8. Innovative Anti Crash Absorber for a Crashworthy Landing Gear

    NASA Astrophysics Data System (ADS)

    Guida, Michele; Marulo, Francesco; Montesarchio, Bruno; Bruno, Massimiliano

    2014-06-01

    This paper defines an innovative concept to anti-crash absorber in composite material to be integrated on the landing gear as an energy-absorbing device in crash conditions to absorb the impact energy. A composite cylinder tube in carbon fiber material is installed coaxially to the shock absorber cylinder and, in an emergency landing gear condition, collapses in order to enhance the energy absorption performance of the landing system. This mechanism has been developed as an alternative solution to a high-pressure chamber installed on the Agusta A129 CBT helicopter, which can be considered dangerous when the helicopter operates in hard and/or crash landing. The characteristics of the anti-crash device are presented and the structural layout of a crashworthy landing gear adopting the developed additional energy absorbing stage is outlined. Experimental and numerical results relevant to the material characterization and the force peaks evaluation of the system development are reported. The anti-crash prototype was designed, analysed, optimized, made and finally the potential performances of a landing gear with the additional anti-crash absorber system are tested by drop test and then correlated with a similar test without the anti-crash system, showing that appreciable energy absorbing capabilities and efficiencies can be obtained in crash conditions.

  9. Traffic crash liability determination: Danger and Dodge model.

    PubMed

    Xu, Sikui; Huang, Helai

    2016-10-01

    By proposing a systematic set of rules for traffic crash liability determination, this paper attempts to prove the feasibility and practicability of legal liability in handling traffic crashes. Two sequential elements are identified for crash occurrence, i.e., the occurrence of a dangerous situation and failure in dodging the dangerous situation. A Danger and Dodge model is subsequently established for liability determination in a traffic crash. By investigating the basic mechanism of a crash occurrence, the specific contents of causalties and the effect of the parties' acts in traffic crashes are specified. Based on the theories of social adequancy, the principle of reliance and the duty of care, the study further proposes to use the "peril" of a dangerous situation and the "possibility" of dodging the dangerous situation to appraise the effect of the parties' acts upon a crash occurrence, with the rule of the "pattern deciding effect". The proposed approach would be very helpful to the concreteness of the determination of liability in a traffic crash. Two case studies are presented for demonstration.

  10. The advanced role of computational mechanics and visualization in science and technology: analysis of the Germanwings Flight 9525 crash

    NASA Astrophysics Data System (ADS)

    Chen, Goong; Wang, Yi-Ching; Perronnet, Alain; Gu, Cong; Yao, Pengfei; Bin-Mohsin, Bandar; Hajaiej, Hichem; Scully, Marlan O.

    2017-03-01

    Computational mathematics, physics and engineering form a major constituent of modern computational science, which now stands on an equal footing with the established branches of theoretical and experimental sciences. Computational mechanics solves problems in science and engineering based upon mathematical modeling and computing, bypassing the need for expensive and time-consuming laboratory setups and experimental measurements. Furthermore, it allows the numerical simulations of large scale systems, such as the formation of galaxies that could not be done in any earth bound laboratories. This article is written as part of the 21st Century Frontiers Series to illustrate some state-of-the-art computational science. We emphasize how to do numerical modeling and visualization in the study of a contemporary event, the pulverizing crash of the Germanwings Flight 9525 on March 24, 2015, as a showcase. Such numerical modeling and the ensuing simulation of aircraft crashes into land or mountain are complex tasks as they involve both theoretical study and supercomputing of a complex physical system. The most tragic type of crash involves ‘pulverization’ such as the one suffered by this Germanwings flight. Here, we show pulverizing airliner crashes by visualization through video animations from supercomputer applications of the numerical modeling tool LS-DYNA. A sound validation process is challenging but essential for any sophisticated calculations. We achieve this by validation against the experimental data from a crash test done in 1993 of an F4 Phantom II fighter jet into a wall. We have developed a method by hybridizing two primary methods: finite element analysis and smoothed particle hydrodynamics. This hybrid method also enhances visualization by showing a ‘debris cloud’. Based on our supercomputer simulations and the visualization, we point out that prior works on this topic based on ‘hollow interior’ modeling can be quite problematic and, thus, not

  11. Rayleigh-Taylor instability simulations with CRASH

    NASA Astrophysics Data System (ADS)

    Chou, C.-C.; Fryxell, B.; Drake, R. P.

    2012-03-01

    CRASH is a code package developed for the predictive study of radiative shocks. It is based on the BATSRUS MHD code used extensively for space-weather research. We desire to extend the applications of this code to the study of hydrodynamically unstable systems. We report here the results of Rayleigh-Taylor instability (RTI) simulations with CRASH, as a necessary step toward the study of such systems. Our goal, motivated by the previous comparison of simulations and experiment, is to be able to simulate the magnetic RTI with self-generated magnetic fields produced by the Biermann Battery effect. Here we show results for hydrodynamic RTI, comparing the effects of different solvers and numerical parameters. We find that the early-time behavior converges to the analytical result of the linear theory. We observe that the late-time morphology is sensitive to the numerical scheme and limiter beta. At low-resolution limit, the growth of RTI is highly dependent on the setup and resolution, which we attribute to the large numerical viscosity at low resolution.

  12. Life-threatening motor vehicle crashes in bright sunlight.

    PubMed

    Redelmeier, Donald A; Raza, Sheharyar

    2017-01-01

    Bright sunlight may create visual illusions that lead to driver error, including fallible distance judgment from aerial perspective. We tested whether the risk of a life-threatening motor vehicle crash was increased when driving in bright sunlight.This longitudinal, case-only, paired-comparison analysis evaluated patients hospitalized because of a motor vehicle crash between January 1, 1995 and December 31, 2014. The relative risk of a crash associated with bright sunlight was estimated by evaluating the prevailing weather at the time and place of the crash compared with the weather at the same hour and location on control days a week earlier and a week later.The majority of patients (n = 6962) were injured during daylight hours and bright sunlight was the most common weather condition at the time and place of the crash. The risk of a life-threatening crash was 16% higher during bright sunlight than normal weather (95% confidence interval: 9-24, P < 0.001). The increased risk was accentuated in the early afternoon, disappeared at night, extended to patients with different characteristics, involved crashes with diverse features, not apparent with cloudy weather, and contributed to about 5000 additional patient-days in hospital. The increased risk extended to patients with high crash severity as indicated by ambulance involvement, surgical procedures, length of hospital stay, intensive care unit admission, and patient mortality. The increased risk was not easily attributed to differences in alcohol consumption, driving distances, or anomalies of adverse weather.Bright sunlight is associated with an increased risk of a life-threatening motor vehicle crash. An awareness of this risk might inform driver education, trauma staffing, and safety warnings to prevent a life-threatening motor vehicle crash.

  13. Life-threatening motor vehicle crashes in bright sunlight

    PubMed Central

    Redelmeier, Donald A.; Raza, Sheharyar

    2017-01-01

    Abstract Bright sunlight may create visual illusions that lead to driver error, including fallible distance judgment from aerial perspective. We tested whether the risk of a life-threatening motor vehicle crash was increased when driving in bright sunlight. This longitudinal, case-only, paired-comparison analysis evaluated patients hospitalized because of a motor vehicle crash between January 1, 1995 and December 31, 2014. The relative risk of a crash associated with bright sunlight was estimated by evaluating the prevailing weather at the time and place of the crash compared with the weather at the same hour and location on control days a week earlier and a week later. The majority of patients (n = 6962) were injured during daylight hours and bright sunlight was the most common weather condition at the time and place of the crash. The risk of a life-threatening crash was 16% higher during bright sunlight than normal weather (95% confidence interval: 9–24, P < 0.001). The increased risk was accentuated in the early afternoon, disappeared at night, extended to patients with different characteristics, involved crashes with diverse features, not apparent with cloudy weather, and contributed to about 5000 additional patient-days in hospital. The increased risk extended to patients with high crash severity as indicated by ambulance involvement, surgical procedures, length of hospital stay, intensive care unit admission, and patient mortality. The increased risk was not easily attributed to differences in alcohol consumption, driving distances, or anomalies of adverse weather. Bright sunlight is associated with an increased risk of a life-threatening motor vehicle crash. An awareness of this risk might inform driver education, trauma staffing, and safety warnings to prevent a life-threatening motor vehicle crash. Level of evidence: Epidemiologic Study, level III. PMID:28072708

  14. Comprehensive and Human Capital Crash Costs by Maximum Police-Reported Injury Severity Within Selected Crash Types

    PubMed Central

    Zaloshnja, Eduard; Miller, Ted; Council, Forrest; Persaud, Bhagwant

    2004-01-01

    This paper presents estimates for both the economic and comprehensive costs per crash for three police-coded severity groupings within 16 selected crash types and within two speed limit categories (<=45 and >=50 mph). The economic costs are hard dollar costs. The comprehensive costs include economic costs and quality of life losses. We merged previously developed costs per victim keyed on the Abbreviated Injury Scale (AIS) into US crash data files that scored injuries in both the AIS and police-coded severity scales to produce per crash estimates. The most costly crashes were non-intersection fatal/disabling injury crashes on a road with a speed limit of 50 miles per hour or higher where multiple vehicles crashed head-on or a single vehicle struck a human (over 1.69 and $1.16 million per crash, respectively). The annual cost of police-reported run-off-road collisions, which include both rollovers and object impacts, represented 34% of total costs. PMID:15319129

  15. An empirical assessment of fixed and random parameter logit models using crash- and non-crash-specific injury data.

    PubMed

    Ch Anastasopoulos, Panagiotis; Mannering, Fred L

    2011-05-01

    Traditional crash-severity modeling uses detailed data gathered after a crash has occurred (number of vehicles involved, age of occupants, weather conditions at the time of the crash, types of vehicles involved, crash type, occupant restraint use, airbag deployment, etc.) to predict the level of occupant injury. However, for prediction purposes, the use of such detailed data makes assessing the impact of alternate safety countermeasures exceedingly difficult due to the large number of variables that need to be known. Using 5-year data from interstate highways in Indiana, this study explores fixed and random parameter statistical models using detailed crash-specific data and data that include the injury outcome of the crash but not other detailed crash-specific data (only more general data are used such as roadway geometrics, pavement condition and general weather and traffic characteristics). The analysis shows that, while models that do not use detailed crash-specific data do not perform as well as those that do, random parameter models using less detailed data still can provide a reasonable level of accuracy.

  16. An efficient parallel sampling technique for Multivariate Poisson-Lognormal model: Analysis with two crash count datasets

    DOE PAGES

    Zhan, Xianyuan; Aziz, H. M. Abdul; Ukkusuri, Satish V.

    2015-11-19

    Our study investigates the Multivariate Poisson-lognormal (MVPLN) model that jointly models crash frequency and severity accounting for correlations. The ordinary univariate count models analyze crashes of different severity level separately ignoring the correlations among severity levels. The MVPLN model is capable to incorporate the general correlation structure and takes account of the over dispersion in the data that leads to a superior data fitting. But, the traditional estimation approach for MVPLN model is computationally expensive, which often limits the use of MVPLN model in practice. In this work, a parallel sampling scheme is introduced to improve the original Markov Chainmore » Monte Carlo (MCMC) estimation approach of the MVPLN model, which significantly reduces the model estimation time. Two MVPLN models are developed using the pedestrian vehicle crash data collected in New York City from 2002 to 2006, and the highway-injury data from Washington State (5-year data from 1990 to 1994) The Deviance Information Criteria (DIC) is used to evaluate the model fitting. The estimation results show that the MVPLN models provide a superior fit over univariate Poisson-lognormal (PLN), univariate Poisson, and Negative Binomial models. Moreover, the correlations among the latent effects of different severity levels are found significant in both datasets that justifies the importance of jointly modeling crash frequency and severity accounting for correlations.« less

  17. An efficient parallel sampling technique for Multivariate Poisson-Lognormal model: Analysis with two crash count datasets

    SciTech Connect

    Zhan, Xianyuan; Aziz, H. M. Abdul; Ukkusuri, Satish V.

    2015-11-19

    Our study investigates the Multivariate Poisson-lognormal (MVPLN) model that jointly models crash frequency and severity accounting for correlations. The ordinary univariate count models analyze crashes of different severity level separately ignoring the correlations among severity levels. The MVPLN model is capable to incorporate the general correlation structure and takes account of the over dispersion in the data that leads to a superior data fitting. But, the traditional estimation approach for MVPLN model is computationally expensive, which often limits the use of MVPLN model in practice. In this work, a parallel sampling scheme is introduced to improve the original Markov Chain Monte Carlo (MCMC) estimation approach of the MVPLN model, which significantly reduces the model estimation time. Two MVPLN models are developed using the pedestrian vehicle crash data collected in New York City from 2002 to 2006, and the highway-injury data from Washington State (5-year data from 1990 to 1994) The Deviance Information Criteria (DIC) is used to evaluate the model fitting. The estimation results show that the MVPLN models provide a superior fit over univariate Poisson-lognormal (PLN), univariate Poisson, and Negative Binomial models. Moreover, the correlations among the latent effects of different severity levels are found significant in both datasets that justifies the importance of jointly modeling crash frequency and severity accounting for correlations.

  18. Risk Factors for Fatal and Nonfatal Road Crashes in Iran

    PubMed Central

    Mehmandar, Mohammadreza; Soori, Hamid; Amiri, Mosa; Norouzirad, Reza; Khabzkhoob, Mehdi

    2014-01-01

    Background: Road traffic injuries are among the leading causes of death in the world and Iran. Objectives: The aim of this study was to assess the role of age, sex, education, and time of accident on human casualties and mortalities of road crashes in Iran. Materials and Methods: This study was based on data gathered by Iranian Police Department from the records of road crashes from April 4, 2008 through April 4, 2009. Road crashes are categorized into three types: with no human casualties, with injuries, and with human mortalities. Results: The largest rate of human causalities was observed in people aged between 25 to 34 years (P < 0.001). Illiterate people had 81% smaller odds of causality in road crashes (P < 0.001) in comparison with those with a kind of academic education. Overall, 73.4% of crashes had happened during the last ten days of a month were with human casualties (P < 0.001) and human casualties rate was slightly higher in crashes happened between 1 AM to 5 AM Fatality rate was slightly higher in the females (OR = 2.6, P = 0.068). The smallest odds of fatality were found in the people aged between 18 to 24 years and the highest odds were seen in people ≥ 55 years of age (P < 0.001). In people with a university education, 61.9% of crashes were with fatality (P = 0.026). In addition, 82.8% of crashes during winter, 60.2% of crashes during autumn, and 35.8% of crashes during summer were with mortalities. Overall, 78.3% of crashes with human casualties that had happened during 1 AM to 5 AM led to mortalities. There was also a significant association between injury and its intensity with fastening seatbelts. Conclusions: Older age, university degrees, female sex, wintertime, and the time of accident seem to be the most important risk factors in road crashes that lead to fatalities in Iran. Drivers in Iran should be informed and trained regarding these risk factors, which have direct effect on casualties and mortalities in road crashes. PMID:25389468

  19. The Impact of Built Environment on Pedestrian Crashes and the Identification of Crash Clusters on an Urban University Campus

    PubMed Central

    Dai, Dajun; Taquechel, Emily; Steward, John; Strasser, Sheryl

    2010-01-01

    Objectives: Motor vehicle-pedestrian crash is a significant public health concern. The urban campus of Georgia State University poses unique challenges due to a large number of students and university employees. The objectives of this study are twofold: 1) to examine the correlation between specific features of the built environment on and around the University campus and pedestrian crashes; and 2) to identify crash clusters in the study area using network-based geospatial techniques. Methods: We obtained pedestrian crash data (n=119) from 2003 to 2007 from Georgia Department of Transportation and evaluated environmental features pertaining to the road infrastructure, pedestrian infrastructure and streetscape for each road segment and intersection. Prevalence rate of each feature with pedestrian crashes present was calculated. We used network-based Kernel Density Estimation to identify the high density road segments and intersections, then used network-based K-function to examine the clustering of pedestrian crashes. Results: Over 50% of the crosswalk signs, pedestrian signals, public transit, and location branding signs (more than three) at intersections involved pedestrian crashes. More than half of wider streets (greater than 29 feet), two-way streets, and streets in good condition had pedestrian crashes present. Crashes occurred more frequently in road segments with strong street compactness and mixed land use present and were significantly (p<0.05) clustered in these high-density zones. Conclusion: Findings can be used to understand the correlation between built environment and pedestrian safety, to prioritize the high-density zones for intervention efforts, and to formulate research hypotheses for investigating pedestrian crashes. PMID:20882153

  20. Aircraft Wake RCS Measurement

    NASA Technical Reports Server (NTRS)

    Gilson, William H.

    1994-01-01

    A series of multi-frequency radar measurements of aircraft wakes at altitudes of 5,000 to 25,00 ft. were performed at Kwajalein, R.M.I., in May and June of 1990. Two aircraft were tested, a Learjet 35 and a Lockheed C-5A. The cross-section of the wake of the Learjet was too small for detection at Kwajalein. The wake of the C-5A, although also very small, was detected and measured at VHF, UHF, L-, S-, and C-bands, at distances behind the aircraft ranging from about one hundred meters to tens of kilometers. The data suggest that the mechanism by which aircraft wakes have detectable radar signatures is, contrary to previous expectations, unrelated to engine exhaust but instead due to turbulent mixing by the wake vortices of pre-existing index of refraction gradients in the ambient atmosphere. These measurements were of necessity performed with extremely powerful and sensitive instrumentation radars, and the wake cross-section is too small for most practical applications.

  1. Differences in traffic violations and at-fault crashes between license suspension and revocation.

    PubMed

    Kim, Kwang Sik; Myeong, Myo Hee; Kweon, Young-Jun

    2011-05-01

    Upon conviction for particular traffic offenses, drivers can have their licenses revoked. Drivers who receive license revocation have an opportunity to apply for a sentence reduction, and some of those who apply receive a reduced sanction--license suspension. There may be differences between drivers whose license was revoked as originally sentenced and drivers who received the reduced sanction of license suspension with regard to traffic violations and crashes after driving privileges are restored. This study verified the differences during the follow-up periods of 6, 12, and 18 months using analysis of covariance and the t-test with stratified samples based on the police profiles of approximately 154,000 drivers in South Korea. The study found that drivers in the group whose license had been suspended committed traffic violations and caused traffic crashes less often for all time periods than those whose license had been revoked. However, omitted factors such as the attitude of suspended drivers and exposure to traffic violations and crashes (e.g., driving frequency after license reinstatement), are likely to affect the findings; thus, caution should be exercised when the findings are referenced for policy implications.

  2. CRASH: A BLOCK-ADAPTIVE-MESH CODE FOR RADIATIVE SHOCK HYDRODYNAMICS-IMPLEMENTATION AND VERIFICATION

    SciTech Connect

    Van der Holst, B.; Toth, G.; Sokolov, I. V.; Myra, E. S.; Fryxell, B.; Drake, R. P.; Powell, K. G.; Holloway, J. P.; Stout, Q.; Adams, M. L.; Morel, J. E.; Karni, S.

    2011-06-01

    We describe the Center for Radiative Shock Hydrodynamics (CRASH) code, a block-adaptive-mesh code for multi-material radiation hydrodynamics. The implementation solves the radiation diffusion model with a gray or multi-group method and uses a flux-limited diffusion approximation to recover the free-streaming limit. Electrons and ions are allowed to have different temperatures and we include flux-limited electron heat conduction. The radiation hydrodynamic equations are solved in the Eulerian frame by means of a conservative finite-volume discretization in either one-, two-, or three-dimensional slab geometry or in two-dimensional cylindrical symmetry. An operator-split method is used to solve these equations in three substeps: (1) an explicit step of a shock-capturing hydrodynamic solver; (2) a linear advection of the radiation in frequency-logarithm space; and (3) an implicit solution of the stiff radiation diffusion, heat conduction, and energy exchange. We present a suite of verification test problems to demonstrate the accuracy and performance of the algorithms. The applications are for astrophysics and laboratory astrophysics. The CRASH code is an extension of the Block-Adaptive Tree Solarwind Roe Upwind Scheme (BATS-R-US) code with a new radiation transfer and heat conduction library and equation-of-state and multi-group opacity solvers. Both CRASH and BATS-R-US are part of the publicly available Space Weather Modeling Framework.

  3. Requirements for the crash protection of older vehicle passengers.

    PubMed

    Morris, Andrew; Welsh, Ruth; Hassan, Ahamedali

    2003-01-01

    This study compares injury outcomes in vehicle crashes involving different age groups of belted passengers. Two datasets were considered. Firstly, UK national data revealed that younger passengers are much more likely to be involved in crashes per million miles travelled compared to older passengers although older passengers are much more likely to be killed or seriously injured compared to younger passengers. Secondly, in-depth vehicle crash injury data were examined to determine some of the underlying reasons for the enhanced injury risk amongst older passengers. In crashes of approximately equal severity, the older passenger group were significantly more likely to be fatally injured in frontal crashes (p<0.001). However young passengers were as equally likely to be killed in struck-side crashes compared to the older group. The results also showed that older passengers sustained more serious injuries to the chest region in frontal crashes compared with the younger aged group (p<0.0001) and it is this body region that is particularly problematic. When the data were analysed further, it was found that a large proportion of passengers were female and that in the majority of cases, the seat belt was responsible for injury. Since by the year 2030, 1 in 4 persons will be aged over 65 in most OECD countries, the results suggest a need for intervention through vehicle design including in-vehicle crashworthiness systems that take into account reduced tolerance to impact with ageing.

  4. The effect of traffic tickets on road traffic crashes.

    PubMed

    Factor, Roni

    2014-03-01

    Road traffic crashes are globally a leading cause of death. The current study tests the effect of traffic tickets issued to drivers on subsequent crashes, using a unique dataset that overcomes some shortcomings of previous studies. The study takes advantage of a national longitudinal dataset at the individual level that merges Israeli census data with data on traffic tickets issued by the police and official data on involvement in road traffic crashes over seven years. The results show that the estimated probability of involvement in a subsequent fatal or severe crash was more than eleven times higher for drivers with six traffic tickets per year compared to those with one ticket per year, while controlling for various confounders. However, the majority of fatal and severe crashes involved the larger population of drivers who received up to one ticket on average per year. The current findings indicate that reducing traffic violations may contribute significantly to crash and injury reduction. In addition, mass random enforcement programs may be more effective in reducing fatal and severe crashes than targeting high-risk recidivist drivers.

  5. Driving with Alzheimer disease: the anatomy of a crash.

    PubMed

    Reinach, S J; Rizzo, M; McGehee, D V

    1997-06-01

    Alzheimer disease (AD) affects several abilities that are crucial to automobile driving and can thereby increase the risk for a crash. The specific driver safety errors that lead up to crashes in this driver population, however, remain largely unknown. We developed a graphical means for dissecting these safety-related behaviors for application to car crashes of AD drivers. These crashes occurred in collision avoidance scenarios implemented on the Iowa Driving Simulator. Crash plots were produced by "rewinding" the data stream, then graphing the vehicle speed, path, steering wheel position, pedal positions, and driver gaze up to the very moment of impact. In this way, we were able to display in detail the patterns of vehicle and driver control to determine exactly how a crash occurred. Several different types of antecedent safety errors were noted, ranging from responding inappropriately with the hand and foot controls to not responding at all. In this paper we focus on the performance of a single impaired driver to demonstrate our technique and findings. Understanding the "anatomy" of crashes in cognitively disabled drivers with AD can help guide future efforts at injury prevention and control.

  6. Impact of traffic states on freeway crash involvement rates.

    PubMed

    Yeo, Hwasoo; Jang, Kitae; Skabardonis, Alexander; Kang, Seungmo

    2013-01-01

    Freeway traffic accidents are complicated events that are influenced by multiple factors including roadway geometry, drivers' behavior, traffic conditions and environmental factors. Among the various factors, crash occurrence on freeways is supposed to be strongly influenced by the traffic states representing driving situations that are changed by road geometry and cause the change of drivers' behavior. This paper proposes a methodology to investigate the relationship between traffic states and crash involvements on the freeway. First, we defined section-based traffic states: free flow (FF), back of queue (BQ), bottleneck front (BN) and congestion (CT) according to their distinctive patterns; and traffic states of each freeway section are determined based on actual measurements of traffic data from upstream and downstream ends of the section. Next, freeway crash data are integrated with the traffic states of a freeway section using upstream and downstream traffic measurements. As an illustrative study to show the applicability, we applied the proposed method on a 32-mile section of I-880 freeway. By integrating freeway crash occurrence and traffic data over a three-year period, we obtained the crash involvement rate for each traffic state. The results show that crash involvement rate in BN, BQ, and CT states are approximately 5 times higher than the one in FF. The proposed method shows promise to be used for various safety performance measurement including hot spot identification and prediction of the number of crash involvements on freeway sections.

  7. Drug and Alcohol Involvement in Four Types of Fatal Crashes*

    PubMed Central

    Romano, Eduardo; Voas, Robert B.

    2011-01-01

    Objective: The aim of this study was to explore the relationship of drunk and drugged driving to the occurrence of fatal crashes associated with speeding, failure to obey/yield, inattention, and seat belt nonuse. Method: We examined data for fatally injured drivers involved in single-vehicle crashes killed in states in which more than 79% of the drivers were tested for drugs other than alcohol and had a known result. Results: About 25% of the drivers tested positive for drugs, a figure almost double that estimated by the 2007 National Roadside Survey. Cannabinoids and stimulants each contributed to about 23% of the drug-positive results (6% among all fatally injured single-vehicle drivers). Stimulants more than cannabinoids were found to be associated with the four types of crashes under study. Some drugs showed a protective effect over the four crash types under study. Significant interactions between drugs and alcohol were observed. Stimulants contributed to the different types of fatal crashes irrespective of the levels of alcohol consumed by the drivers. Conclusions: This study provides further evidence of a link between drug consumption and fatal crashes. It also opens the door to some interesting and sometimes unexpected questions regarding the way drugs contribute to crashes, which we found varies depending on the type of crash considered, the class of drug, and the presence of alcohol. Research is also needed on drugs that could have a protective effect on the occurrence of fatal crashes. These findings could be highly relevant to the design of drug-related traffic laws and programs targeted at curbing drugged driving. PMID:21683038

  8. Evidence of human induce factors in automotive crashes in Nigeria.

    PubMed

    Abidemi, Awopeju K

    2013-01-01

    Nigeria is one of the countries in Africa highly affected by automotive crashes which led to establishment of Federal Road Safety Corps (FRSC). The organization fought and is fighting against reckless driving in the country to prevent loss of life through automotive crashes. The record of the organization and the Statistical investigation of the researcher reveal that most of the crashes were due to human error such as alcoholism, inexperience and peer influence on the high-way. The data for the research was collected from published report of FRSC 2012 and analyzed using chi-square dependency test and charts due to the nature of the presentation. Ratios were used to determine Number of people killed per Road Total Crashes (RTC), Casualty per RTC and RTC severity Index from 2007 to 2010 in the country. Among the human induced factors, it was discovered that most of the drivers involved in road crashes were drunk during the period and the years of experience play major role in the automotive crashes as drivers with less than 2years of experience were more involved than the other groups. In the consideration of life style of drivers involve in road crashes, it was discovered that drivers with less than 30years of age are vulnerable to road crashes than drivers with ages higher than 30years. Among the findings, the most common automobile in Nigeria road crashes is commercial buses in the years considered. It was recommended that proper and adequate training should be given to drivers on the high-way to prevent injuries and loss of life. Alcoholism should be discouraged in totality and age of obtaining drivers license could be increased in developing countries such as Nigeria.

  9. U.S. Civil Air Show Crashes, 1993 to 2013

    PubMed Central

    Ballard, Sarah-Blythe; Osorio, Victor B.

    2016-01-01

    This study provides new public health data about U.S. civil air shows. Risk factors for fatalities in civil air show crashes were analyzed. The value of the FIA score in predicting fatal outcomes was evaluated. With the use of the FAA’s General Aviation and Air Taxi Survey and the National Transportation Safety Board’s data, the incidence of civil air show crashes from 1993 to 2013 was calculated. Fatality risk factors for crashes were analyzed by means of regression methods. The FIA index was validated to predict fatal outcomes by using the factors of fire, instrument conditions, and away-from-airport location, and was evaluated through receiver operating characteristic (ROC) curves. The civil air show crash rate was 31 crashes per 1,000 civil air events. Of the 174 civil air show crashes that occurred during the study period, 91 (52%) involved at least one fatality; on average, 1.1 people died per fatal crash. Fatalities were associated with four major risk factors: fire [adjusted odds ratio (AOR) = 7.1, 95% confidence interval (CI) = 2.4 to 20.6, P < .001], pilot error (AOR = 5.2, 95% CI = 1.8 to 14.5, P = .002), aerobatic flight (AOR = 3.6, 95% CI = 1.6 to 8.2, P = .002), and off-airport location (AOR = 3.4, 95% CI = 1.5 to 7.5, P = .003). The area under the FIA score’s ROC curve was 0.71 (95% CI = 0.64 to 0.78). Civil air show crashes were marked by a high risk of fatal outcomes to pilots in aerobatic performances but rare mass casualties. The FIA score was not a valid measurement of fatal risk in civil air show crashes. PMID:27773963

  10. Overview of the Transport Rotorcraft Airframe Crash Testbed (TRACT) Full Scale Crash Tests

    NASA Technical Reports Server (NTRS)

    Annett, Martin; Littell, Justin

    2015-01-01

    The Transport Rotorcraft Airframe Crash Testbed (TRACT) full-scale tests were performed at NASA Langley Research Center's Landing and Impact Research Facility in 2013 and 2014. Two CH-46E airframes were impacted at 33-ft/s forward and 25-ft/s vertical combined velocities onto soft soil, which represents a severe, but potentially survivable impact scenario. TRACT 1 provided a baseline set of responses, while TRACT 2 included retrofits with composite subfloors and other crash system improvements based on TRACT 1. For TRACT 2, a total of 18 unique experiments were conducted to evaluate Anthropomorphic Test Devices (ATD) responses, seat and restraint performance, cargo restraint effectiveness, patient litter behavior, and activation of emergency locator transmitters and crash sensors. Combinations of Hybrid II, Hybrid III, and ES-2 ATDs were placed in forward and side facing seats and occupant results were compared against injury criteria. The structural response of the airframe was assessed based on accelerometers located throughout the airframe and using three-dimensional photogrammetric techniques. Analysis of the photogrammetric data indicated regions of maximum deflection and permanent deformation. The response of TRACT 2 was noticeably different in the horizontal direction due to changes in the cabin configuration and soil surface, with higher acceleration and damage occurring in the cabin. Loads from ATDs in energy absorbing seats and restraints were within injury limits. Severe injury was likely for ATDs in forward facing passenger seats.

  11. Evaluation of the Second Transport Rotorcraft Airframe Crash Testbed (TRACT 2) Full Scale Crash Test

    NASA Technical Reports Server (NTRS)

    Annett, Martin; Littell, Justin

    2015-01-01

    Two Transport Rotorcraft Airframe Crash Testbed (TRACT) full-scale tests were performed at NASA Langley Research Center's Landing and Impact Research Facility in 2013 and 2014. Two CH-46E airframes were impacted at 33-ft/s forward and 25-ft/s vertical combined velocities onto soft soil, which represents a severe, but potentially survivable impact scenario. TRACT 1 provided a baseline set of responses, while TRACT 2 included retrofits with composite subfloors and other crash system improvements based on TRACT 1. For TRACT 2, a total of 18 unique experiments were conducted to evaluate ATD responses, seat and restraint performance, cargo restraint effectiveness, patient litter behavior, and activation of emergency locator transmitters and crash sensors. Combinations of Hybrid II, Hybrid III, and ES-2 Anthropomorphic Test Devices (ATDs) were placed in forward and side facing seats and occupant results were compared against injury criteria. The structural response of the airframe was assessed based on accelerometers located throughout the airframe and using three-dimensional photogrammetric techniques. Analysis of the photogrammetric data indicated regions of maximum deflection and permanent deformation. The response of TRACT 2 was noticeably different in the longitudinal direction due to changes in the cabin configuration and soil surface, with higher acceleration and damage occurring in the cabin. Loads from ATDs in energy absorbing seats and restraints were within injury limits. Severe injury was likely for ATDs in forward facing passenger seats.

  12. Crash Testing of Helicopter Airframe Fittings

    NASA Technical Reports Server (NTRS)

    Clarke, Charles W.; Townsend, William; Boitnott, Richard

    2004-01-01

    As part of the Rotary Wing Structures Technology Demonstration (RWSTD) program, a surrogate RAH-66 seat attachment fitting was dynamically tested to assess its response to transient, crash impact loads. The dynamic response of this composite material fitting was compared to the performance of an identical fitting subjected to quasi-static loads of similar magnitude. Static and dynamic tests were conducted of both smaller bench level and larger full-scale test articles. At the bench level, the seat fitting was supported in a steel fixture, and in the full-scale tests, the fitting was integrated into a surrogate RAH-66 forward fuselage. Based upon the lessons learned, an improved method to design, analyze, and test similar composite material fittings is proposed.

  13. Crash test for the Copenhagen problem.

    PubMed

    Nagler, Jan

    2004-06-01

    The Copenhagen problem is a simple model in celestial mechanics. It serves to investigate the behavior of a small body under the gravitational influence of two equally heavy primary bodies. We present a partition of orbits into classes of various kinds of regular motion, chaotic motion, escape and crash. Collisions of the small body onto one of the primaries turn out to be unexpectedly frequent, and their probability displays a scale-free dependence on the size of the primaries. The analysis reveals a high degree of complexity so that long term prediction may become a formidable task. Moreover, we link the results to chaotic scattering theory and the theory of leaking Hamiltonian systems.

  14. Use of Real-Time Ground-To-Air Video during Aeromedical Response to Traffic Crashes

    NASA Astrophysics Data System (ADS)

    Perina, D.

    2002-08-01

    The purpose of this feasibility study was to determine whether the use of ground-based video imaging by local rescue squad personnel, along with real-time transmission of this information to the Pegasus helicopter medical crew, is technically feasible and of sufficient quality to be used as a tool to improve pre-hospital care provided to crash victims. The scope of this project was to investigate various types of existing technology and equipment that may allow for the desired communication linkage between aircraft and ground responders either as is or with achievable modifications. Additionally, other stakeholder entities in this project would be identified and approached to solicit cooperation in the subsequent deployment of the equipment.

  15. Crash Certification by Analysis - Are We There Yet?

    NASA Technical Reports Server (NTRS)

    Jackson, Karen E.; Fasanella, Edwin L.; Lyle, Karen H.

    2006-01-01

    This paper addresses the issue of crash certification by analysis. This broad topic encompasses many ancillary issues including model validation procedures, uncertainty in test data and analysis models, probabilistic techniques for test-analysis correlation, verification of the mathematical formulation, and establishment of appropriate qualification requirements. This paper will focus on certification requirements for crashworthiness of military helicopters; capabilities of the current analysis codes used for crash modeling and simulation, including some examples of simulations from the literature to illustrate the current approach to model validation; and future directions needed to achieve "crash certification by analysis."

  16. Projecting Fatalities in Crashes Involving Older Drivers, 2000-2025

    SciTech Connect

    Hu, P.S.

    2001-03-23

    As part of this research effort, we developed a new methodology for projecting elderly traffic crash fatalities. This methodology separates exposure to crashes from crash risk per se, and further divides exposure into two components, the number of miles driven and the likelihood of being a driver. This component structure permits conceptually different determinants of traffic fatalities to be projected separately and has thorough motivation in behavioral theory. It also permits finer targeting of particular aspects of projections that need improvement and closer linking of projections to possible policy instruments for influencing them.

  17. Crash Simulation of a Vertical Drop Test of a B737 Fuselage Section with Overhead Bins and Luggage

    NASA Technical Reports Server (NTRS)

    Jackson, Karen E.; Fasanella, Edwin L.

    2004-01-01

    The focus of this paper is to describe a crash simulation of a 30-ft/s vertical drop test of a Boeing 737 (B737) fuselage section. The drop test of the 10-ft. long fuselage section of a B737 aircraft was conducted in November of 2000 at the FAA Technical Center in Atlantic City, NJ. The fuselage section was outfitted with two different commercial overhead stowage bins. In addition, 3,229-lbs. of luggage were packed in the cargo hold to represent a maximum take-off weight condition. The main objective of the test was to evaluate the response and failure modes of the overhead stowage bins in a narrow-body transport fuselage section when subjected to a severe, but survivable, impact. A secondary objective of the test was to generate experimental data for correlation with the crash simulation. A full-scale 3-dimensional finite element model of the fuselage section was developed and a crash simulation was conducted using the explicit, nonlinear transient dynamic code, MSC.Dytran. Pre-test predictions of the fuselage and overhead bin responses were generated for correlation with the drop test data. A description of the finite element model and an assessment of the analytical/experimental correlation are presented. In addition, suggestions for modifications to the model to improve correlation are proposed.

  18. Crash tests of four low-wing twin-engine airplanes with truss-reinforced fuselage structure

    NASA Technical Reports Server (NTRS)

    Williams, M. S.; Fasanella, E. L.

    1982-01-01

    Four six-place, low-wing, twin-engine, general aviation airplane test specimens were crash tested under controlled free flight conditions. All airplanes were impacted on a concrete test surface at a nomial flight path velocity of 27 m/sec. Two tests were conducted at a -15 deg flight path angle (0 deg pitch angle and 15 deg pitch angle), and two were conducted at a -30 deg flight path angle (-30 deg pitch angle). The average acceleration time histories (crash pulses) in the cabin area for each principal direction were calculated for each crash test. In addition, the peak floor accelerations were calculated for each test as a function of aircraft fuselage longitudinal station number. Anthropomorphic dummy accelerations were analyzed using the dynamic response index and severity index (SI) models. Parameters affecting the dummy restraint system were studied; these parameters included the effect of no upper torso restraint, measurement of the amount of inertia-reel strap pullout before locking, measurement of dummy chest forward motion, and loads in the restraints. With the SI model, the dummies with no shoulder harness received head impacts above the concussive threshold.

  19. Annoyance and acceptability judgements of noise produced by three types of aircraft by residents living near JFK Airport

    NASA Technical Reports Server (NTRS)

    Borsky, P. N.

    1974-01-01

    A random sample of selected communities near JFK Airport were interviewed. Subsamples, with differing feelings of fear of aircraft crashes and different locations of residence were invited to participate in a laboratory experiment. The subjects were exposed to tape recordings of simulated flyovers of aircraft in approach and departure operations at nominal distances from the airport. The subjects judged the extent of noise annoyance and acceptability of the aircraft noises. Results indicate that level of noise is most significant in affecting annoyance judgements. Subjects with feelings of high fear report significantly more annoyance and less acceptability of aircraft noise than subjects with feelings of low fear.

  20. Aircraft cybernetics

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The use of computers for aircraft control, flight simulation, and inertial navigation is explored. The man-machine relation problem in aviation is addressed. Simple and self-adapting autopilots are described and the assets and liabilities of digital navigation techniques are assessed.

  1. Evaluation of the First Transport Rotorcraft Airframe Crash Testbed (TRACT 1) Full-Scale Crash Test

    NASA Technical Reports Server (NTRS)

    Annett, Martin S.; Littell, Justin D.; Jackson, Karen E.; Bark, Lindley W.; DeWeese, Rick L.; McEntire, B. Joseph

    2014-01-01

    In 2012, the NASA Rotary Wing Crashworthiness Program initiated the Transport Rotorcraft Airframe Crash Testbed (TRACT) research program by obtaining two CH-46E helicopters from the Navy CH-46E Program Office (PMA-226) at the Navy Flight Readiness Center in Cherry Point, North Carolina. Full-scale crash tests were planned to assess dynamic responses of transport-category rotorcraft under combined horizontal and vertical impact loading. The first crash test (TRACT 1) was performed at NASA Langley Research Center's Landing and Impact Research Facility (LandIR), which enables the study of critical interactions between the airframe, seat, and occupant during a controlled crash environment. The CH-46E fuselage is categorized as a medium-lift rotorcraft with fuselage dimensions comparable to a regional jet or business jet. The first TRACT test (TRACT 1) was conducted in August 2013. The primary objectives for TRACT 1 were to: (1) assess improvements to occupant loads and displacement with the use of crashworthy features such as pre-tensioning active restraints and energy absorbing seats, (2) develop novel techniques for photogrammetric data acquisition to measure occupant and airframe kinematics, and (3) provide baseline data for future comparison with a retrofitted airframe configuration. Crash test conditions for TRACT 1 were 33-ft/s forward and 25-ft/s vertical combined velocity onto soft soil, which represent a severe, but potentially survivable impact scenario. The extraordinary value of the TRACT 1 test was reflected by the breadth of meaningful experiments. A total of 8 unique experiments were conducted to evaluate ATD responses, seat and restraint performance, cargo restraint effectiveness, patient litter behavior, and photogrammetric techniques. A combination of Hybrid II, Hybrid III, and ES-2 Anthropomorphic Test Devices (ATDs) were placed in forward and side facing seats and occupant results were compared against injury criteria. Loads from ATDs in energy

  2. Facilities and Methods Used in Full-scale Airplane Crash-fire Investigation

    NASA Technical Reports Server (NTRS)

    Black, Dugald O.

    1952-01-01

    The facilities and the techniques employed in the conduct of full scale airplane crash-fire studies currently being conducted at the NACA Lewis laboratory are discussed herein. This investigation is part of a comprehensive study of the airplane crash-fire problem. The crash configuration chosen, the general physical layout of the crash site, the test methods, the instrumentation, the data-recording systems, and the post-crash examination procedure are described

  3. Structure and dynamics of sawteeth crashes in ASDEX Upgrade

    NASA Astrophysics Data System (ADS)

    Igochine, V.; Boom, J.; Classen, I.; Dumbrajs, O.; Günter, S.; Lackner, K.; Pereverzev, G.; Zohm, H.; ASDEX Upgrade Team

    2010-12-01

    The crash phase of the sawteeth in ASDEX Upgrade tokamak [Herrmann et al., Fusion Sci. Technol. 44(3), 569 (2003)] is investigated in detail in this paper by means of soft x-ray (SXR) and electron cyclotron emission (ECE) diagnostics. Analysis of precursor and postcursor (1,1) modes shows that the crash does not affect the position of the resonant surface q =1. Our experimental results suggest that sawtooth crash models should contain two ingredients to be consistent with experimental observations: (1) the (1,1) mode structure should survive the crash and (2) the flux changes should be small to preserve the position of the q =1 surface close to its original location. Detailed structure of the reconnection point was investigated with ECE imaging diagnostic. It is shown that reconnection starts locally. The expelled core is hot which is consistent with SXR tomography results. The observed results can be explained in the framework of a stochastic model.

  4. Factors contributing to intercity commercial bus drivers' crash involvement risk.

    PubMed

    Besharati, Mohammad Mehdi; Kashani, Ali Tavakoli

    2017-03-20

    The aim of this study was to examine the influence of demographic, environmental and occupational factors as well as behavioural characteristics of intercity bus drivers, on their crash involvement risk. A total number of 107 intercity bus drivers from Tehran, Iran were participated in the study. Logistic regression model suggested that smokers, those who drive during night to morning, less experienced drivers as well as those who operate older buses are more likely to be involved in crashes. In addition, one unit increase in the weekly driving hours might significantly increase the drivers' crash involvement risk. The model results also indicated that hazard monitoring, fatigue proneness and thrill seeking might be considered as other significant predictors of crash involvement risk. Implications of results are discussed.

  5. Bayesian log-periodic model for financial crashes

    NASA Astrophysics Data System (ADS)

    Rodríguez-Caballero, Carlos Vladimir; Knapik, Oskar

    2014-10-01

    This paper introduces a Bayesian approach in econophysics literature about financial bubbles in order to estimate the most probable time for a financial crash to occur. To this end, we propose using noninformative prior distributions to obtain posterior distributions. Since these distributions cannot be performed analytically, we develop a Markov Chain Monte Carlo algorithm to draw from posterior distributions. We consider three Bayesian models that involve normal and Student's t-distributions in the disturbances and an AR(1)-GARCH(1,1) structure only within the first case. In the empirical part of the study, we analyze a well-known example of financial bubble - the S&P 500 1987 crash - to show the usefulness of the three methods under consideration and crashes of Merval-94, Bovespa-97, IPCMX-94, Hang Seng-97 using the simplest method. The novelty of this research is that the Bayesian models provide 95% credible intervals for the estimated crash time.

  6. Where Medical Pot Is Legal, Fatal Car Crashes Often Decline

    MedlinePlus

    ... 162675.html Where Medical Pot Is Legal, Fatal Car Crashes Often Decline It's possible that these state ... and Human Services. More Health News on: Marijuana Motor Vehicle Safety Recent Health News Related MedlinePlus Health ...

  7. Why Do Markets Crash? Bitcoin Data Offers Unprecedented Insights

    PubMed Central

    Donier, Jonathan; Bouchaud, Jean-Philippe

    2015-01-01

    Crashes have fascinated and baffled many canny observers of financial markets. In the strict orthodoxy of the efficient market theory, crashes must be due to sudden changes of the fundamental valuation of assets. However, detailed empirical studies suggest that large price jumps cannot be explained by news and are the result of endogenous feedback loops. Although plausible, a clear-cut empirical evidence for such a scenario is still lacking. Here we show how crashes are conditioned by the market liquidity, for which we propose a new measure inspired by recent theories of market impact and based on readily available, public information. Our results open the possibility of a dynamical evaluation of liquidity risk and early warning signs of market instabilities, and could lead to a quantitative description of the mechanisms leading to market crashes. PMID:26448333

  8. Relationship between organisational safety culture dimensions and crashes.

    PubMed

    Varmazyar, Sakineh; Mortazavi, Seyed Bagher; Arghami, Shirazeh; Hajizadeh, Ebrahim

    2016-01-01

    Knowing about organisational safety culture in public transportation system can provide an appropriate guide to establish effective safety measures and interventions to improve safety at work. The aim of this study was investigation of association between safety culture dimensions (leadership styles and company values, usage of crashes information and prevention programmes, management commitment and safety policy, participation and control) with involved self-reported crashes. The associations were considered through Spearman correlation, Pearson chi-square test and logistic regression. The results showed an association among self-reported crashes (occurrence or non-occurrence) and factors including leadership styles and company values; management commitment and safety policy; and control. Moreover, it was found a negative correlation and an odds ratio less than one between control and self-reported crashes.

  9. Why Do Markets Crash? Bitcoin Data Offers Unprecedented Insights.

    PubMed

    Donier, Jonathan; Bouchaud, Jean-Philippe

    2015-01-01

    Crashes have fascinated and baffled many canny observers of financial markets. In the strict orthodoxy of the efficient market theory, crashes must be due to sudden changes of the fundamental valuation of assets. However, detailed empirical studies suggest that large price jumps cannot be explained by news and are the result of endogenous feedback loops. Although plausible, a clear-cut empirical evidence for such a scenario is still lacking. Here we show how crashes are conditioned by the market liquidity, for which we propose a new measure inspired by recent theories of market impact and based on readily available, public information. Our results open the possibility of a dynamical evaluation of liquidity risk and early warning signs of market instabilities, and could lead to a quantitative description of the mechanisms leading to market crashes.

  10. Structure and dynamics of sawteeth crashes in ASDEX Upgrade

    SciTech Connect

    Igochine, V.; Guenter, S.; Lackner, K.; Pereverzev, G.; Zohm, H.; Boom, J.; Classen, I.; Dumbrajs, O.

    2010-12-15

    The crash phase of the sawteeth in ASDEX Upgrade tokamak [Herrmann et al., Fusion Sci. Technol. 44(3), 569 (2003)] is investigated in detail in this paper by means of soft x-ray (SXR) and electron cyclotron emission (ECE) diagnostics. Analysis of precursor and postcursor (1,1) modes shows that the crash does not affect the position of the resonant surface q=1. Our experimental results suggest that sawtooth crash models should contain two ingredients to be consistent with experimental observations: (1) the (1,1) mode structure should survive the crash and (2) the flux changes should be small to preserve the position of the q=1 surface close to its original location. Detailed structure of the reconnection point was investigated with ECE imaging diagnostic. It is shown that reconnection starts locally. The expelled core is hot which is consistent with SXR tomography results. The observed results can be explained in the framework of a stochastic model.

  11. Light airplane crash tests at three pitch angles

    NASA Technical Reports Server (NTRS)

    Vaughan, V. L., Jr.; Alfaro-Bou, E.

    1979-01-01

    Three similar twin-engine general aviation airplane specimens were crash tested at an impact dynamics research facility at 27 m/sec, a flight path angle of -15 deg, and pitch angles of -15 deg, 0 deg, and 15 deg. Other crash parameters were held constant. The test facility, instrumentation, test specimens, and test method are briefly described. Structural damage and accelerometer data for each of the three impact conditions are presented and discussed.

  12. Light Airplane Crash Test at Three Pitch Angles

    NASA Technical Reports Server (NTRS)

    Vaughan, Victor L., Jr.; Alfaro-Bou, Emilio

    1979-01-01

    Three similar twin-engine general-aviation airplane specimens were crash tested at the Langley Impact Dynamics Research Facility at 27 m/sec, a flight-path angle of -15deg, and pithch angles of -15deg, 0deg, and 15deg. Other crash parameters were held constant. The test facility, instrumentation, test specimens, and test method are briefly described. Structural damage and accelerometer data for each of the three impact conditions are presented and discussed.

  13. A Review of Research and Development in Crashworthiness of General Aviation Aircraft: Seats, Restraints and Floor Structures

    DTIC Science & Technology

    1990-02-01

    accident rates in general aviation. 3 q’ ) RtSUM~k Une recherche documentaire a W effectude afin de determiner l’dtat de nos connaissances sur les aspects...extensive computer analyses are necessary because the costs of full-scale aircraft tests are prohibitive. Wittlin 4 1) briefly outlined aircraft crash...subfloors. These analyses are required to defint the requirements for retrofit and new designs. The introduction of the FAA regulations [681 on dynamic

  14. Macroscopic spatial analysis of pedestrian and bicycle crashes.

    PubMed

    Siddiqui, Chowdhury; Abdel-Aty, Mohamed; Choi, Keechoo

    2012-03-01

    This study investigates the effect of spatial correlation using a Bayesian spatial framework to model pedestrian and bicycle crashes in Traffic Analysis Zones (TAZs). Aggregate models for pedestrian and bicycle crashes were estimated as a function of variables related to roadway characteristics, and various demographic and socio-economic factors. It was found that significant differences were present between the predictor sets for pedestrian and bicycle crashes. The Bayesian Poisson-lognormal model accounting for spatial correlation for pedestrian crashes in the TAZs of the study counties retained nine variables significantly different from zero at 95% Bayesian credible interval. These variables were - total roadway length with 35 mph posted speed limit, total number of intersections per TAZ, median household income, total number of dwelling units, log of population per square mile of a TAZ, percentage of households with non-retired workers but zero auto, percentage of households with non-retired workers and one auto, long term parking cost, and log of total number of employment in a TAZ. A separate distinct set of predictors were found for the bicycle crash model. In all cases the Bayesian models with spatial correlation performed better than the models that did not account for spatial correlation among TAZs. This finding implies that spatial correlation should be considered while modeling pedestrian and bicycle crashes at the aggregate or macro-level.

  15. Benefits of a low severity frontal crash test.

    PubMed

    Digges, Kennerly; Dalmotas, Dainius

    2007-01-01

    The US Federal Motor Vehicle Safety Standard for frontal protection requires vehicle crash tests into a rigid barrier with two belted dummies in the front seats. The standard was recently modified to require two separate 56 Kph frontal tests. In one test the dummies are 50% males. In the other test, the dummies are 5% females. Analysis of crash test data indicates that the 56 Kph test does not encourage technology to reduce chest injuries in lower severity crashes. Tests conducted by Transport Canada provide data from belted 5% female dummies in the front seats of vehicles that were subjected crashes into a rigid barrier at 40 Kph. An analysis of the results showed that for many vehicles, the risks of serious chest injuries were higher in the 40 Kph test than in a 56 Kph test. This paper examines the benefits that would result from a requirement for a low severity (40 Kph) frontal barrier crash test with two belted 5% female dummies and more stringent chest injury requirements. A preliminary benefits analysis for chest deflection allowable in the range of 28 mm. to 36 mm. was conducted. A standard that limits the chest deflection to 34 mm. would reduce serious chest injury by 16% to 24% for the belted population in frontal crashes.

  16. Three Cases of Spine Fractures after an Airplane Crash.

    PubMed

    Lee, Han Joo; Moon, Bong Ju; Pennant, William A; Shin, Dong Ah; Kim, Keung Nyun; Yoon, Do Heum; Ha, Yoon

    2015-10-01

    While injuries to the spine after an airplane crash are not rare, most crashes result in fatal injuries. As such, few studies exist that reported on spine fractures sustained during airplane accidents. In this report, we demonstrate three cases of spine fractures due to crash landing of a commercial airplane. Three passengers perished from injuries after the crash landing, yet most of the passengers and crew on board survived, with injuries ranging from minor to severe. Through evaluating our three spine fracture patients, it was determined that compression fracture of the spine was the primary injury related to the airplane accident. The first patient was a 20-year-old female who sustained a T6-8 compression fracture without neurologic deterioration. The second patient was a 33-year-old female with an L2 compression fracture, and the last patient was a 49-year-old male patient with a T8 compression fracture. All three patients were managed conservatively and required spinal orthotics. During the crash, each of these patients were subjected to direct, downward high gravity z-axis (Gz) force, which gave rise to load on the spine vertically, thereby causing compression fracture. Therefore, new safety methods should be developed to prevent excessive Gz force during airplane crash landings.

  17. Three Cases of Spine Fractures after an Airplane Crash

    PubMed Central

    Lee, Han Joo; Moon, Bong Ju; Pennant, William A.; Shin, Dong Ah; Kim, Keung Nyun; Yoon, Do Heum

    2015-01-01

    While injuries to the spine after an airplane crash are not rare, most crashes result in fatal injuries. As such, few studies exist that reported on spine fractures sustained during airplane accidents. In this report, we demonstrate three cases of spine fractures due to crash landing of a commercial airplane. Three passengers perished from injuries after the crash landing, yet most of the passengers and crew on board survived, with injuries ranging from minor to severe. Through evaluating our three spine fracture patients, it was determined that compression fracture of the spine was the primary injury related to the airplane accident. The first patient was a 20-year-old female who sustained a T6-8 compression fracture without neurologic deterioration. The second patient was a 33-year-old female with an L2 compression fracture, and the last patient was a 49-year-old male patient with a T8 compression fracture. All three patients were managed conservatively and required spinal orthotics. During the crash, each of these patients were subjected to direct, downward high gravity z-axis (Gz) force, which gave rise to load on the spine vertically, thereby causing compression fracture. Therefore, new safety methods should be developed to prevent excessive Gz force during airplane crash landings. PMID:27169094

  18. Prescription of antiepileptics and the risk of road traffic crash.

    PubMed

    Orriols, Ludivine; Foubert-Samier, Alexandra; Gadegbeku, Blandine; Delorme, Bernard; Tricotel, Aurore; Philip, Pierre; Moore, Nicholas; Lagarde, Emmanuel

    2013-03-01

    Studies assessing the impact of epilepsy and its medication on the risk of road traffic crashes have shown inconsistent results. The aim in this study was to assess this risk using French databases. Data from three French national databases were extracted and matched: the national health care insurance database, police reports, and the national police database of injurious crashes. Only antiepileptics prescribed predominantly in epilepsy were studied (phenobarbital, phenytoin, ethosuximide, valproic acid, vigabatrin, tiagabin, levitiracetam, zonisamide, and lacosamide). A case-control analysis comparing responsible and non-responsible drivers and a case-crossover analysis were performed. Drivers (72 685) involved in an injurious crash in France between July 2005 and May 2008, were included. Drivers exposed to prescribed antiepileptic medicines (n = 251) had an increased risk of being responsible for a crash (OR 1.74 [1.29-2.34]). The association was also significant for the most severe epileptic patients (n = 99; OR = 2.20 [1.31-3.69]). Case-crossover analysis found no association between crash risk and treatment prescription. Patients with prescription of antiepileptic drugs should be cautioned about their potential risk of road traffic crash. This risk is however more likely to be related to seizures than to the effect of antiepileptic medicines.

  19. Fatal motorcycle crashes: a growing public health problem in Cambodia.

    PubMed

    Roehler, Douglas R; Ear, Chariya; Parker, Erin M; Sem, Panhavuth; Ballesteros, Michael F

    2015-01-01

    This study examines the risk characteristics of fatal motorcycle crashes in Cambodia over a 5-year period (2007-2011). Secondary data analyses were conducted using the Cambodia Road Crash and Victim Information System, the only comprehensive and integrated road crash surveillance system in the country. Researchers from the Centers for Disease Control and Prevention and Handicap International found that (1) males are dying in motorcycle crashes roughly seven times more frequently than females; (2) motorcyclist fatalities increased by about 30% from 2007 to 2011; (3) the motorcyclist death rates per 100,000 population increased from 7.4 to 8.7 deaths from 2007 to 2011; and (4) speed-related crashes and not wearing motorcycle helmet were commonly reported for motorcyclist fatalities at approximately 50% and over 80% through the study years, respectively. Additionally, this study highlights that Cambodia has the highest motorcycle death rate in South-East Asia, far surpassing Thailand, Malaysia, and Myanmar. By recognising the patterns of fatal motorcycle crashes in Cambodia, local road-safety champions and stakeholders can design targeted interventions and preventative measures to improve road safety among motorcyclists.

  20. Pilot-aircraft system reponse to wind shear

    NASA Technical Reports Server (NTRS)

    Turkel, B. S.; Frost, W.

    1980-01-01

    The nonlinear aircraft motion and automatic control model is expanded to incorporate the human pilot into simulations of aircraft response to wind to wind shear. The human pilot is described by a constant gains lag filter. Two runs are carried out using pilot transfer functions. Fixed-stick, autopilot, and manned computer simulations are made with an aircraft having characteristics of a small commuter type aircraft flown through longitudinal winds measured by a Doppler radar beamed along the glide slope. Simulations are also made flying an aircraft through sinusoidal head wind and tail wind shears at the phugoid frequency to evaluate the response of manned aircraft in thunderstorm wind environments.

  1. Aircraft Corrosion

    DTIC Science & Technology

    1981-08-01

    chlore mais dans une proportion semblable b cells d’une eau de vil)e ; - lea solides, d’aprbs lea analyses chimique et criatallographique, paraissaiont...IATA member airlines at $100 million based on 1976 operations. Thus the numbers are large, but detailed analyses on specific aircraft types, in known...demonstrate this in any quantitative way with accurate figures. Better information is required on the cost of corrosion, together with analyses of the

  2. Aircraft Ducting

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Templeman Industries developed the Ultra-Seal Ducting System, an environmental composite air duct with a 50 percent weight savings over current metallic ducting, but could not find a commercial facility with the ability to test it. Marshall Space Flight Center conducted a structural evaluation of the duct, equivalent to 86 years of take-offs and landings in an aircraft. Boeing Commercial Airplane Group and McDonnell Douglas Corporation are currently using the ducts.

  3. Energy Absorbing Seat System for an Agricultural Aircraft

    NASA Technical Reports Server (NTRS)

    Kellas, Sotiris; Jones, Lisa E. (Technical Monitor)

    2002-01-01

    A task was initiated to improve the energy absorption capability of an existing aircraft seat through cost-effective retrofitting, while keeping seat-weight increase to a minimum. This task was undertaken as an extension of NASA ongoing safety research and commitment to general aviation customer needs. Only vertical crash scenarios have been considered in this task which required the energy absorbing system to protect the seat occupant in a range of crash speeds up to 31 ft/sec. It was anticipated that, the forward and/or side crash accelerations could be attenuated with the aid of airbags, the technology of which is currently available in automobiles and military helicopters. Steps which were followed include, preliminary crush load determination, conceptual design of cost effective energy absorbers, fabrication and testing (static and dynamic) of energy absorbers, system analysis, design and fabrication of dummy seat/rail assembly, dynamic testing of dummy seat/rail assembly, and finally, testing of actual modified seat system with a dummy occupant. A total of ten full scale tests have been performed including three of the actual aircraft seat. Results from full-scale tests indicated that occupant loads were attenuated successfully to survivable levels.

  4. Effect of Advanced Location Methods on Search and Rescue Duration for General Aviation Aircraft Accidents in the Contiguous United States

    ERIC Educational Resources Information Center

    Wallace, Ryan J.

    2013-01-01

    The purpose of this study was to determine the impact of advanced search and rescue devices and techniques on search duration for general aviation aircraft crashes. The study assessed three categories of emergency locator transmitters, including 121.5 MHz, 406 MHz, and GPS-Assisted 406 MHz devices. The impact of the COSPAS-SARSAT organization…

  5. Higher Crash and Near-Crash Rates in Teenaged Drivers With Lower Cortisol Response

    PubMed Central

    Ouimet, Marie Claude; Brown, Thomas G.; Guo, Feng; Klauer, Sheila G.; Simons-Morton, Bruce G.; Fang, Youjia; Lee, Suzanne E.; Gianoulakis, Christina; Dingus, Thomas A.

    2014-01-01

    IMPORTANCE Road traffic crashes are one of the leading causes of injury and death among teenagers worldwide. Better understanding of the individual pathways to driving risk may lead to better-targeted intervention in this vulnerable group. OBJECTIVE To examine the relationship between cortisol, a neurobiological marker of stress regulation linked to risky behavior, and driving risk. DESIGN, SETTING, AND PARTICIPANTS The Naturalistic Teenage Driving Study was designed to continuously monitor the driving behavior of teenagers by instrumenting vehicles with kinematic sensors, cameras, and a global positioning system. During 2006–2008, a community sample of 42 newly licensed 16-year-old volunteer participants in the United States was recruited and driving behavior monitored. It was hypothesized in teenagers that higher cortisol response to stress is associated with (1) lower crash and near-crash (CNC) rates during their first 18 months of licensure and (2) faster reduction in CNC rates over time. MAIN OUTCOMES AND MEASURES Participants’ cortisol response during a stress-inducing task was assessed at baseline, followed by measurement of their involvement in CNCs and driving exposure during their first 18 months of licensure. Mixed-effect Poisson longitudinal regression models were used to examine the association between baseline cortisol response and CNC rates during the follow-up period. RESULTS Participants with a higher baseline cortisol response had lower CNC rates during the follow-up period (exponential of the regression coefficient, 0.93; 95%CI, 0.88–0.98) and faster decrease in CNC rates over time (exponential of the regression coefficient, 0.98; 95%, CI, 0.96–0.99). CONCLUSIONS AND RELEVANCE Cortisol is a neurobiological marker associated with teenaged-driving risk. As in other problem-behavior fields, identification of an objective marker of teenaged-driving risk promises the development of more personalized intervention approaches. PMID:24710522

  6. Modeling Programs Increase Aircraft Design Safety

    NASA Technical Reports Server (NTRS)

    2012-01-01

    Flutter may sound like a benign word when associated with a flag in a breeze, a butterfly, or seaweed in an ocean current. When used in the context of aerodynamics, however, it describes a highly dangerous, potentially deadly condition. Consider the case of the Lockheed L-188 Electra Turboprop, an airliner that first took to the skies in 1957. Two years later, an Electra plummeted to the ground en route from Houston to Dallas. Within another year, a second Electra crashed. In both cases, all crew and passengers died. Lockheed engineers were at a loss as to why the planes wings were tearing off in midair. For an answer, the company turned to NASA s Transonic Dynamics Tunnel (TDT) at Langley Research Center. At the time, the newly renovated wind tunnel offered engineers the capability of testing aeroelastic qualities in aircraft flying at transonic speeds near or just below the speed of sound. (Aeroelasticity is the interaction between aerodynamic forces and the structural dynamics of an aircraft or other structure.) Through round-the-clock testing in the TDT, NASA and industry researchers discovered the cause: flutter. Flutter occurs when aerodynamic forces acting on a wing cause it to vibrate. As the aircraft moves faster, certain conditions can cause that vibration to multiply and feed off itself, building to greater amplitudes until the flutter causes severe damage or even the destruction of the aircraft. Flutter can impact other structures as well. Famous film footage of the Tacoma Narrows Bridge in Washington in 1940 shows the main span of the bridge collapsing after strong winds generated powerful flutter forces. In the Electra s case, faulty engine mounts allowed a type of flutter known as whirl flutter, generated by the spinning propellers, to transfer to the wings, causing them to vibrate violently enough to tear off. Thanks to the NASA testing, Lockheed was able to correct the Electra s design flaws that led to the flutter conditions and return the

  7. The Increased Risk of Road Crashes in Attention Deficit Hyperactivity Disorder (ADHD) Adult Drivers: Driven by Distraction? Results from a Responsibility Case-Control Study

    PubMed Central

    El Farouki, Kamal; Lagarde, Emmanuel; Orriols, Ludivine; Bouvard, Manuel-Pierre; Contrand, Benjamin; Galéra, Cédric

    2014-01-01

    Background and Objective Both distractions (external and internal) and attention-deficit/hyperactivity disorder (ADHD) are serious risk factors for traffic crashes and injuries. However, it is still unknown if ADHD (a chronic condition) modifies the effect of distractions (irregular hazards) on traffic crashes. The objective of this study was to assess the effects of distractions and ADHD on traffic crash responsibility. Methods A responsibility case-control study was conducted in the adult emergency department of Bordeaux University Hospital, France. Subjects were recruited among drivers injured in a motor vehicle crash between April 2010 and August 2011. Responsibility levels were estimated using a standardized method. Frequencies of exposures were compared between drivers responsible and drivers not responsible for the crash. Independent risk factors were identified using a multivariate logistic regression including test interactions between distractions and ADHD. Results A total of 777 subjects were included in the analysis. Factors associated with responsibility were distraction induced by an external event (adjusted OR (aOR)  = 1.47; 95% confidence interval (CI) [1.06–2.05]), distraction induced by an internal thought (aOR = 2.38; CI: [1.50–3.77]) and ADHD (aOR = 2.18 CI: [1.22–3.88]). The combined effect of ADHD and external distractions was strongly associated with responsibility for the crash (aOR = 5.79 CI: [2.06–16.32]). Interaction assessment showed that the attributable proportion due to the interaction among participants with both exposures was 68%. Discussion Adults with ADHD are a population at higher risk of being responsible for a road traffic crash when exposed to external distractions. This result reinforces the need to diagnose adult ADHD and to include road safety awareness messages delivered by the physician. Developing advanced driver assistance systems devoted to the management of attention lapses is also

  8. Daedalus Project's Light Eagle - Human powered aircraft

    NASA Technical Reports Server (NTRS)

    1987-01-01

    autopilot that could be used on high altitude or human powered aircraft, and determining the power required to fly the Daedalus aircraft. The research flights began in late December 1987 with a shake-down of the Light Eagle instrumentation and data transfer links. The first flight of the Daedalus 87 also occurred during this time. On February 7, 1988, the Daedalus 87 aircraft crashed on Rogers Dry Lakebed. The Daedalus 88, which later set the world record, was then shipped from MIT to replace the 87's research flights, and for general checkout procedures. Due to the accident, flight testing was extended four weeks and thus ended in mid-March 1988 after having achieved the major goals of the program; exploring the dynamics of low Reynolds number aircraft, and investigating the aeroelastic behavior of lightweight aircraft. The information obtained from this program had direct applications to the later design of many high-altitude, long endurance aircraft.

  9. United States Navy - Canadian forces solid state flight data recorder/crash position locator experiment on the B-720 controlled impact demonstration

    NASA Technical Reports Server (NTRS)

    Watters, D. M.

    1986-01-01

    The operation of a radio beacon position locator during and after the remotely controlled transport aircraft is discussed. The radio beacon transmission was actuated and was picked up by the Navy P-3A chase aircraft for a short time, after which reception was lost. The pilot reported that he received a signal on both 121.5 MHz and 243 MHz for a period of approximately 5 seconds. Five minutes after the crash a portable direction finding unit located on the roof of the NASA Dryden Flight Research Facility, 4 miles distant from the crash, was unable to pick up the beacon transmission. The fire crews started fighting the fires approximately 90 seconds after the time of impact. Navy personnel access to the crash site was allowed on the morning of December 2, 1984. Radio beacon locator was found resting top side up, 15 feet forward and 13 feet perpendicular from the tray location the starboard side of the aircraft. An immediate inspection indicated the airfoil suffered moderate fire damage with paint peeling but not intumescing. The visual marker strobe lamp housings were intact but extensively burned such that it was impossible to see if the lamps had survived. The airfoil suffered minor structural damage, with assorted dents, etc. The extended plunger on the ARU-21 release unit indicated that the pyrotechnic deployment system operated. The radio beacon base (tray) suffered some heat and fire damage, and was charred and blackened by smoke. The frangible switch in the nose survived and the switch in the belly was recovered and found to have actuated. It is assumed that this switch fired the ARU-21 squib. There were no other release switches installed in the normally open system in the aircraft.

  10. Modeling Composite Laminate Crushing for Crash Analysis

    NASA Technical Reports Server (NTRS)

    Fleming, David C.; Jones, Lisa (Technical Monitor)

    2002-01-01

    Crash modeling of composite structures remains limited in application and has not been effectively demonstrated as a predictive tool. While the global response of composite structures may be well modeled, when composite structures act as energy-absorbing members through direct laminate crushing the modeling accuracy is greatly reduced. The most efficient composite energy absorbing structures, in terms of energy absorbed per unit mass, are those that absorb energy through a complex progressive crushing response in which fiber and matrix fractures on a small scale dominate the behavior. Such failure modes simultaneously include delamination of plies, failure of the matrix to produce fiber bundles, and subsequent failure of fiber bundles either in bending or in shear. In addition, the response may include the significant action of friction, both internally (between delaminated plies or fiber bundles) or externally (between the laminate and the crushing surface). A figure shows the crushing damage observed in a fiberglass composite tube specimen, illustrating the complexity of the response. To achieve a finite element model of such complex behavior is an extremely challenging problem. A practical crushing model based on detailed modeling of the physical mechanisms of crushing behavior is not expected in the foreseeable future. The present research describes attempts to model composite crushing behavior using a novel hybrid modeling procedure. Experimental testing is done is support of the modeling efforts, and a test specimen is developed to provide data for validating laminate crushing models.

  11. Flight-crash events in turbulence.

    PubMed

    Xu, Haitao; Pumir, Alain; Falkovich, Gregory; Bodenschatz, Eberhard; Shats, Michael; Xia, Hua; Francois, Nicolas; Boffetta, Guido

    2014-05-27

    The statistical properties of turbulence differ in an essential way from those of systems in or near thermal equilibrium because of the flux of energy between vastly different scales at which energy is supplied and at which it is dissipated. We elucidate this difference by studying experimentally and numerically the fluctuations of the energy of a small fluid particle moving in a turbulent fluid. We demonstrate how the fundamental property of detailed balance is broken, so that the probabilities of forward and backward transitions are not equal for turbulence. In physical terms, we found that in a large set of flow configurations, fluid elements decelerate faster than accelerate, a feature known all too well from driving in dense traffic. The statistical signature of rare "flight-crash" events, associated with fast particle deceleration, provides a way to quantify irreversibility in a turbulent flow. Namely, we find that the third moment of the power fluctuations along a trajectory, nondimensionalized by the energy flux, displays a remarkable power law as a function of the Reynolds number, both in two and in three spatial dimensions. This establishes a relation between the irreversibility of the system and the range of active scales. We speculate that the breakdown of the detailed balance characterized here is a general feature of other systems very far from equilibrium, displaying a wide range of spatial scales.

  12. A novel approach for analyzing severe crash patterns on multilane highways.

    PubMed

    Pande, Anurag; Abdel-Aty, Mohamed

    2009-09-01

    This study presents a novel approach for analysis of patterns in severe crashes that occur on mid-block segments of multilane highways with partially limited access. A within stratum matched crash vs. non-crash classification approach is adopted towards that end. Under this approach crashes serve as units of analysis and it does not require aggregation of crash data over arterial segments of arbitrary lengths. Also, the proposed approach does not use information on non-severe crashes and hence is not affected by under-reporting of the minor crashes. Random samples of time, day of week, and location (i.e., milepost) combinations were collected for multilane arterials in the state of Florida and matched with severe crashes from the corresponding corridor to form matched strata consisting of severe crash and non-crash cases. For these cases, geometric design/roadside and traffic characteristics were derived based on the corresponding milepost locations. Four groups of crashes, severe rear-end, lane-change related, pedestrian, and single-vehicle/off-road crashes, on multilane arterials segments were compared separately to the non-crash cases. Severe lane-change related crashes may primarily be attributed to exposure while single-vehicle crashes and pedestrian crashes have no significant relationship with the ADT (Average Daily Traffic). For severe rear-end crashes speed limit, ADT, K-factor, time of day/day of week, median type, pavement condition, and presence of horizontal curvature were significant factors. The proposed approach uses general roadway characteristics as independent variables rather than event-specific information (i.e., crash characteristics such as driver/vehicle details); it has the potential to fit within a safety evaluation framework for arterial segments.

  13. Effects of Dram Shop, Responsible Beverage Service Training, and State Alcohol Control Laws on Underage Drinking Driver Fatal Crash Ratios

    PubMed Central

    Scherer, Michael; Fell, James C.; Thomas, Sue; Voas, Robert B.

    2015-01-01

    Objectives In this study, we aimed to determine whether three minimum legal drinking age 21 (MLDA-21) laws—dram shop liability, responsible beverage service (RBS) training, and state control of alcohol sales—have had an impact on underage drinking-and-driving fatal crashes using annual state-level data, and compared states with strong laws to those with weak laws to examine their effect on beer consumption and fatal crash ratios. Methods Using the Fatality Analysis Reporting System, we calculated the ratio of drinking to nondrinking drivers under age 21 involved in fatal crashes as our key outcome measure. We used structural equation modeling to evaluate the three MLDA-21 laws. We controlled for covariates known to impact fatal crashes including: 17 additional MLDA-21 laws; administrative license revocation; blood alcohol concentration limits of .08 and .10 for driving; seat belt laws; sobriety checkpoint frequency; unemployment rates; and vehicle miles traveled. Outcome variables, in addition to the fatal crash ratios of drinking to nondrinking drivers under age 21 included state per capita beer consumption. Results Dram shop liability laws were associated with a 2.4% total effect decrease (direct effects: β = .019, p = .018). Similarly, RBS training laws were associated with a 3.6% total effect decrease (direct effects: β = .048, p = .001) in the ratio of drinking to nondrinking drivers under age 21 involved in fatal crashes. There was a significant relationship between dram shop liability law strength and per capita beer consumption, F (4, 1528) = 24.32, p < .001, partial η2 = .016, showing states with strong dram shop liability laws (Mean (M) = 1.276) averaging significantly lower per capita beer consumption than states with weak laws (M = 1.340). Conclusions Dram shop liability laws and RBS laws were both associated with significantly reduced per capita beer consumption and fatal crash ratios. In practical terms, this means that dram shop liability laws

  14. Flight dynamics and control modelling of damaged asymmetric aircraft

    NASA Astrophysics Data System (ADS)

    Ogunwa, T. T.; Abdullah, E. J.

    2016-10-01

    This research investigates the use of a Linear Quadratic Regulator (LQR) controller to assist commercial Boeing 747-200 aircraft regains its stability in the event of damage. Damages cause an aircraft to become asymmetric and in the case of damage to a fraction (33%) of its left wing or complete loss of its vertical stabilizer, the loss of stability may lead to a fatal crash. In this study, aircraft models for the two damage scenarios previously mentioned are constructed using stability derivatives. LQR controller is used as a direct adaptive control design technique for the observable and controllable system. Dynamic stability analysis is conducted in the time domain for all systems in this study.

  15. Correlation and assessment of structural airplane crash data with flight parameters at impact

    NASA Technical Reports Server (NTRS)

    Carden, H. D.

    1982-01-01

    Crash deceleration pulse data from a crash dynamics program on general aviation airplanes and from transport crash data were analyzed. Structural airplane crash data and flight parameters at impact were correlated. Uncoupled equations for the normal and longitudinal floor impulses in the cabin area of the airplane were derived, and analytical expressions for structural crushing during impact and horizontal slide out were also determined. Agreement was found between experimental and analytical data for general aviation and transport airplanes over a relatively wide range of impact parameter. Two possible applications of the impulse data are presented: a postcrash evaluation of crash test parameters and an assumed crash scenario.

  16. Compulsive Cell Phone Use and History of Motor Vehicle Crash

    PubMed Central

    O’Connor, Stephen S.; Whitehill, Jennifer M.; King, Kevin M.; Kernic, Mary A.; Boyle, Linda Ng; Bresnahan, Brian; Mack, Christopher D.; Ebel, Beth E.

    2013-01-01

    Introduction Few studies have examined the psychological factors underlying the association between cell phone use and motor vehicle crash. We sought to examine the factor structure and convergent validity of a measure of problematic cell phone use and explore whether compulsive cell phone use is associated with a history of motor vehicle crash. Methods We recruited a sample of 383 undergraduate college students to complete an on-line assessment that included cell phone use and driving history. We explored the dimensionality of the Cell Phone Overuse Scale (CPOS) using factor analytic methods. Ordinary least squares regression models were used to examine associations between identified subscales and measures of impulsivity, alcohol use, and anxious relationship style to establish convergent validity. We used negative binomial regression models to investigate associations between the CPOS and motor vehicle crash incidence. Results We found the CPOS to be comprised of four subscales: anticipation, activity interfering, emotional reaction, and problem recognition. Each displayed significant associations with aspects of impulsivity, problematic alcohol use, and anxious relationship style characteristics. Only the anticipation subscale demonstrated statistically significant associations with reported motor vehicle crash incidence, controlling for clinical and demographic characteristics (RR 1.13, CI 1.01 to 1.26). For each one-point increase on the 6-point anticipation subscale, risk for previous motor vehicle crash increased by 13%. Conclusions Crash risk is strongly associated with heightened anticipation about incoming phone calls or messages. The mean score on the CPOS is associated with increased risk of motor vehicle crash but does not reach statistical significance. PMID:23910571

  17. Mopeds and Scooters: Crash Outcomes in a High Traffic State

    PubMed Central

    Miggins, Makesha; Lottenberg, Lawrence; Liu, Huazhi; Moldawer, Lyle; Efron, Philip; Ang, Darwin

    2014-01-01

    Background Moped and scooter crash outcomes in the United States were last reported over 20 years ago. These vehicles have experienced resurgence in popularity with sales that have increased up to 60% in recent years. The purpose of this study is to identify risk factors between severe and non-severe driver related injuries and to identify modifiable risk factors. Methods The Florida Traffic Crash Records Database (FTCRD) was used to identify all crashes involving mopeds and scooters occurring between 2002 and 2008. A total of 5,660 moped crashes were evaluated. Multivariate logistic regression was used to determine the strength of association of severe injury for each risk factor. Results Over 90% of drivers involved in moped or scooter crashes were uninsured. Only 17% of all drivers wore helmets. Alcohol and drug use was a significant risk factor severe and lethal crashes OR 2.09, 95% CI (1.64, 2.66). Risk factors amenable for state intervention and associated with increased severe or lethal injury were unpaved roads OR 1.57, 95% CI (1.30, 1.88); driving speeds > 20 mph OR 2.02, 95% CI (1.73, 2.36); posted speed limits >30 mph OR 1.40, 95% CI (1.22, 1.62); major roadways with 4 or more lanes OR 1.83, 95% CI (1.04, 3.21); and poor lighting conditions OR 1.69, 95% CI (1.23, 2.32). Conclusions These results suggest that most of the traffic infrastructure does not accommodate the safety of moped and scooter drivers. Focused interventions and further investigation into statewide traffic rules may improve moped crash outcomes. PMID:21399547

  18. Driving cessation and self-reported car crashes in older drivers: the impact of cognitive impairment and dementia in a population-based study.

    PubMed

    Lafont, Sylviane; Laumon, Bernard; Helmer, Catherine; Dartigues, Jean-François; Fabrigoule, Colette

    2008-09-01

    The complexity of driving activity has incited numerous developed countries to initiate evaluative procedures in elderly people, varying according to first evaluation age, frequency, and screening tools. The objective of this paper is to improve the knowledge of the driving cessation process regarding factors associated with crash involvement. Driving cessation and self-reported crashes during the past 5 years were analyzed with multivariate models, in a cross-sectional study including a population-based sample of 1051 drivers aged 65 years and more. Visual trouble, Parkinson disease, dementia, and stroke history were associated with driving cessation. Future dementia was associated with self-reported crashes only. Attentional and executive deficits were associated with both outcomes. The detection of attentional and executive deficits should be included in driving evaluation procedures to improve awareness of these deficits by older drivers.

  19. Educating with Aircraft Models

    ERIC Educational Resources Information Center

    Steele, Hobie

    1976-01-01

    Described is utilization of aircraft models, model aircraft clubs, and model aircraft magazines to promote student interest in aerospace education. The addresses for clubs and magazines are included. (SL)

  20. Injury Risk Functions in Frontal Impacts Using Data from Crash Pulse Recorders

    PubMed Central

    Stigson, Helena; Kullgren, Anders; Rosén, Erik

    2012-01-01

    Knowledge of how crash severity influences injury risk in car crashes is essential in order to create a safe road transport system. Analyses of real-world crashes increase the ability to obtain such knowledge. The aim of this study was to present injury risk functions based on real-world frontal crashes where crash severity was measured with on-board crash pulse recorders. Results from 489 frontal car crashes (26 models of four car makes) with recorded acceleration-time history were analysed. Injury risk functions for restrained front seat occupants were generated for maximum AIS value of two or greater (MAIS2+) using multiple logistic regression. Analytical as well as empirical injury risk was plotted for several crash severity parameters; change of velocity, mean acceleration and peak acceleration. In addition to crash severity, the influence of occupant age and gender was investigated. A strong dependence between injury risk and crash severity was found. The risk curves reflect that small changes in crash severity may have a considerable influence on the risk of injury. Mean acceleration, followed by change of velocity, was found to be the single variable that best explained the risk of being injured (MAIS2+) in a crash. Furthermore, all three crash severity parameters were found to predict injury better than age and gender. However, age was an important factor. The very best model describing MAIS2+ injury risk included delta V supplemented by an interaction term of peak acceleration and age. PMID:23169136

  1. Intersection crash prediction modeling with macro-level data from various geographic units.

    PubMed

    Lee, Jaeyoung; Abdel-Aty, Mohamed; Cai, Qing

    2017-03-21

    There have been great efforts to develop traffic crash prediction models for various types of facilities. The crash models have played a key role to identify crash hotspots and evaluate safety countermeasures. In recent, many macro-level crash prediction models have been developed to incorporate highway safety considerations in the long-term transportation planning process. Although the numerous macro-level studies have found that a variety of demographic and socioeconomic zonal characteristics have substantial effects on traffic safety, few studies have attempted to coalesce micro-level with macro-level data from existing geographic units for estimating crash models. In this study, the authors have developed a series of intersection crash models for total, severe, pedestrian, and bicycle crashes with macro-level data for seven spatial units. The study revealed that the total, severe, and bicycle crash models with ZIP-code tabulation area data performs the best, and the pedestrian crash models with census tract-based data outperforms the competing models. Furthermore, it was uncovered that intersection crash models can be drastically improved by only including random-effects for macro-level entities. Besides, the intersection crash models are even further enhanced by including other macro-level variables. Lastly, the pedestrian and bicycle crash modeling results imply that several macro-level variables (e.g., population density, proportions of specific age group, commuters who walk, or commuters using bicycle, etc.) can be a good surrogate exposure for those crashes.

  2. Potential Occupant Injury Reduction in Pre-Crash System Equipped Vehicles in the Striking Vehicle of Rear-end Crashes.

    PubMed

    Kusano, Kristofer D; Gabler, Hampton C

    2010-01-01

    To mitigate the severity of rear-end and other collisions, Pre-Crash Systems (PCS) are being developed. These active safety systems utilize radar and/or video cameras to determine when a frontal crash, such as a front-to-back rear-end collisions, is imminent and can brake autonomously, even with no driver input. Of these PCS features, the effects of autonomous pre-crash braking are estimated. To estimate the maximum potential for injury reduction due to autonomous pre-crash braking in the striking vehicle of rear-end crashes, a methodology is presented for determining 1) the reduction in vehicle crash change in velocity (ΔV) due to PCS braking and 2) the number of injuries that could be prevented due to the reduction in collision severity. Injury reduction was only performed for belted drivers, as unbelted drivers have an unknown risk of being thrown out of position. The study was based on 1,406 rear-end striking vehicles from NASS / CDS years 1993 to 2008. PCS parameters were selected from realistic values and varied to examine the effect on system performance. PCS braking authority was varied from 0.5 G's to 0.8 G's while time to collision (TTC) was held at 0.45 seconds. TTC was then varied from 0.3 second to 0.6 seconds while braking authority was held constant at 0.6 G's. A constant braking pulse (step function) and ramp-up braking pulse were used. The study found that automated PCS braking could reduce the crash ΔV in rear-end striking vehicles by an average of 12% - 50% and avoid 0% - 14% of collisions, depending on PCS parameters. Autonomous PCS braking could potentially reduce the number of injured drivers who are belted by 19% to 57%.

  3. Identify sequence of events likely to result in severe crash outcomes.

    PubMed

    Wu, Kun-Feng; Thor, Craig P; Ardiansyah, Muhammad Nashir

    2016-11-01

    The current practice of crash characterization in highway engineering reduces multiple dimensions of crash contributing factors and their relative sequential connections, crash sequences, into broad definitions, resulting in crash categories such as head-on, sideswipe, rear-end, angle, and fixed-object. As a result, crashes that are classified in the same category may contain many different crash sequences. This makes it difficult to develop effective countermeasures because these crash categorizations are based on the outcomes rather than the preceding events. Consequently, the efficacy of a countermeasure designed for a specific type of crash may not be appropriate due to different pre-crash sequences. This research seeks to explore the use of event sequence to characterize crashes. Additionally, this research seeks to identify crash sequences that are likely to result in severe crash outcomes so that researchers can develop effective countermeasures to reduce severe crashes. This study utilizes the sequence of events from roadway departure crashes in the Fatality Analysis Reporting System (FARS), and converts the information to form a new categorization called "crash sequences." The similarity distance between each pair of crash sequences were calculated using the Optimal Matching approach. Cluster analysis was applied to group crash sequences that are etiologically similar in terms of the similarity distance. A hybrid model was constructed to mitigate the potential sample selection bias of FARS data, which is biased toward more severe crashes. The major findings include: (1) in terms of a roadway departure crash, the crash sequences that are most likely to result in high crash severity include a vehicle that first crosses the median or centerline, runs-off-road on the left, and then collides with a roadside fixed-object; (2) seat-belt and airbag usage reduces the probability of dying in a roadway departure crash by 90%; and (3) occupants who are seated on the

  4. Enabling Radiative Transfer on AMR grids in CRASH

    NASA Astrophysics Data System (ADS)

    Hariharan, N.; Graziani, L.; Ciardi, B.; Miniati, F.; Bungartz, H.-J.

    2017-01-01

    We introduce CRASH-AMR, a new version of the cosmological Radiative Transfer (RT) code CRASH, enabled to use refined grids. This new feature allows us to attain higher resolution in our RT simulations and thus to describe more accurately ionisation and temperature patterns in high density regions. We have tested CRASH-AMR by simulating the evolution of an ionised region produced by a single source embedded in gas at constant density, as well as by a more realistic configuration of multiple sources in an inhomogeneous density field. While we find an excellent agreement with the previous version of CRASH when the AMR feature is disabled, showing that no numerical artifact has been introduced in CRASH-AMR, when additional refinement levels are used the code can simulate more accurately the physics of ionised gas in high density regions. This result has been attained at no computational loss, as RT simulations on AMR grids with maximum resolution equivalent to that of a uniform cartesian grid can be run with a gain of up to 60% in computational time.

  5. Injury Differences Between Small and Large Overlap Frontal Crashes

    PubMed Central

    Hallman, Jason J.; Yoganandan, Narayan; Pintar, Frank A.; Maiman, Dennis J.

    2011-01-01

    Because small overlap impacts have recently emerged as a crash mode posing great injury risk to occupants, a detailed analysis of US crash data was conducted using the NASS/CDS and CIREN databases. Frontal crashes were subcategorized into small overlap impact (SOI) and large overlap impact (LOI) using crash and crush characteristics from the datasets. Injuries to head, spine, chest, hip and pelvis, and lower extremities were parsed and compared between crash types. MAIS 3+ occupants in NASS/CDS and CIREN demonstrated increased incidence of head, chest, spine, and hip/pelvis injuries in SOI compared to LOI. In NASS/CDS, subgaleal hematoma represented 48.6% of SOI head injury codes but 27.6% in LOI. Cervical spine posterior element fractures also represented greater proportions of SOI spine injuries (e.g., facet fractures: 27.8 vs. 14.0%), and proximal femur fractures represented a greater proportion of hip/pelvis injuries (e.g., intertrochanteric fracture: 32.5 vs. 11.8%). Tarsal/metatarsal fractures were a lesser proportion of lower extremity injuries in SOI compared to LOI. Occupant contact points inducing these injuries were observed in CIREN cases in some instances without compartment intrusion. These injuries suggest the substantial role of occupant kinematics in SOI which may induce suboptimal occupant restraint interaction. PMID:22105392

  6. Impact of traffic oscillations on freeway crash occurrences.

    PubMed

    Zheng, Zuduo; Ahn, Soyoung; Monsere, Christopher M

    2010-03-01

    Traffic oscillations are typical features of congested traffic flow that are characterized by recurring decelerations followed by accelerations (stop-and-go driving). The negative environmental impacts of these oscillations are widely accepted, but their impact on traffic safety has been debated. This paper describes the impact of freeway traffic oscillations on traffic safety. This study employs a matched case-control design using high-resolution traffic and crash data from a freeway segment. Traffic conditions prior to each crash were taken as cases, while traffic conditions during the same periods on days without crashes were taken as controls. These were also matched by presence of congestion, geometry and weather. A total of 82 cases and about 80,000 candidate controls were extracted from more than three years of data from 2004 to 2007. Conditional logistic regression models were developed based on the case-control samples. To verify consistency in the results, 20 different sets of controls were randomly extracted from the candidate pool for varying control-case ratios. The results reveal that the standard deviation of speed (thus, oscillations) is a significant variable, with an average odds ratio of about 1.08. This implies that the likelihood of a (rear-end) crash increases by about 8% with an additional unit increase in the standard deviation of speed. The average traffic states prior to crashes were less significant than the speed variations in congestion.

  7. Urban sprawl as a risk factor in motor vehicle crashes

    USGS Publications Warehouse

    Ewing, Reid; Hamidi, Shima; Grace, James B.

    2016-01-01

    A decade ago, compactness/sprawl indices were developed for metropolitan areas and counties which have been widely used in health and other research. In this study, we first update the original county index to 2010, then develop a refined index that accounts for more relevant factors, and finally seek to test the relationship between sprawl and traffic crash rates using structural equation modelling. Controlling for covariates, we find that sprawl is associated with significantly higher direct and indirect effects on fatal crash rates. The direct effect is likely due to the higher traffic speeds in sprawling areas, and the indirect effect is due to greater vehicle miles driven in such areas. Conversely, sprawl has negative direct relationships with total crashes and non-fatal injury crashes, and these offset (and sometimes overwhelm) the positive indirect effects of sprawl on both types of crashes through the mediating effect of increased vehicle miles driven. The most likely explanation is the greater prevalence of fender benders and other minor accidents in the low speed, high conflict traffic environments of compact areas, negating the lower vehicle miles travelled per capita in such areas.

  8. Motor vehicle drivers' injuries in train-motor vehicle crashes.

    PubMed

    Zhao, Shanshan; Khattak, Aemal

    2015-01-01

    The objectives of this research were to: (1) identify a more suitable model for modeling injury severity of motor vehicle drivers involved in train-motor vehicle crashes at highway-rail grade crossings from among three commonly used injury severity models and (2) to investigate factors associated with injury severity levels of motor vehicle drivers involved in train-motor vehicle crashes at such crossings. The 2009-2013 highway-rail grade crossing crash data and the national highway-rail crossing inventory data were combined to produce the analysis dataset. Four-year (2009-2012) data were used for model estimation while 2013 data were used for model validation. The three injury severity levels-fatal, injury and no injury-were based on the reported intensity of motor-vehicle drivers' injuries at highway-rail grade crossings. The three injury severity models evaluated were: ordered probit, multinomial logit and random parameter logit. A comparison of the three models based on different criteria showed that the random parameter logit model and multinomial logit model were more suitable for injury severity analysis of motor vehicle drivers involved in crashes at highway-rail grade crossings. Some of the factors that increased the likelihood of more severe crashes included higher train and vehicle speeds, freight trains, older drivers, and female drivers. Where feasible, reducing train and motor vehicle speeds and nighttime lighting may help reduce injury severities of motor vehicle drivers.

  9. Tilt rotor aircraft aeroacoustics

    NASA Technical Reports Server (NTRS)

    George, Albert R.; Smith, Charles A.; Maisel, Martin D.; Brieger, John T.

    1989-01-01

    This paper studies the state of knowledge and the needed improvement in noise methodology and measurements for tilt rotor aircraft. Similarities and differences between tilt rotor aeroacoustic conditions and helicopter and propeller experience are identified. A discussion of the possible principal noise mechanisms throughout the flight envelope shows a need for further experimental and analytical investigations to develop an adequate understanding of the important sources and influencing factors. Existing experimental data from flight tests suggest terminal area noise reduction by operating within certain portions of the conversion flight envelope. Prediction methods are found to provide approximate indications only for low frequency harmonic and broadband noise for several of the tilt rotor's operating conditions. The acoustic effects of the hover case 'fountain' flow are pronounced and need further research. Impulsive noise and high frequency harmonic noise remain problems, as on helicopters, pending major improvements in wake, unsteady aerodynamics, and acoustics methodology.

  10. Macro-level pedestrian and bicycle crash analysis: Incorporating spatial spillover effects in dual state count models.

    PubMed

    Cai, Qing; Lee, Jaeyoung; Eluru, Naveen; Abdel-Aty, Mohamed

    2016-08-01

    This study attempts to explore the viability of dual-state models (i.e., zero-inflated and hurdle models) for traffic analysis zones (TAZs) based pedestrian and bicycle crash frequency analysis. Additionally, spatial spillover effects are explored in the models by employing exogenous variables from neighboring zones. The dual-state models such as zero-inflated negative binomial and hurdle negative binomial models (with and without spatial effects) are compared with the conventional single-state model (i.e., negative binomial). The model comparison for pedestrian and bicycle crashes revealed that the models that considered observed spatial effects perform better than the models that did not consider the observed spatial effects. Across the models with spatial spillover effects, the dual-state models especially zero-inflated negative binomial model offered better performance compared to single-state models. Moreover, the model results clearly highlighted the importance of various traffic, roadway, and sociodemographic characteristics of the TAZ as well as neighboring TAZs on pedestrian and bicycle crash frequency.

  11. Evaluation of Test/Analysis Correlation Methods for Crash Applications

    NASA Technical Reports Server (NTRS)

    Lyle, Karen H.; Bark, Lindley W.; Jackson, Karen E.

    2001-01-01

    A project has been initiated to improve crash test and analysis correlation. The work in this paper concentrated on the test and simulation results for a fuselage section. Two drop tests of the section were conducted. The first test was designed to excite the linear structural response for comparison with finite element modal analysis results. The second test was designed to provide data for correlation with crash simulations. An MSC.Dytran model was developed to generate nonlinear transient dynamic results. Following minor modifications, the same model was executed in MSC.Nastran to generate modal analysis results. The results presented in this paper concentrate on evaluation of correlation methodologies for crash test data and finite element simulation results.

  12. A mixed methods investigation of bicycle exposure in crash rates.

    PubMed

    Fournier, Nicholas; Christofa, Eleni; Knodler, Michael A

    2017-03-01

    Crash rates are an essential tool enabling researchers and practitioners to assess whether a location is truly more dangerous, or simply serves a higher volume of vehicles. Unfortunately, this simple crash rate is far more difficult to calculate for bicycles due to data challenges and the fact that they are uniquely exposed to both bicycle and automobile volumes on shared roadways. Bicycle count data, though increasingly more available, still represents a fraction of the available count data for automobiles. Further compounding on this, bicycle demand estimation methods often require more data than automobiles to account for the high variability that bicycle demand is subject to. This paper uses a combination of mixed methods to overcome these challenges and to perform an investigation of crash rates and exposure to different traffic volumes.

  13. Road traffic crashes managed by Rescue 1122 in Lahore, Pakistan.

    PubMed

    Tahir, Navid; Naseer, Rizwan; Khan, Samina Mohsin; Macassa, Gloria; Hashmi, Waseem; Durrani, Mohsin

    2012-01-01

    The objective of this retrospective study was to describe demographic characteristics, injury patterns and causes of road traffic crashes (RTCs) managed by Rescue 1122 in Lahore, Pakistan during the period 2005-2010. In total 123,268 RTCs were reported and responded by Rescue 1122 ambulance service during the study period. Of the 132,504 victims of RTCs, there were 67% male and 33% female subjects, and the maximum share (65%) was reported among people aged 16-35 years. Motorcyclists were involved in 45% of crashes, with over-speeding (40%) found to be the major reason of these collisions. Similarly, minor injuries (65%) and fractures (25%) were the most reported outcome of these crashes. It is concluded that data from ambulance services, if appropriately collected, can provide valuable epidemiological information to monitor RTCs in developing countries. However, in Pakistan, the collection of data as well as the registration process needs further improvement.

  14. Marginal effect of increasing ageing drivers on injury crashes.

    PubMed

    Tay, Richard

    2008-11-01

    The safety effects of the ageing driving population have been a topic of research interests in health and transportation economics in recent years due to the ageing of the baby boomers. This study adds to the current knowledge by examining the marginal effects of changing the driver mix on injury crashes using data from the Canadian Province of Alberta between 1990 and 2004. Results from a Poisson regression model reveal that increasing the number of young and ageing drivers will result in an increase in the number of injury crashes whereas increasing the number of middle-aged drivers will result in a reduction. These results are in contrast to those obtained in a previous study on the marginal effects of changing the driver mix on fatal crashes in the Australian State of Queensland and some possible explanations for the differing results are provided.

  15. Stock market dynamics: Before and after stock market crashes

    NASA Astrophysics Data System (ADS)

    Siokis, Fotios M.

    2012-02-01

    This paper presents a brief analysis on the distribution of magnitude of major stock market shocks. Based on the Gutenberg-Richter law in geophysics, we model the dynamics of market index returns prior and after major crashes in search of statistical regularities. For a large number of market crashes, our analysis suggests that the distribution of market volatility before and after the stock market crash is described well by the Gutenberg-Richter law, which reflects the scale-invariance and self-similarity of the underlying dynamics by a robust power-law relation. In addition, the rate of the decay of the aftershock sequence is well described by another power law, which is known as the Omori law. Power law relaxation seems to be a common behavior observed in complex systems such as the financial markets.

  16. An improved human display model for occupant crash simulation programs

    NASA Technical Reports Server (NTRS)

    Willmert, K. D.; Potter, T. E.

    1975-01-01

    An improved three-dimensional display model of a human being which can be used to display the results of three-dimensional simulation programs that predict the positions of an occupant during impact of a vehicle was presented. The model allows the user to view the occupant from any orientation in any position during the crash. The display model assumes the usual break up of the body into rigid segments which is normal for occupant crash simulation programs, but the shape of the segments in the display model are not necessarily the same as those used in the crash simulation. The display model is proportioned so as to produce a realistic drawing of the human body in any position. Joints connecting the segments are also drawn to improve realism.

  17. Option pricing during post-crash relaxation times

    NASA Astrophysics Data System (ADS)

    Dibeh, Ghassan; Harmanani, Haidar M.

    2007-07-01

    This paper presents a model for option pricing in markets that experience financial crashes. The stochastic differential equation (SDE) of stock price dynamics is coupled to a post-crash market index. The resultant SDE is shown to have stock price and time dependent volatility. The partial differential equation (PDE) for call prices is derived using risk-neutral pricing. European call prices are then estimated using Monte Carlo and finite difference methods. Results of the model show that call option prices after the crash are systematically less than those predicted by the Black-Scholes model. This is a result of the effect of non-constant volatility of the model that causes a volatility skew.

  18. An investigation of crash avoidance in a complex system

    NASA Astrophysics Data System (ADS)

    Hart, Michael L.; Lamper, David; Johnson, Neil F.

    2002-12-01

    Complex systems can exhibit unexpected large changes, e.g. a crash in a financial market. We examine the large endogenous changes arising within a non-trivial generalization of the minority game: the grand canonical minority game. Using a Markov-Chain description, we study the many possible paths the system may take. This ‘many-worlds’ view not only allows us to predict the start and end of a crash in this system, but also to investigate how such a crash may be avoided. We find that the system can be ‘immunized’ against large changes: by inducing small changes today, much larger changes in the future can be prevented.

  19. Chain-reaction crash on a highway in high visibility

    NASA Astrophysics Data System (ADS)

    Nagatani, Takashi

    2016-05-01

    We study the chain-reaction crash (multiple-vehicle collision) in high-visibility condition on a highway. In the traffic situation, drivers control their vehicles by both gear-changing and braking. Drivers change the gears according to the headway and brake according to taillights of the forward vehicle. We investigate whether or not the first collision induces the chain-reaction crash numerically. It is shown that dynamic transitions occur from no collisions, through a single collision, to multiple collisions with decreasing the headway. Also, we find that the dynamic transition occurs from the finite chain reaction to the infinite chain reaction when the headway is less than the critical value. We compare the multiple-vehicle collisions in high-visibility with that in low-visibility. We derive the transition points and the region maps for the chain-reaction crash in high visibility.

  20. Mechanisms of cervical spine injuries for non-fatal motorcycle road crash.

    PubMed

    Ooi, S S; Wong, S V; Radin Umar, R S; Azhar, A A; Yeap, J S; Megat Ahmad, M M H

    2004-06-01

    Cervical spine injuries such as subluxation and fracture dislocation have long been known to result in severe consequences, as well as the trauma management itself. The injury to the region has been identified as one of the major causes of death in Malaysian motorcyclists involved in road crashes, besides head and chest injuries (Pang, 1999). Despite this, cervical spine injury in motorcyclists is not a well-studied injury, unlike the whiplash injury in motorcar accidents. The present study is a retrospective study on the mechanisms of injury in cervical spine sustained by Malaysian motorcyclists, who were involved in road crash using an established mechanistic classification system. This will serve as an initial step to look at the cervical injuries pattern. The information obtained gives engineer ideas to facilitate design and safety features to reduce injuries. All cervical spine injured motorcyclists admitted to Hospital Kuala Lumpur between January 1, 2000 and December 31, 2001 were included in the present study. Based on the medical notes and radiological investigations (X-rays, CT and MRI scans), the mechanisms of injuries were formulated using the injury mechanics classification. The result shows that flexion of the cervical vertebrae is the most common vertebral kinematics in causing injury to motorcyclists. This indicates that the cervical vertebrae sustained a high-energy loading at flexion movement in road crash, and exceeded its tolerance level. The high frequency of injury at the C5 vertebra, C6 vertebra and C5-C6 intervertebral space are recorded. Classification based on the Abbreviated Injury Scale (AIS) is made to give a view on injury severity, 9.1% of the study samples have been classified as AIS code 1, 51.5% with AIS 2 and 21.2% with AIS 3.

  1. Future aircraft networks and schedules

    NASA Astrophysics Data System (ADS)

    Shu, Yan

    2011-07-01

    Because of the importance of air transportation scheduling, the emergence of small aircraft and the vision of future fuel-efficient aircraft, this thesis has focused on the study of aircraft scheduling and network design involving multiple types of aircraft and flight services. It develops models and solution algorithms for the schedule design problem and analyzes the computational results. First, based on the current development of small aircraft and on-demand flight services, this thesis expands a business model for integrating on-demand flight services with the traditional scheduled flight services. This thesis proposes a three-step approach to the design of aircraft schedules and networks from scratch under the model. In the first step, both a frequency assignment model for scheduled flights that incorporates a passenger path choice model and a frequency assignment model for on-demand flights that incorporates a passenger mode choice model are created. In the second step, a rough fleet assignment model that determines a set of flight legs, each of which is assigned an aircraft type and a rough departure time is constructed. In the third step, a timetable model that determines an exact departure time for each flight leg is developed. Based on the models proposed in the three steps, this thesis creates schedule design instances that involve almost all the major airports and markets in the United States. The instances of the frequency assignment model created in this thesis are large-scale non-convex mixed-integer programming problems, and this dissertation develops an overall network structure and proposes iterative algorithms for solving these instances. The instances of both the rough fleet assignment model and the timetable model created in this thesis are large-scale mixed-integer programming problems, and this dissertation develops subproblem schemes for solving these instances. Based on these solution algorithms, this dissertation also presents

  2. Modeling crash spatial heterogeneity: random parameter versus geographically weighting.

    PubMed

    Xu, Pengpeng; Huang, Helai

    2015-02-01

    The widely adopted techniques for regional crash modeling include the negative binomial model (NB) and Bayesian negative binomial model with conditional autoregressive prior (CAR). The outputs from both models consist of a set of fixed global parameter estimates. However, the impacts of predicting variables on crash counts might not be stationary over space. This study intended to quantitatively investigate this spatial heterogeneity in regional safety modeling using two advanced approaches, i.e., random parameter negative binomial model (RPNB) and semi-parametric geographically weighted Poisson regression model (S-GWPR). Based on a 3-year data set from the county of Hillsborough, Florida, results revealed that (1) both RPNB and S-GWPR successfully capture the spatially varying relationship, but the two methods yield notably different sets of results; (2) the S-GWPR performs best with the highest value of Rd(2) as well as the lowest mean absolute deviance and Akaike information criterion measures. Whereas the RPNB is comparable to the CAR, in some cases, it provides less accurate predictions; (3) a moderately significant spatial correlation is found in the residuals of RPNB and NB, implying the inadequacy in accounting for the spatial correlation existed across adjacent zones. As crash data are typically collected with reference to location dimension, it is desirable to firstly make use of the geographical component to explore explicitly spatial aspects of the crash data (i.e., the spatial heterogeneity, or the spatially structured varying relationships), then is the unobserved heterogeneity by non-spatial or fuzzy techniques. The S-GWPR is proven to be more appropriate for regional crash modeling as the method outperforms the global models in capturing the spatial heterogeneity occurring in the relationship that is model, and compared with the non-spatial model, it is capable of accounting for the spatial correlation in crash data.

  3. Variability in Crash and Near-Crash Risk among Novice Teenage Drivers: A Naturalistic Study

    PubMed Central

    Guo, Feng; Simons-Morton, Bruce G.; Klauer, Sheila E.; Ouimet, Marie Claude; Dingus, Thomas A.; Lee, Suzanne E.

    2013-01-01

    Objective Using video monitoring technologies, we investigated teenage driving risk variation during the first 18 months of independent driving. Study design Driving data were collected on 42 teenagers whose vehicles were instrumented with sophisticated video and data recording devices. Surveys on demographic and personality characteristics were administered at baseline. Drivers were classified into three risk groups using a K-mean clustering method based on crash and near-crash (CNC) rate. The change in CNC rates over time was evaluated by mixed-effect Poisson models. Results Compared with the first three months after licensure (first quarter), the CNC rate for participants during the third, fourth and fifth quarters decreased significantly to 59%, 62%, and 48%, respectively. Three distinct risk groups were identified with CNC rates of 21.8 (high-risk), 8.3 (moderate-risk), and 2.1 (low-risk) per 10000 kilometers traveled. High- and low-risk drivers showed no significant change in CNC rates throughout the 18-month study period. CNC rates for moderate-risk drivers decreased substantially from 8.8 per 10000 kilometers in the first quarter to 0.8 and 3.2 in the fourth and fifth quarters, respectively. The three groups were not distinguishable with respect to personality characteristics. Conclusion Teenage CNC rates varied substantially, with distinct high-, moderate-, and low-risk groups. Risk declined over time only in the moderate-risk group. The high-risk drivers appeared to be insensitive to experience, with CNC rates consistently high throughout the 18-month study period, and the moderate-risk group appeared to learn from experience. PMID:23992677

  4. Modular disposable can (MODCAN) crash cushion: A concept investigation

    NASA Technical Reports Server (NTRS)

    Knoell, A.; Wilson, A.

    1976-01-01

    A conceptual design investigation of an improved highway crash cushion system is presented. The system is referred to as a modular disposable can (MODCAN) crash system. It is composed of a modular arrangement of disposable metal beverage cans configured to serve as an effective highway impact attenuation system. Experimental data, design considerations, and engineering calculations supporting the design development are presented. Design performance is compared to that of a conventional steel drum system. It is shown that the MODCAN concepts offers the potential for smoother and safer occupant deceleration for a larger class of vehicle impact weights than the steel drum device.

  5. Mass fatality aircraft disaster processing.

    PubMed

    Clark, M A; Clark, S R; Perkins, D G

    1989-07-01

    On Dec. 12, 1985, a contract transport carrying 248 U.S. Army personnel crashed on takeoff at Gander, Nfld., Canada, killing all the passengers as well as the crew of eight. This was the worst aircraft accident in U.S. military history and, at the time was the fifth worst accident in aviation history. Cooperation between the governments of Canada and the United States allowed for the transport of all human remains to the U.S. Air Force mortuary facility at Dover AFB, DE, where they were processed, identified, and ultimately returned to their families for burial. Under ideal circumstances, any medical examiner's office or mortuary facility would be overwhelmed by a mass disaster of this magnitude. Before the arrival of the first shipment of bodies, a concerted planning effort was undertaken and the facility arranged so that remains would pass in a logical sequence through a series of 10 "work stations." This report details the process and outlines the logistics of the operations.

  6. Aircraft Electric Secondary Power

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Technologies resulted to aircraft power systems and aircraft in which all secondary power is supplied electrically are discussed. A high-voltage dc power generating system for fighter aircraft, permanent magnet motors and generators for aircraft, lightweight transformers, and the installation of electric generators on turbine engines are among the topics discussed.

  7. Investigation of pedestrian crashes on two-way two-lane rural roads in Ethiopia.

    PubMed

    Tulu, Getu Segni; Washington, Simon; Haque, Md Mazharul; King, Mark J

    2015-05-01

    Understanding pedestrian crash causes and contributing factors in developing countries is critically important as they account for about 55% of all traffic crashes. Not surprisingly, considerable attention in the literature has been paid to road traffic crash prediction models and methodologies in developing countries of late. Despite this interest, there are significant challenges confronting safety managers in developing countries. For example, in spite of the prominence of pedestrian crashes occurring on two-way two-lane rural roads, it has proven difficult to develop pedestrian crash prediction models due to a lack of both traffic and pedestrian exposure data. This general lack of available data has further hampered identification of pedestrian crash causes and subsequent estimation of pedestrian safety performance functions. The challenges are similar across developing nations, where little is known about the relationship between pedestrian crashes, traffic flow, and road environment variables on rural two-way roads, and where unique predictor variables may be needed to capture the unique crash risk circumstances. This paper describes pedestrian crash safety performance functions for two-way two-lane rural roads in Ethiopia as a function of traffic flow, pedestrian flows, and road geometry characteristics. In particular, random parameter negative binomial model was used to investigate pedestrian crashes. The models and their interpretations make important contributions to road crash analysis and prevention in developing countries. They also assist in the identification of the contributing factors to pedestrian crashes, with the intent to identify potential design and operational improvements.

  8. Characteristics of cyclist crashes in Italy using latent class analysis and association rule mining

    PubMed Central

    De Angelis, Marco; Marín Puchades, Víctor; Fraboni, Federico; Pietrantoni, Luca

    2017-01-01

    The factors associated with severity of the bicycle crashes may differ across different bicycle crash patterns. Therefore, it is important to identify distinct bicycle crash patterns with homogeneous attributes. The current study aimed at identifying subgroups of bicycle crashes in Italy and analyzing separately the different bicycle crash types. The present study focused on bicycle crashes that occurred in Italy during the period between 2011 and 2013. We analyzed categorical indicators corresponding to the characteristics of infrastructure (road type, road signage, and location type), road user (i.e., opponent vehicle and cyclist’s maneuver, type of collision, age and gender of the cyclist), vehicle (type of opponent vehicle), and the environmental and time period variables (time of the day, day of the week, season, pavement condition, and weather). To identify homogenous subgroups of bicycle crashes, we used latent class analysis. Using latent class analysis, the bicycle crash data set was segmented into 19 classes, which represents 19 different bicycle crash types. Logistic regression analysis was used to identify the association between class membership and severity of the bicycle crashes. Finally, association rules were conducted for each of the latent classes to uncover the factors associated with an increased likelihood of severity. Association rules highlighted different crash characteristics associated with an increased likelihood of severity for each of the 19 bicycle crash types. PMID:28158296

  9. Characteristics of cyclist crashes in Italy using latent class analysis and association rule mining.

    PubMed

    Prati, Gabriele; De Angelis, Marco; Marín Puchades, Víctor; Fraboni, Federico; Pietrantoni, Luca

    2017-01-01

    The factors associated with severity of the bicycle crashes may differ across different bicycle crash patterns. Therefore, it is important to identify distinct bicycle crash patterns with homogeneous attributes. The current study aimed at identifying subgroups of bicycle crashes in Italy and analyzing separately the different bicycle crash types. The present study focused on bicycle crashes that occurred in Italy during the period between 2011 and 2013. We analyzed categorical indicators corresponding to the characteristics of infrastructure (road type, road signage, and location type), road user (i.e., opponent vehicle and cyclist's maneuver, type of collision, age and gender of the cyclist), vehicle (type of opponent vehicle), and the environmental and time period variables (time of the day, day of the week, season, pavement condition, and weather). To identify homogenous subgroups of bicycle crashes, we used latent class analysis. Using latent class analysis, the bicycle crash data set was segmented into 19 classes, which represents 19 different bicycle crash types. Logistic regression analysis was used to identify the association between class membership and severity of the bicycle crashes. Finally, association rules were conducted for each of the latent classes to uncover the factors associated with an increased likelihood of severity. Association rules highlighted different crash characteristics associated with an increased likelihood of severity for each of the 19 bicycle crash types.

  10. Prevalence and factors associated with road traffic crash among bus drivers in Hanoi, Vietnam.

    PubMed

    La, Quang Ngoc; Lee, Andy H; Meuleners, Lynn B; Van Duong, Dat

    2013-01-01

    Bus provides a main mode of public transport in Vietnam, but the risk of road traffic crash for bus drivers is unknown. This retrospective study estimated the crash prevalence among bus drivers in Hanoi, Vietnam, and identified driver characteristics affecting their crashes. Information on bus crashes for the period 2006-2009 was collected by interviewing drivers from five bus companies in Hanoi using a structured questionnaire. Logistic regression analysis was performed to determine pertinent risk factors affecting the crash prevalence for bus drivers. Of the total 365 participants recruited, 73 drivers reported 76 crashes, giving an overall crash prevalence of 20%. Among the crashed group, three drivers (4%) were involved in two crashes during the past 3 years. Crashes mainly occurred on streets or local roads (81%). Migrant worker (adjusted odds ratio (OR) 4.26, 95% confidence interval (CI) 2.20-8.25) and insufficient income perceived (OR 2.60, 95% CI 1.37-4.93) were identified to be significantly associated with the crash risk. Further prospective and qualitative studies are needed to provide detailed crash characteristics as well as behaviour and perception of bus drivers, so that an effective intervention can be developed to improve road safety and to prevent traffic injury of these drivers.

  11. Characteristics of Crashes with Farm Equipment that Increase Potential for Injury

    ERIC Educational Resources Information Center

    Peek-Asa, Corinne; Sprince, Nancy L.; Whitten, Paul S.; Falb, Scott R.; Madsen, Murray D.; Zwerling, Craig

    2007-01-01

    Context: Crash fatality and injury rates are higher on rural roadways than other roadway types. Although slow-moving farm vehicles and equipment are risk factors on rural roads, little is known about the characteristics of crashes with farm vehicles/equipment. Purpose: To describe crashes and injuries for the drivers of farm vehicles/equipment and…

  12. Pilot-aircraft system response to wind shear

    NASA Technical Reports Server (NTRS)

    Turkel, B. S.; Frost, W.; Camp, D. W.

    1980-01-01

    The nonlinear aircraft motion and automatic control computer model of Frost and Reddy has been expanded to incorporate the human pilot into simulations of aircraft response to wind shear. Fixed-stick, autopilot, and manned computer simulations are made with an aircraft having characteristics of a Queen Air (small commuter-type aircraft) flown through longitudinal winds measured by a Doppler radar beamed along the glide slope during the SESAME '79 experiments in Oklahoma. Simulations are also made flying a model Boeing 727 through sinusoidal head wind to tail wind shears at the phugoid frequency to evaluate the response of manned aircraft in thunderstorm wind environments.

  13. Asphyxia in Motor Vehicle Crashes: Analysis of Crash-Related Variables Using National Automotive Sampling System Crashworthiness Data System and Forensic Case Studies.

    PubMed

    Storvik, Steven G; Campbell, Julius Q; Wheeler, Jeffrey B

    2017-03-07

    Rates of death because of asphyxia in motor vehicle crashes have been previously estimated using county and statewide data sets, but national estimates have not been reported. The literature regarding asphyxia in motor vehicle crashes primarily involves discussions about clinical findings, and crash-related variables have been sparsely reported. The current study calculated a nationwide fatality rate for asphyxia in motor vehicle crashes of 1.4%. Seventeen case studies of asphyxia were also reported providing crash-, vehicle-, and occupant-related variables. These included type of accident, crash severity, seat belt use, containment status, extent of occupant compartment intrusion, height, weight, and injury pattern. The data presented can be used to better understand the injury mechanism, identify risk factors, develop possible protective countermeasures, and create situational awareness for emergency responders and investigators.

  14. Federal Market Information Technology in the Post Flash Crash Era: Roles for Supercomputing

    SciTech Connect

    Bethel, E. Wes; Leinweber, David; Ruebel, Oliver; Wu, Kesheng

    2011-09-16

    This paper describes collaborative work between active traders, regulators, economists, and supercomputing researchers to replicate and extend investigations of the Flash Crash and other market anomalies in a National Laboratory HPC environment. Our work suggests that supercomputing tools and methods will be valuable to market regulators in achieving the goal of market safety, stability, and security. Research results using high frequency data and analytics are described, and directions for future development are discussed. Currently the key mechanism for preventing catastrophic market action are “circuit breakers.” We believe a more graduated approach, similar to the “yellow light” approach in motorsports to slow down traffic, might be a better way to achieve the same goal. To enable this objective, we study a number of indicators that could foresee hazards in market conditions and explore options to confirm such predictions. Our tests confirm that Volume Synchronized Probability of Informed Trading (VPIN) and a version of volume Herfindahl-Hirschman Index (HHI) for measuring market fragmentation can indeed give strong signals ahead of the Flash Crash event on May 6 2010. This is a preliminary step toward a full-fledged early-warning system for unusual market conditions.

  15. Maxillofacial and ocular injuries in motor vehicle crashes.

    PubMed Central

    Brookes, Christopher Noel

    2004-01-01

    BACKGROUND: Injuries from motor vehicle crashes constitute a leading cause of death in the young and a high degree of morbidity and mortality in all age groups. Facial trauma has been consistently shown to be the single most common injury to the occupants of vehicles involved in crashes. This has been confirmed by more recent studies which have demonstrated a continuing high incidence of facial fractures amongst belted drivers. Airbags have been advocated as a supplemental restraint system. However, their deployment can cause injury particularly if the driver is of short stature, unrestrained or out of position within the vehicle. METHODS: The Crash Injury Research Engineering Network (CIREN) project aims to correlate the injuries received by occupants in vehicle crashes with the biomechanics of vehicle deformation. All cases of facial injury which presented to the University of Michigan Medical Center, USA in 1999 were retrospectively evaluated with reference to the methods of occupant restraint and to the correlation between the injuries sustained and vehicle deformation. RESULTS AND CONCLUSIONS: The case analysis confirmed the value of airbags to the safety of vehicle occupants but reinforced the conclusion that they must still be considered supplemental restraint systems. New generation airbags will minimise the risk of injury even to small stature or out of position occupants as they will prevent deployment in situations where they may have an adverse effect. PMID:15140296

  16. Pedestrian crash trends and potential countermeasures from around the world.

    PubMed

    Zegeer, Charles V; Bushell, Max

    2012-01-01

    As automobile transportation continues to increase around the world, bicyclists, pedestrians, and motorcyclists, also known as vulnerable road users (VRUs), will become more susceptible to traffic crashes, especially in countries where traffic laws are poorly enforced. Many countries, however, are employing innovative strategies to ensure that road users can more safely navigate the urban landscape. While bicyclists and motorcyclists are important road users, this paper will focus on pedestrian crash problems and solutions. Pedestrians are most at risk in urban areas due in part to the large amount of pedestrian and vehicle activity in urban areas. With this in mind, designing safe, accessible, and comprehensive facilities for pedestrians is vital to reducing pedestrian crashes. This paper will provide some insight into the magnitude of the pedestrian crash problem around the world, and will offer some lessons learned from several countries, particularly in Europe and the U.S., for improving pedestrian safety. Beginning with pedestrian safety statistics at the global, regional, and national levels, this paper will address potential countermeasures and strategies for improving pedestrian safety from an international perspective.

  17. STOCK MARKET CRASH AND EXPECTATIONS OF AMERICAN HOUSEHOLDS*

    PubMed Central

    HUDOMIET, PÉTER; KÉZDI, GÁBOR; WILLIS, ROBERT J.

    2011-01-01

    SUMMARY This paper utilizes data on subjective probabilities to study the impact of the stock market crash of 2008 on households’ expectations about the returns on the stock market index. We use data from the Health and Retirement Study that was fielded in February 2008 through February 2009. The effect of the crash is identified from the date of the interview, which is shown to be exogenous to previous stock market expectations. We estimate the effect of the crash on the population average of expected returns, the population average of the uncertainty about returns (subjective standard deviation), and the cross-sectional heterogeneity in expected returns (disagreement). We show estimates from simple reduced-form regressions on probability answers as well as from a more structural model that focuses on the parameters of interest and separates survey noise from relevant heterogeneity. We find a temporary increase in the population average of expectations and uncertainty right after the crash. The effect on cross-sectional heterogeneity is more significant and longer lasting, which implies substantial long-term increase in disagreement. The increase in disagreement is larger among the stockholders, the more informed, and those with higher cognitive capacity, and disagreement co-moves with trading volume and volatility in the market. PMID:21547244

  18. A mathematical definition of the financial bubbles and crashes

    NASA Astrophysics Data System (ADS)

    Watanabe, Kota; Takayasu, Hideki; Takayasu, Misako

    2007-09-01

    We check the validity of the mathematical method of detecting financial bubbles or crashes, which is based on a data fitting with an exponential function. We show that the period of a bubble can be determined nearly uniquely independent of the precision of data. The method is widely applicable for stock market data such as the Internet bubble.

  19. Fatigue and crashes: the case of freight transport in Colombia.

    PubMed

    Torregroza-Vargas, Nathaly M; Bocarejo, Juan Pablo; Ramos-Bonilla, Juan P

    2014-11-01

    Truck drivers have been involved in a significant number of road fatalities in Colombia. To identify variables that could be associated with crashes in which truck drivers are involved, a logistic regression model was constructed. The model had as the response variable a dichotomous variable that included the presence or absence of a crash during a specific trip. As independent variables the model included information regarding a driver's work shift, with variables that could be associated with driver's fatigue. The model also included potential confounders related with road conditions. With the model, it was possible to determine the odds ratio of a crash in relation to several variables, adjusting for confounding. To collect the information about the trips included in the model, a survey among truck drivers was conducted. The results suggest strong associations between crashes (i.e., some of them statistically significant) with the number of stops made during the trip, and the average time of each stop. Survey analysis allowed us to identify the practices that contribute to generating fatigue and unhealthy conditions on the road among professional drivers. A review of national regulations confirmed the lack of legislation on this topic.

  20. Car-Crash Experiment for the Undergraduate Laboratory

    ERIC Educational Resources Information Center

    Ball, Penny L.; And Others

    1974-01-01

    Describes an interesting, inexpensive, and highly motivating experiment to study uniform and accelerated motion by measuring the position of a car as it crashes into a rigid wall. Data are obtained from a sequence of pictures made by a high speed camera. (Author/SLH)

  1. Finite pressure effects on the tokamak sawtooth crash

    SciTech Connect

    Nishimura, Yasutaro

    1998-07-01

    The sawtooth crash is a hazardous, disruptive phenomenon that is observed in tokamaks whenever the safety factor at the magnetic axis is below unity. Recently, Tokamak Test Fusion Reactor (TFTR) experimental data has revealed interesting features of the dynamical pressure evolution during the crash phase. Motivated by the experimental results, this dissertation focuses on theoretical modeling of the finite pressure effects on the nonlinear stage of the sawtooth crash. The crash phase has been studied numerically employed a toroidal magnetohydrodynamic (MHD) initial value code deduced from the FAR code. For the first time, by starting from a concentric equilibrium, it has been shown that the evolution through an m/n = 1/1 magnetic island induces secondary high-n ballooning instabilities. The magnetic island evolution gives rise to convection of the pressure inside the inversion radius and builds up a steep pressure gradient across the island separatrix, or current sheet, and thereby triggers ballooning instabilities below the threshold for the axisymmetric equilibrium. Due to the onset of secondary ballooning modes, concomitant fine scale vortices and magnetic stochasticity are generated. These effects produce strong flows across the current sheet, and thereby significant modify the m = 1 driven magnetic reconnection process. The resultant interaction of the high-n ballooning modes with the magnetic reconnection process is discussed.

  2. School Bus Crash Rates on Routine and Nonroutine Routes

    ERIC Educational Resources Information Center

    O'Neal, Elizabeth; Ramirez, Marizen; Hamann, Cara; Young, Tracy; Stahlhut, Mary; Peek-Asa, Corinne

    2014-01-01

    Background: Although prior research has established that school buses are a safe form of transportation, crashes can produce catastrophic consequences. School buses have 2 types of routes: predictable, routine routes that take children to and from school and less predictable, nonroutine routes for school events. No studies have examined school bus…

  3. Magnetorheological impact seat suspensions for ground vehicle crash mitigation

    NASA Astrophysics Data System (ADS)

    Bai, Xian-Xu; Wereley, Norman M.

    2014-04-01

    Semi-active magnetorheological energy absorbers (MREAs) are one type of the most promising actuator for both the vibration and shock control. This paper investigates the frontal crash mitigation performance of semi-active MR impact seat suspensions for ground vehicles. The characteristics of two MREAs, a conventional MREA and an MREA with an internal bypass, with an identical volume, are theoretically evaluated and compared. To explore the control effectiveness of MREAs in the shock control systems, the mechanical model of a 4-degree-of-freedom (4DOF) sliding seat suspension system with MREAs is constructed. An optimal Bingham number control, which is to minimize the crash pulse loads transmitted to occupants by utilizing maximum stroke of the MREAs based on initial velocity of crash pulse, mass, and damping, is proposed and developed to improve the crash mitigation performance of the 4DOF MR sliding seat suspension control systems. The simulated control performances of the mitigation systems based on the MREAs with different functional structures are evaluated, compared, and analyzed. The research results indicate that (1) the constant stroking load velocity range of the MREAs is of significance to evaluate the controllability of the MREAs (i.e., the effectiveness of the semi-active shock control systems), and (2) suboptimal Bingham number control cannot realize "soft landing" (i.e., either an end-stop impact or incomplete utilization of the MREA stroke happens).

  4. Teenaged Drivers and Fatal Crash Responsibility. Preliminary Report.

    ERIC Educational Resources Information Center

    Williams, Allan F.; Karpf, Ronald S.

    According to data obtained for the year 1978 from the Fatal Accident Reporting System (FARS) and from state governments under contract to the National Highway Traffic Safety Administration, teenaged drivers (especially males) have much higher rates of fatal crash involvement than older drivers. In addition, teenaged drivers are more likely than…

  5. Crash Injury Management Instructor Training Institute: Final Report.

    ERIC Educational Resources Information Center

    Cleven, Arlene M.

    The purpose of this study was to expose key individuals to the National Highway Traffic Safety Administration (NHTSA)-developed curriculum materials for crash injury management and to teach them how to teach. The scope of the training effort is described using a detailed discussion and separate conclusions for the following tasks: planning,…

  6. STOCK MARKET CRASH AND EXPECTATIONS OF AMERICAN HOUSEHOLDS.

    PubMed

    Hudomiet, Péter; Kézdi, Gábor; Willis, Robert J

    2011-01-01

    This paper utilizes data on subjective probabilities to study the impact of the stock market crash of 2008 on households' expectations about the returns on the stock market index. We use data from the Health and Retirement Study that was fielded in February 2008 through February 2009. The effect of the crash is identified from the date of the interview, which is shown to be exogenous to previous stock market expectations. We estimate the effect of the crash on the population average of expected returns, the population average of the uncertainty about returns (subjective standard deviation), and the cross-sectional heterogeneity in expected returns (disagreement). We show estimates from simple reduced-form regressions on probability answers as well as from a more structural model that focuses on the parameters of interest and separates survey noise from relevant heterogeneity. We find a temporary increase in the population average of expectations and uncertainty right after the crash. The effect on cross-sectional heterogeneity is more significant and longer lasting, which implies substantial long-term increase in disagreement. The increase in disagreement is larger among the stockholders, the more informed, and those with higher cognitive capacity, and disagreement co-moves with trading volume and volatility in the market.

  7. En route noise of two turboprop aircraft

    NASA Technical Reports Server (NTRS)

    Dobrzynski, Werner

    1990-01-01

    In order to weigh en route noise emissions originating from future propfan powered aircraft, a data base of emission levels from conventional turboprop aircraft is needed. For this reason flyover noise measurements on two twin-engine turboprop aircraft were conducted at flight heights between 17,000 and 21,000 ft. Acoustic data are presented together with propeller operational parameters and environmental meteorological data. Narrowband spectral analyses demonstrate the characteristic features of the measured propeller noise signatures: Noise spectra are dominated by the propeller rotational noise fundamental frequency and pronounced noise beats occur as a consequence of different rotational speeds of the propellers.

  8. Distributed radar sensors for aircraft detection

    NASA Astrophysics Data System (ADS)

    Canavan, G. H.

    1991-04-01

    Radars suitable for aircraft detection could be deployed on singlet space-based interceptor (SBI) platforms. They could operate at short ranges and still achieve useful search rates. Powers are modest and insensitive to frequency; the dominant costs are the pulsers and phased-array elements. A fundamental simplification results from mounting the radar on the life jacket rather than the SBI. Many satellites could be processed to derive aircraft trajectories sufficiently accurate for the commitment of fighters or defensive missiles.

  9. Analysis of NTSB Aircraft-Assisted Pilot Suicides: 1982-2014.

    PubMed

    Politano, P Michael; Walton, Robert O

    2016-04-01

    On March 24, 2015, a Germanwings aircraft crashed in the Alps. The suicidal copilot killed himself and 150 others. Pilot suicide is rare, but does happen. This research analyzed the National Transportation Safety Board's accident database (eADMS) looking for pilots who died by suicide in flight. Fifty-one suicides were identified. Gender, age, and other characteristics were examined. Average age of suicidal pilots was 38, significantly different from the average age of 45 for all male pilots involved in aircraft accidents. A discriminant function accurately identified suicidal incidents at 96%. There was a high false-positive rate limiting the usefulness of the discriminant function.

  10. Properties of aircraft tire materials

    NASA Technical Reports Server (NTRS)

    Dodge, Richard N.; Clark, Samuel K.

    1988-01-01

    A summary is presented of measured elastomeric composite response suitable for linear structural and thermoelastic analysis in aircraft tires. Both real and loss properties are presented for a variety of operating conditions including the effects of temperature and frequency. Suitable micro-mechanics models are used for predictions of these properties for other material combinations and the applicability of laminate theory is discussed relative to measured values.

  11. Aircraft interior noise reduction by alternate resonance tuning

    NASA Technical Reports Server (NTRS)

    Bliss, Donald B.; Gottwald, James A.; Srinivasan, Ramakrishna; Gustaveson, Mark B.

    1990-01-01

    Existing interior noise reduction techniques for aircraft fuselages perform reasonably well at higher frequencies, but are inadequate at lower frequencies, particularly with respect to the low blade passage harmonics with high forcing levels found in propeller aircraft. A method is being studied which considers aircraft fuselage lined with panels alternately tuned to frequencies above and below the frequency that must be attenuated. Adjacent panels would oscillate at equal amplitude, to give equal source strength, but with opposite phase. Provided these adjacent panels are acoustically compact, the resulting cancellation causes the interior acoustic modes to become cutoff, and therefore be non-propagating and evanescent. This interior noise reduction method, called Alternate Resonance Tuning (ART), is currently being investigated both theoretically and experimentally. This new concept has potential application to reducing interior noise due to the propellers in advanced turboprop aircraft as well as for existing aircraft configurations.

  12. A model-based, multichannel, real-time capable sawtooth crash detector

    NASA Astrophysics Data System (ADS)

    van den Brand, H.; de Baar, M. R.; van Berkel, M.; Blanken, T. C.; Felici, F.; Westerhof, E.; Willensdorfer, M.; The ASDEX Upgrade Team; The EUROfusion MST1 Team

    2016-07-01

    Control of the time between sawtooth crashes, necessary for ITER and DEMO, requires real-time detection of the moment of the sawtooth crash. In this paper, estimation of sawtooth crash times is demonstrated using the model-based interacting multiple model (IMM) estimator, based on simplified models for the sawtooth crash. In contrast to previous detectors, this detector uses the spatial extent of the sawtooth crash as detection characteristic. The IMM estimator is tuned and applied to multiple ECE channels at once. A model for the sawtooth crash is introduced, which is used in the IMM algorithm. The IMM algorithm is applied to seven datasets from the ASDEX Upgrade tokamak. Five crash models with different mixing radii are used. All sawtooth crashes that have been identified beforehand by visual inspection of the data, are detected by the algorithm. A few additional detections are made, which upon closer inspection are seen to be sawtooth crashes, which show a partial reconnection. A closer inspection of the detected normal crashes shows that about 42% are not well fitted by any of the full reconnection models and show some characteristics of a partial reconnection. In some case, the measurement time is during the sawtooth crashes, which also results in an incorrect estimate of the mixing radius. For data provided at a sampling rate of 1 kHz, the run time of the IMM estimator is below 1 ms, thereby fulfilling real-time requirements.

  13. Comorbidities and Crash Involvement among Younger and Older Drivers

    PubMed Central

    Papa, Michela; Boccardi, Virginia; Prestano, Raffaele; Angellotti, Edith; Desiderio, Manuela; Marano, Luigi; Rizzo, Maria Rosaria; Paolisso, Giuseppe

    2014-01-01

    Previous studies identified comorbidities as predictors of older driver performance and driving pattern, while the direct impact of comorbidities on road crash risk in elderly drivers is still unknown. The present study is a cross-sectional aimed at investigating the association between levels of comorbidity and crash involvement in adult and elderly drivers. 327 drivers were stratified according to age range in two groups: elderly drivers (age ≥70 years old, referred as older) and adult drivers (age <70 years old, referred as younger). Driving information was obtained through a driving questionnaire. Distance traveled was categorized into low, medium and high on the basis of kilometers driven in a year. CIRS-illness severity (IS) and CIRS-comorbidity indices (CI) in all populations were calculated. Older drivers had a significantly higher crash involvements rate (p = .045) compared with the younger group based on the number of licensed drivers. Dividing comorbidity indices into tertiles among all licensed subjects, the number of current drivers significantly decreased (p<.0001) with increasing level of comorbidity. The number of current drivers among older subjects significantly decreased with increasing comorbidity level (p = .026) while no difference among younger group was found (p = .462). Among younger drivers with increasing comorbidity level, the number of road accidents significantly increased (p = .048) and the logistic regression analysis showed that comorbidity level significantly associated with crash involvement independent of gender and driving exposure. Older subjects with high level of comorbidity are able to self-regulate driving while comorbidity burden represents a significant risk factor for crash involvements among younger drivers. PMID:24722619

  14. Epidemiology of hot-air balloon crashes in the U.S., 1984-88.

    PubMed

    Frankenfield, D L; Baker, S P

    1994-01-01

    Hot-air ballooning crashes in the U.S. during 1984-88 were examined using National Transportation Safety Board reports. The 138 crashes occurred most frequently during recreational flights (51% of the total) and paid rides (28%). A total of 480 persons were involved; 6 were killed and 123 seriously injured. Pilot error contributed to 88% of the crashes, and equipment failure or malfunction to 11%. Of the six fatal crashes, five involved collision with power lines. Crashes occurring outside optimal flying times accounted for 15% of the total. Pilots with 10 h or less flight time accounted for fewer than expected crashes. All five student pilots flying solo sustained serious injuries. Suggested prevention efforts include better training in avoidance of power lines and proper handling of rapid descents; more stringent and frequent flight testing of pilots; and a longer training period before granting pilot certificates. Attention should be given to delethalizing balloon crashes and encouraging the use of protective equipment.

  15. Developing crash modification functions to assess safety effects of adding bike lanes for urban arterials with different roadway and socio-economic characteristics.

    PubMed

    Park, Juneyoung; Abdel-Aty, Mohamed; Lee, Jaeyoung; Lee, Chris

    2015-01-01

    Although many researchers have estimated crash modification factors (CMFs) for specific treatments (or countermeasures), there is a lack of studies that explored the heterogeneous effects of roadway characteristics on crash frequency among treated sites. Generally, the CMF estimated by before-after studies represents overall safety effects of the treatment in a fixed value. However, as each treated site has different roadway characteristics, there is a need to assess the variation of CMFs among the treated sites with different roadway characteristics through crash modification functions (CMFunctions). The main objective of this research is to determine relationships between the safety effects of adding a bike lane and the roadway characteristics through (1) evaluation of CMFs for adding a bike lane using observational before-after with empirical Bayes (EB) and cross-sectional methods, and (2) development of simple and full CMFunctions which are describe the CMF in a function of roadway characteristics of the sites. Data was collected for urban arterials in Florida, and the Florida-specific full SPFs were developed. Moreover, socio-economic parameters were collected and included in CMFunctions and SPFs (1) to capture the effects of the variables that represent volume of bicyclists and (2) to identify general relationship between the CMFs and these characteristics. In order to achieve better performance of CMFunctions, data mining techniques were used. The results of both before-after and cross-sectional methods show that adding a bike lane on urban arterials has positive safety effects (i.e., CMF<1) for all crashes and bike crashes. It was found that adding a bike lane is more effective in reducing bike crashes than all crashes. It was also found that the CMFs vary across the sites with different roadway characteristics. In particular, annual average daily traffic (AADT), number of lanes, AADT per lane, median width, bike lane width, and lane width are significant

  16. Particulate Characterization and Control Evaluation for Carbon Fiber Composite Aircraft Crash Recovery Operations

    DTIC Science & Technology

    2010-03-01

    Mixed Cellulose Ester MMD Mass Median Diameter MWCNT Multi Walled Carbon Nanotubes MPPS Most Penetrating Particle Size NEAT Nanoparticle Emission...CNT Carbon Nanotube CPC Condensation Particle Counter DRI Direct Reading Instrument EAD Electrical Aerosol Detector GSD Geometric Standard...Equipment PVC Polyvinyl Chloride SWCNT Single Walled Carbon Nanotubes TEM Transmission Electron Microscopy TLV Threshold Limit Value TO Technical

  17. Examination of Air Force Crash Damaged or Disabled Aircraft Recovery Program Resourcing

    DTIC Science & Technology

    2011-06-01

    resulted in a “lifting kit consisting of six 23-tonne pneumatic lifting bags, two 73-tonne large-extension hydraulic jacks and one set of tethering...edition. Mason OH: Thomson . Schwartz, Norton A. “Toward More Efficient Military Logistics”. National Defense Industrial Association Logistics...NAME(S) AND ADDRESS(ES) AF/A4/7PY-Lt Col Robert Charlesworth Office #4B1089 Robert.Charlesworth@pentagon.af.mil

  18. Analytical Modeling of Transport Aircraft Crash Scenarios to Obtain Floor Pulses.

    DTIC Science & Technology

    1983-04-01

    airplane design , airportIoff-runway hazards and accident avoidance procedures 1-5 1-3 Transportation fatalities, 1980-81 1-6 1-4 Trend of accidents rates...4.5:1.5 loading (test no. 10) condition 9-15 9-11 Potential improved body block design 9-16 9-12 Dynamic response factor curves for triangular pulse 9...significant. The following grouping is possible: 0 Airplane Design Related - accidents which occur around airports; i.e., on the runway or within 350 a

  19. Aircraft Crash Survival Design Guide. Volume 1. Design Criteria and Checklists

    DTIC Science & Technology

    1989-12-01

    50th 99 percentile dummy (Reference 36) it, Test 1 and a clad 95th-percentile dummy in Test 2. Dynamic testing of multipla -occupant seats shnuld be...Idiyn nir-rf l ATFl rAr T nflrTn Rubbins, D. H.., et al, uEVELUOI’IIE I Ali,’u TEa , I ING ur ilIURlMIU JLLMI nLJI IN, SYST[ MS , Highway Safety Research

  20. Propulsion controlled aircraft computer

    NASA Technical Reports Server (NTRS)

    Cogan, Bruce R. (Inventor)

    2010-01-01

    A low-cost, easily retrofit Propulsion Controlled Aircraft (PCA) system for use on a wide range of commercial and military aircraft consists of an propulsion controlled aircraft computer that reads in aircraft data including aircraft state, pilot commands and other related data, calculates aircraft throttle position for a given maneuver commanded by the pilot, and then displays both current and calculated throttle position on a cockpit display to show the pilot where to move throttles to achieve the commanded maneuver, or is automatically sent digitally to command the engines directly.

  1. Spatial panel analyses of alcohol outlets and motor vehicle crashes in California: 1999–2008

    PubMed Central

    Ponicki, William R.; Gruenewald, Paul J.; Remer, Lillian G.

    2014-01-01

    Although past research has linked alcohol outlet density to higher rates of drinking and many related social problems, there is conflicting evidence of density’s association with traffic crashes. An abundance of local alcohol outlets simultaneously encourages drinking and reduces driving distances required to obtain alcohol, leading to an indeterminate expected impact on alcohol-involved crash risk. This study separately investigates the effects of outlet density on (1) the risk of injury crashes relative to population and (2) the likelihood that any given crash is alcohol-involved, as indicated by police reports and single-vehicle nighttime status of crashes. Alcohol outlet density effects are estimated using Bayesian misalignment Poisson analyses of all California ZIP codes over the years 1999–2008. These misalignment models allow panel analysis of ZIP-code data despite frequent redefinition of postal-code boundaries, while also controlling for overdispersion and the effects of spatial autocorrelation. Because models control for overall retail density, estimated alcohol-outlet associations represent the extra effect of retail establishments selling alcohol. The results indicate a number of statistically well-supported associations between retail density and crash behavior, but the implied effects on crash risks are relatively small. Alcohol-serving restaurants have a greater impact on overall crash risks than on the likelihood that those crashes involve alcohol, whereas bars primarily affect the odds that crashes are alcohol-involved. Off-premise outlet density is negatively associated with risks of both crashes and alcohol involvement, while the presence of a tribal casino in a ZIP code is linked to higher odds of police-reported drinking involvement. Alcohol outlets in a given area are found to influence crash risks both locally and in adjacent ZIP codes, and significant spatial autocorrelation also suggests important relationships across geographical units

  2. The effects of age, gender, and crash types on drivers' injury-related health care costs.

    PubMed

    Shen, Sijun; Neyens, David M

    2015-04-01

    There are many studies that evaluate the effects of age, gender, and crash types on crash related injury severity. However, few studies investigate the effects of those crash factors on the crash related health care costs for drivers that are transported to hospital. The purpose of this study is to examine the relationships between drivers' age, gender, and the crash types, as well as other crash characteristics (e.g., not wearing a seatbelt, weather condition, and fatigued driving), on the crash related health care costs. The South Carolina Crash Outcome Data Evaluation System (SC CODES) from 2005 to 2007 was used to construct six separate hierarchical linear regression models based on drivers' age and gender. The results suggest that older drivers have higher health care costs than younger drivers and male drivers tend to have higher health care costs than female drivers in the same age group. Overall, single vehicle crashes had the highest health care costs for all drivers. For males older than 64-years old sideswipe crashes are as costly as single vehicle crashes. In general, not wearing a seatbelt, airbag deployment, and speeding were found to be associated with higher health care costs. Distraction-related crashes are more likely to be associated with lower health care costs in most cases. Furthermore this study highlights the value of considering drivers in subgroups, as some factors have different effects on health care costs in different driver groups. Developing an understanding of longer term outcomes of crashes and their characteristics can lead to improvements in vehicle technology, educational materials, and interventions to reduce crash-related health care costs.

  3. Evaluation of rear-end crash risk at work zone using work zone traffic data.

    PubMed

    Meng, Qiang; Weng, Jinxian

    2011-07-01

    This paper aims to evaluate the rear-end crash risk at work zone activity area and merging area, as well as analyze the impacts of contributing factors by using work zone traffic data. Here, the rear-end crash risk is referred to as the probability that a vehicle is involved in a rear-end crash accident. The deceleration rate to avoid the crash (DRAC) is used in measuring rear-end crash risk. Based on work zone traffic data in Singapore, three rear-end crash risk models are developed to examine the relationship between rear-end crash risk at activity area and its contributing factors. The fourth rear-end crash risk model is developed to examine the effects of merging behavior on crash risk at merging area. The ANOVA results show that the rear-end crash risk at work zone activity area is statistically different from lane positions. Model results indicate that rear-end crash risk at work zone activity area increases with heavy vehicle percentage and lane traffic flow rate. An interesting finding is that the lane closer to work zone is strongly associated with higher rear-end crash risk. A truck has much higher probability involving in a rear-end accident than a car. Further, the expressway work zone activity area is found to have much larger crash risk than arterial work zone activity area. The merging choice has the dominated effect on risk reduction, suggesting that encouraging vehicles to merge early may be the most effective method to reduce rear-end crash risk at work zone merging area.

  4. Crash risk analysis for Shanghai urban expressways: A Bayesian semi-parametric modeling approach.

    PubMed

    Yu, Rongjie; Wang, Xuesong; Yang, Kui; Abdel-Aty, Mohamed

    2016-10-01

    Urban expressway systems have been developed rapidly in recent years in China; it has become one key part of the city roadway networks as carrying large traffic volume and providing high traveling speed. Along with the increase of traffic volume, traffic safety has become a major issue for Chinese urban expressways due to the frequent crash occurrence and the non-recurrent congestions caused by them. For the purpose of unveiling crash occurrence mechanisms and further developing Active Traffic Management (ATM) control strategies to improve traffic safety, this study developed disaggregate crash risk analysis models with loop detector traffic data and historical crash data. Bayesian random effects logistic regression models were utilized as it can account for the unobserved heterogeneity among crashes. However, previous crash risk analysis studies formulated random effects distributions in a parametric approach, which assigned them to follow normal distributions. Due to the limited information known about random effects distributions, subjective parametric setting may be incorrect. In order to construct more flexible and robust random effects to capture the unobserved heterogeneity, Bayesian semi-parametric inference technique was introduced to crash risk analysis in this study. Models with both inference techniques were developed for total crashes; semi-parametric models were proved to provide substantial better model goodness-of-fit, while the two models shared consistent coefficient estimations. Later on, Bayesian semi-parametric random effects logistic regression models were developed for weekday peak hour crashes, weekday non-peak hour crashes, and weekend non-peak hour crashes to investigate different crash occurrence scenarios. Significant factors that affect crash risk have been revealed and crash mechanisms have been concluded.

  5. Spatial panel analyses of alcohol outlets and motor vehicle crashes in California: 1999-2008.

    PubMed

    Ponicki, William R; Gruenewald, Paul J; Remer, Lillian G

    2013-06-01

    Although past research has linked alcohol outlet density to higher rates of drinking and many related social problems, there is conflicting evidence of density's association with traffic crashes. An abundance of local alcohol outlets simultaneously encourages drinking and reduces driving distances required to obtain alcohol, leading to an indeterminate expected impact on alcohol-involved crash risk. This study separately investigates the effects of outlet density on (1) the risk of injury crashes relative to population and (2) the likelihood that any given crash is alcohol-involved, as indicated by police reports and single-vehicle nighttime status of crashes. Alcohol outlet density effects are estimated using Bayesian misalignment Poisson analyses of all California ZIP codes over the years 1999-2008. These misalignment models allow panel analysis of ZIP-code data despite frequent redefinition of postal-code boundaries, while also controlling for overdispersion and the effects of spatial autocorrelation. Because models control for overall retail density, estimated alcohol-outlet associations represent the extra effect of retail establishments selling alcohol. The results indicate a number of statistically well-supported associations between retail density and crash behavior, but the implied effects on crash risks are relatively small. Alcohol-serving restaurants have a greater impact on overall crash risks than on the likelihood that those crashes involve alcohol, whereas bars primarily affect the odds that crashes are alcohol-involved. Off-premise outlet density is negatively associated with risks of both crashes and alcohol involvement, while the presence of a tribal casino in a ZIP code is linked to higher odds of police-reported drinking involvement. Alcohol outlets in a given area are found to influence crash risks both locally and in adjacent ZIP codes, and significant spatial autocorrelation also suggests important relationships across geographical units

  6. Predicting crash likelihood and severity on freeways with real-time loop detector data.

    PubMed

    Xu, Chengcheng; Tarko, Andrew P; Wang, Wei; Liu, Pan

    2013-08-01

    Real-time crash risk prediction using traffic data collected from loop detector stations is useful in dynamic safety management systems aimed at improving traffic safety through application of proactive safety countermeasures. The major drawback of most of the existing studies is that they focus on the crash risk without consideration of crash severity. This paper presents an effort to develop a model that predicts the crash likelihood at different levels of severity with a particular focus on severe crashes. The crash data and traffic data used in this study were collected on the I-880 freeway in California, United States. This study considers three levels of crash severity: fatal/incapacitating injury crashes (KA), non-incapacitating/possible injury crashes (BC), and property-damage-only crashes (PDO). The sequential logit model was used to link the likelihood of crash occurrences at different severity levels to various traffic flow characteristics derived from detector data. The elasticity analysis was conducted to evaluate the effect of the traffic flow variables on the likelihood of crash and its severity.The results show that the traffic flow characteristics contributing to crash likelihood were quite different at different levels of severity. The PDO crashes were more likely to occur under congested traffic flow conditions with highly variable speed and frequent lane changes, while the KA and BC crashes were more likely to occur under less congested traffic flow conditions. High speed, coupled with a large speed difference between adjacent lanes under uncongested traffic conditions, was found to increase the likelihood of severe crashes (KA). This study applied the 20-fold cross-validation method to estimate the prediction performance of the developed models. The validation results show that the model's crash prediction performance at each severity level was satisfactory. The findings of this study can be used to predict the probabilities of crash at

  7. Comparison of pregnant and non-pregnant occupant crash and injury characteristics based on national crash data.

    PubMed

    Manoogian, Sarah

    2015-01-01

    The objective of this study was to provide specific characteristics of injuries and crash characteristics for pregnant occupants from the National Automotive Sampling System/Crashworthiness Data System (NASS/CDS) database for pregnant women as a group, broken down by trimester, and compared to non-pregnant women. Using all NASS/CDS cases collected between the years 2000 and 2012 with at least one pregnant occupant, the entire pregnant data set included 321,820 vehicles, 324,535 occupants, and 640,804 injuries. The pregnant occupant data were compared to the characteristics of NASS/CDS cases for 14,719,533 non-pregnant females 13-44 years old in vehicle crashes from 2000 to 2012. Sixty five percent of pregnant women were located in the front left seat position and roughly the same percentage of pregnant women was wearing a lap and shoulder belt. The average change in velocity was 11.6 mph for pregnant women and over 50% of crashes for pregnant women were frontal collisions. From these collisions, less than seven percent of pregnant women sustained MAIS 2+ injuries. Minor differences between the pregnant and non-pregnant occupants were identified in the body region and source of injuries sustained. However, the data indicated no large differences in injury or crash characteristics based on trimester of pregnancy. Moreover, the risk of an MAIS 2+ level injury for pregnant occupants is similar to the risk of injury for non-pregnant occupants based on the total vehicle change in velocity. Overall this study provides useful data for researchers to focus future efforts in pregnant occupant research. Additionally, this study reinforces that more detailed and complete data on pregnant crashes needs to be collected to understand the risk for pregnant occupants.

  8. A computer simulation of aircraft evacuation with fire

    NASA Technical Reports Server (NTRS)

    Middleton, V. E.

    1983-01-01

    A computer simulation was developed to assess passenger survival during the post-crash evacuation of a transport category aircraft when fire is a major threat. The computer code, FIREVAC, computes individual passenger exit paths and times to exit, taking into account delays and congestion caused by the interaction among the passengers and changing cabin conditions. Simple models for the physiological effects of the toxic cabin atmosphere are included with provision for including more sophisticated models as they become available. Both wide-body and standard-body aircraft may be simulated. Passenger characteristics are assigned stochastically from experimentally derived distributions. Results of simulations of evacuation trials and hypothetical evacuations under fire conditions are presented.

  9. Fatal Traffic Crashes Involving Drinking Drivers: What have we Learned?

    PubMed Central

    Fell, James C.; Tippetts, A. Scott; Voas, Robert B.

    2009-01-01

    Alcohol involvement in fatal crashes (any driver with a blood alcohol concentration [BAC] = .01g/dL or greater) in 2007 was more than three times higher at night (6 p.m.–6 a.m.) than during the day (6 a.m.–6 p.m.) (62% versus 19%). Alcohol involvement was 35% during weekdays compared to 54% on weekends. Nearly one in four drivers (23%) of personal vehicles (e.g., passenger cars or light trucks) and more than one in four motorcyclists (27%) in fatal crashes were intoxicated (i.e., had a BAC equal to or greater than the .08 g/dL illegal limit in the United States). In contrast, only 1% of the commercial drivers of heavy trucks had BACs equal to .08 g/dL or higher. More than a quarter (26%) of the drivers with high BACs (≥.15 g/dL) did not have valid licenses. The 21- to 24-age group had the highest proportion (35%) of drivers with BACs≥.08 g/dL, followed by the 25- to 34-age group (29%). The oldest and the youngest drivers had the lowest percentages of BACs≥ .08 g/dL: those aged 75 or older were at 4%, and those aged 16 to 20 were at 17%. Utah had the lowest rate of intoxicated drivers in fatal crashes at one in every eight drivers (12%), followed by Kentucky, Indiana, Iowa, New Hampshire, and Kansas, all at 17%. Montana (31%), South Carolina (31%), and North Dakota (39%) all had more than 3 in 10 drivers in fatal crashes who were intoxicated in 2007. The United States enjoyed a remarkable downward trend in alcohol-related crashes between 1982 and 1995, which has since leveled off. That trend coincided with a period during which per capita national alcohol consumption declined, the number of young drivers decreased, and the proportion of female drivers increased. Those factors alone, however, did not appear to account for the overall reduction. This provides further evidence that impaired-driving laws and safety program activity may have been responsible for at least some of the decline. However, there was a general worldwide decline in alcohol

  10. The Inquiry into the Waterfall train crash: implications for medical examinations of safety-critical workers.

    PubMed

    Hocking, Bruce

    2006-02-06

    The implications arising from the Inquiry into the Waterfall train crash for medical examinations of safety-critical workers are discussed. Examinations need to be appropriate for the level of risk in the job and apply current medical thinking. A careful balance is required between the various legal obligations, including duty of care, disability discrimination and privacy. The frequency of examinations depends on a combination of medical, economic and logistical factors. Health professionals who conduct examinations should be familiar with the occupation of the person being examined. Ethical relationships with the worker's general practitioner or specialist(s) must be observed. The procedures associated with the examinations are as important in achieving safety as the actual examinations. These include complying with relevant standards; providing all relevant documentation with a referral for an examination; acting on the doctor's report appropriately; and auditing the process.

  11. A Hybrid Latent Class Analysis Modeling Approach to Analyze Urban Expressway Crash Risk.

    PubMed

    Yu, Rongjie; Wang, Xuesong; Abdel-Aty, Mohamed

    2017-04-01

    Crash risk analysis is rising as a hot research topic as it could reveal the relationships between traffic flow characteristics and crash occurrence risk, which is beneficial to understand crash mechanisms which would further refine the design of Active Traffic Management System (ATMS). However, the majority of the current crash risk analysis studies have ignored the impact of geometric characteristics on crash risk estimation while recent studies proved that crash occurrence risk was affected by the various alignment features. In this study, a hybrid Latent Class Analysis (LCA) modeling approach was proposed to account for the heterogeneous effects of geometric characteristics. Crashes were first segmented into homogenous subgroups, where the optimal number of latent classes was identified based on bootstrap likelihood ratio tests. Then, separate crash risk analysis models were developed using Bayesian random parameter logistic regression technique; data from Shanghai urban expressway system were employed to conduct the empirical study. Different crash risk contributing factors were unveiled by the hybrid LCA approach and better model goodness-of-fit was obtained while comparing to an overall total crash model. Finally, benefits of the proposed hybrid LCA approach were discussed.

  12. Crash data quality for road safety research: Current state and future directions.

    PubMed

    Imprialou, Marianna; Quddus, Mohammed

    2017-03-02

    Crash databases are one of the primary data sources for road safety research. Therefore, their quality is fundamental for the accuracy of crash analyses and, consequently the design of effective countermeasures. Although crash data often suffer from correctness and completeness issues, these are rarely discussed or addressed in crash analyses. Crash reports aim to answer the five "W" questions (i.e. When?, Where?, What?, Who? and Why?) of each crash by including a range of attributes. This paper reviews current literature on the state of crash data quality for each of these questions separately. The most serious data quality issues appear to be: inaccuracies in crash location and time, difficulties in data linkage (e.g. with traffic data) due to inconsistencies in databases, severity misclassification, inaccuracies and incompleteness of involved users' demographics and inaccurate identification of crash contributory factors. It is shown that the extent and the severity of data quality issues are not equal between attributes and the level of impact in road safety analyses is not yet entirely known. This paper highlights areas that require further research and provides some suggestions for the development of intelligent crash reporting systems.

  13. Single- versus multi-vehicle bicycle road crashes in Victoria, Australia.

    PubMed

    Boufous, Soufiane; de Rome, Liz; Senserrick, Teresa; Ivers, Rebecca Q

    2013-10-01

    The aim of the study is to compare trends, circumstances and outcomes of single- versus multi-vehicle bicycle on-road crashes in Victoria, Australia, through the analysis of police records and hospital admissions between January 2004 and December 2008. The results show that over 80% of on-road single-vehicle bicycle crashes occurred as a result of the cyclist losing control of the bicycle with the remainder involving collisions with objects. Compared with multi-vehicle crashes, single-vehicle crashes were more likely to occur in the dark, in wet conditions and in rural areas. Over half of the cyclists hospitalised as result of on-road crashes were injured in single-vehicle crashes and this proportion seems to be increasing over time. Single-vehicle crashes were associated with hospitalised injuries as severe as those resulting from multivehicle crashes. The findings highlight the significant burden of serious injury associated with single-vehicle bicycle road crashes. Further research is needed to investigate in greater detail the risk factors of these crashes and the effectiveness of countermeasures to reduce their burden.

  14. Investigating driver injury severity patterns in rollover crashes using support vector machine models.

    PubMed

    Chen, Cong; Zhang, Guohui; Qian, Zhen; Tarefder, Rafiqul A; Tian, Zong

    2016-05-01

    Rollover crash is one of the major types of traffic crashes that induce fatal injuries. It is important to investigate the factors that affect rollover crashes and their influence on driver injury severity outcomes. This study employs support vector machine (SVM) models to investigate driver injury severity patterns in rollover crashes based on two-year crash data gathered in New Mexico. The impacts of various explanatory variables are examined in terms of crash and environmental information, vehicle features, and driver demographics and behavior characteristics. A classification and regression tree (CART) model is utilized to identify significant variables and SVM models with polynomial and Gaussian radius basis function (RBF) kernels are used for model performance evaluation. It is shown that the SVM models produce reasonable prediction performance and the polynomial kernel outperforms the Gaussian RBF kernel. Variable impact analysis reveals that factors including comfortable driving environment conditions, driver alcohol or drug involvement, seatbelt use, number of travel lanes, driver demographic features, maximum vehicle damages in crashes, crash time, and crash location are significantly associated with driver incapacitating injuries and fatalities. These findings provide insights for better understanding rollover crash causes and the impacts of various explanatory factors on driver injury severity patterns.

  15. What do cyclists need to see to avoid single-bicycle crashes?

    PubMed

    Schepers, Paul; den Brinker, Berry

    2011-04-01

    The number of single-bicycle crash victims is substantial in countries with high levels of cycling. To study the role of visual characteristics of the infrastructure, such as pavement markings, in single-bicycle crashes, a study in two steps was conducted. In Study 1, a questionnaire study was conducted among bicycle crash victims (n = 734). Logistic regression was used to study the relationship between the crashes and age, light condition, alcohol use, gaze direction and familiarity with the crash scene. In Study 2, the image degrading and edge detection method (IDED-method) was used to investigate the visual characteristics of 21 of the crash scenes. The results of the studies indicate that crashes, in which the cyclist collided with a bollard or road narrowing or rode off the road, were related to the visual characteristics of bicycle facilities. Edge markings, especially in curves of bicycle tracks, and improved conspicuity of bollards are recommended. STATEMENT OF RELEVANCE: Elevated single-bicycle crash numbers are common in countries with high levels of cycling. No research has been conducted on what cyclists need to see to avoid this type of crash. The IDED-method to investigate crash scenes is new and proves to be a powerful tool to quantify 'visual accessibility'.

  16. Investigation of time and weather effects on crash types using full Bayesian multivariate Poisson lognormal models.

    PubMed

    El-Basyouny, Karim; Barua, Sudip; Islam, Md Tazul

    2014-12-01

    Previous research shows that various weather elements have significant effects on crash occurrence and risk; however, little is known about how these elements affect different crash types. Consequently, this study investigates the impact of weather elements and sudden extreme snow or rain weather changes on crash type. Multivariate models were used for seven crash types using five years of daily weather and crash data collected for the entire City of Edmonton. In addition, the yearly trend and random variation of parameters across the years were analyzed by using four different modeling formulations. The proposed models were estimated in a full Bayesian context via Markov Chain Monte Carlo simulation. The multivariate Poisson lognormal model with yearly varying coefficients provided the best fit for the data according to Deviance Information Criteria. Overall, results showed that temperature and snowfall were statistically significant with intuitive signs (crashes decrease with increasing temperature; crashes increase as snowfall intensity increases) for all crash types, while rainfall was mostly insignificant. Previous snow showed mixed results, being statistically significant and positively related to certain crash types, while negatively related or insignificant in other cases. Maximum wind gust speed was found mostly insignificant with a few exceptions that were positively related to crash type. Major snow or rain events following a dry weather condition were highly significant and positively related to three crash types: Follow-Too-Close, Stop-Sign-Violation, and Ran-Off-Road crashes. The day-of-the-week dummy variables were statistically significant, indicating a possible weekly variation in exposure. Transportation authorities might use the above results to improve road safety by providing drivers with information regarding the risk of certain crash types for a particular weather condition.

  17. An empirical analysis of run-off-road injury severity crashes involving large trucks.

    PubMed

    Al-Bdairi, Nabeel Saleem Saad; Hernandez, Salvador

    2017-03-04

    In recent years, there has been an increasing interest in understanding the contributory factors to run-off-road (ROR) crashes in the US, especially those where large trucks are involved. Although there have been several efforts to understand large-truck crashes, the relationship between crash factors, crash severity, and ROR crashes is not clearly understood. The intent of this research is to develop statistical models that provide additional insight into the effects that various contributory factors related to the person (driver), vehicle, crash, roadway, and environment have on ROR injury severity. An ordered random parameter probit was estimated to predict the likelihood of three injury severity categories using Oregon crash data: severe, minor, and no injury. The modeling approach accounts for unobserved heterogeneity (i.e., unobserved factors). The results showed that five parameter estimates were found to be random and normally distributed, and varied across ROR crash observations. These were factors related to crashes that occurred between January and April, raised median type, loss of control of a vehicle, the indicator variable of speed not involved, and the indicator variable of two vehicles or more involved in the crashes. In contrast, eight variables were found to be fixed across ROR observations. Looking more closely at the fixed parameter results, large-truck drivers who are not licensed in Oregon have a higher probability of experiencing no injury ROR crash outcomes, and human related factor, fatigue, increases the probability of minor injury. The modeling framework presented in this work offers a flexible methodology to analyze ROR crashes involving large trucks while accounting for unobserved heterogeneity. This information can aid safety planners and the trucking industry in identifying appropriate countermeasures to help mitigate the number and severity of large-truck ROR crashes.

  18. Evaluation of the predictability of real-time crash risk models.

    PubMed

    Xu, Chengcheng; Liu, Pan; Wang, Wei

    2016-09-01

    The primary objective of the present study was to investigate the predictability of crash risk models that were developed using high-resolution real-time traffic data. More specifically the present study sought answers to the following questions: (a) how to evaluate the predictability of a real-time crash risk model; and (b) how to improve the predictability of a real-time crash risk model. The predictability is defined as the crash probability given the crash precursor identified by the crash risk model. An equation was derived based on the Bayes' theorem for estimating approximately the predictability of crash risk models. The estimated predictability was then used to quantitatively evaluate the effects of the threshold of crash precursors, the matched and unmatched case-control design, and the control-to-case ratio on the predictability of crash risk models. It was found that: (a) the predictability of a crash risk model can be measured as the product of prior crash probability and the ratio between sensitivity and false alarm rate; (b) there is a trade-off between the predictability and sensitivity of a real-time crash risk model; (c) for a given level of sensitivity, the predictability of the crash risk model that is developed using the unmatched case-controlled sample is always better than that of the model developed using the matched case-controlled sample; and (d) when the control-to-case ratio is beyond 4:1, the increase in control-to-case ratio does not lead to clear improvements in predictability.

  19. What Influences the Association between Previous and Future Crashes among Cyclists? A Propensity Score Analysis

    PubMed Central

    Tin Tin, Sandar; Woodward, Alistair; Ameratunga, Shanthi

    2014-01-01

    Background It is known that experience of a previous crash is related to incidence of future crashes in a cohort of New Zealand cyclists. This paper investigated if the strength of such association differed by crash involvement propensity and by the need for medical care in the previous crash. Methods The Taupo Bicycle Study involved 2590 adult cyclists recruited in 2006 and followed over a median period of 4.6 years through linkage to four national databases. The crash involvement propensity was estimated using propensity scores based on the participants' demographic, cycling and residential characteristics. Cox regression modelling for repeated events was performed with multivariate and propensity score adjustments. Analyses were then stratified by quintiles of the propensity score. Results A total of 801 (31.0%) participants reported having experienced at least one bicycle crash in the twelve months prior to the baseline survey. They had a higher risk of experiencing crash events during follow-up (hazard ratio (HR): 1.43; 95% CI: 1.28, 1.60) but in the stratified analysis, this association was significant only in the highest two quintiles of the propensity score where the likelihood of having experienced a crash was more than 33%. The association was stronger for previous crashes that had received medical care (HR 1.63; 95% CI: 1.41, 1.88) compared to those that had not (HR 1.30; 95% CI: 1.14, 1.49). Conclusions Previous crash experience increased the risk of future crash involvement in high-risk cyclists and the association was stronger for previous crashes attended medically. What distinguishes the high risk group warrants closer investigation, and the findings indicate also that health service providers could play an important role in prevention of bicycle crash injuries. PMID:24489945

  20. Determination of tailless aircraft tumbling and stability characteristics through computational fluid dynamics

    NASA Astrophysics Data System (ADS)

    Saephan, Syta

    Tailless aircraft configurations such as flying wings are susceptible to tumbling. Tumbling involves an autorotative pitching motion primarily about an axis parallel to the aircraft's lateral axis combined with planar translation. Tumbling is the suspected cause of a tailless aircraft (Northrop YB-49) crash in the late 1940s and is a potential problem for future flying wing and blended wing body aircraft. It may be difficult if not impossible for a tailless aircraft to escape the tumbling motion once it begins. It is therefore important for aircraft designers to know the causes of tumbling in order to prevent its onset. Tumbling has been demonstrated in qualitative free-flight wind tunnel experiments, but few have attempted to quantify the motion using computational fluid dynamics. The purpose of this research is to use computational fluid dynamics to study the tumbling characteristics of a tailless aircraft and then determine dynamic stability information from the simulations. Specifically, the effects of initial conditions, degrees-of-freedom, Reynolds number, and aircraft static margin will be investigated. Lumped pitch damping derivatives will be determined from the simulations.