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Sample records for highway traffic simulation

  1. Simulations of highway traffic with various degrees of automation

    SciTech Connect

    Doss, E.; Hanebutte, U.; Vitela, J.; Brown-VanHoozer, A.; Ewing, T.; Tentner, A.

    1996-10-01

    A traffic simulator to study highway traffic under various degrees of automation is being developed at Argonne National Laboratory (ANL). The key components of this simulator include a global and a local Expert Drive Mode, a human factor study and a graphical user interface. Further, an Autonomous Intelligent Cruise Control (AICC) which is based on a neural network controller is described and results for a typical driving scenario are given.

  2. Simulation study of traffic accidents on a three-lane highway

    NASA Astrophysics Data System (ADS)

    Chang, Jau-Yang; Lai, Wun-Cing

    2015-07-01

    Unsuitable driving behaviors often lead to the occurrence of traffic accidents. To reduce accidents and to prolong human life, simulated investigations are highly desirable to evaluate the effect of traffic safety in terms of number of traffic accidents. In this paper, a three-lane traffic flow model is proposed to analyze the probability of the occurrence of traffic accidents on highway. We define appropriate driving rules for the forward moving and lane changing of the vehicles. Three types of vehicle accidents are designed to investigate the relationships between different driving behaviors and traffic accidents. We simulate four road driving strategies, and compute the traffic flow, velocity, lane-changing frequency and the probability of the occurrence of traffic accidents for different road driving strategies. According to the simulation and analysis, it is shown that the probability of the occurrence of traffic accidents can be reduced by using the specified road driving strategies. Additionally, we found that the occurrence of traffic accidents can be avoided when the slow vehicles are suitably constrained to move on a three-lane highway.

  3. Theory and Simulation for Traffic Characteristics on the Highway with a Slowdown Section

    PubMed Central

    Xu, Dejie; Mao, Baohua; Rong, Yaping; Wei, Wei

    2015-01-01

    We study the traffic characteristics on a single-lane highway with a slowdown section using the deterministic cellular automaton (CA) model. Based on the theoretical analysis, the relationships among local mean densities, velocities, traffic fluxes, and global densities are derived. The results show that two critical densities exist in the evolutionary process of traffic state, and they are significant demarcation points for traffic phase transition. Furthermore, the changing laws of the two critical densities with different length of limit section are also investigated. It is shown that only one critical density appears if a highway is not slowdown section; nevertheless, with the growing length of slowdown section, one critical density separates into two critical densities; if the entire highway is slowdown section, they finally merge into one. The contrastive analysis proves that the analytical results are consistent with the numerical ones. PMID:26089864

  4. Theory and Simulation for Traffic Characteristics on the Highway with a Slowdown Section.

    PubMed

    Xu, Dejie; Mao, Baohua; Rong, Yaping; Wei, Wei

    2015-01-01

    We study the traffic characteristics on a single-lane highway with a slowdown section using the deterministic cellular automaton (CA) model. Based on the theoretical analysis, the relationships among local mean densities, velocities, traffic fluxes, and global densities are derived. The results show that two critical densities exist in the evolutionary process of traffic state, and they are significant demarcation points for traffic phase transition. Furthermore, the changing laws of the two critical densities with different length of limit section are also investigated. It is shown that only one critical density appears if a highway is not slowdown section; nevertheless, with the growing length of slowdown section, one critical density separates into two critical densities; if the entire highway is slowdown section, they finally merge into one. The contrastive analysis proves that the analytical results are consistent with the numerical ones.

  5. Traffic calming along rural highways crossing small urban communities: driving simulator experiment.

    PubMed

    Galante, Francesco; Mauriello, Filomena; Montella, Alfonso; Pernetti, Mariano; Aria, Massimo; D'Ambrosio, Antonio

    2010-11-01

    The paper investigated drivers' speed behaviour in a section of a rural highway crossing a small urban community in the existing scenario without any traffic calming device and in two different design scenarios with traffic calming in the urban community. Two gateways and four integrative traffic calming devices along the route within the urban area were tested. The gateways were aimed at slowing down the vehicles entering in the built-up area, while the traffic calming devices were aimed at complementing the gateway effect inside the built-up area. Two design options were tested: first option (alt1) is a combination of low cost measures, whereas the second option (alt2) is more expensive as includes a chicane and requires land acquisition. Drivers' behaviour was investigated by means of a driving simulator experiment. The VERA dynamic-driving simulator operating at the TEST Road Safety Laboratory located in Naples (Italy) was used. Simulation results were validated by the comparison of speed behaviour in the real world and in the driving simulator, in the scenario without traffic calming. Analysis of the driving simulator experiment results was performed using two different approaches: (a) explorative description of data by cluster analysis; (b) inferential procedures about population using statistical tests. Cluster analysis was carried out in order to test if the drivers' speed behaviour in the different design alternatives was substantially different. Statistical tests were performed in order to verify if speeds in specific sections were significantly different. Cluster analysis looked at speed profiles, whereas statistical tests looked at speed data in specific points. The obtained results showed a different behaviour of drivers approaching the urban community in the existing scenario and in the design scenarios. In the south direction, mean speed reduction ranging between 16 and 17 km/h, with 5% level of significance, was observed. In the north direction

  6. Coherent moving states in highway traffic

    NASA Astrophysics Data System (ADS)

    Helbing, Dirk; Huberman, Bernardo A.

    1998-12-01

    Advances in multiagent simulation techniques have made possible the study of realistic highway traffic patterns and have allowed theories based on driver behaviour to be tested. Such simulations display various empirical features of traffic flows, and are used to design traffic controls that maximize the throughput of vehicles on busy highways. In addition to its intrinsic economic value, vehicular traffic is of interest because it may be relevant to social phenomena in which diverse individuals compete with each other under certain constraints,. Here we report simulations of heterogeneous traffic which demonstrate that cooperative, coherent states can arise from competitive interactions between vehicles. As the density of vehicles increases, their interactions cause a transition into a highly correlated state in which all vehicles move with approximately the same speed, analogous to the motion of a solid block. This state is safer because it has a reduced lane-changing rate, and the traffic flow is high and stable. The coherent state disappears when the vehicle density exceeds a critical value. We observe the effect also in real Dutch traffic data.

  7. Highway Traffic Safety Manpower Functions Guide.

    ERIC Educational Resources Information Center

    Daugherty, Ronald D.; And Others

    The purpose of the project, "Revision and Update of Traffic Safety Manpower Training Program Development Guide," was to develop the HIGHWAY TRAFFIC SAFETY MANPOWER FUNCTIONS GUIDE. This document provides an organizational schema illustrating the functions essential to be performed and the interrelationship of these functions to carry out…

  8. Simulation study of traffic car accidents in single-lane highway

    NASA Astrophysics Data System (ADS)

    Bentaleb, Khalid; Lakouari, Noureddine; Marzoug, Rachid; Ez-Zahraouy, Hamid; Benyoussef, Abdelilah

    2014-11-01

    In this paper we numerically study the probability Pac of the occurrence of car accidents in the extended Nagel-Schreckenberg (NS) model in the case of mixture of fast (Vmax1=5) and slow vehicles (Vmax2=1) by taking also to the risky overtaking of fast vehicles. In comparison with previous existing models, we find that accidents can occur in the free traffic phase and/or congested one depending on the overtaking rate of fast vehicles. The effect of evacuation of damaged vehicles from the road with probabilities Pevf and Pevs of fast and slow vehicles respectively on the traffic flow behavior is also computed.

  9. Traffic Flow on a 3-LANE Highway

    NASA Astrophysics Data System (ADS)

    Chen, Wen-Yao; Huang, Ding-Wei; Huang, Wei-Neng; Hwang, Wen-Liang

    The traffic flow on a 3-lane highway is investigated using a cellular automaton method. Two different kinds of vehicles, cars and trucks, with different driving behaviors are presented on the highway. It is found that in the high density region, a control scheme requiring passing from the inner lane will enhance the traffic flow; while restricting the trucks to the outer lane will enhance the flow in the low density region and also has the benefit of suppressing the unnecessary lane-changing rate.

  10. Highway Safety Program Manual: Volume 10: Traffic Records.

    ERIC Educational Resources Information Center

    National Highway Traffic Safety Administration (DOT), Washington, DC.

    Volume 10 of the 19-volume Highway Safety Program Manual (which provides guidance to State and local governments on preferred highway safety practices) focuses on traffic records. The purpose and specific objectives of a traffic records program are discussed. Federal authority in the area of highway safety and policies regarding a traffic records…

  11. Highway Safety Program Manual: Volume 13: Traffic Engineering Services.

    ERIC Educational Resources Information Center

    National Highway Traffic Safety Administration (DOT), Washington, DC.

    Volume 13 of the 19-volume Highway Safety Program Manual (which provides guidance to State and local governments on preferred highway safety practices) focuses on traffic engineering services. The introduction outlines the purposes and objectives of Highway Safety Program Standard 13 and the Highway Safety Program Manual. Program development and…

  12. Highway Safety Program Manual: Volume 7: Traffic Courts.

    ERIC Educational Resources Information Center

    National Highway Traffic Safety Administration (DOT), Washington, DC.

    Volume 7 of the 19-volume Highway Safety Program Manual (which provides guidance to State and local governments on preferred highway safety practices) focuses on traffic courts, their purpose and objectives. Federal authority in the area of traffic courts are described. Program development and operations (a study of courts trying traffic cases, a…

  13. Highway Safety Program Manual: Volume 15: Police Traffic Services.

    ERIC Educational Resources Information Center

    National Highway Traffic Safety Administration (DOT), Washington, DC.

    Volume 15 of the 19-volume Highway Safety Program Manual (which provides guidance to State and local governments on preferred highway safety practices) focuses on police traffic services. The purpose and objectives of a police services program are described. Federal authority in the areas of highway safety and policies regarding a police traffic…

  14. Multi-scale traffic safety and operational performance study of large trucks on mountainous interstate highway.

    PubMed

    Chen, Suren; Chen, Feng; Wu, Jun

    2011-01-01

    In addition to multi-vehicle accidents, large trucks are also prone to single-vehicle accidents on the mountainous interstate highways due to the complex terrain and fast-changing weather. By integrating both historical data analysis and simulations, a multi-scale approach is developed to evaluate the traffic safety and operational performance of large trucks on mountainous interstate highways in both scales of individual vehicle as well as traffic on the whole highway. A typical mountainous highway in Colorado is studied for demonstration purposes. Firstly, the ten-year historical accident records are analyzed to identify the accident-vulnerable-locations (AVLs) and site-specific critical adverse driving conditions. Secondly, simulation-based single-vehicle assessment is performed for different driving conditions at those AVLs along the whole corridor. Finally, the cellular-automaton (CA)-based simulation is carried out to evaluate the multi-vehicle traffic safety as well as the operational performance of the traffic by considering the actual speed limits, including the differential speed limits (DSL) at some locations. It is found that the multi-scale approach can provide insightful and comprehensive observations of the highway performance, which is especially important for mountainous highways.

  15. Cellular Automaton Models of Highway Traffic Flow Considering Lane-Control and Speed-Control

    NASA Astrophysics Data System (ADS)

    Qian, Yong-Sheng; Li, Wen-Jun; Zeng, Jun-Wei; Wang, Min; Du, Jia-Wei; Guang, Xiao-Ping

    2011-10-01

    As two kinds of management modes of highway traffic control, lane-control, and speed-control produce different effect under different conditions. In this paper, traffic flow cellular automaton models for four-lane highway system with two opposing directions under the above two modes are established considering car and truck mixed running. Through computer numerical simulating, the fundamental diagrams with different parameters are obtained, and after the analysis of density-flux diagrams, the variation discipline of flux with traffic density under different control models is gained. The results indicate that, compared with lane-control, utilization ratio of road can be further improved with speed-control when the truck number increases. The research result is of great significance for reasonable providing theoretical guidance for highway traffic control.

  16. Failure of classical traffic flow theories: Stochastic highway capacity and automatic driving

    NASA Astrophysics Data System (ADS)

    Kerner, Boris S.

    2016-05-01

    In a mini-review Kerner (2013) it has been shown that classical traffic flow theories and models failed to explain empirical traffic breakdown - a phase transition from metastable free flow to synchronized flow at highway bottlenecks. The main objective of this mini-review is to study the consequence of this failure of classical traffic-flow theories for an analysis of empirical stochastic highway capacity as well as for the effect of automatic driving vehicles and cooperative driving on traffic flow. To reach this goal, we show a deep connection between the understanding of empirical stochastic highway capacity and a reliable analysis of automatic driving vehicles in traffic flow. With the use of simulations in the framework of three-phase traffic theory, a probabilistic analysis of the effect of automatic driving vehicles on a mixture traffic flow consisting of a random distribution of automatic driving and manual driving vehicles has been made. We have found that the parameters of automatic driving vehicles can either decrease or increase the probability of the breakdown. The increase in the probability of traffic breakdown, i.e., the deterioration of the performance of the traffic system can occur already at a small percentage (about 5%) of automatic driving vehicles. The increase in the probability of traffic breakdown through automatic driving vehicles can be realized, even if any platoon of automatic driving vehicles satisfies condition for string stability.

  17. Analysis of Yearly Traffic Fluctuation on Latvian Highways

    NASA Astrophysics Data System (ADS)

    Freimanis, A.; Paeglı¯tis, A.

    2015-11-01

    Average annual daily traffic and average annual truck traffic are two most used metrics for road management decisions. They are calculated from data gathered by continuous counting stations embedded in road pavement, manual counting sessions or mobile counting devices. Last two usually do not last longer than a couple of weeks so the information gathered is influenced by yearly traffic fluctuations. Data containing a total of 8,186,871 vehicles or 1989 days from 4 WIM stations installed on highways in Latvia were used in this study. Each of the files was supposed to contain data from only 1 day and additional data were deleted. No other data cleaning steps were performed, which increased the number of vehicles as counting systems sometimes split vehicles into two. Weekly traffic and weekly truck traffic was normalized against respective average values. Each weekly value was then plotted against its number in a year for better visual perception. Weekly traffic amplitudes were used to assess differences between different locations and standard deviations for fluctuation comparison of truck and regular traffic at the same location. Results show that truck traffic fluctuates more than regular traffic during a year, especially around holidays. Differences between counting locations were larger for regular traffic than truck traffic. These results show that average annual daily traffic could be influenced more if short term counting results are adjusted by factors derived from unsuitable continuous counting stations, but truck traffic is more influenced by the time of year in which counting is done.

  18. Basic Course in Highway Traffic Records; Course Guide.

    ERIC Educational Resources Information Center

    National Highway Traffic Safety Administration (DOT), Washington, DC.

    The twelve-part course is structured on a modular basis to allow the various topical areas and units of instruction to satisfy differing training requirements of state and local agencies which vary from state to state. It is specifically designed to provide guidence to state highway safety program management personnel, traffic records…

  19. Colleges and Universities Highway Traffic and Safety Centers.

    ERIC Educational Resources Information Center

    Aaron, James E., Ed.; Ritzel, Dale O., Ed.

    After consideration of the organizing of university safety centers and the growth and role of such centers in the future, descriptions are presented of the activities and practices in each of 16 existing college and university highway traffic and safety centers. Information is presented regarding center objectives, programs, staff composition,…

  20. Multilane simulations of traffic phases.

    PubMed

    Davis, L C

    2004-01-01

    The optimal velocity model, as modified by the author, is used in simulations of traffic on a dual-lane highway and a single-lane highway with an on-ramp. The equilibrium solutions of the modified model cover a two-dimensional region of flow-density space beneath the fundamental-diagram curve, rather than just lying on the curve as in the original model. Thus it satisfies a requirement of the three-phase model of Kerner [Phys. Rev. Lett. 81, 3797 (2002)]. Synchronization of velocity across dual lanes due to frequent lane changes is observed in free flow. True synchronized flow, as determined by the region of density-flow space it occupies, is obtained in on-ramp simulations with typical driver reaction times. A gradual change to the formation of a jam is observed for increasing delay times.

  1. 49 CFR 234.261 - Highway traffic signal pre-emption.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Highway traffic signal pre-emption. 234.261... Maintenance, Inspection, and Testing Inspections and Tests § 234.261 Highway traffic signal pre-emption. Highway traffic signal pre-emption interconnections, for which a railroad has maintenance...

  2. 49 CFR 234.261 - Highway traffic signal pre-emption.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Highway traffic signal pre-emption. 234.261 Section 234.261 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD....261 Highway traffic signal pre-emption. Highway traffic signal pre-emption interconnections, for...

  3. 49 CFR 234.261 - Highway traffic signal pre-emption.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Highway traffic signal pre-emption. 234.261... Maintenance, Inspection, and Testing Inspections and Tests § 234.261 Highway traffic signal pre-emption. Highway traffic signal pre-emption interconnections, for which a railroad has maintenance...

  4. 49 CFR 234.261 - Highway traffic signal pre-emption.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Highway traffic signal pre-emption. 234.261 Section 234.261 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD....261 Highway traffic signal pre-emption. Highway traffic signal pre-emption interconnections, for...

  5. 49 CFR 234.261 - Highway traffic signal pre-emption.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Highway traffic signal pre-emption. 234.261 Section 234.261 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD....261 Highway traffic signal pre-emption. Highway traffic signal pre-emption interconnections, for...

  6. Advanced traffic control strategies for intelligent vehicle highway systems

    NASA Astrophysics Data System (ADS)

    Gartner, Nathan H.; Stamatiadis, C.; Tarnoff, P. J.

    1995-01-01

    This paper discusses traffic signal control strategies that are suitable for advanced traffic management within IVHS (Intelligent Vehicle Highway Systems). The strategies consist of a multi-level design for the real-time, traffic-adaptive control of the urban signal network system. Each control level has different response characteristics, with the more advanced levels incorporating in a nested fashion the capabilities of the lower levels. A principal goal of the new multi-level design is to invoke a selected control strategy when it can provide the greatest benefit.

  7. Macroscopic modeling for traffic flow on three-lane highways

    NASA Astrophysics Data System (ADS)

    Chen, Jianzhong; Fang, Yuan

    2015-04-01

    In this paper, a macroscopic traffic flow model for three-lane highways is proposed. The model is an extension of the speed gradient model by taking into account the lane changing. The new source and sink terms of lane change rate are added into the continuity equations and the speed dynamic equations to describe the lane-changing behavior. The result of the steady state analysis shows that our model can describe the lane usage inversion phenomenon. The numerical results demonstrate that the present model effectively reproduces several traffic phenomena observed in real traffic such as shock and rarefaction waves, stop-and-go waves and local clusters.

  8. Highway traffic estimation of improved precision using the derivative-free nonlinear Kalman Filter

    NASA Astrophysics Data System (ADS)

    Rigatos, Gerasimos; Siano, Pierluigi; Zervos, Nikolaos; Melkikh, Alexey

    2015-12-01

    The paper proves that the PDE dynamic model of the highway traffic is a differentially flat one and by applying spatial discretization its shows that the model's transformation into an equivalent linear canonical state-space form is possible. For the latter representation of the traffic's dynamics, state estimation is performed with the use of the Derivative-free nonlinear Kalman Filter. The proposed filter consists of the Kalman Filter recursion applied on the transformed state-space model of the highway traffic. Moreover, it makes use of an inverse transformation, based again on differential flatness theory which enables to obtain estimates of the state variables of the initial nonlinear PDE model. By avoiding approximate linearizations and the truncation of nonlinear terms from the PDE model of the traffic's dynamics the proposed filtering methods outperforms, in terms of accuracy, other nonlinear estimators such as the Extended Kalman Filter. The article's theoretical findings are confirmed through simulation experiments.

  9. Simple cellular automaton model for traffic breakdown, highway capacity, and synchronized flow

    NASA Astrophysics Data System (ADS)

    Kerner, Boris S.; Klenov, Sergey L.; Schreckenberg, Michael

    2011-10-01

    We present a simple cellular automaton (CA) model for two-lane roads explaining the physics of traffic breakdown, highway capacity, and synchronized flow. The model consists of the rules “acceleration,” “deceleration,” “randomization,” and “motion” of the Nagel-Schreckenberg CA model as well as “overacceleration through lane changing to the faster lane,” “comparison of vehicle gap with the synchronization gap,” and “speed adaptation within the synchronization gap” of Kerner's three-phase traffic theory. We show that these few rules of the CA model can appropriately simulate fundamental empirical features of traffic breakdown and highway capacity found in traffic data measured over years in different countries, like characteristics of synchronized flow, the existence of the spontaneous and induced breakdowns at the same bottleneck, and associated probabilistic features of traffic breakdown and highway capacity. Single-vehicle data derived in model simulations show that synchronized flow first occurs and then self-maintains due to a spatiotemporal competition between speed adaptation to a slower speed of the preceding vehicle and passing of this slower vehicle. We find that the application of simple dependences of randomization probability and synchronization gap on driving situation allows us to explain the physics of moving synchronized flow patterns and the pinch effect in synchronized flow as observed in real traffic data.

  10. Simple cellular automaton model for traffic breakdown, highway capacity, and synchronized flow.

    PubMed

    Kerner, Boris S; Klenov, Sergey L; Schreckenberg, Michael

    2011-10-01

    We present a simple cellular automaton (CA) model for two-lane roads explaining the physics of traffic breakdown, highway capacity, and synchronized flow. The model consists of the rules "acceleration," "deceleration," "randomization," and "motion" of the Nagel-Schreckenberg CA model as well as "overacceleration through lane changing to the faster lane," "comparison of vehicle gap with the synchronization gap," and "speed adaptation within the synchronization gap" of Kerner's three-phase traffic theory. We show that these few rules of the CA model can appropriately simulate fundamental empirical features of traffic breakdown and highway capacity found in traffic data measured over years in different countries, like characteristics of synchronized flow, the existence of the spontaneous and induced breakdowns at the same bottleneck, and associated probabilistic features of traffic breakdown and highway capacity. Single-vehicle data derived in model simulations show that synchronized flow first occurs and then self-maintains due to a spatiotemporal competition between speed adaptation to a slower speed of the preceding vehicle and passing of this slower vehicle. We find that the application of simple dependences of randomization probability and synchronization gap on driving situation allows us to explain the physics of moving synchronized flow patterns and the pinch effect in synchronized flow as observed in real traffic data.

  11. Highway traffic noise prediction based on GIS

    NASA Astrophysics Data System (ADS)

    Zhao, Jianghua; Qin, Qiming

    2014-05-01

    Before building a new road, we need to predict the traffic noise generated by vehicles. Traditional traffic noise prediction methods are based on certain locations and they are not only time-consuming, high cost, but also cannot be visualized. Geographical Information System (GIS) can not only solve the problem of manual data processing, but also can get noise values at any point. The paper selected a road segment from Wenxi to Heyang. According to the geographical overview of the study area and the comparison between several models, we combine the JTG B03-2006 model and the HJ2.4-2009 model to predict the traffic noise depending on the circumstances. Finally, we interpolate the noise values at each prediction point and then generate contours of noise. By overlaying the village data on the noise contour layer, we can get the thematic maps. The use of GIS for road traffic noise prediction greatly facilitates the decision-makers because of GIS spatial analysis function and visualization capabilities. We can clearly see the districts where noise are excessive, and thus it becomes convenient to optimize the road line and take noise reduction measures such as installing sound barriers and relocating villages and so on.

  12. Mechanisms for spatio-temporal pattern formation in highway traffic models.

    PubMed

    Wilson, R Eddie

    2008-06-13

    A key qualitative requirement for highway traffic models is the ability to replicate a type of traffic jam popularly referred to as a phantom jam, shock wave or stop-and-go wave. Despite over 50 years of modelling, the precise mechanisms for the generation and propagation of stop-and-go waves and the associated spatio-temporal patterns are in dispute. However, the increasing availability of empirical datasets, such as those collected from motorway incident detection and automatic signalling system (MIDAS) inductance loops in the UK or the next-generation simulation trajectory data (NGSIM) project in the USA, means that we can expect to resolve these questions definitively in the next few years. This paper will survey the essence of the competing explanations of highway traffic pattern formation and introduce and analyse a new mechanism, based on dynamical systems theory and bistability, which can help resolve the conflict.

  13. Assessment of Traffic Noise on Highway Passing from Urban Agglomeration

    NASA Astrophysics Data System (ADS)

    Vijay, Ritesh; Kori, Chandan; Kumar, Manoj; Chakrabarti, T.; Gupta, Rajesh

    2014-09-01

    Assessment of traffic noise pollution in developing countries is complex due to heterogeneity in traffic conditions like traffic volume, road width, honking, etc. To analyze the impact of such variables, a research study was carried out on a national highway passing from an urban agglomeration. Traffic volume and noise levels (L10, Lmin, Lmax, Leq and L90) were measured during morning and evening peak hours. Contribution of noise by individual vehicle was estimated using passenger car noise unit. Extent of noise pollution and impact of noisy vehicles were estimated using noise pollution level and traffic noise index, respectively. Noise levels were observed to be above the prescribed Indian and International standards. As per audio spectrum analysis of traffic noise, honking contributed an additional 3-4 dB(A) noise. Based on data analysis, a positive relationship was observed between noise levels and honking while negative correlation was observed between noise levels and road width. The study suggests that proper monitoring and analysis of traffic data is required for better planning of noise abatement measures.

  14. Risk factors in highway traffic accidents: a case control study.

    PubMed

    Hijar, M; Carrillo, C; Flores, M; Anaya, R; Lopez, V

    2000-09-01

    The objective of this study was to identify risk factors related to the driver, the vehicle and the environment, that are associated with motor vehicles accidents on highways. A case and control design was used where the case was: the driver of a motor vehicle who was involved in an accident while traveling on the Mexico-Cuernavaca highway; and the control was: the driver or a motor vehicle who, traveling on the highway, completed the trip without being involved in a traffic accident. Risk factors associated with the occurrence of a traffic accident (P > 0.05) were: age under 25 years, frequent travel, traveling to work, alcohol consumption, driving during the daylight, on a week-day, under adverse weather conditions and in the Mexico Cuernavaca direction of road. Risks adjusted by logistic regression were: age under 25 years odds ratio (OR) 3.01, confidence interval (CI) (95%) 1.46-6.18; work as a travel reason OR 1.74, CI 1.06 2.86; alcohol intake OR 4.70, Cl 1.62 13.6; driving under adverse weather conditions OR 5.70, CI 3.66-8.85; traveling on a week-day OR 1.84, CI 1.14-2.94; during daylight hours OR 4.23, CI 2.36-7.58 and in the Mexico Cuernavaca direction of road OR 2.69, CI 1.67 4.32. The identification of factors associated with the risk of being involved in a highway traffic accident allows us to propose primary prevention measures for this important public health problem.

  15. Field experimental study of traffic-induced turbulence on highways

    NASA Astrophysics Data System (ADS)

    Alonso-Estébanez, A.; Pascual-Muñoz, P.; Yagüe, C.; Laina, R.; Castro-Fresno, D.

    2012-12-01

    This paper is focused on traffic-induced turbulence (TIT) analysis from a field campaign performed in 2011, using ultrasonic anemometers deployed in the M-12 Highways, Madrid (Spain). The study attempts to improve knowledge about the influence of traffic-related parameters on turbulence. Linear relationships between vehicle speed and turbulent kinetic energy (TKE) values are found with coefficients of determination (R2) of 0.75 and 0.55 for the lorry and van respectively. The vehicle-induced fluctuations in the wind components (u‧, v‧ and w‧) showed the highest values for the longitudinal component (v) because of the wake-passing effect. In the analysis of wake produced by moving vehicles it is indicated how the turbulence dissipates in relation to a distance d and height h. The TKE values were found to be higher at the measuring points closer to the surface during the wake analysis.

  16. 49 CFR 1.95 - Delegations to the National Highway Traffic Safety Administrator.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Secretary by 49 U.S.C. 20134(a) with respect to laws administered by the National Highway Traffic Safety... legislators to consider proposals related to safety belt use laws. The National Highway Traffic Safety... the Clean Air Act, Public Law 90-148, as amended . (i) Carry out the following functions and exercise...

  17. The Traffic Adaptive Data Dissemination (TrAD) Protocol for both Urban and Highway Scenarios

    PubMed Central

    Tian, Bin; Hou, Kun Mean; Zhou, Haiying

    2016-01-01

    The worldwide economic cost of road crashes and injuries is estimated to be US$518 billion per year and the annual congestion cost in France is estimated to be €5.9 billion. Vehicular Ad hoc Networks (VANETs) are one solution to improve transport features such as traffic safety, traffic jam and infotainment on wheels, where a great number of event-driven messages need to be disseminated in a timely way in a region of interest. In comparison with traditional wireless networks, VANETs have to consider the highly dynamic network topology and lossy links due to node mobility. Inter-Vehicle Communication (IVC) protocols are the keystone of VANETs. According to our survey, most of the proposed IVC protocols focus on either highway or urban scenarios, but not on both. Furthermore, too few protocols, considering both scenarios, can achieve high performance. In this paper, an infrastructure-less Traffic Adaptive data Dissemination (TrAD) protocol which takes into account road traffic and network traffic status for both highway and urban scenarios will be presented. TrAD has double broadcast suppression techniques and is designed to adapt efficiently to the irregular road topology. The performance of the TrAD protocol was evaluated quantitatively by means of realistic simulations taking into account different real road maps, traffic routes and vehicular densities. The obtained simulation results show that TrAD is more efficient in terms of packet delivery ratio, number of transmissions and delay in comparison with the performance of three well-known reference protocols. Moreover, TrAD can also tolerate a reasonable degree of GPS drift and still achieve efficient data dissemination. PMID:27338393

  18. The Traffic Adaptive Data Dissemination (TrAD) Protocol for both Urban and Highway Scenarios.

    PubMed

    Tian, Bin; Hou, Kun Mean; Zhou, Haiying

    2016-06-21

    The worldwide economic cost of road crashes and injuries is estimated to be US$518 billion per year and the annual congestion cost in France is estimated to be €5.9 billion. Vehicular Ad hoc Networks (VANETs) are one solution to improve transport features such as traffic safety, traffic jam and infotainment on wheels, where a great number of event-driven messages need to be disseminated in a timely way in a region of interest. In comparison with traditional wireless networks, VANETs have to consider the highly dynamic network topology and lossy links due to node mobility. Inter-Vehicle Communication (IVC) protocols are the keystone of VANETs. According to our survey, most of the proposed IVC protocols focus on either highway or urban scenarios, but not on both. Furthermore, too few protocols, considering both scenarios, can achieve high performance. In this paper, an infrastructure-less Traffic Adaptive data Dissemination (TrAD) protocol which takes into account road traffic and network traffic status for both highway and urban scenarios will be presented. TrAD has double broadcast suppression techniques and is designed to adapt efficiently to the irregular road topology. The performance of the TrAD protocol was evaluated quantitatively by means of realistic simulations taking into account different real road maps, traffic routes and vehicular densities. The obtained simulation results show that TrAD is more efficient in terms of packet delivery ratio, number of transmissions and delay in comparison with the performance of three well-known reference protocols. Moreover, TrAD can also tolerate a reasonable degree of GPS drift and still achieve efficient data dissemination.

  19. The research of highway traffic accident management and pre-alarm system

    NASA Astrophysics Data System (ADS)

    Xu, Jianping; Zhang, Tiejun; Wan, Jiaonan; Zhang, Juwen; Wang, Rui

    For the rigorous traffic safety issues resulting from rapid transportation development, as well as the more and more attention paid to the traffic accidents dynamic analysis and pre-alarm methods, combined with the practical needs of the highway safety management, this paper summarizes the experience of traffic safety pre-alarm research both in domestic and abroad, designs the frame of highway traffic accident management and pre-alarm system from the function and software engineering requirement, and refines kernel modules such as accident prone section judgement, traffic safety pre-alarm analysis and perfecting safety measures analysis, in order to guide the exploitation and application of the system.

  20. Large scale traffic simulations

    SciTech Connect

    Nagel, K.; Barrett, C.L. |; Rickert, M. |

    1997-04-01

    Large scale microscopic (i.e. vehicle-based) traffic simulations pose high demands on computational speed in at least two application areas: (i) real-time traffic forecasting, and (ii) long-term planning applications (where repeated {open_quotes}looping{close_quotes} between the microsimulation and the simulated planning of individual person`s behavior is necessary). As a rough number, a real-time simulation of an area such as Los Angeles (ca. 1 million travellers) will need a computational speed of much higher than 1 million {open_quotes}particle{close_quotes} (= vehicle) updates per second. This paper reviews how this problem is approached in different projects and how these approaches are dependent both on the specific questions and on the prospective user community. The approaches reach from highly parallel and vectorizable, single-bit implementations on parallel supercomputers for Statistical Physics questions, via more realistic implementations on coupled workstations, to more complicated driving dynamics implemented again on parallel supercomputers. 45 refs., 9 figs., 1 tab.

  1. a Markov-Process Inspired CA Model of Highway Traffic

    NASA Astrophysics Data System (ADS)

    Wang, Fa; Li, Li; Hu, Jian-Ming; Ji, Yan; Ma, Rui; Jiang, Rui

    To provide a more accurate description of the driving behaviors especially in car-following, namely a Markov-Gap cellular automata model is proposed in this paper. It views the variation of the gap between two consequent vehicles as a Markov process whose stationary distribution corresponds to the observed gap distribution. This new model provides a microscopic simulation explanation for the governing interaction forces (potentials) between the queuing vehicles, which cannot be directly measurable for traffic flow applications. The agreement between empirical observations and simulation results suggests the soundness of this new approach.

  2. PLUS highway network analysis: Case of in-coming traffic burden in 2013

    NASA Astrophysics Data System (ADS)

    Asrah, Norhaidah Mohd; Djauhari, Maman Abdurachman; Mohamad, Ismail

    2017-05-01

    PLUS highway is the largest concessionary in Malaysia. The study on PLUS highway development, in order to overcome the demand for efficient road transportation, is crucial. If the highways have better interconnected network, it will help the economic activities such as trade to increase. If economic activities are increasing, the benefit will come to the people and state. In its turn, it will help the leaders to plan and conduct national development program. In this paper, network analysis approach will be used to study the in-coming traffic burden during the year of 2013. The highway network linking all the toll plazas is a dynamic network. The objective of this study is to learn and understand about highway network in terms of the in-coming traffic burden entering to each toll plazas along PLUS highway. For this purpose, the filtered network topology based on the forest of all possible minimum spanning trees is used. The in-coming traffic burden of a city is represented by the number of cars passing through the corresponding toll plaza. To interpret the filtered network, centrality measures such as degree centrality, betweenness centrality, closeness centrality, eigenvector centrality are used. An overall centrality will be proposed if those four measures are assumed to have the same role. Based on the results, some suggestions and recommendations for PLUS highway network development will be delivered to PLUS highway management.

  3. Dollars for lives: the effect of highway capital investments on traffic fatalities.

    PubMed

    Nguyen-Hoang, Phuong; Yeung, Ryan

    2014-12-01

    This study examines the effect of highway capital investments on highway fatalities. We used state-level data from the 48 contiguous states in the United States from 1968 through 2010 to estimate the effects on highway fatalities of capital expenditures and highway capital stock. We estimated these effects by controlling for a set of control variables together with state and year dummy variables and state-specific linear time trends. We found that capital expenditures and capital stock had significant and negative effects on highway fatalities. States faced with declines in gas tax revenues have already cut back drastically on spending on roads including on maintenance and capital outlay. If this trend continues, it may undermine traffic safety. While states and local governments are currently fiscally strained, it is important for them to continue investments in roadways to enhance traffic safety and, more significantly, to save lives. Copyright © 2014 National Safety Council and Elsevier Ltd. All rights reserved.

  4. Basic Course in Highway Traffic Records. Student Guide.

    ERIC Educational Resources Information Center

    National Highway Traffic Safety Administration (DOT), Washington, DC.

    This course in Traffic Records will introduce the student to the basic concepts of an integrated State Traffic Records System. The course is built around the Design Manual for State Traffic Records Systems. The pertinent parts of the design manual have not been reproduced with this study guide but are referenced in the introductory pages for each…

  5. Highway Car Traffic as a Complex System: The Physicist's Point of View

    SciTech Connect

    Boccara, Nino

    2005-04-20

    A simple cellular automaton model of highway car traffic flow will be presented. This system exhibits a second-order phase transition between the free-moving phase and the jammed phase. Using concepts borrowed from the theory of phase transitions in statistical physics, it can be shown that random braking is the symmetry-breaking field conjugate to the order parameter. For a given value of the speed limit, it is then possible to determine the values of the usual critical exponents using computer simulations. These numerical results can also be obtained within the framework of an approximate technique going beyond the mean-field approximation. It can be shown that the critical exponents satisfy a scaling relation, which can be derived assuming that the order parameter is a generalized homogeneous function in the vicinity of the phase transition point.

  6. Traffic flow through multi-lane tollbooths on a toll highway

    NASA Astrophysics Data System (ADS)

    Komada, Kazuhito; Nagatani, Takashi

    2010-06-01

    We study the traffic states and queuing occurring in traffic flow on a toll highway with multi-lane tollgates. The traffic states change with increasing density and varying number of tollgates. When the manual-collection vehicles sort themselves into the tollgates, the queues occur just in front of the tollgates if the vehicular density is higher than a critical value. The queuing in front of tollgates is induced by the competition between the lane expansion and slowdown effects. When the lane expansion effect is superior to the slowdown effect, no queuing occurs. We derive the fundamental diagrams (current-density diagrams) for the traffic flow on the toll highway. The current saturates at the nearest tollgate at a low density and the saturation extends to the next-nearest tollgate with increasing density.

  7. Hunting at the highway: traffic noise reduces foraging efficiency in acoustic predators.

    PubMed

    Siemers, Björn M; Schaub, Andrea

    2011-06-07

    Noise pollution from human traffic networks and industrial activity impacts vast areas of our planet. While anthropogenic noise effects on animal communication are well documented, we have very limited understanding of noise impact on more complex ecosystem processes, such as predator-prey interactions, albeit urgently needed to devise mitigation measures. Here, we show that traffic noise decreases the foraging efficiency of an acoustic predator, the greater mouse-eared bat (Myotis myotis). These bats feed on large, ground-running arthropods that they find by listening to their faint rustling sounds. We measured the bats' foraging performance on a continuous scale of acoustically simulated highway distances in a behavioural experiment, designed to rule out confounding factors such as general noise avoidance. Successful foraging bouts decreased and search time drastically increased with proximity to the highway. At 7.5 m to the road, search time was increased by a factor of five. From this increase, we predict a 25-fold decrease in surveyed ground area and thus in foraging efficiency for a wild bat. As most of the bats' prey are predators themselves, the noise impact on the bats' foraging performance will have complex effects on the food web and ultimately on the ecosystem stability. Similar scenarios apply to other ecologically important and highly protected acoustic predators, e.g. owls. Our study provides the empirical basis for quantitative predictions of anthropogenic noise impacts on ecosystem processes. It highlights that an understanding of the effects of noise emissions and other forms of 'sensory pollution' are crucially important for the assessment of environmental impact of human activities.

  8. Hunting at the highway: traffic noise reduces foraging efficiency in acoustic predators

    PubMed Central

    Siemers, Björn M.; Schaub, Andrea

    2011-01-01

    Noise pollution from human traffic networks and industrial activity impacts vast areas of our planet. While anthropogenic noise effects on animal communication are well documented, we have very limited understanding of noise impact on more complex ecosystem processes, such as predator–prey interactions, albeit urgently needed to devise mitigation measures. Here, we show that traffic noise decreases the foraging efficiency of an acoustic predator, the greater mouse-eared bat (Myotis myotis). These bats feed on large, ground-running arthropods that they find by listening to their faint rustling sounds. We measured the bats' foraging performance on a continuous scale of acoustically simulated highway distances in a behavioural experiment, designed to rule out confounding factors such as general noise avoidance. Successful foraging bouts decreased and search time drastically increased with proximity to the highway. At 7.5 m to the road, search time was increased by a factor of five. From this increase, we predict a 25-fold decrease in surveyed ground area and thus in foraging efficiency for a wild bat. As most of the bats' prey are predators themselves, the noise impact on the bats' foraging performance will have complex effects on the food web and ultimately on the ecosystem stability. Similar scenarios apply to other ecologically important and highly protected acoustic predators, e.g. owls. Our study provides the empirical basis for quantitative predictions of anthropogenic noise impacts on ecosystem processes. It highlights that an understanding of the effects of noise emissions and other forms of ‘sensory pollution’ are crucially important for the assessment of environmental impact of human activities. PMID:21084347

  9. Altered pulmonary function in children with asthma associated with highway traffic near residence.

    PubMed

    Margolis, Helene G; Mann, Jennifer K; Lurmann, Frederick W; Mortimer, Kathleen M; Balmes, John R; Hammond, S Katharine; Tager, Ira B

    2009-04-01

    Cross-sectional analyses were conducted to evaluate the effects of exposure to highway traffic on pulmonary function in Fresno, California. Traffic and spirometry data were available for 214 children (enrollment ages six to 11 years). Multiple linear regression was used to evaluate the relations between pulmonary function and traffic parameters. Heavy-duty vehicle count was used as a surrogate measure for diesel-related exposures. Pulmonary function was non-significantly associated with longer distance-to-road and non-significantly associated with higher traffic intensity. Evaluation of effect modification by FEF(25-75)/FVC (a measure of intrinsic airway size) showed that all pulmonary function measures of flow were significantly inversely related to a traffic metric that incorporates traffic intensity and roadway proximity. The results indicate that residence proximity to highway traffic is associated with lower pulmonary function among children with asthma, and smaller airway size is an important modifier of the effect of traffic exposure on pulmonary function and a marker of increased susceptibility.

  10. 49 CFR 1.50 - Delegation to the National Highway Traffic Safety Administrator.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 1 2011-10-01 2011-10-01 false Delegation to the National Highway Traffic Safety Administrator. 1.50 Section 1.50 Transportation Office of the Secretary of Transportation ORGANIZATION AND...) Section 2014, first responder vehicle safety program; (14) Section 2015, driver performance study; (15...

  11. 49 CFR 1.95 - Delegations to the National Highway Traffic Safety Administrator.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... program to prohibit racial profiling; (2) Section 2001(d) , relating to transfers of funds; (3) Section... program; (16) Section 2017(a), relating to older driver safety and, (b) , relating to law enforcement... Secretary by 49 U.S.C. 20134(a) with respect to laws administered by the National Highway Traffic Safety...

  12. The physics of empirical nuclei for spontaneous traffic breakdown in free flow at highway bottlenecks

    NASA Astrophysics Data System (ADS)

    Kerner, Boris S.; Koller, Micha; Klenov, Sergey L.; Rehborn, Hubert; Leibel, Michael

    2015-11-01

    Based on an empirical study of real field traffic data measured in 1996-2014 through road detectors installed on German freeways, we reveal physical features of empirical nuclei for spontaneous traffic breakdown in free flow at highway bottlenecks. A microscopic stochastic three-phase traffic model of the nucleation of spontaneous traffic breakdown presented in the article explains the empirical findings. It turns out that in the most cases a nucleus for the breakdown occurs through an interaction of one of waves in free flow with an empirical permanent speed disturbance localized at a highway bottleneck. The wave is a localized structure in free flow, in which the total flow rate is larger and the speed averaged across the highway is smaller than outside the wave. The waves in free flow appear due to oscillations in the percentage of slow vehicles; these waves propagate with the average speed of slow vehicles in free flow. Any of the empirical waves exhibits a two-dimensional asymmetric spatiotemporal structure: Wave's characteristics are different in different highway lanes.

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

    PubMed

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

    2017-02-17

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

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

    PubMed Central

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

    2017-01-01

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

  15. Traffic flow on a toll highway with electronic and traditional tollgates

    NASA Astrophysics Data System (ADS)

    Komada, Kazuhito; Masukura, Shuichi; Nagatani, Takashi

    2009-12-01

    We study the traffic states and jams occurring in traffic flow on a two-lane toll highway with electronic and manual (traditional) tollgates. The electronic and manual collection vehicles sort themselves into their respective lanes at low density, while they mix at each tollgate at high density. We derive the fundamental diagrams (flow-density diagrams) for the electronic and manual collection vehicles. The traffic states change with increasing density and varying the ratio. Dynamical phase transitions occur. It is shown that the fundamental diagrams for the two tollgates depend greatly on the density and fraction of both vehicles.

  16. Basic Course in Highway Traffic Records. Instructor's Guide.

    ERIC Educational Resources Information Center

    National Highway Traffic Safety Administration (DOT), Washington, DC.

    The scope and content of this traffic records course are outlined in a chart (Course Structure) and tabulation (Overview of Course Content). General course objectives follow the overview. These define for the instructor the broad objectives, module by module, which the course is designed to reach. The last part of this section gives a detailed…

  17. Alternative method of highway traffic safety analysis for developing countries using delphi technique and Bayesian network.

    PubMed

    Mbakwe, Anthony C; Saka, Anthony A; Choi, Keechoo; Lee, Young-Jae

    2016-08-01

    Highway traffic accidents all over the world result in more than 1.3 million fatalities annually. An alarming number of these fatalities occurs in developing countries. There are many risk factors that are associated with frequent accidents, heavy loss of lives, and property damage in developing countries. Unfortunately, poor record keeping practices are very difficult obstacle to overcome in striving to obtain a near accurate casualty and safety data. In light of the fact that there are numerous accident causes, any attempts to curb the escalating death and injury rates in developing countries must include the identification of the primary accident causes. This paper, therefore, seeks to show that the Delphi Technique is a suitable alternative method that can be exploited in generating highway traffic accident data through which the major accident causes can be identified. In order to authenticate the technique used, Korea, a country that underwent similar problems when it was in its early stages of development in addition to the availability of excellent highway safety records in its database, is chosen and utilized for this purpose. Validation of the methodology confirms the technique is suitable for application in developing countries. Furthermore, the Delphi Technique, in combination with the Bayesian Network Model, is utilized in modeling highway traffic accidents and forecasting accident rates in the countries of research.

  18. Cellular automata for traffic simulations

    NASA Astrophysics Data System (ADS)

    Wolf, Dietrich E.

    1999-02-01

    Traffic phenomena such as the transition from free to congested flow, lane inversion and platoon formation can be accurately reproduced using cellular automata. Being computationally extremely efficient, they simulate large traffic systems many times faster than real time so that predictions become feasible. A riview of recent results is given. The presence of metastable states at the jamming transition is discussed in detail. A simple new cellular automation is introduced, in which the interaction between cars is Galilei-invariant. It is shown that this type of interaction accounts for metastable states in a very natural way.

  19. Modeling highway-traffic headway distributions using superstatistics.

    PubMed

    Abul-Magd, A Y

    2007-11-01

    We study traffic clearance distributions (i.e., the instantaneous gap between successive vehicles) and time-headway distributions by applying the Beck and Cohen superstatistics. We model the transition from free phase to congested phase with the increase of vehicle density as a transition from the Poisson statistics to that of the random-matrix theory. We derive an analytic expression for the spacing distributions that interpolates from the Poisson distribution and Wigner's surmise and apply it to the distributions of the net distance and time gaps among the succeeding cars at different densities of traffic flow. The obtained distribution fits the experimental results for single-vehicle data of the Dutch freeway A9 and the German freeway A5.

  20. Effect of desired speed variability on highway traffic flow

    NASA Astrophysics Data System (ADS)

    Lipshtat, Azi

    2009-06-01

    Traffic flow is a function of many natural, environmental, and human factors. Not only that weather and road condition can vary, but drivers’ decisions and policies also can affect the flow. Here we analyze the effect of distribution of desired speeds. We show that a broader distribution can reduce the flow efficiency and increase congestions. Since different drivers react differently to changes in weather or road conditions, such a change leads to a change in desired speed distribution as well. As a result, nonintuitive changes in traffic flow may occur. Besides providing insight and analyzing the underlying mechanism of a collective phenomenon, this example sheds light on a fundamental aspect of computational modeling. Although “mean-field” models that deal with average values only and ignore variability are simpler and easier to analyze, they can very easily turn into oversimplifications and miss relevant qualitative phenomena.

  1. Effect of desired speed variability on highway traffic flow.

    PubMed

    Lipshtat, Azi

    2009-06-01

    Traffic flow is a function of many natural, environmental, and human factors. Not only that weather and road condition can vary, but drivers' decisions and policies also can affect the flow. Here we analyze the effect of distribution of desired speeds. We show that a broader distribution can reduce the flow efficiency and increase congestions. Since different drivers react differently to changes in weather or road conditions, such a change leads to a change in desired speed distribution as well. As a result, nonintuitive changes in traffic flow may occur. Besides providing insight and analyzing the underlying mechanism of a collective phenomenon, this example sheds light on a fundamental aspect of computational modeling. Although "mean-field" models that deal with average values only and ignore variability are simpler and easier to analyze, they can very easily turn into oversimplifications and miss relevant qualitative phenomena.

  2. Drowsy drivers--medical implication of highway traffic safety.

    PubMed

    Pant, S

    2011-01-01

    The estimates of the contribution of drowsiness and fatigue to the number of road crashes is often neglected considerably, due both to under-reporting of these factors by drivers, and technical difficulty in investigating the problem. Preventing and treating the reasons for falling asleep behind the wheel may have considerable contribution in traffic safety. Therefore the licensing authorities in co-operation with the medical profession should attend more closely to the issue of sleep related disorders and their implications for driving in cases with notoriously high risk. The police and other enforcement authorities need appropriate knowledge and procedures to detect drivers at risk of falling asleep while driving. Considering the increasing number of road traffic accidents day per day, it is a need of the hour to detect drivers possibly at risk, and to take appropriate precautions in terms of education, advice and treatment regimes, as well as restrictions on licensing.

  3. Traffic-related air quality assessment for open road tolling highway facility.

    PubMed

    Lin, Jie; Yu, Dan

    2008-09-01

    Open road tolling (ORT) design has been considered as an effective means of smoothing highway traffic and reducing travel delay on toll highways. In this paper it is demonstrated that ORT can also achieve significant air quality benefits over the conventional toll plaza design. The near roadside carbon monoxide (CO) concentration levels can be reduced by up to 37%, and diesel particulate matter (DPM) emissions can decrease by as much as 58%. These large expected air quality benefits have great implications to the regional efforts of reducing mobile source air pollution toward achieving attainment status and healthier living environment.

  4. A study on traffic weaving segment level of service on Malaysia urban highway

    NASA Astrophysics Data System (ADS)

    Abdullah, Rohaya; Sadullah, Ahmad Farhan Mohd

    2017-07-01

    The objective of this research is to observe weaving problems, analyze the capacity of the weaving segment and to identify the behavior of the Malaysian driver at urban freeway weaving segment. Field data collected during non - peak hours at km. 138.6-138.2 (north bound) Seberang Jaya: Penang Bridge, km.16.8 to km.17.0 Sunway Mentari: Damansara-Puchong Highway and km.21.4 to km.21.9 Puchong Intan: Damansara-Puchong Highway. These segments behave as a bottleneck during peak hour. The data collected are traffic volume, vehicle composition and the road geometry. The drivers behavior pattern at the freeway weaving segment is observed. This research analyses by two different methodologies, the first analysis is by referring to the US Highway Capacity Manual 2010 and the second analysis through a modified method to suit the local traffic composition. The consideration of motorcycle and light heavy vehicle in the analysis lead to a different evaluation of weaving segment capacity. The analysis results show a slight difference between both methods. LOS, weaving speed and density prediction by the modified method is slightly higher than the HCM method. These results, suggest that the numbers of light heavy vehicle and motorcycle contribute to the amount of traffic volume because the value factors of Passenger Car Equivalent (PCE). The adoption of the widely used method without taking consideration of local traffic condition, might lead to improper road planning or design or road operation management.

  5. Highway traffic segmentation using super-resolution and Gaussian mixture model

    NASA Astrophysics Data System (ADS)

    Yousef, Amr Hussein; Flora, Jeff; Iftekharuddin, Khan

    2013-09-01

    One benefit of employing computer vision techniques to extract individual vehicles from a highway traffic scene is the abundance of networked, traffic surveillance cameras that may be leveraged as the input video. However, the acquisition sensors that are monitoring the highway traffic will have very limited quality. Additionally, video streams are heavily compressed, causing noise and, in some cases, visible artifacts to be introduced into the video. Further challenges are presented by external environmental and weather conditions, such as rain, fog, and snow, that cause video blurring or noise. The resulting output of a segmentation algorithm yields poorer results, with many vehicles undetected or partially detected. Our goal is to extract individual vehicles from a highway traffic scenes using super-resolution and the utilization of Gaussian mixture model algorithm (GMM). We used a speeded-up enhanced stochastic Wiener filter for SR reconstruction and restoration. It can be used to remove artifacts and enhance the visual quality of the reconstructed images and can be implemented efficiently in the frequency domain. The filter derivation depends on the continuous-discrete-continuous (CDC) model that represents most of the degradations encountered during the image-gathering and image-display processes. Then, we use GMM followed by the clustering of individual vehicles. Individual vehicles are detected from the segmented scene through the use of a series of morphological operations, followed by two-dimensional connected component labeling. We evaluate our hybrid approach quantitatively in the segmentation of the extracted vehicles.

  6. PM10 source apportionment in a Swiss Alpine valley impacted by highway traffic.

    PubMed

    Ducret-Stich, Regina E; Tsai, Ming-Yi; Thimmaiah, Devraj; Künzli, Nino; Hopke, Philip K; Phuleria, Harish C

    2013-09-01

    Although trans-Alpine highway traffic exhaust is one of the major sources of air pollution along the highway valleys of the Alpine regions, little is known about its contribution to residential exposure and impact on respiratory health. In this paper, source-specific contributions to particulate matter with an aerodynamic diameter < 10 μm (PM10) and their spatio-temporal distribution were determined for later use in a pediatric asthma panel study in an Alpine village. PM10 sources were identified by positive matrix factorization using chemical trace elements, elemental, and organic carbon from daily PM10 filters collected between November 2007 and June 2009 at seven locations within the village. Of the nine sources identified, four were directly road traffic-related: traffic exhaust, road dust, tire and brake wear, and road salt contributing 16 %, 8 %, 1 %, and 2 % to annual PM10 concentrations, respectively. They showed a clear dependence with distance to highway. Additional contributions were identified from secondary particles (27 %), biomass burning (18 %), railway (11 %), and mineral dust including a local construction site (13 %). Comparing these source contributions with known source-specific biomarkers (e.g., levoglucosan, nitro-polycyclic aromatic hydrocarbons) showed high agreement with biomass burning, moderate with secondary particles (in winter), and lowest agreement with traffic exhaust.

  7. Impact of overland traffic on heavy metal levels in highway dust and soils of Istanbul, Turkey.

    PubMed

    Guney, Mert; Onay, Turgut T; Copty, Nadim K

    2010-05-01

    The purpose of this study was to investigate the impact of overland traffic on the spatial distribution of heavy metals in urban soils (Istanbul, Turkey). Road dust, surface, and subsurface soil samples were collected from a total of 41 locations along highways with dense traffic and secondary roads with lower traffic and analyzed for lead (Pb), zinc (Zn), and copper (Cu) concentrations. Statistical evaluation of the heavy metal concentrations observed along highways and along the secondary roads showed that the data were bimodally distributed. The maximum observed Pb, Zn, and Cu concentrations were 1,573, 522 and 136 mg/kg, respectively, in surface soils along highways and 99.3, 156, and 38.1 mg/kg along secondary roads. Correlation analysis of the metal concentrations in road dust, surface and 20-cm depth soils suggests the presence of a common pollution source. However, metal concentrations in the deeper soils were substantially lower than those observed at the surface, indicating low mobility of heavy metals, especially for Pb and Zn. A modified kriging approach that honors the bimodality of the data was used to estimate the spatial distribution of the surface concentrations of metals, and to identify hotspots. Results indicate that despite the presence of some industrial zones within the study area, traffic is the main heavy metal pollution source.

  8. Analysis of traffic accident injury severity on Spanish rural highways using Bayesian networks.

    PubMed

    de Oña, Juan; Mujalli, Randa Oqab; Calvo, Francisco J

    2011-01-01

    Several different factors contribute to injury severity in traffic accidents, such as driver characteristics, highway characteristics, vehicle characteristics, accidents characteristics, and atmospheric factors. This paper shows the possibility of using Bayesian Networks (BNs) to classify traffic accidents according to their injury severity. BNs are capable of making predictions without the need for pre assumptions and are used to make graphic representations of complex systems with interrelated components. This paper presents an analysis of 1536 accidents on rural highways in Spain, where 18 variables representing the aforementioned contributing factors were used to build 3 different BNs that classified the severity of accidents into slightly injured and killed or severely injured. The variables that best identify the factors that are associated with a killed or seriously injured accident (accident type, driver age, lighting and number of injuries) were identified by inference. Copyright © 2010 Elsevier Ltd. All rights reserved.

  9. Pedestrians’ adherence to road traffic regulations on the N1 Highway in Accra, Ghana

    PubMed Central

    Noora, Charles Lwanga; Afari, Edwin Andrews; Nuoh, Robert Domo; Adjei, Eric Yirenkyi; Anthony, Gershon Kobla; Abdulai, Marijanatu; Sackey, Samuel Oko; Kenu, Ernest; Nyarko, Kofi Mensah

    2016-01-01

    Introduction Pedestrian behavior and adherence to road traffic regulation is vital in the prevention and control of road traffic accidents (RTA) especially on highways in Ghana. We assessed pedestrians’ adherence to road crossing regulations on the George Walker Bush (N1) Highway in Accra. Methods We conducted a cross sectional study of pedestrians crossing the N1 highway from both sides of the road between 7:00 am and 11:00am. We observed all pedestrians using a checklist and interviewed 413 using a structured questionnaire. We collected data on basic demographics, and pedestrians’ knowledge on road crossing (exposures). Data was, cleaned and analyzed using Epi-info version 3.5.4. Pearson Chi-square was used to assess differences in proportions for categorical variables. Binary logistic regression was used to test for association between pedestrian choice of route and exposures. Results We observed (n = 1856) pedestrians crossing the road during the study period; 1155 (62.2%) males, 461 (24.8%) did not use the approved route(s). Majority 317(76.8%) were adults between the ages of 20-49, mostly males 265 (56.4%). Most people (92.7%) had at least basic education. AOR for sex (male) was 1.7(1.1-2.6), and regular use of Highway (always) was 0.4(0.2-0.8) at 95% CI. Conclusion One out of every 4pedestrians using the N1 Highway used an unapproved route. Majority of pedestrians who regularly cross the Highway at unapproved routes were males. We recommend vigorous public education and addition of more footbridges. PMID:28149436

  10. Using mobile monitoring to visualise diurnal variation of traffic pollutants across two near-highway neighbourhoods

    NASA Astrophysics Data System (ADS)

    Pattinson, Woodrow; Longley, Ian; Kingham, Simon

    2014-09-01

    It is widely accepted that concentrations of primary traffic pollutants can vary substantially across relatively small urban areas. Fixed-site monitors have been shown to be largely inadequate for representing concentrations at nearby locations, resulting in the increasing use of spatial modelling or mobile sampling methods to achieve spatial saturation. In this study, we employ the use of a simple bicycle to sample concentrations of ultrafine particles (UFPs), carbon monoxide (CO) and particulate matter (PM10) at two small areas (<2.5 km2) in South Auckland, New Zealand. Portable instruments were mounted inside a custom-built casing at the front of the bicycle and every street within each study area was sampled in a grid-like fashion, at four times of day (07:00, 12:00, 17:00 and 22:00). Each area has a six-lane highway running through its centre and the core aim was to visualise and describe spatial variability of pollutant levels about the highway, main arterials and quieter streets, at periods of contrasting meteorological and traffic conditions. A total of 20 sampling runs in each area (five at each of the four timings) were conducted. Meteorological data were logged continuously at background sites within each study area. Results show that the influence of highway traffic (UFPs, CO) was strongest during the mornings and late evenings when wind speeds were low, while for the midday and afternoon timings, concentrations were highest at the arterial and shopping zones. Concentrations of PM10 appeared to be strongest in the residential areas during mornings and late evenings, suggesting an influence of wood burning for home heating. For all timings combined, for all three pollutants, it appears the arterial roads featuring shops and numerous intersections with traffic lights, had a stronger influence on concentrations than the busier but more free-flowing highways. This study provides not only an insight into microspatial hotspot variation across suburbs, but

  11. Software for Simulating Air Traffic

    NASA Technical Reports Server (NTRS)

    Sridhar, Banavar; Bilimoria, Karl; Grabbe, Shon; Chatterji, Gano; Sheth, Kapil; Mulfinger, Daniel

    2006-01-01

    Future Air Traffic Management Concepts Evaluation Tool (FACET) is a system of software for performing computational simulations for evaluating advanced concepts of advanced air-traffic management. FACET includes a program that generates a graphical user interface plus programs and databases that implement computational models of weather, airspace, airports, navigation aids, aircraft performance, and aircraft trajectories. Examples of concepts studied by use of FACET include aircraft self-separation for free flight; prediction of air-traffic-controller workload; decision support for direct routing; integration of spacecraft-launch operations into the U.S. national airspace system; and traffic- flow-management using rerouting, metering, and ground delays. Aircraft can be modeled as flying along either flight-plan routes or great-circle routes as they climb, cruise, and descend according to their individual performance models. The FACET software is modular and is written in the Java and C programming languages. The architecture of FACET strikes a balance between flexibility and fidelity; as a consequence, FACET can be used to model systemwide airspace operations over the contiguous U.S., involving as many as 10,000 aircraft, all on a single desktop or laptop computer running any of a variety of operating systems. Two notable applications of FACET include: (1) reroute conformance monitoring algorithms that have been implemented in one of the Federal Aviation Administration s nationally deployed, real-time, operational systems; and (2) the licensing and integration of FACET with the commercially available Flight Explorer, which is an Internet- based, real-time flight-tracking system.

  12. Pollination of lark daisy on roadsides declines as traffic speed increases along an Amazonian highway.

    PubMed

    Dargas, J H F; Chaves, S R; Fischer, E

    2016-05-01

    Ecological disturbances caused by roadways have previously been reported, but traffic speed has not been addressed. We investigate effects of traffic speed on pollination of Centratherum punctatum (Asteraceae) along an Amazonian highway roadside. We hypothesised that frequency of flower visitors, duration of single visits and pollen deposition on stigmas will vary negatively as traffic speed increases. After measuring vehicle velocities, we classified three road sections as low-, mid- and high-velocity traffic. The main pollinator bee, Augochlora sp., visited C. punctatum inflorescences with decreasing frequency from low- to high-velocity roadside sections, whereas the nectar thief butterflies did the opposite. Duration of single visits by bees and butterflies was shorter, and arrival of pollen on C. punctatum stigmas was lower, in high- than in low-velocity roadside. Air turbulence due to passing vehicles increases with velocity and disturbed the flower visitors. Overall, results support that traffic velocity negatively affects foraging of flower visitors and the pollination of C. punctatum on roadsides.

  13. Radical precursors and related species from traffic as observed and modeled at an urban highway junction.

    PubMed

    Rappenglück, Bernhard; Lubertino, Graciela; Alvarez, Sergio; Golovko, Julia; Czader, Beata; Ackermann, Luis

    2013-11-01

    Nitrous acid (HONO) and formaldehyde (HCHO) are important precursors for radicals and are believed to favor ozone formation significantly. Traffic emission data for both compounds are scarce and mostly outdated. A better knowledge of today's HCHO and HONO emissions related to traffic is needed to refine air quality models. Here the authors report results from continuous ambient air measurements taken at a highway junction in Houston, Texas, from July 15 to October 15, 2009. The observational data were compared with emission estimates from currently available mobile emission models (MOBILE6; MOVES [MOtor Vehicle Emission Simulator]). Observations indicated a molar carbon monoxide (CO) versus nitrogen oxides (NO(x)) ratio of 6.01 +/- 0.15 (r2 = 0.91), which is in agreement with other field studies. Both MOBILE6 and MOVES overestimate this emission ratio by 92% and 24%, respectively. For HCHO/CO, an overall slope of 3.14 +/- 0.14 g HCHO/kg CO was observed. Whereas MOBILE6 largely underestimates this ratio by 77%, MOVES calculates somewhat higher HCHO/CO ratios (1.87) than MOBILE6, but is still significantly lower than the observed ratio. MOVES shows high HCHO/CO ratios during the early morning hours due to heavy-duty diesel off-network emissions. The differences of the modeled CO/NO(x) and HCHO/CO ratios are largely due to higher NO(x) and HCHO emissions in MOVES (30% and 57%, respectively, increased from MOBILE6 for 2009), as CO emissions were about the same in both models. The observed HONO/NO(x) emission ratio is around 0.017 +/- 0.0009 kg HONO/kg NO(x) which is twice as high as in MOVES. The observed NO2/NO(x) emission ratio is around 0.16 +/- 0.01 kg NO2/kg NO(x), which is a bit more than 50% higher than in MOVES. MOVES overestimates the CO/CO2 emission ratio by a factor of 3 compared with the observations, which is 0.0033 +/- 0.0002 kg CO/kg CO2. This as well as CO/NO(x) overestimation is coming from light-duty gasoline vehicles.

  14. Analysis of traffic accident size for Korean highway using structural equation models.

    PubMed

    Lee, Ju-Yeon; Chung, Jin-Hyuk; Son, Bongsoo

    2008-11-01

    Accident size can be expressed as the number of involved vehicles, the number of damaged vehicles, the number of deaths and/or the number of injured. Accident size is the one of the important indices to measure the level of safety of transportation facilities. Factors such as road geometric condition, driver characteristic and vehicle type may be related to traffic accident size. However, all these factors interact in complicate ways so that the interrelationships among the variables are not easily identified. A structural equation model is adopted to capture the complex relationships among variables because the model can handle complex relationships among endogenous and exogenous variables simultaneously and furthermore it can include latent variables in the model. In this study, we use 2649 accident data occurred on highways in Korea and estimate relationship among exogenous factors and traffic accident size. The model suggests that road factors, driver factors and environment factors are strongly related to the accident size.

  15. Microscopic theory of spatial-temporal congested traffic patterns at highway bottlenecks

    NASA Astrophysics Data System (ADS)

    Kerner, Boris S.; Klenov, Sergey L.

    2003-09-01

    A microscopic theory of spatial-temporal congested traffic patterns at highway bottlenecks due to on-ramps, merge bottlenecks (a reduction of highway lanes), and off-ramps is presented. The basic postulate of three-phase traffic theory is used, which claims that homogeneous (in space and time) model solutions (steady states) of synchronized flow cover a two dimensional region in the flow-density plane [B. S. Kerner, Phys. Rev. Lett. 81, 3797 (1998); Trans. Res. Rec. 1678, 160 (1999)]. Phase transitions leading to diverse congested patterns, pattern evolution, and pattern nonlinear features have been found. Diagrams of congested patterns, i.e., regions of the pattern emergence dependent on traffic demand, have been derived. Diverse effects of metastability with respect to the pattern formation have been found. The microscopic theory allows us to explain the main empirical pattern features at on-ramps and off-ramps which have recently been found [B. S. Kerner, Phys. Rev. E 65, 046138 (2002)]. (i) Rather than moving jams, synchronized flow first occurs at bottlenecks if the flow rate is slowly increasing. Wide moving jams can spontaneously occur only in synchronized flow. (ii) General patterns (GP) and synchronized flow patterns (SP) can spontaneously emerge at the bottlenecks. There can be the widening SP (WSP), the moving SP (MSP), and the localized SP. (iii) At on-ramps cases of “weak” and “strong” congestion should be distinguished. In contrast to weak congestion, under strong congestion the flow rate in synchronized flow in GP reaches a limit flow rate, the frequency of the moving jam emergence reaches a maximum, i.e., the GP characteristics under strong congestion do not depend on traffic demand. (iv) At the off-ramp GP with weak congestion occur. (v) A study of the pattern formation on a highway with two bottlenecks shows that diverse expanded patterns can occur, which cover both bottlenecks. SP first emerged at the downstream bottleneck can be caught

  16. Microscopic theory of spatial-temporal congested traffic patterns at highway bottlenecks.

    PubMed

    Kerner, Boris S; Klenov, Sergey L

    2003-09-01

    A microscopic theory of spatial-temporal congested traffic patterns at highway bottlenecks due to on-ramps, merge bottlenecks (a reduction of highway lanes), and off-ramps is presented. The basic postulate of three-phase traffic theory is used, which claims that homogeneous (in space and time) model solutions (steady states) of synchronized flow cover a two dimensional region in the flow-density plane [B. S. Kerner, Phys. Rev. Lett. 81, 3797 (1998); Trans. Res. Rec. 1678, 160 (1999)]. Phase transitions leading to diverse congested patterns, pattern evolution, and pattern nonlinear features have been found. Diagrams of congested patterns, i.e., regions of the pattern emergence dependent on traffic demand, have been derived. Diverse effects of metastability with respect to the pattern formation have been found. The microscopic theory allows us to explain the main empirical pattern features at on-ramps and off-ramps which have recently been found [B. S. Kerner, Phys. Rev. E 65, 046138 (2002)]. (i) Rather than moving jams, synchronized flow first occurs at bottlenecks if the flow rate is slowly increasing. Wide moving jams can spontaneously occur only in synchronized flow. (ii) General patterns (GP) and synchronized flow patterns (SP) can spontaneously emerge at the bottlenecks. There can be the widening SP (WSP), the moving SP (MSP), and the localized SP. (iii) At on-ramps cases of "weak" and "strong" congestion should be distinguished. In contrast to weak congestion, under strong congestion the flow rate in synchronized flow in GP reaches a limit flow rate, the frequency of the moving jam emergence reaches a maximum, i.e., the GP characteristics under strong congestion do not depend on traffic demand. (iv) At the off-ramp GP with weak congestion occur. (v) A study of the pattern formation on a highway with two bottlenecks shows that diverse expanded patterns can occur, which cover both bottlenecks. SP first emerged at the downstream bottleneck can be caught at the

  17. Motor vehicle driver injury severity study under various traffic control at highway-rail grade crossings in the United States.

    PubMed

    Hao, Wei; Daniel, Janice

    2014-12-01

    Based on the Federal Railway Administration (FRA) database, approximately 62% of the collisions at highway-rail crossings occurred at locations with active controls (gate and flashing lights), followed by passive controls (cross bucks and stop signs) with approximately 28% of accidents. The study applied an ordered probit model to explore the determinants of driver injury severity under various control measures at highway-rail grade crossing in the United States. The analysis found that schedule factor (peak hour), visibility, motor vehicle speed, train speed, driver's age, area type, traffic volume and highway pavement impact driver injury severity at both active and passive highway-rail crossings. For both active and passive control highway-rail grade crossings, speed control for both trains and vehicles will significantly reduce driver injury severity. However, the level of influence by vehicle speed and train speed at passive control is higher compared with active control. Paving highways at highway-rail grade crossings will also help to reduce driver injury severity at highway-rail crossing accidents. Published by Elsevier Ltd.

  18. A queuing model for road traffic simulation

    SciTech Connect

    Guerrouahane, N.; Aissani, D.; Bouallouche-Medjkoune, L.; Farhi, N.

    2015-03-10

    We present in this article a stochastic queuing model for the raod traffic. The model is based on the M/G/c/c state dependent queuing model, and is inspired from the deterministic Godunov scheme for the road traffic simulation. We first propose a variant of M/G/c/c state dependent model that works with density-flow fundamental diagrams rather than density-speed relationships. We then extend this model in order to consider upstream traffic demand as well as downstream traffic supply. Finally, we show how to model a whole raod by concatenating raod sections as in the deterministic Godunov scheme.

  19. Summary of Work Performed Pursuant to the Development of Training Manuals for a Highway Safety Workshop for Traffic Court Judges.

    ERIC Educational Resources Information Center

    Abt Associates, Inc., Cambridge, MA.

    The report summarizes the work involved in developing a highway safety workshop for traffic court judges. It describes the testing of previously developed workshop materials and their evaluation, resulting in a contract modification to redesign and refocus the workshop. The report identifies the resources and procedures used in this development…

  20. Simulating effects of highway embankments on estuarine circulation

    USGS Publications Warehouse

    Lee, Jonathan K.; Schaffranek, Raymond W.; Baltzer, Robert A.

    1994-01-01

    A two-dimensional depth-averaged, finite-difference, numerical model was used to simulate tidal circulation and mass transport in the Port Royal Sound. South Carolina, estuarine system. The purpose of the study was to demonstrate the utility of the Surface-Water. Integrated. Flow and Transport model (SWIFT2D) for evaluating changes in circulation patterns and mass transport caused by highway-crossing embankments. A model of subregion of Port Royal Sound including the highway crossings and having a grid size of 61 m (200ft) was derived from a 183-m (600-ft) model of the entire Port Royal Sound estuarine system. The 183-m model was used to compute boundary-value data for the 61-m submodel, which was then used to simulate flow conditions with and without the highway embankments in place. The numerical simulations show that, with the highway embankment in place, mass transport between the Broad River and Battery Creek is reduced and mass transport between the Beaufort River and Battery Creek is increased. The net result is that mass transport into and out of upper Battery Creek is reduced. The presence of the embankments also alters circulation patterns within Battery Creek.

  1. Driver behaviours on rural highways with and without curbs - a driving simulator based study.

    PubMed

    Yang, Qiang; Overton, Ryan; Han, Lee D; Yan, Xuedong; Richards, Stephen H

    2014-01-01

    The speed limit of 55 mph (88 km/h) is used typically on rural highways in the U.S. When curbs are installed, a lower speed limit is suggested because running into curbs at high speeds may cause significant vehicular damage and severe injuries. However, it has been argued that lowering the speed limit may cause confusion in drivers, who do not perceive the risk and tend to operate their vehicles at the same speed as before. To better understand driver behaviour on two-lane rural highways before and after curb installation, the authors conducted a series of experiments on a high-fidelity driving simulator in different posted speed limit, curb installation, lateral curb clearance, weather, visibility, and traffic conditions. Results of the study suggest that driver behaviours are influenced by the various factors in a complex and interrelated manner. It is likely that curbs have no influence on a driver's selection of speed. Drivers do perceive the risk from the curb or the opposing traffic when selecting their lane positions. The available space between the curb and the opposing traffic is crucial and has significant effects on driving behaviours. The subjective effects of drivers are found to be influential to driving behaviours.

  2. 77 FR 24560 - National Highway Traffic Safety Administration Electric Vehicle Safety Technical Symposium

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-24

    ...The National Highway Traffic Safety Administration (NHTSA) is announcing a technical symposium that will be held in Washington, DC on May 18, 2012 to discuss safety considerations for electric vehicles powered by lithium-ion (Li-ion) batteries. The symposium will include brief NHTSA presentations outlining current agency research and activities related to Li-ion batteries and Li-ion battery-powered vehicles, as well as presentations by the Department of Energy, voluntary standards bodies, and automotive and battery manufacturers. Information on the date, time, location, and framework for this public event is included in this notice. Because of space limitations, registration by May 11, 2012 is highly recommended. There are no fees to register or to attend this event.

  3. Traffic states induced by slowdown sections on two-lane highway

    NASA Astrophysics Data System (ADS)

    Hanaura, Hirotoshi; Masukura, Shuichi; Nagatani, Takashi

    2009-04-01

    We study the traffic states and jams occurring on a two-lane highway with a few slowdown sections. We derive the fundamental diagrams (flow-density diagrams). The fundamental diagrams on first and second lanes depend highly on the configuration of slowdown sections. The occupancy fraction of vehicles on first and second lanes varies with configuration of slowdown sections and also changes with density for the definite configuration. When a jam is formed on a lane, the flow (current) saturates on the lane. The saturated flow is given by the maximal value of the current of the slowdown section. The relationship between the densities before and after the jam is derived analytically. The dependence of jam lengths on density is derived numerically and analytically.

  4. Characterization of highway traffic noise generated by rigid pavement contraction joints

    NASA Astrophysics Data System (ADS)

    Ellis, Lawrin T.; Niezrecki, Christopher; Bloomquist, David

    2003-04-01

    Contraction joints in rigid (concrete) pavements are required to permit expansion of each monolithic section of roadway. At higher speeds, the major source of highway noise is attributed to vehicle tire/roadway interaction. Current concerns about limiting the impact of highway traffic noise has forced transportation agencies to consider strategies to control noise generated by tire/roadway interaction. Within this work the difference in noise generated by 1/4- vs 3/8-in. joint widths is conducted. The study focuses on passenger vehicles including a sedan and a light duty van/truck. Both vehicle in-cabin and roadside noise levels are measured for vehicle speeds of 50, 60, and 70 miles per hour. For the sedan, the minimum and maximum observed in-cabin differences were determined to be 1.08 and 1.82 dB(A), respectively. Minimum and maximum observed roadside differences are 1.19 and 2.58 dB(A), respectively. Van tests resulted in minimum and maximum observed in-cabin differences of 0.60 and 1.09 dB(A) and minimum and maximum observed roadside differences of 1.05 and 3.18 dB(A), respectively. This paper contains details of reference standards, test methods, and the results obtained.

  5. Investigation on the role of traffic volume in accidents on urban highways.

    PubMed

    Ayati, Esmaeel; Abbasi, Ehsan

    2011-06-01

    Roadway safety is a major concern for the general public and public agencies, as roadway crashes claim many lives and cause substantial economic loss each year. In Iran, a large number of vehicles are involved in road accidents each year, which cause many deaths and extensive property damage; such accidents are among the major causes of death and disability in the country. To reduce roadway accidents, the factors that affect the occurrence and severity of accidents should be scrutinized to prevent or reduce their effect. The method that many researchers have adopted to determine the effective parameters surrounding road accidents in recent years is through statistical modeling of accidents. In this article, the role of different kinds of vehicles in traffic flow are investigated separately in terms of the likelihood of crashes on urban highways, and the vehicles are divided into three groups: passenger cars, heavy vehicles, and light non-passenger car vehicles. Poisson and negative binomial (NB) regression models were applied to model the accidents in this research, which were categorized into two groups: no injury (property damage only) accidents and more severe (injury and fatal) accidents. Ultimately, we conclude that light non-passenger car vehicles (i.e., taxis and motorcycles) play the largest role in the occurrence of crashes on urban highways for both types of accidents. Copyright © 2011. Published by Elsevier Ltd.

  6. Traffic flow theory and traffic flow simulation models. Transportation research record

    SciTech Connect

    1996-12-31

    ;Contents: Comparison of Simulation Modules of TRANSYT and INTEGRATION Models; Evaluation of SCATSIM-RTA Adaptive Traffic Network Simulation Model; Comparison NETSIM, NETFLO I, and NETFLO II Traffic Simulation Models for Fixed-Time Signal Control; Traffic Flow Simulation Through Parallel Processing; Cluster Analysis as Tool in Traffic Engineering; Traffic Platoon Dispersion Modeling on Arterial Streets; Hybrid Model for Estimating Permitted Left-Turn Saturations Flow Rate; and Passing Sight Distance and Overtaking Dilemma on Two-Lane Roads.

  7. Analysis of traffic accidents on rural highways using Latent Class Clustering and Bayesian Networks.

    PubMed

    de Oña, Juan; López, Griselda; Mujalli, Randa; Calvo, Francisco J

    2013-03-01

    One of the principal objectives of traffic accident analyses is to identify key factors that affect the severity of an accident. However, with the presence of heterogeneity in the raw data used, the analysis of traffic accidents becomes difficult. In this paper, Latent Class Cluster (LCC) is used as a preliminary tool for segmentation of 3229 accidents on rural highways in Granada (Spain) between 2005 and 2008. Next, Bayesian Networks (BNs) are used to identify the main factors involved in accident severity for both, the entire database (EDB) and the clusters previously obtained by LCC. The results of these cluster-based analyses are compared with the results of a full-data analysis. The results show that the combined use of both techniques is very interesting as it reveals further information that would not have been obtained without prior segmentation of the data. BN inference is used to obtain the variables that best identify accidents with killed or seriously injured. Accident type and sight distance have been identify in all the cases analysed; other variables such as time, occupant involved or age are identified in EDB and only in one cluster; whereas variables vehicles involved, number of injuries, atmospheric factors, pavement markings and pavement width are identified only in one cluster. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Reducing Traffic Congestions by Introducing CACC-Vehicles on a Multi-Lane Highway Using Agent-Based Approach

    NASA Technical Reports Server (NTRS)

    Arnaout, Georges M.; Bowling, Shannon R.

    2011-01-01

    Traffic congestion is an ongoing problem of great interest to researchers from different areas in academia. With the emerging technology for inter-vehicle communication, vehicles have the ability to exchange information with predecessors by wireless communication. In this paper, we present an agent-based model of traffic congestion and examine the impact of having CACC (Cooperative Adaptive Cruise Control) embedded vehicle(s) on a highway system consisting of 4 traffic lanes without overtaking. In our model, CACC vehicles adapt their acceleration/deceleration according to vehicle-to-vehicle inter-communication. We analyze the average speed of the cars, the shockwaves, and the evolution of traffic congestion throughout the lifecycle of the model. The study identifies how CACC vehicles affect the dynamics of traffic flow on a complex network and reduce the oscillatory behavior (stop and go) resulting from the acceleration/deceleration of the vehicles.

  9. A new access density definition and its correlation with crash rates by microscopic traffic simulation method.

    PubMed

    Huang, Bing; Zhang, Yu; Lu, Linjun; Lu, Jian John

    2014-03-01

    Better access management can improve highway safety by reducing potential crashes and conflicts. To make adequate access management decisions, it is essential to understand the impact of different access types on roadway safety, usually represented by the crash rate of a roadway segment. The objective of this paper is to propose a new access density definition reflecting the impact of traffic speed variation of different access types. The traffic speed variation was obtained from a microscopic traffic simulation software package TSIS-CORSIM. A sample roadway Temple Terrace Highway was selected to perform traffic simulation. Access Weight was obtained from traffic speed variation, and access density was obtained from access weight. The proposed access density was then compared with the existing definition by analyzing their correlations with crash rates on one suburban street in Temple Terrace, Florida. The comparison demonstrates that crash rates are more highly correlated with the proposed access density than that in the previous study, which is helpful for Federal Highway Administration (FHWA), United States Department of Transportation (USDOT), and transportation consulting companies to regulate the construction, management and design of roadway segments. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Role of highway traffic on spatial and temporal distributions of air pollutants in a Swiss Alpine valley.

    PubMed

    Ducret-Stich, Regina E; Tsai, Ming-Yi; Ragettli, Martina S; Ineichen, Alex; Kuenzli, Nino; Phuleria, Harish C

    2013-07-01

    Traffic-related air pollutants show high spatial variability near roads, posing a challenge to adequately assess exposures. Recent modeling approaches (e.g. dispersion models, land-use regression (LUR) models) have addressed this but mostly in urban areas where traffic is abundant. In contrast, our study area was located in a rural Swiss Alpine valley crossed by the main North-south transit highway of Switzerland. We conducted an extensive measurement campaign collecting continuous nitrogen dioxide (NO₂), particulate number concentrations (PN), daily respirable particulate matter (PM10), elemental carbon (EC) and organic carbon (OC) at one background, one highway and seven mobile stations from November 2007 to June 2009. Using these measurements, we built a hybrid model to predict daily outdoor NO₂ concentrations at residences of children participating in an asthma panel study. With the exception of OC, daily variations of the pollutants followed the temporal trends of heavy-duty traffic counts on the highway. In contrast, variations of weekly/seasonal means were strongly determined by meteorological conditions, e.g., winter inversion episodes. For pollutants related to primary exhaust emissions (i.e. NO₂, EC and PN) local spatial variation strongly depended on proximity to the highway. Pollutant concentrations decayed to background levels within 150 to 200 m from the highway. Two separate daily NO₂ prediction models were built using LUR approaches with (a) short-term traffic and weather data (model 1) and (b) subsequent addition of daily background NO₂ to previous model (model 2). Models 1 and 2 explained 70% and 91% of the variability in outdoor NO₂ concentrations, respectively. The biweekly averaged predictions from the final model 2 agreed very well with the independent biweekly integrated passive measurements taken at thirteen homes and nine community sites (validation R(2)=0.74). The excellent spatio-temporal performance of our model provides a

  11. Simulation Study of Traffic Accidents in Bidirectional Traffic Models

    NASA Astrophysics Data System (ADS)

    Moussa, Najem

    Conditions for the occurrence of bidirectional collisions are developed based on the Simon-Gutowitz bidirectional traffic model. Three types of dangerous situations can occur in this model. We analyze those corresponding to head-on collision; rear-end collision and lane-changing collision. Using Monte Carlo simulations, we compute the probability of the occurrence of these collisions for different values of the oncoming cars' density. It is found that the risk of collisions is important when the density of cars in one lane is small and that of the other lane is high enough. The influence of different proportions of heavy vehicles is also studied. We found that heavy vehicles cause an important reduction of traffic flow on the home lane and provoke an increase of the risk of car accidents.

  12. Air pollution due to traffic, air quality monitoring along three sections of National Highway N-5, Pakistan.

    PubMed

    Ali, Mahboob; Athar, Makshoof

    2008-01-01

    Transportation system has contributed significantly to the development of human civilization; on the other hand it has an enormous impact on the ambient air quality in several ways. In this paper the air and noise pollution at selected sites along three sections of National Highway was monitored. Pakistan National Highway Authority has started a Highway Improvement program for rehabilitations and maintenance of National highways to improve the traffic flows, and would ultimately improve the air quality along highways. The ambient air quality and noise level was monitored at nine different locations along these sections of highways to quantify the air pollution. The duration of monitoring at individual location was 72 h. The most of the sampling points were near the urban or village population, schools or hospitals, in order to quantify the air pollution at most affected locations along these roads. A database consisting of information regarding the source of emission, local metrology and air quality may be created to assess the profile of air quality in the area.

  13. Terminal area air traffic control simulation

    NASA Technical Reports Server (NTRS)

    1977-01-01

    To study the impact of advanced aeronautical technologies on operations to and from terminal airports, a computer model of air traffic movements was developed. The advantages of fast-time simulation are discussed, and the arrival scheduling and flight simulation are described. A New York area study, user's guide, and programmer's guide are included.

  14. Hopf bifurcation analysis for a dissipative system with asymmetric interaction: Analytical explanation of a specific property of highway traffic

    NASA Astrophysics Data System (ADS)

    Nomura, Yasuyuki; Saito, Satoshi; Ishiwata, Ryosuke; Sugiyama, Yuki

    2016-01-01

    A dissipative system with asymmetric interaction, the optimal velocity model, shows a Hopf bifurcation concerned with the transition from a homogeneous motion to the formation of a moving cluster, such as the emergence of a traffic jam. We investigate the properties of Hopf bifurcation depending on the particle density, using the dynamical system for the traveling cluster solution of the continuum system derived from the original discrete system of particles. The Hopf bifurcation is revealed as a subcritical one, and the property explains well the specific phenomena in highway traffic: the metastability of jamming transition and the hysteresis effect in the relation of car density and flow rate.

  15. Hopf bifurcation analysis for a dissipative system with asymmetric interaction: Analytical explanation of a specific property of highway traffic.

    PubMed

    Nomura, Yasuyuki; Saito, Satoshi; Ishiwata, Ryosuke; Sugiyama, Yuki

    2016-01-01

    A dissipative system with asymmetric interaction, the optimal velocity model, shows a Hopf bifurcation concerned with the transition from a homogeneous motion to the formation of a moving cluster, such as the emergence of a traffic jam. We investigate the properties of Hopf bifurcation depending on the particle density, using the dynamical system for the traveling cluster solution of the continuum system derived from the original discrete system of particles. The Hopf bifurcation is revealed as a subcritical one, and the property explains well the specific phenomena in highway traffic: the metastability of jamming transition and the hysteresis effect in the relation of car density and flow rate.

  16. Computationally Lightweight Air-Traffic-Control Simulation

    NASA Technical Reports Server (NTRS)

    Knight, Russell

    2005-01-01

    An algorithm for computationally lightweight simulation of automated air traffic control (ATC) at a busy airport has been derived. The algorithm is expected to serve as the basis for development of software that would be incorporated into flight-simulator software, the ATC component of which is not yet capable of handling realistic airport loads. Software based on this algorithm could also be incorporated into other computer programs that simulate a variety of scenarios for purposes of training or amusement.

  17. Impact of highway traffic and the acoustic screen on the content and spatial distribution of heavy metals in soils.

    PubMed

    Różański, Szymon; Jaworska, Hanna; Matuszczak, Katarzyna; Nowak, Joanna; Hardy, Amber

    2017-03-30

    Recent years have witnessed intensification of road traffic and, with it, the amount of substances emitted by vehicles. Such emissions need to be monitored for public health purposes. The aim of this study was to evaluate the impact of the highway traffic on the total content and bioavailability of Zn, Cu, Ni, Cd, Cr and Pb in nearby soils as well as influence of an acoustic screen on spatial distribution of the metals. The material included 40 soil samples collected from 15 research points located 5, 10, 25 and 50 m away from the road acoustic screen and from 4 points between the screen and the highway. Additionally, 5 research points were located next to the metal barrier. Selected physicochemical properties of soils were determined: soil texture, soil pH, TOC and CaCO3 content. The total content of heavy metals in the soils was determined by AAS after digestion in aqua regia and bioavailable forms in 1 M diethylenetriaminepentaacetic acid. The research found low impact of the highway traffic on the content of heavy metals in soils; however, due to a very short period of this potential impact (5 years), the moderately polluted category of geo-accumulation index of cadmium and high bioavailability of lead indicate the need of repeating the research within the next several years. Furthermore, the road acoustic screen significantly influenced spatial distribution of the metals in soils.

  18. Chemical and physical characterization of traffic particles in four different highway environments in the Helsinki metropolitan area

    NASA Astrophysics Data System (ADS)

    Enroth, Joonas; Saarikoski, Sanna; Niemi, Jarkko; Kousa, Anu; Ježek, Irena; Močnik, Griša; Carbone, Samara; Kuuluvainen, Heino; Rönkkö, Topi; Hillamo, Risto; Pirjola, Liisa

    2016-05-01

    Traffic-related pollution is a major concern in urban areas due to its deleterious effects on human health. The characteristics of the traffic emissions on four highway environments in the Helsinki metropolitan area were measured with a mobile laboratory, equipped with state-of-the-art instrumentation. Concentration gradients were observed for all traffic-related pollutants, particle number (CN), particulate mass (PM1), black carbon (BC), organics, and nitrogen oxides (NO and NO2). Flow dynamics in different environments appeared to be an important factor for the dilution of the pollutants. For example, the half-decay distances for the traffic-related CN concentrations varied from 8 to 83 m at different sites. The PM1 emissions from traffic mostly consisted of organics and BC. At the most open site, the ratio of organics to BC increased with distance to the highway, indicating condensation of volatile and semi-volatile organics on BC particles. These condensed organics were shown to be hydrocarbons as the fraction of hydrocarbon fragments in organics increased. Regarding the CN size distributions, particle growth during the dilution was not observed; however the mass size distributions measured with a soot particle aerosol mass spectrometer (SP-AMS), showed a visible shift of the mode, detected at ˜ 100 nm at the roadside, to a larger size when the distance to the roadside increased. The fleet average emission factors appeared to be lower for the CN and higher for the NO2 than ten years ago. The reason is likely to be the increased fraction of light-duty (LD) diesel vehicles in the past ten years. The fraction of heavy-duty (HD) traffic, although constituting less than 10 % of the total traffic flow, was found to have a large impact on the emissions.

  19. Spatial and temporal differences in traffic-related air pollution in three urban neighborhoods near an interstate highway

    PubMed Central

    Patton, Allison P.; Perkins, Jessica; Zamore, Wig; Levy, Jonathan I.; Brugge, Doug; Durant, John L.

    2014-01-01

    Relatively few studies have characterized differences in intra- and inter-neighborhood traffic-related air pollutant (TRAP) concentrations and distance-decay gradients in along an urban highway for the purposes of exposure assessment. The goal of this work was to determine the extent to which intra- and inter-neighborhood differences in TRAP concentrations can be explained by traffic and meteorology in three pairs of neighborhoods along Interstate 93 (I-93) in the metropolitan Boston area (USA). We measured distance-decay gradients of seven TRAPs (PNC, pPAH, NO, NOX, BC, CO, PM2.5) in near-highway (<400 m) and background areas (>1 km) in Somerville, Dorchester/South Boston, Chinatown and Malden to determine whether (1) spatial patterns in concentrations and inter-pollutant correlations differ between neighborhoods, and (2) variation within and between neighborhoods can be explained by traffic and meteorology. The neighborhoods ranged in area from 0.5 to 2.3 km2. Mobile monitoring was performed over the course of one year in each pair of neighborhoods (one pair of neighborhoods per year in three successive years; 35-47 days of monitoring in each neighborhood). Pollutant levels generally increased with highway proximity, consistent with I-93 being a major source of TRAP; however, the slope and extent of the distance-decay gradients varied by neighborhood as well as by pollutant, season and time of day. Correlations among pollutants differed between neighborhoods (e.g., ρ = 0.35-0.80 between PNC and NOX and ρ = 0.11-0.60 between PNC and BC) and were generally lower in Dorchester/South Boston than in the other neighborhoods. We found that the generalizability of near-road gradients and near-highway/urban background contrasts was limited for near-highway neighborhoods in a metropolitan area with substantial local street traffic. Our findings illustrate the importance of measuring gradients of multiple pollutants under different ambient conditions in individual near-highway

  20. Spatial and temporal differences in traffic-related air pollution in three urban neighborhoods near an interstate highway.

    PubMed

    Patton, Allison P; Perkins, Jessica; Zamore, Wig; Levy, Jonathan I; Brugge, Doug; Durant, John L

    2014-12-01

    Relatively few studies have characterized differences in intra- and inter-neighborhood traffic-related air pollutant (TRAP) concentrations and distance-decay gradients in along an urban highway for the purposes of exposure assessment. The goal of this work was to determine the extent to which intra- and inter-neighborhood differences in TRAP concentrations can be explained by traffic and meteorology in three pairs of neighborhoods along Interstate 93 (I-93) in the metropolitan Boston area (USA). We measured distance-decay gradients of seven TRAPs (PNC, pPAH, NO, NOX, BC, CO, PM2.5) in near-highway (<400 m) and background areas (>1 km) in Somerville, Dorchester/South Boston, Chinatown and Malden to determine whether (1) spatial patterns in concentrations and inter-pollutant correlations differ between neighborhoods, and (2) variation within and between neighborhoods can be explained by traffic and meteorology. The neighborhoods ranged in area from 0.5 to 2.3 km(2). Mobile monitoring was performed over the course of one year in each pair of neighborhoods (one pair of neighborhoods per year in three successive years; 35-47 days of monitoring in each neighborhood). Pollutant levels generally increased with highway proximity, consistent with I-93 being a major source of TRAP; however, the slope and extent of the distance-decay gradients varied by neighborhood as well as by pollutant, season and time of day. Correlations among pollutants differed between neighborhoods (e.g., ρ = 0.35-0.80 between PNC and NOX and ρ = 0.11-0.60 between PNC and BC) and were generally lower in Dorchester/South Boston than in the other neighborhoods. We found that the generalizability of near-road gradients and near-highway/urban background contrasts was limited for near-highway neighborhoods in a metropolitan area with substantial local street traffic. Our findings illustrate the importance of measuring gradients of multiple pollutants under different ambient conditions in individual near-highway

  1. Spatial and temporal differences in traffic-related air pollution in three urban neighborhoods near an interstate highway

    NASA Astrophysics Data System (ADS)

    Patton, Allison P.; Perkins, Jessica; Zamore, Wig; Levy, Jonathan I.; Brugge, Doug; Durant, John L.

    2014-12-01

    Relatively few studies have characterized differences in intra- and inter-neighborhood traffic-related air pollutant (TRAP) concentrations and distance-decay gradients in neighborhoods along an urban highway for the purposes of exposure assessment. The goal of this work was to determine the extent to which intra- and inter-neighborhood differences in TRAP concentrations can be explained by traffic and meteorology in three pairs of neighborhoods along Interstate 93 (I-93) in the metropolitan Boston area (USA). We measured distance-decay gradients of seven TRAPs (PNC, pPAH, NO, NOX, BC, CO, PM2.5) in near-highway (<400 m) and background areas (>1 km) in Somerville, Dorchester/South Boston, Chinatown and Malden to determine whether (1) spatial patterns in concentrations and inter-pollutant correlations differ between neighborhoods, and (2) variation within and between neighborhoods can be explained by traffic and meteorology. The neighborhoods ranged in area from 0.5 to 2.3 km2. Mobile monitoring was performed over the course of one year in each pair of neighborhoods (one pair of neighborhoods per year in three successive years; 35-47 days of monitoring in each neighborhood). Pollutant levels generally increased with highway proximity, consistent with I-93 being a major source of TRAP; however, the slope and extent of the distance-decay gradients varied by neighborhood as well as by pollutant, season and time of day. Spearman correlations among pollutants differed between neighborhoods (e.g., ρ = 0.35-0.80 between PNC and NOX and ρ = 0.11-0.60 between PNC and BC) and were generally lower in Dorchester/South Boston than in the other neighborhoods. We found that the generalizability of near-road gradients and near-highway/urban background contrasts was limited for near-highway neighborhoods in a metropolitan area with substantial local street traffic. Our findings illustrate the importance of measuring gradients of multiple pollutants under different ambient

  2. Speed Distribution on Two-Lane Rural Highways with Mixed Traffic: A Case Study in North East India

    NASA Astrophysics Data System (ADS)

    Saha, Pritam; Roy, Nabanita; Sarkar, Ashoke Kumar; Pal, Manish

    2017-06-01

    This work focuses on minimising inaccuracies in distributional assumptions of speed data on two-lane roads with heterogeneous traffic to improve accuracy in capacity and level of service analysis. Accordingly, field study was conducted on a two-lane highway in India that exhibits heterogeneity in its traffic composition. Two distribution functions, namely, normal and logistic were examined for the observed speed data. The appropriate function was chosen using a methodology based on K-S test and field validation. Logistic distribution function was found to exhibit its aptness in describing speed under such traffic and was, thereby, considered in estimating the limiting speed of slower vehicles that tends to obstruct the flow of traffic. Vehicles that move at or below this speed cause delay to the faster ones resulting in formation of platoons at moderate and heavy flow when passing is restricted. Since the percent time-spent-following, a performance measure to assess level-of-service of two-lane highways, considers proportion of vehicles that are trapped inside platoons, it is imperative to estimate the limiting speed of slower vehicles correctly to approximate the delayed vehicles.

  3. Metropolitan Road Traffic Simulation on FPGAs.

    SciTech Connect

    Tripp J. L.; Mortveit, H. S.; Hansson, A. A.; Gokhale, M.

    2005-01-01

    This work demonstrates that road traffic simulation of entire metropolitan areas is possible with reconfigurable supercomputing that combines 64-bit microprocessors and FPGAs in a high bandwidth, low latency interconnect. Previously, traffic simulation on FPGAs was limited to very short road segments or required a very large number of FPGAs. Our data streaming approach overcomes scaling issues associated with direct implementations and still allows for high-level parallelism by dividing the data sets between hardware and software across the reconfigurable supercomputer. Using one FPGA on the Cray XD1 supercomputer, we are able to achieve a 34.4 x speed up over the AMD microprocessor. System integration issues must be optimized to exploit this speedup in the overall simulation.

  4. Cellular automata models for diffusion of information and highway traffic flow

    NASA Astrophysics Data System (ADS)

    Fuks, Henryk

    In the first part of this work we study a family of deterministic models for highway traffic flow which generalize cellular automaton rule 184. This family is parameterized by the speed limit m and another parameter k that represents degree of 'anticipatory driving'. We compare two driving strategies with identical maximum throughput: 'conservative' driving with high speed limit and 'anticipatory' driving with low speed limit. Those two strategies are evaluated in terms of accident probability. We also discuss fundamental diagrams of generalized traffic rules and examine limitations of maximum achievable throughput. Possible modifications of the model are considered. For rule 184, we present exact calculations of the order parameter in a transition from the moving phase to the jammed phase using the method of preimage counting, and use this result to construct a solution to the density classification problem. In the second part we propose a probabilistic cellular automaton model for the spread of innovations, rumors, news, etc., in a social system. We start from simple deterministic models, for which exact expressions for the density of adopters are derived. For a more realistic model, based on probabilistic cellular automata, we study the influence of a range of interaction R on the shape of the adoption curve. When the probability of adoption is proportional to the local density of adopters, and individuals can drop the innovation with some probability p, the system exhibits a second order phase transition. Critical line separating regions of parameter space in which asymptotic density of adopters is positive from the region where it is equal to zero converges toward the mean-field line when the range of the interaction increases. In a region between R=1 critical line and the mean-field line asymptotic density of adopters depends on R, becoming zero if R is too small (smaller than some critical value). This result demonstrates the importance of connectivity in

  5. Low Earth Orbit satellite traffic simulator

    NASA Technical Reports Server (NTRS)

    Hoelzel, John

    1995-01-01

    This paper describes a significant tool for Low Earth Orbit (LEO) capacity analysis, needed to support marketing, economic, and design analysis, known as a Satellite Traffic Simulator (STS). LEO satellites typically use multiple beams to help achieve the desired communication capacity, but the traffic demand in these beams in usually not uniform. Simulations of dynamic, average, and peak expected demand per beam is a very critical part of the marketing, economic, and design analysis necessary to field a viable LEO system. An STS is described in this paper which can simulate voice, data and FAX traffic carried by LEO satellite beams and Earth Station Gateways. It is applicable world-wide for any LEO satellite constellations operating over any regions. For aeronautical applications to LEO satellites. the anticipates aeronautical traffic (Erlangs for each hour of the day to be simulated) is prepared for geographically defined 'area targets' (each major operational region for the respective aircraft), and used as input to the STS. The STS was designed by Constellations Communications Inc. (CCI) and E-Systems for usage in Brazil in accordance with an ESCA/INPE Statement Of Work, and developed by Analytical Graphics Inc. (AGI) to execute on top of its Satellite Tool Kit (STK) commercial software. The STS simulates constellations of LEO satellite orbits, with input of traffic intensity (Erlangs) for each hour of the day generated from area targets (such as Brazilian States). accumulated in custom LEO satellite beams, and then accumulated in Earth Station Gateways. The STS is a very general simulator which can accommodate: many forms of orbital element and Walker Constellation input; simple beams or any user defined custom beams; and any location of Gateways. The paper describes some of these features, including Manual Mode dynamic graphical display of communication links, to illustrate which Gateway links are accessible and which links are not, at each 'step' of the

  6. Low Earth Orbit satellite traffic simulator

    NASA Technical Reports Server (NTRS)

    Hoelzel, John

    1995-01-01

    This paper describes a significant tool for Low Earth Orbit (LEO) capacity analysis, needed to support marketing, economic, and design analysis, known as a Satellite Traffic Simulator (STS). LEO satellites typically use multiple beams to help achieve the desired communication capacity, but the traffic demand in these beams in usually not uniform. Simulations of dynamic, average, and peak expected demand per beam is a very critical part of the marketing, economic, and design analysis necessary to field a viable LEO system. An STS is described in this paper which can simulate voice, data and FAX traffic carried by LEO satellite beams and Earth Station Gateways. It is applicable world-wide for any LEO satellite constellations operating over any regions. For aeronautical applications to LEO satellites. the anticipates aeronautical traffic (Erlangs for each hour of the day to be simulated) is prepared for geographically defined 'area targets' (each major operational region for the respective aircraft), and used as input to the STS. The STS was designed by Constellations Communications Inc. (CCI) and E-Systems for usage in Brazil in accordance with an ESCA/INPE Statement Of Work, and developed by Analytical Graphics Inc. (AGI) to execute on top of its Satellite Tool Kit (STK) commercial software. The STS simulates constellations of LEO satellite orbits, with input of traffic intensity (Erlangs) for each hour of the day generated from area targets (such as Brazilian States). accumulated in custom LEO satellite beams, and then accumulated in Earth Station Gateways. The STS is a very general simulator which can accommodate: many forms of orbital element and Walker Constellation input; simple beams or any user defined custom beams; and any location of Gateways. The paper describes some of these features, including Manual Mode dynamic graphical display of communication links, to illustrate which Gateway links are accessible and which links are not, at each 'step' of the

  7. Investigating risk factors of traffic casualties at private highway-railroad grade crossings in the United States.

    PubMed

    Haleem, Kirolos

    2016-10-01

    Private highway-railroad grade crossings (HRGCs) are intersections of highways and railroads on roadways that are not maintained by a public authority. Since no public authority maintains private HRGCs, fatal and injury crashes at these locations are of concern. However, no study has been conducted at private HRGCs to identify the safety issues that might exist and how to alleviate them. This study identifies the significant predictors of traffic casualties (including both injuries and fatalities) at private HRGCs in the U.S. using six years of nationwide crashes from 2009 to 2014. Two levels of injury severity were considered, injury (including fatalities and injuries) and no injury. The study investigates multiple predictors, e.g., temporal crash characteristics, geometry, railroad, traffic, vehicle, and environment. The study applies both the mixed logit and binary logit models. The mixed logit model was found to outperform the binary logit model. The mixed logit model revealed that drivers who did not stop, railroad equipment that struck highway users, higher train speeds, non-presence of advance warning signs, concrete road surface type, and cloudy weather were associated with an increase in injuries and fatalities. For example, a one-mile-per-hour higher train speed increases the probability of fatality by 22%. On the contrary, male drivers, PM peak periods, and presence of warning devices at both approaches were associated with a fatality reduction. Potential strategies are recommended to alleviate injuries and fatalities at private HRGCs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Green supply chain: Simulating road traffic congestion

    NASA Astrophysics Data System (ADS)

    Jalal, Muhammad Zulqarnain Hakim Abd; Nawawi, Mohd Kamal Mohd; Laailatul Hanim Mat Desa, Wan; Khalid, Ruzelan; Khalid Abduljabbar, Waleed; Ramli, Razamin

    2017-09-01

    With the increasing awareness of the consumers about environmental issues, businesses, households and governments increasingly want use green products and services which lead to green supply chain. This paper discusses a simulation study of a selected road traffic system that will contribute to the air pollution if in the congestion state. Road traffic congestion (RTC) can be caused by a temporary obstruction, a permanent capacity bottleneck in the network itself, and stochastic fluctuation in demand within a particular sector of the network, leading to spillback and queue propagation. A discrete-event simulation model is developed to represent the real traffic light control (TLC) system condition during peak hours. Certain performance measures such as average waiting time and queue length were measured using the simulation model. Existing system uses pre-set cycle time to control the light changes which is fixed time cycle. In this research, we test several other combination of pre-set cycle time with the objective to find the best system. In addition, we plan to use a combination of the pre-set cycle time and a proximity sensor which have the authority to manipulate the cycle time of the lights. The sensors work in such situation when the street seems to have less occupied vehicles, obviously it may not need a normal cycle for green light, and automatically change the cycle to street where vehicle is present.

  9. Collision Avoidance for Airport Traffic Simulation Evaluation

    NASA Technical Reports Server (NTRS)

    Jones, Denise R.; Prinzel, Lawrence J., III; Shelton, Kevin J.; Bailey, Randall E.; Otero, Sharon D.; Barker, Glover D.

    2010-01-01

    A Collision Avoidance for Airport Traffic (CAAT) concept for the airport Terminal Maneuvering Area (TMA) was evaluated in a simulation study at the National Aeronautics and Space Administration (NASA) Langley Research Center. CAAT is being designed to enhance surface situation awareness and provide cockpit alerts of potential conflicts during runway, taxi, and low altitude air-to-air operations. The purpose of the study was to evaluate pilot reaction to conflict events in the TMA near the airport, different alert timings for various scenarios, alerting display concepts, and directive alerting concepts. This paper gives an overview of the conflict detection and resolution (CD&R) concept, simulation study, and test results

  10. Traffic and Driving Simulator Based on Architecture of Interactive Motion

    PubMed Central

    Paz, Alexander; Veeramisti, Naveen; Khaddar, Romesh; de la Fuente-Mella, Hanns; Modorcea, Luiza

    2015-01-01

    This study proposes an architecture for an interactive motion-based traffic simulation environment. In order to enhance modeling realism involving actual human beings, the proposed architecture integrates multiple types of simulation, including: (i) motion-based driving simulation, (ii) pedestrian simulation, (iii) motorcycling and bicycling simulation, and (iv) traffic flow simulation. The architecture has been designed to enable the simulation of the entire network; as a result, the actual driver, pedestrian, and bike rider can navigate anywhere in the system. In addition, the background traffic interacts with the actual human beings. This is accomplished by using a hybrid mesomicroscopic traffic flow simulation modeling approach. The mesoscopic traffic flow simulation model loads the results of a user equilibrium traffic assignment solution and propagates the corresponding traffic through the entire system. The microscopic traffic flow simulation model provides background traffic around the vicinities where actual human beings are navigating the system. The two traffic flow simulation models interact continuously to update system conditions based on the interactions between actual humans and the fully simulated entities. Implementation efforts are currently in progress and some preliminary tests of individual components have been conducted. The implementation of the proposed architecture faces significant challenges ranging from multiplatform and multilanguage integration to multievent communication and coordination. PMID:26491711

  11. Traffic and Driving Simulator Based on Architecture of Interactive Motion.

    PubMed

    Paz, Alexander; Veeramisti, Naveen; Khaddar, Romesh; de la Fuente-Mella, Hanns; Modorcea, Luiza

    2015-01-01

    This study proposes an architecture for an interactive motion-based traffic simulation environment. In order to enhance modeling realism involving actual human beings, the proposed architecture integrates multiple types of simulation, including: (i) motion-based driving simulation, (ii) pedestrian simulation, (iii) motorcycling and bicycling simulation, and (iv) traffic flow simulation. The architecture has been designed to enable the simulation of the entire network; as a result, the actual driver, pedestrian, and bike rider can navigate anywhere in the system. In addition, the background traffic interacts with the actual human beings. This is accomplished by using a hybrid mesomicroscopic traffic flow simulation modeling approach. The mesoscopic traffic flow simulation model loads the results of a user equilibrium traffic assignment solution and propagates the corresponding traffic through the entire system. The microscopic traffic flow simulation model provides background traffic around the vicinities where actual human beings are navigating the system. The two traffic flow simulation models interact continuously to update system conditions based on the interactions between actual humans and the fully simulated entities. Implementation efforts are currently in progress and some preliminary tests of individual components have been conducted. The implementation of the proposed architecture faces significant challenges ranging from multiplatform and multilanguage integration to multievent communication and coordination.

  12. 49 CFR 1.94 - The National Highway Traffic Safety Administration.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... research, development, and demonstration program; administering highway safety grant programs to encourage... information system improvements, motorcyclist safety, and child safety restraints; administering a nationwide... importation of motor vehicles and motor vehicle equipment; conducting research, development, and testing...

  13. Spontaneous phase transition from free flow to synchronized flow in traffic on a single-lane highway

    NASA Astrophysics Data System (ADS)

    Jin, Cheng-Jie; Wang, Wei; Jiang, Rui; Zhang, H. M.; Wang, Hao

    2013-01-01

    Traffic flow complexity comes from the car-following and lane-changing behavior. Based on empirical data for individual vehicle speeds and time headways measured on a single-lane highway section, we have studied the traffic flow properties induced by pure car-following behavior. We have found that a spontaneous sudden drop in velocity could happen in a platoon of vehicles when the velocity of the leading vehicle is quite high (˜70 km/h). In contrast, when the velocity of the leading vehicle in a platoon slows down, such a spontaneous sudden drop of velocity has not been observed. Our finding indicates that traffic breakdown on a single-lane road might be a phase transition from free flow to synchronized flow (F→S transition). We have found that the flow rate within the emergent synchronized flow can be either smaller or larger than the flow rate in the free flow within which the synchronized flow propagates. Our empirical findings support Kerner's three-phase theory in which traffic breakdown is associated with an F→S transition.

  14. Spontaneous phase transition from free flow to synchronized flow in traffic on a single-lane highway.

    PubMed

    Jin, Cheng-Jie; Wang, Wei; Jiang, Rui; Zhang, H M; Wang, Hao

    2013-01-01

    Traffic flow complexity comes from the car-following and lane-changing behavior. Based on empirical data for individual vehicle speeds and time headways measured on a single-lane highway section, we have studied the traffic flow properties induced by pure car-following behavior. We have found that a spontaneous sudden drop in velocity could happen in a platoon of vehicles when the velocity of the leading vehicle is quite high (~70 km/h). In contrast, when the velocity of the leading vehicle in a platoon slows down, such a spontaneous sudden drop of velocity has not been observed. Our finding indicates that traffic breakdown on a single-lane road might be a phase transition from free flow to synchronized flow (F→S transition). We have found that the flow rate within the emergent synchronized flow can be either smaller or larger than the flow rate in the free flow within which the synchronized flow propagates. Our empirical findings support Kerner's three-phase theory in which traffic breakdown is associated with an F→S transition.

  15. [Amphetamine use by truck drivers on highways of Sao Paulo State: a risk for the occurrence of traffic accidents?].

    PubMed

    Takitane, Juliana; de Oliveira, Lucio Garcia; Endo, Ligia Góes; de Oliveira, Keziah Cristina Barbosa Gruber; Muñoz, Daniel Romero; Yonamine, Mauricio; Leyton, Vilma

    2013-05-01

    The use of amphetamines in Brazil is common among truck drivers, which may be an important factor in the occurrence of traffic accidents. This article seeks to estimate the prevalence of amphetamine use among truck drivers. Drivers (N = 134) were stopped on two different highways in Sao Paulo state and they were asked to answer a questionnaire and provide a urine sample for toxicological analysis. All data were analyzed on Stata 8.0. All participants were males with low levels of schooling, whose mean age was 40.8 years. The presence of amphetamines was detected in 10.8% of all urine samples collected, being commonly justified in order to make truck drivers able to maintain their state of awareness. Amphetamine use was detected among truck drivers on Sao Paulo highways. The problem is that when the stimulant effects wear off, sleepiness due to sleep deprivation reduces concentration and good driver performance, making drivers vulnerable to traffic accidents and the related effects.

  16. Source apportionment of organic pollutants of a highway-traffic-influenced urban area in Bayreuth (Germany) using biomarker and stable carbon isotope signatures.

    PubMed

    Glaser, Bruno; Dreyer, Annekatrin; Bock, Michael; Fiedler, Stefan; Mehring, Marion; Heitmann, Tobias

    2005-06-01

    Traffic- and urban-influenced areas are prone to enhanced pollution with products of incomplete combustion of fossil fuels and biomass such as black carbon or polycyclic aromatic hydrocarbons (PAHs). Black carbon is composed of aromatic and graphitic structures and may act as a carrier for pollutants such as PAHs and heavy metals. However, little is known about possible contributions of traffic-derived black carbon to the black carbon inventory in soils. Similar uncertainties exist regarding the contribution of different pollutant sources to total PAH and black carbon contents. Therefore, the objective of this study was to quantify the importance of traffic pollution to black carbon and PAH inventories in soils. PAH contamination of soils adjacent to a major German highway in the urban area of Bayreuth with about 50,000 vehicles per day was in the same order of magnitude compared to highway-close soils reported in other studies. Using molecular (black carbon and PAHs) and compound-specific stable carbon isotope evidence (PAHs) it was demonstrated that this contamination originated not only from automobile exhausts, here primarily diesel, but also from tire abrasion and tailpipe soot which significantly contributed to the traffic-caused black carbon and PAH contamination. Low molecular weight PAHs were more widely transported than their heavy molecular counterparts (local distillation), whereas highway-traffic-caused black carbon contamination was distributed to at least 30 m from the highway. On the other hand, urban fire exhausts were distributed more homogeneously among the urban area.

  17. Simulation of the hydraulic performance of highway filter drains through laboratory models and stormwater management tools.

    PubMed

    Sañudo-Fontaneda, Luis A; Jato-Espino, Daniel; Lashford, Craig; Coupe, Stephen J

    2017-05-23

    Road drainage is one of the most relevant assets in transport infrastructure due to its inherent influence on traffic management and road safety. Highway filter drains (HFDs), also known as "French Drains", are the main drainage system currently in use in the UK, throughout 7000 km of its strategic road network. Despite being a widespread technique across the whole country, little research has been completed on their design considerations and their subsequent impact on their hydraulic performance, representing a gap in the field. Laboratory experiments have been proven to be a reliable indicator for the simulation of the hydraulic performance of stormwater best management practices (BMPs). In addition to this, stormwater management tools (SMT) have been preferentially chosen as a design tool for BMPs by practitioners from all over the world. In this context, this research aims to investigate the hydraulic performance of HFDs by comparing the results from laboratory simulation and two widely used SMT such as the US EPA's stormwater management model (SWMM) and MicroDrainage®. Statistical analyses were applied to a series of rainfall scenarios simulated, showing a high level of accuracy between the results obtained in laboratory and using SMT as indicated by the high and low values of the Nash-Sutcliffe and R (2) coefficients and root-mean-square error (RMSE) reached, which validated the usefulness of SMT to determine the hydraulic performance of HFDs.

  18. 78 FR 26847 - Including Specific Pavement Types in Federal-aid Highway Traffic Noise Analyses

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-08

    ...) If you have done or currently are doing tire pavement research: What is this research? Why are you... analyses, the FHWA is referring to these pavements used in the PEI Study, but also any other specific... in the highway industry, the FHWA is interested in how some of these new technologies and techniques...

  19. 75 FR 39820 - Procedures for Abatement of Highway Traffic Noise and Construction Noise

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-13

    ....regulations.gov . Regulations.gov is available 24 hours each day, 365 days each year. Electronic submission...., Environmental Science Associates, HNTB Corporation, Karel Cubic and Sharon Paul Carpenter), 1 university (East... decrease criterion and substantial increase criteria's 5-15 dB(A) range. Design Year, two State highway...

  20. Boundary Layer Model for Air Pollutant Concentrations Due to Highway Traffic

    ERIC Educational Resources Information Center

    Ragland, Kenneth W.; Peirce, J. Jeffrey

    1975-01-01

    A numerical solution of the three-dimensional steady-state diffusion equation for a finite width line source is presented. The wind speed and eddy diffusivity as a function of height above the roadway are obtained. Normalized ground level and elevated concentrations near a highway are obtained for winds perpendicular, parallel, and at 45 degrees.…

  1. Boundary Layer Model for Air Pollutant Concentrations Due to Highway Traffic

    ERIC Educational Resources Information Center

    Ragland, Kenneth W.; Peirce, J. Jeffrey

    1975-01-01

    A numerical solution of the three-dimensional steady-state diffusion equation for a finite width line source is presented. The wind speed and eddy diffusivity as a function of height above the roadway are obtained. Normalized ground level and elevated concentrations near a highway are obtained for winds perpendicular, parallel, and at 45 degrees.…

  2. Microscopic theory of traffic-flow instability governing traffic breakdown at highway bottlenecks: Growing wave of increase in speed in synchronized flow

    NASA Astrophysics Data System (ADS)

    Kerner, Boris S.

    2015-12-01

    We have revealed a growing local speed wave of increase in speed that can randomly occur in synchronized flow (S) at a highway bottleneck. The development of such a traffic flow instability leads to free flow (F) at the bottleneck; therefore, we call this instability an S →F instability. Whereas the S →F instability leads to a local increase in speed (growing acceleration wave), in contrast, the classical traffic flow instability introduced in the 1950s-1960s and incorporated later in a huge number of traffic flow models leads to a growing wave of a local decrease in speed (growing deceleration wave). We have found that the S →F instability can occur only if there is a finite time delay in driver overacceleration. The initial speed disturbance of increase in speed (called "speed peak") that initiates the S →F instability occurs usually at the downstream front of synchronized flow at the bottleneck. There can be many speed peaks with random amplitudes that occur randomly over time. It has been found that the S →F instability exhibits a nucleation nature: Only when a speed peak amplitude is large enough can the S →F instability occur; in contrast, speed peaks of smaller amplitudes cause dissolving speed waves of a local increase in speed (dissolving acceleration waves) in synchronized flow. We have found that the S →F instability governs traffic breakdown—a phase transition from free flow to synchronized flow (F →S transition) at the bottleneck: The nucleation nature of the S →F instability explains the metastability of free flow with respect to an F →S transition at the bottleneck.

  3. Microscopic theory of traffic-flow instability governing traffic breakdown at highway bottlenecks: Growing wave of increase in speed in synchronized flow.

    PubMed

    Kerner, Boris S

    2015-12-01

    We have revealed a growing local speed wave of increase in speed that can randomly occur in synchronized flow (S) at a highway bottleneck. The development of such a traffic flow instability leads to free flow (F) at the bottleneck; therefore, we call this instability an S→F instability. Whereas the S→F instability leads to a local increase in speed (growing acceleration wave), in contrast, the classical traffic flow instability introduced in the 1950s-1960s and incorporated later in a huge number of traffic flow models leads to a growing wave of a local decrease in speed (growing deceleration wave). We have found that the S→F instability can occur only if there is a finite time delay in driver overacceleration. The initial speed disturbance of increase in speed (called "speed peak") that initiates the S→F instability occurs usually at the downstream front of synchronized flow at the bottleneck. There can be many speed peaks with random amplitudes that occur randomly over time. It has been found that the S→F instability exhibits a nucleation nature: Only when a speed peak amplitude is large enough can the S→F instability occur; in contrast, speed peaks of smaller amplitudes cause dissolving speed waves of a local increase in speed (dissolving acceleration waves) in synchronized flow. We have found that the S→F instability governs traffic breakdown-a phase transition from free flow to synchronized flow (F→S transition) at the bottleneck: The nucleation nature of the S→F instability explains the metastability of free flow with respect to an F→S transition at the bottleneck.

  4. Traffic-related trace elements in soils along six highway segments on the Tibetan Plateau: Influence factors and spatial variation.

    PubMed

    Wang, Guanxing; Zeng, Chen; Zhang, Fan; Zhang, Yili; Scott, Christopher A; Yan, Xuedong

    2017-03-01

    The accumulation of traffic-related trace elements in soil as the result of anthropogenic activities raises serious concerns about environmental pollution and public health. Traffic is the main source of trace elements in roadside soil on the Tibetan Plateau, an area otherwise devoid of industrial emissions. Indeed, the rapid development of tourism and transportation in this region means it is becoming increasingly important to identify the accumulation levels, influence distance, spatial distribution, and other relevant factors influencing trace elements. In this study, 229 soil samples along six segments of the major transportation routes on the Tibetan Plateau (highways G214, S308, and G109), were collected for analysis of eight trace elements (Cr, Co, Ni, As, Cu, Zn, Cd, and Pb). The results of statistical analyses showed that of the eight trace elements in soils, Cu, Zn, Cd, and Pb were primarily derived from traffic. The relationship between the trace element accumulation levels and the distance from the roadside followed an exponential decline, with the exception of Segment 3, the only unpaved gravel road studied. In addition, the distance of influence from the roadside varied by trace element and segment, ranging from 16m to 144m. Background values for each segment were different because of soil heterogeneity, while a number of other potential influencing factors (including traffic volume, road surface material, roadside distance, land cover, terrain, and altitude) all had significant effects on trace-element concentrations. Overall, however, concentrations along most of the road segments investigated were at, or below, levels defined as low on the Nemero Synthesis index.

  5. Characterization of traffic-related PM concentration distribution and fluctuation patterns in near-highway urban residential street canyons.

    PubMed

    Hahn, Intaek; Brixey, Laurie A; Wiener, Russell W; Henkle, Stacy W; Baldauf, Richard

    2009-12-01

    Analyses of outdoor traffic-related particulate matter (PM) concentration distribution and fluctuation patterns in urban street canyons within a microscale distance of less than 500 m from a highway source are presented as part of the results from the Brooklyn Traffic Real-Time Ambient Pollutant Penetration and Environmental Dispersion (B-TRAPPED) study. Various patterns of spatial and temporal changes in the street canyon PM concentrations were investigated using time-series data of real-time PM concentrations measured during multiple monitoring periods. Concurrent time-series data of local street canyon wind conditions and wind data from the John F. Kennedy (JFK) International Airport National Weather Service (NWS) were used to characterize the effects of various wind conditions on the behavior of street canyon PM concentrations.Our results suggest that wind direction may strongly influence time-averaged mean PM concentration distribution patterns in near-highway urban street canyons. The rooftop-level wind speeds were found to be strongly correlated with the PM concentration fluctuation intensities in the middle sections of the street blocks. The ambient turbulence generated by shifting local wind directions (angles) showed a good correlation with the PM concentration fluctuation intensities along the entire distance of the first and second street blocks only when the wind angle standard deviations were larger than 30 degrees. Within-canyon turbulent shearing, caused by fluctuating local street canyon wind speeds, showed no correlation with PM concentration fluctuation intensities. The time-averaged mean PM concentration distribution along the longitudinal distances of the street blocks when wind direction was mostly constantly parallel to the street was found to be similar to the distribution pattern for the entire monitoring period when wind direction fluctuated wildly. Finally, we showed that two different PM concentration metrics-time-averaged mean

  6. Assessment of palladium footprint from road traffic in two highway environments.

    PubMed

    Clément, N; Muresan, B; Hedde, M; François, D

    2015-12-01

    Palladium (Pd) is an emerging eco-toxic pollutant from vehicle catalytic converters, emitted worldwide for more than two decades. Nowadays, the spatial extent of Pd fallout is growing along roads, but its subsequent fate in neighboring terrestrial ecosystems has not been extensively addressed yet. Two sites representative of contrasted natural environments (field, forest) but located under similar ambient conditions were selected to isolate and analyze the specific impact of vehicular Pd, along highway A71, France. Pd impregnation was assessed along 200-m-long transects perpendicular to the highway. Contents were measured in soils, earthworms, plant communities of the right of way (ROW), and the neighboring field (crop weeds), as well as in a moss, and bramble and ivy leaves in the forest. The direct impact of Pd fallouts appears to be confined in the grassy verge of the highway: ROW soils ([Pd] = 52-65 ng g(-1)), earthworms ([Pd] = 18-38 ng g(-1)), and plant community ([Pd] = 10-23 ng g(-1)). Pd footprint is pointed out by the accumulation index calculated for earthworms and plant communities even though transfer coefficients indicate the absence of bioaccumulation (TCs < 1). An indirect longer range transfer of Pd is identified, induced by hydric transport of organic matter.

  7. 78 FR 53497 - Uniform Procedures for State Highway Safety Grant Programs

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-29

    ... National Highway Traffic Safety Administration Uniform Procedures for State Highway Safety Grant Programs AGENCY: National Highway Traffic Safety Administration, DOT. ACTION: Request for public comment on..., National Highway Traffic Safety Administration, Office of Regional Operations and Program...

  8. 23 CFR 500.204 - TMS components for highway traffic data.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ..., shall address the components in paragraphs (b) through (h) of this section. (b) Precision of reported... counters of traffic volumes, vehicle classification, and vehicle weight to provide estimates of changes in... subpart. As appropriate, sufficient continuous counts of vehicle classification and vehicle weight...

  9. 23 CFR 500.204 - TMS components for highway traffic data.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ..., shall address the components in paragraphs (b) through (h) of this section. (b) Precision of reported... counters of traffic volumes, vehicle classification, and vehicle weight to provide estimates of changes in... subpart. As appropriate, sufficient continuous counts of vehicle classification and vehicle weight...

  10. 23 CFR 500.204 - TMS components for highway traffic data.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ..., shall address the components in paragraphs (b) through (h) of this section. (b) Precision of reported... counters of traffic volumes, vehicle classification, and vehicle weight to provide estimates of changes in... subpart. As appropriate, sufficient continuous counts of vehicle classification and vehicle weight...

  11. 23 CFR 500.204 - TMS components for highway traffic data.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ..., shall address the components in paragraphs (b) through (h) of this section. (b) Precision of reported... counters of traffic volumes, vehicle classification, and vehicle weight to provide estimates of changes in... subpart. As appropriate, sufficient continuous counts of vehicle classification and vehicle weight...

  12. Examining Road Traffic Mortality Status in China: A Simulation Study

    PubMed Central

    Schwebel, David C.; Li, Li; Hu, Guoqing

    2016-01-01

    Background Data from the Chinese police service suggest substantial reductions in road traffic injuries since 2002, but critics have questioned the accuracy of those data, especially considering conflicting data reported by the health department. Methods To address the gap between police and health department data and to determine which may be more accurate, we conducted a simulation study based on the modified Smeed equation, which delineates a non-linear relation between road traffic mortality and the level of motorization in a country or region. Our goal was to simulate trends in road traffic mortality in China and compare performances in road traffic safety management between China and 13 other countries. Results Chinese police data indicate a peak in road traffic mortalities in 2002 and a significant and a gradual decrease in population-based road traffic mortality since 2002. Health department data show the road traffic mortality peaked in 2012. In addition, police data suggest China’s road traffic mortality peaked at a much lower motorization level (0.061 motor vehicles per person) in 2002, followed by a reduction in mortality to a level comparable to that of developed countries. Simulation results based on health department data suggest high road traffic mortality, with a mortality peak in 2012 at a moderate motorization level (0.174 motor vehicles per person). Comparisons to the other 13 countries suggest the health data from China may be more valid than the police data. Conclusion Our simulation data indicate China is still at a stage of high road traffic mortality, as suggested by health data, rather than a stage of low road traffic mortality, as suggested by police data. More efforts are needed to integrate safety into road design, improve road traffic management, improve data quality, and alter unsafe behaviors of pedestrians, drivers and passengers in China. PMID:27071008

  13. Examining Road Traffic Mortality Status in China: A Simulation Study.

    PubMed

    Huang, Helai; Yin, Qingyi; Schwebel, David C; Li, Li; Hu, Guoqing

    2016-01-01

    Data from the Chinese police service suggest substantial reductions in road traffic injuries since 2002, but critics have questioned the accuracy of those data, especially considering conflicting data reported by the health department. To address the gap between police and health department data and to determine which may be more accurate, we conducted a simulation study based on the modified Smeed equation, which delineates a non-linear relation between road traffic mortality and the level of motorization in a country or region. Our goal was to simulate trends in road traffic mortality in China and compare performances in road traffic safety management between China and 13 other countries. Chinese police data indicate a peak in road traffic mortalities in 2002 and a significant and a gradual decrease in population-based road traffic mortality since 2002. Health department data show the road traffic mortality peaked in 2012. In addition, police data suggest China's road traffic mortality peaked at a much lower motorization level (0.061 motor vehicles per person) in 2002, followed by a reduction in mortality to a level comparable to that of developed countries. Simulation results based on health department data suggest high road traffic mortality, with a mortality peak in 2012 at a moderate motorization level (0.174 motor vehicles per person). Comparisons to the other 13 countries suggest the health data from China may be more valid than the police data. Our simulation data indicate China is still at a stage of high road traffic mortality, as suggested by health data, rather than a stage of low road traffic mortality, as suggested by police data. More efforts are needed to integrate safety into road design, improve road traffic management, improve data quality, and alter unsafe behaviors of pedestrians, drivers and passengers in China.

  14. Fifteenth Space Simulation Conference: Support the Highway to Space Through Testing

    NASA Technical Reports Server (NTRS)

    Stecher, Joseph (Editor)

    1988-01-01

    The Institute of Environmental Sciences Fifteenth Space Simulation Conference, Support the Highway to Space Through Testing, provided participants a forum to acquire and exchange information on the state-of-the-art in space simulation, test technology, thermal simulation and protection, contamination, and techniques of test measurements.

  15. Coordination of Emergency Medical Services for a Major Road Traffic Accident on a Swiss Suburban Highway.

    PubMed

    Dami, Fabrice; Fuchs, Vincent; Péclard, Etienne; Potin, Mathieu; Vallotton, Laurent; Carron, Pierre-Nicolas

    2009-06-01

    On 9th April 2008 at 2:14 p.m., on the highway between Lausanne and Vevey in western Switzerland, there was a 72-car pileup including five trucks that caused one death and injured 26 others. The relatively light toll was attributed to reduced vehicular speeds on account of foggy weather, together with the quick actions and effectiveness of the first responders and the excellent collaboration between the various rescue groups (medical rescue services, fire and police departments). For the first time, we used an innovative on-site medical command and control system, based on a binomial team. Two hours after the accident, the last of the injured had been evacuated and first aid on the site had ended. This article describes how the Emergency Medical Services from the State of Vaud, Switzerland, handled the situation and how the binomial team is structured.

  16. Traffic scenario generation technique for piloted simulation studies

    NASA Technical Reports Server (NTRS)

    Williams, David H.; Wells, Douglas C.

    1985-01-01

    Piloted simulation studies of cockpit traffic display concepts require the development of representative traffic scenarios. With the exception of specific aircraft interaction issues, most research questions can be addressed using traffic scenarios consisting of prerecorded aircraft movements merged together to form a desired traffic pattern. Prerecorded traffic scenarios have distinct research advantages, allowing control of traffic encounters with repeatability of scenarios between different test subjects. A technique is described for generation of prerecorded jet transport traffic scenarios suitable for use in piloted simulation studies. Individual flight profiles for the aircraft in the scenario are created interactively with a computer program designed specifically for this purpose. The profiles are then time-correlated and merged into a complete scenario. This technique was used to create traffic scenarios for the Denver, Colorado area with operations centered at Stapleton International Airport. Traffic scenarios for other areas may also be created using this technique, with appropriate modifications made to the navigation fix locations contained in the flight profile generation program.

  17. A Teamwork-Oriented Air Traffic Control Simulator

    DTIC Science & Technology

    2006-06-01

    Traffic Control, Teamwork, Pilot , En-route controller, Approach Controller, Tower Controller, XML, OOP, RMI, Simulation. 16. PRICE CODE 17. SECURITY...Cases .........................................................30 4. Pilot Use Cases...Control Specification .............................................................43 4. Pilot Specification

  18. A Circuit Simulation Technique for Congested Network Traffic Assignment Problem

    NASA Astrophysics Data System (ADS)

    Cho, Hsun-Jung; Huang, Heng

    2007-12-01

    The relation between electrical circuit and traffic network has been proposed by Sasaki and Inouye, but they proposed link cost function is a linear function which cannot present the congestion situation. Cho and Huang extended the link cost function to a nonlinear function which can explain the congested network. In this paper, we proposed a foremost and novel approach to solve the traffic assignment problem (TAP) by simulating the electrical circuit network which consists of nonlinear link cost function models. Comparing with the solutions of Frank-Wolfe algorithm, the simulation results are nearly identical. Thus, the simulation of a network circuit model can be applied to solve network traffic assignment problems. Finally, two examples are proposed, and the results confirmed that electrical circuit simulation is workable in solving congested network traffic assignment problems.

  19. Lightweight simulation of air traffic control using simple temporal networks

    NASA Technical Reports Server (NTRS)

    Knight, Russell

    2005-01-01

    We provide a formulation of the air traffic control problem and a solver for this problem that makes use of temporal constraint networks and simple geometric reasoning. We provide results showing that this approach is practical for realistic simulated problems.

  20. Lightweight simulation of air traffic control using simple temporal networks

    NASA Technical Reports Server (NTRS)

    Knight, Russell

    2005-01-01

    We provide a formulation of the air traffic control problem and a solver for this problem that makes use of temporal constraint networks and simple geometric reasoning. We provide results showing that this approach is practical for realistic simulated problems.

  1. Simulation Study of Traffic Flow At a Three Way Intersection

    DTIC Science & Technology

    1988-09-01

    INTERSECTION by Chong Chul Song September 1988 Thesis Advisor: Peter A. W. Lewis Approved for public release; distribution is unlimited i~ K...II Title (Include security classification) SIMULATION STUDY OF TRAFFIC FLOW AT A THREE WAY INTERSECTION 12 Personal Author(s) Chong Chul Song 13a...distribution is unlimited. Simulation Study of Traffic Flow at a Three Way Intersection by Chong Chul Song Major, Republic Of Korea Army B.S., Korea

  2. The influence of curbs on driver behaviors in four-lane rural highways--A driving simulator based study.

    PubMed

    Yang, Qiang; Overton, Ryan; Han, Lee D; Yan, Xuedong; Richards, Stephen H

    2013-01-01

    The speed limit of 55mph (88km/h) is typically used on rural highways in the U.S. For locations where curbs are installed along these roadways, some transportation agencies have suggested the use of a lower 45mph (72km/h) speed limit because, according to AASHTO, running into curbs at high speeds may cause significant vehicular damage and even severe injuries. However, it has also been argued that lowering the speed limit after the installation of curbs may cause confusion in drivers, who do not perceive the risk associated with the newly installed curbs and tend to operate their vehicles at the same speed as before. To better understand driver behavior on rural highways before and after curb installation, and with different speed limits, researchers at the University of Tennessee conducted a series of experiments in two-lane and four-lane highways on a high-fidelity driving simulator. This paper mainly presents the findings from the four-lane study, and compares the results from the previous two-lane study. The scenario matrix consists of several dimensions including posted speed limit (45 and 55mph, or 72 and 88km/h), curb installation, lateral clearance between the edge of travel lane and the curb (2ft, 6ft, and no-curb, or 0.6m, 1.8m, and no-curb), weather (clear and fog), traffic conditions in the next lane (1400veh/h and 400veh/h), etc. For each subject under different experimental scenarios, detailed driving parameters, such as driving speed and vehicle position in the travel lane, were recorded and analyzed subsequently. Results of the study suggest that driver behaviors are influenced by the various factors in a complex and interrelated manner. It is likely that drivers do not perceive the risk from the curb in determining their speed on four-lane rural highways. However, it is found that curbs may provide certain guidance to drivers, especially in selecting lane position. Compared to the previous research in two-lane conditions, it is found that drivers

  3. Simulation Study of Port Container Terminal Quay Side Traffic

    NASA Astrophysics Data System (ADS)

    Lau, Y. K. H.; Lee, M. Y. N.

    This paper studies the berth operation, in particular, the quay side traffic condition in one of the busiest container port in Hong Kong. The developed simulation model effectively incorporates both the traffic model and service model, built using the AutoMod simulation tool. Sensitivity analysis was performed on different scenarios and configurations at the quay side. The results reveal that an increase in the number of internal tractors increases the productivity of the quay cranes, and the deployment of a traffic controller can improve the traffic congestions but may not help to improve the utilization of the quay cranes. Apart from the flow control of the tractors, the closure of tractor lanes under a quay crane also reduces the performance of the quay crane. The simulation studies performed provides a definitive basis for evaluating the performance of the berth and for determining the potential for the operation improvements of a port container terminal in general.

  4. Synchronized flow in oversaturated city traffic.

    PubMed

    Kerner, Boris S; Klenov, Sergey L; Hermanns, Gerhard; Hemmerle, Peter; Rehborn, Hubert; Schreckenberg, Michael

    2013-11-01

    Based on numerical simulations with a stochastic three-phase traffic flow model, we reveal that moving queues (moving jams) in oversaturated city traffic dissolve at some distance upstream of the traffic signal while transforming into synchronized flow. It is found that, as in highway traffic [Kerner, Phys. Rev. E 85, 036110 (2012)], such a jam-absorption effect in city traffic is explained by a strong driver's speed adaptation: Time headways (space gaps) between vehicles increase upstream of a moving queue (moving jam), resulting in moving queue dissolution. It turns out that at given traffic signal parameters, the stronger the speed adaptation effect, the shorter the mean distance between the signal location and the road location at which moving queues dissolve fully and oversaturated traffic consists of synchronized flow only. A comparison of the synchronized flow in city traffic found in this Brief Report with synchronized flow in highway traffic is made.

  5. Probabilistic physical characteristics of phase transitions at highway bottlenecks: Incommensurability of three-phase and two-phase traffic-flow theories

    NASA Astrophysics Data System (ADS)

    Kerner, Boris S.; Klenov, Sergey L.; Schreckenberg, Michael

    2014-05-01

    Physical features of induced phase transitions in a metastable free flow at an on-ramp bottleneck in three-phase and two-phase cellular automaton (CA) traffic-flow models have been revealed. It turns out that at given flow rates at the bottleneck, to induce a moving jam (F→J transition) in the metastable free flow through the application of a time-limited on-ramp inflow impulse, in both two-phase and three-phase CA models the same critical amplitude of the impulse is required. If a smaller impulse than this critical one is applied, neither F→J transition nor other phase transitions can occur in the two-phase CA model. We have found that in contrast with the two-phase CA model, in the three-phase CA model, if the same smaller impulse is applied, then a phase transition from free flow to synchronized flow (F→S transition) can be induced at the bottleneck. This explains why rather than the F→J transition, in the three-phase theory traffic breakdown at a highway bottleneck is governed by an F→S transition, as observed in real measured traffic data. None of two-phase traffic-flow theories incorporates an F→S transition in a metastable free flow at the bottleneck that is the main feature of the three-phase theory. On the one hand, this shows the incommensurability of three-phase and two-phase traffic-flow theories. On the other hand, this clarifies why none of the two-phase traffic-flow theories can explain the set of fundamental empirical features of traffic breakdown at highway bottlenecks.

  6. Probabilistic physical characteristics of phase transitions at highway bottlenecks: incommensurability of three-phase and two-phase traffic-flow theories.

    PubMed

    Kerner, Boris S; Klenov, Sergey L; Schreckenberg, Michael

    2014-05-01

    Physical features of induced phase transitions in a metastable free flow at an on-ramp bottleneck in three-phase and two-phase cellular automaton (CA) traffic-flow models have been revealed. It turns out that at given flow rates at the bottleneck, to induce a moving jam (F → J transition) in the metastable free flow through the application of a time-limited on-ramp inflow impulse, in both two-phase and three-phase CA models the same critical amplitude of the impulse is required. If a smaller impulse than this critical one is applied, neither F → J transition nor other phase transitions can occur in the two-phase CA model. We have found that in contrast with the two-phase CA model, in the three-phase CA model, if the same smaller impulse is applied, then a phase transition from free flow to synchronized flow (F → S transition) can be induced at the bottleneck. This explains why rather than the F → J transition, in the three-phase theory traffic breakdown at a highway bottleneck is governed by an F → S transition, as observed in real measured traffic data. None of two-phase traffic-flow theories incorporates an F → S transition in a metastable free flow at the bottleneck that is the main feature of the three-phase theory. On the one hand, this shows the incommensurability of three-phase and two-phase traffic-flow theories. On the other hand, this clarifies why none of the two-phase traffic-flow theories can explain the set of fundamental empirical features of traffic breakdown at highway bottlenecks.

  7. Structural monitoring of a highway bridge using passive noise recordings from street traffic.

    PubMed

    Salvermoser, Johannes; Hadziioannou, Céline; Stähler, Simon C

    2015-12-01

    Structural damage on bridges presents a hazard to public safety and can lead to fatalities. This article contributes to the development of an alternative monitoring system for civil structures, based on passive measurements of seismic elastic waves. Cross-correlations of traffic noise recorded at geophone receiver pairs were found to be sufficiently stable for comparison and sensitive to velocity changes in the medium. As such velocity variations could be caused by damage, their detection would be valuable in structural health monitoring systems. A method, originally introduced for seismological applications and named Passive Image Interferometry, was used to quantify small velocity fluctuations in the medium and thereby observe structural changes. Evaluation of more than 2 months of continuous geophone recordings at a reinforced concrete bridge yielded velocity variations Δv/v in the range of -1.5% to +2.1%. The observed fluctuations correlate with associated temperature time series with a striking resemblance which is remarkable for two completely independent data sets. Using a linear regression approach, a relationship between temperature and velocity variations of on average 0.064% °C(-1) can be identified. This value corresponds well to other studies on concrete structures.

  8. Simulating traditional traffic data from satellite data: Preparing for real satellite data test

    NASA Astrophysics Data System (ADS)

    Jafar, Fatmeh Nazmi Ahmad

    This research addresses demonstrating that vehicles can in fact be detected in satellite imagery. A possible test that would allow such a demonstration would compare traditional ground data to ground data simulated from satellite data. Ground data could be simulated from satellite imagery by estimating when the vehicles assumed to be observed in the satellite imagery would pass a ground counter location. Even if all vehicles could be observed in the imagery, there could still be errors when estimating the times the observed vehicles would pass the ground counter location. In this research, we investigate the errors involved with simulating ground data from satellite data and determine which errors seem most important. Specifically, we investigate distance and speed errors. We find that the speed errors have a much greater effect than the distance errors in estimating when imaged vehicles would pass the ground counter location and that the distance errors involved can essentially be ignored. We then investigate the effect of speed errors in estimating volume counts past a ground counter from imaged satellite data. We define a measure to reflect the variation in the volume counts estimated from the image-based volume estimates. The value of the variation measure is reduced when the time of the image acquisition is included in the time interval of the estimated count past the ground counter location. In this case, the variation does not depend on the length of the count interval and equals the difference between the ratios of maximum speed to average highway speed and minimum assumed speed to average highway speed. When simulating ground data from image data on a highway with a platoon of traffic concentrated at a specific segment of the highway, the count interval that includes the platoon of traffic can be determined. The variation in volume measure would be reduced for such a count interval. The variation in the volume measure is also shown to be reduced when the

  9. Traffic simulations on parallel computers using domain decomposition techniques

    SciTech Connect

    Hanebutte, U.R.; Tentner, A.M.

    1995-12-31

    Large scale simulations of Intelligent Transportation Systems (ITS) can only be achieved by using the computing resources offered by parallel computing architectures. Domain decomposition techniques are proposed which allow the performance of traffic simulations with the standard simulation package TRAF-NETSIM on a 128 nodes IBM SPx parallel supercomputer as well as on a cluster of SUN workstations. Whilst this particular parallel implementation is based on NETSIM, a microscopic traffic simulation model, the presented strategy is applicable to a broad class of traffic simulations. An outer iteration loop must be introduced in order to converge to a global solution. A performance study that utilizes a scalable test network that consist of square-grids is presented, which addresses the performance penalty introduced by the additional iteration loop.

  10. Traffic and emission simulation in China based on statistical methodology

    NASA Astrophysics Data System (ADS)

    Liu, Huan; He, Kebin; Barth, Matthew

    2011-02-01

    To better understand how the traffic control can affect vehicle emissions, a novel TRaffic And Vehicle Emission Linkage (TRAVEL) approach was developed based on local traffic activity and emission data. This approach consists of a two-stage mapping from general traffic information to traffic flow patterns, and then to the aggregated emission rates. 39 traffic flow patterns and corresponding emission rates for light-duty and heavy-duty vehicles considering emission standards classification are generated. As a case study, vehicle activity and emissions during the Beijing Olympics were simulated and compared to BAU scenario. Approximately 42-65% of the gaseous pollutants and 24% of the particle pollutants from cars, taxies and buses were reduced. These results are validated by traffic and air quality monitoring data during the Olympics, as well as other emission inventory studies. This approach improves the ability to fast predict emission variation from traffic control measurements in several typical Chinese cities. Comments related to application of this approach with both advantages and limitations are included.

  11. [The characteristics of computer simulation of traffic accidents].

    PubMed

    Zou, Dong-Hua; Liu, Ning-Guo; Chen, Jian-Guo; Jin, Xian-Long; Zhang, Xiao-Yun; Zhang, Jian-Hua; Chen, Yi-Jiu

    2008-12-01

    To reconstruct the collision process of traffic accident and the injury mode of the victim by computer simulation technology in forensic assessment of traffic accident. Forty actual accidents were reconstructed by stimulation software and high performance computer based on analysis of the trace evidences at the scene, damage of the vehicles and injury of the victims, with 2 cases discussed in details. The reconstruction correlated very well in 28 cases, well in 9 cases, and suboptimal in 3 cases with the above parameters. Accurate reconstruction of the accident would be helpful for assessment of the injury mechanism of the victims. Reconstruction of the collision process of traffic accident and the injury mechanism of the victim by computer simulation is useful in traffic accident assessment.

  12. Simulating Timescale Dynamics of Network Traffic Using Homogeneous Modeling

    PubMed Central

    Yuan, Jian; Mills, Kevin L.

    2006-01-01

    Simulating and understanding traffic dynamics in large networks are difficult and challenging due to the complexity of such networks and the limitations inherent in simulation modeling. Typically, simulation models used to study traffic dynamics include substantial detail representing protocol mechanisms across several layers of functionality. Such models must be restricted in space and time in order to be computationally tractable. We propose an alternative simulation approach that uses homogeneous modeling with an increased level of abstraction, in order to explore networks at larger space-time scales than otherwise feasible and to develop intuition and insight about the space-time dynamics of large networks. To illustrate the utility of our approach, we examine some current understandings of the timescale dynamics of network traffic, and we discuss some speculative results obtained with homogeneous modeling. Using a wavelet-based technique, we show correlation structures, and changes in correlation structures, of network traffic under variations in traffic sources, transport mechanisms, and network structure. Our simulation results justify further investigation of our approach, which might benefit from cross-verifications against more detailed simulation models. PMID:27274931

  13. Evaluation of Intersection Traffic Control Measures through Simulation

    NASA Astrophysics Data System (ADS)

    Asaithambi, Gowri; Sivanandan, R.

    2015-12-01

    Modeling traffic flow is stochastic in nature due to randomness in variables such as vehicle arrivals and speeds. Due to this and due to complex vehicular interactions and their manoeuvres, it is extremely difficult to model the traffic flow through analytical methods. To study this type of complex traffic system and vehicle interactions, simulation is considered as an effective tool. Application of homogeneous traffic models to heterogeneous traffic may not be able to capture the complex manoeuvres and interactions in such flows. Hence, a microscopic simulation model for heterogeneous traffic is developed using object oriented concepts. This simulation model acts as a tool for evaluating various control measures at signalized intersections. The present study focuses on the evaluation of Right Turn Lane (RTL) and Channelised Left Turn Lane (CLTL). A sensitivity analysis was performed to evaluate RTL and CLTL by varying the approach volumes, turn proportions and turn lane lengths. RTL is found to be advantageous only up to certain approach volumes and right-turn proportions, beyond which it is counter-productive. CLTL is found to be advantageous for lower approach volumes for all turn proportions, signifying the benefits of CLTL. It is counter-productive for higher approach volume and lower turn proportions. This study pinpoints the break-even points for various scenarios. The developed simulation model can be used as an appropriate intersection lane control tool for enhancing the efficiency of flow at intersections. This model can also be employed for scenario analysis and can be valuable to field traffic engineers in implementing vehicle-type based and lane-based traffic control measures.

  14. Relaxation Criteria for Iterated Traffic Simulations

    NASA Astrophysics Data System (ADS)

    Kelly, Terence; Nagel, Kai

    Iterative transportation microsimulations adjust traveler route plans by iterating between a microsimulation and a route planner. At each iteration, the route planner adjusts individuals' route choices based on the preceding microsimulations. Empirically, this process yields good results, but it is usually unclear when to stop the iterative process when modeling real-world traffic. This paper investigates several criteria to judge relaxation of the iterative process, emphasizing criteria related to traveler decision-making.

  15. Analyzing the influence of median cross-section design on highway safety using vehicle dynamics simulations.

    PubMed

    Stine, Jason S; Hamblin, Bridget C; Brennan, Sean N; Donnell, Eric T

    2010-11-01

    Although vehicle dynamics simulations have long been used in vehicle design and crash reconstruction, their use for highway design is rare. This paper investigates the safety of highway medians through iterative simulations of off-road median encroachments. The commercially available software CarSim was used to simulate over one hundred thousand encroachments, representing the entire passenger vehicle fleet and a wide range of encroachment angles, departure speeds, steering inputs, and braking inputs. Each individual simulation output was then weighted using data from previous studies to reflect the probability of each specific accident scenario occurring in a real-life median encroachment. Results of this analysis illustrate the relative influence of median cross-section geometry on the resulting accident outcomes. The simulations indicate that the overall safety of a highway median depends on the occurrence of both vehicle rollover and median crossover events, and the cross-section shape, slope, and width are all shown to greatly affect each of these incidents. An evaluation of the simulation results was conducted with vehicle trajectories from previous experimental crash tests. Further assessment of the aggregate simulation results to actual crash data was achieved through comparison with several databases of crash statistics. Both efforts showed a strong agreement between the simulations and the real-life crash data.

  16. Urban traffic-network performance: flow theory and simulation experiments

    SciTech Connect

    Williams, J.C.

    1986-01-01

    Performance models for urban street networks were developed to describe the response of a traffic network to given travel-demand levels. The three basic traffic flow variables, speed, flow, and concentration, are defined at the network level, and three model systems are proposed. Each system consists of a series of interrelated, consistent functions between the three basic traffic-flow variables as well as the fraction of stopped vehicles in the network. These models are subsequently compared with the results of microscopic simulation of a small test network. The sensitivity of one of the model systems to a variety of network features was also explored. Three categories of features were considered, with the specific features tested listed in parentheses: network topology (block length and street width), traffic control (traffic signal coordination), and traffic characteristics (level of inter-vehicular interaction). Finally, a fundamental issue concerning the estimation of two network-level parameters (from a nonlinear relation in the two-fluid theory) was examined. The principal concern was that of comparability of these parameters when estimated with information from a single vehicle (or small group of vehicles), as done in conjunction with previous field studies, and when estimated with network-level information (i.e., all the vehicles), as is possible with simulation.

  17. Two-lane traffic simulations with a blockage induced by an accident car

    NASA Astrophysics Data System (ADS)

    Zhu, H. B.; Lei, L.; Dai, S. Q.

    2009-07-01

    Based on the two-lane traffic model proposed by Chowdhury et al., a highway traffic model with a blockage induced by an accident car is proposed, in which both symmetric lane changing rules and asymmetric lane changing rules are adopted. The fundamental diagrams and spatial-temporal profiles are presented after the numerical simulation and the jam transition is studied. It is shown that the accident car not only causes a local jam behind the accident car, but also causes vehicles to cluster in the bypass lane. The asymmetric lane changing rules are more advantageous in reducing the local jam than the symmetric lane changing rules when the accident car is in the right lane, and the symmetric lane changing rules are superior when the accident car is in the left lane. Furthermore the curves of lane-changing frequency against the total density are given. It is found that the vehicles will change lane more frequently when traffic is inhomogeneous with different types of vehicle or with an accident car.

  18. Exact-Differential Large-Scale Traffic Simulation

    SciTech Connect

    Hanai, Masatoshi; Suzumura, Toyotaro; Theodoropoulos, Georgios; Perumalla, Kalyan S

    2015-01-01

    Analyzing large-scale traffics by simulation needs repeating execution many times with various patterns of scenarios or parameters. Such repeating execution brings about big redundancy because the change from a prior scenario to a later scenario is very minor in most cases, for example, blocking only one of roads or changing the speed limit of several roads. In this paper, we propose a new redundancy reduction technique, called exact-differential simulation, which enables to simulate only changing scenarios in later execution while keeping exactly same results as in the case of whole simulation. The paper consists of two main efforts: (i) a key idea and algorithm of the exact-differential simulation, (ii) a method to build large-scale traffic simulation on the top of the exact-differential simulation. In experiments of Tokyo traffic simulation, the exact-differential simulation shows 7.26 times as much elapsed time improvement in average and 2.26 times improvement even in the worst case as the whole simulation.

  19. Study on traffic states and jamming transitions for two-lane highway including a bus by using a model with calibrated optimal velocity function

    NASA Astrophysics Data System (ADS)

    Li, Zhipeng; Yi, Yi

    2014-07-01

    In this paper, traffic states and jamming transitions on two-lane highway including a bus are studied by using a car following model with a calibrated optimal velocity function. We derive a new flow-density diagram with four distinctly separated traffic states, which is different from that of the earlier study obtained by applying the OVM with theoretical optimal velocity function. The spatio-temporal diagrams are presented to illustrate phase characteristics of each traffic state. It is found that the phase characteristic features of two of four states are different from any state of the earlier result, and traffic flow of state 2 and state 3 can reproduce some characteristics observed from empirical investigations such as centralized lane-changing, hanging tail of cluster, and synchronized flow. In addition, we have clarified the lane-changing behaviors and their effects on two-lane traffic flow including a bus. It is shown that the velocity oscillations behind the bus can help the lane-changing in state 2 and the behaviors of lane-changing are the important reason of forming of the synchronized flow in state 3. It is also concluded that lane-changing can only improve the current in the region of middle density.

  20. Cellular automata simulation of traffic including cars and bicycles

    NASA Astrophysics Data System (ADS)

    Vasic, Jelena; Ruskin, Heather J.

    2012-04-01

    As 'greening' of all aspects of human activity becomes mainstream, transportation science is also increasingly focused around sustainability. Modal co-existence between motorised and non-motorised traffic on urban networks is, in this context, of particular interest for traffic flow modelling. The main modelling problems here are posed by the heterogeneity of vehicles, including size and dynamics, and by the complex interactions at intersections. Herein we address these with a novel technique, based on one-dimensional cellular automata components, for modelling network infrastructure and its occupancy by vehicles. We use this modelling approach, together with a corresponding vehicle behaviour model, to simulate combined car and bicycle traffic for two elemental scenarios-examples of components that would be used in the building of an arbitrary network. Results of simulations performed on these scenarios, (i) a stretch of road and (ii) an intersection causing conflict between cars and bicycles sharing a lane, are presented and analysed.

  1. Increasing Intelligence in Inter-Vehicle Communications to Reduce Traffic Congestions: Experiments in Urban and Highway Environments

    PubMed Central

    Filho, Geraldo P. R.; Guidoni, Daniel L.; Pessin, Gustavo; Villas, Leandro A.; Ueyama, Jó

    2016-01-01

    Intelligent Transportation Systems (ITS) rely on Inter-Vehicle Communication (IVC) to streamline the operation of vehicles by managing vehicle traffic, assisting drivers with safety and sharing information, as well as providing appropriate services for passengers. Traffic congestion is an urban mobility problem, which causes stress to drivers and economic losses. In this context, this work proposes a solution for the detection, dissemination and control of congested roads based on inter-vehicle communication, called INCIDEnT. The main goal of the proposed solution is to reduce the average trip time, CO emissions and fuel consumption by allowing motorists to avoid congested roads. The simulation results show that our proposed solution leads to short delays and a low overhead. Moreover, it is efficient with regard to the coverage of the event and the distance to which the information can be propagated. The findings of the investigation show that the proposed solution leads to (i) high hit rate in the classification of the level of congestion, (ii) a reduction in average trip time, (iii) a reduction in fuel consumption, and (iv) reduced CO emissions PMID:27526048

  2. Increasing Intelligence in Inter-Vehicle Communications to Reduce Traffic Congestions: Experiments in Urban and Highway Environments.

    PubMed

    Meneguette, Rodolfo I; Filho, Geraldo P R; Guidoni, Daniel L; Pessin, Gustavo; Villas, Leandro A; Ueyama, Jó

    2016-01-01

    Intelligent Transportation Systems (ITS) rely on Inter-Vehicle Communication (IVC) to streamline the operation of vehicles by managing vehicle traffic, assisting drivers with safety and sharing information, as well as providing appropriate services for passengers. Traffic congestion is an urban mobility problem, which causes stress to drivers and economic losses. In this context, this work proposes a solution for the detection, dissemination and control of congested roads based on inter-vehicle communication, called INCIDEnT. The main goal of the proposed solution is to reduce the average trip time, CO emissions and fuel consumption by allowing motorists to avoid congested roads. The simulation results show that our proposed solution leads to short delays and a low overhead. Moreover, it is efficient with regard to the coverage of the event and the distance to which the information can be propagated. The findings of the investigation show that the proposed solution leads to (i) high hit rate in the classification of the level of congestion, (ii) a reduction in average trip time, (iii) a reduction in fuel consumption, and (iv) reduced CO emissions.

  3. Mobile monitoring of particle number concentration and other traffic-related air pollutants in a near-highway neighborhood over the course of a year

    PubMed Central

    Padró-Martínez, Luz T.; Patton, Allison P.; Trull, Jeffrey B.; Zamore, Wig; Brugge, Doug; Durant, John L.

    2012-01-01

    Accurate quantification of exposures to traffic-related air pollution in near-highway neighborhoods is challenging due to the high degree of spatial and temporal variation of pollutant levels. The objective of this study was to measure air pollutant levels in a near-highway urban area over a wide range of traffic and meteorological conditions using a mobile monitoring platform. The study was performed in a 2.3-km2 area in Somerville, Massachusetts (USA), near Interstate I-93, a highway that carries 150,000 vehicles per day. The mobile platform was equipped with rapid-response instruments and was driven repeatedly along a 15.4-km route on 55 days between September 2009 and August 2010. Monitoring was performed in 4–6-hour shifts in the morning, afternoon and evening on both weekdays and weekends in winter, spring, summer and fall. Measurements were made of particle number concentration (PNC; 4–3,000 nm), particle size distribution, fine particle mass (PM2.5), particle-bound polycyclic aromatic hydrocarbons (pPAH), black carbon (BC), carbon monoxide (CO), and nitrogen oxides (NO and NOx). The highest pollutant concentrations were measured within 0–50 m of I-93 with distance-decay gradients varying depending on traffic and meteorology. The most pronounced variations were observed for PNC. Annual median PNC 0–50 m from I-93 was two-fold higher compared to the background area (>1 km from I-93). In general, PNC levels were highest in winter and lowest in summer and fall, higher on weekdays and Saturdays compared to Sundays, and higher during morning rush hour compared to later in the day. Similar spatial and temporal trends were observed for NO, CO and BC, but not for PM2.5. Spatial variations in PNC distance-decay gradients were non-uniform largely due to contributions from local street traffic. Hour-to-hour, day-to-day and season-to-season variations in PNC were of the same magnitude as spatial variations. Datasets containing fine-scale temporal and spatial

  4. Mobile monitoring of particle number concentration and other traffic-related air pollutants in a near-highway neighborhood over the course of a year.

    PubMed

    Padró-Martínez, Luz T; Patton, Allison P; Trull, Jeffrey B; Zamore, Wig; Brugge, Doug; Durant, John L

    2012-12-01

    Accurate quantification of exposures to traffic-related air pollution in near-highway neighborhoods is challenging due to the high degree of spatial and temporal variation of pollutant levels. The objective of this study was to measure air pollutant levels in a near-highway urban area over a wide range of traffic and meteorological conditions using a mobile monitoring platform. The study was performed in a 2.3-km(2) area in Somerville, Massachusetts (USA), near Interstate I-93, a highway that carries 150,000 vehicles per day. The mobile platform was equipped with rapid-response instruments and was driven repeatedly along a 15.4-km route on 55 days between September 2009 and August 2010. Monitoring was performed in 4-6-hour shifts in the morning, afternoon and evening on both weekdays and weekends in winter, spring, summer and fall. Measurements were made of particle number concentration (PNC; 4-3,000 nm), particle size distribution, fine particle mass (PM(2.5)), particle-bound polycyclic aromatic hydrocarbons (pPAH), black carbon (BC), carbon monoxide (CO), and nitrogen oxides (NO and NO(x)). The highest pollutant concentrations were measured within 0-50 m of I-93 with distance-decay gradients varying depending on traffic and meteorology. The most pronounced variations were observed for PNC. Annual median PNC 0-50 m from I-93 was two-fold higher compared to the background area (>1 km from I-93). In general, PNC levels were highest in winter and lowest in summer and fall, higher on weekdays and Saturdays compared to Sundays, and higher during morning rush hour compared to later in the day. Similar spatial and temporal trends were observed for NO, CO and BC, but not for PM(2.5). Spatial variations in PNC distance-decay gradients were non-uniform largely due to contributions from local street traffic. Hour-to-hour, day-to-day and season-to-season variations in PNC were of the same magnitude as spatial variations. Datasets containing fine-scale temporal and spatial

  5. Simulating Human Cognition in the Domain of Air Traffic Control

    NASA Technical Reports Server (NTRS)

    Freed, Michael; Johnston, James C.; Null, Cynthia H. (Technical Monitor)

    1995-01-01

    Experiments intended to assess performance in human-machine interactions are often prohibitively expensive, unethical or otherwise impractical to run. Approximations of experimental results can be obtained, in principle, by simulating the behavior of subjects using computer models of human mental behavior. Computer simulation technology has been developed for this purpose. Our goal is to produce a cognitive model suitable to guide the simulation machinery and enable it to closely approximate a human subject's performance in experimental conditions. The described model is designed to simulate a variety of cognitive behaviors involved in routine air traffic control. As the model is elaborated, our ability to predict the effects of novel circumstances on controller error rates and other performance characteristics should increase. This will enable the system to project the impact of proposed changes to air traffic control procedures and equipment on controller performance.

  6. Simulating Human Cognition in the Domain of Air Traffic Control

    NASA Technical Reports Server (NTRS)

    Freed, Michael; Johnston, James C.; Null, Cynthia H. (Technical Monitor)

    1995-01-01

    Experiments intended to assess performance in human-machine interactions are often prohibitively expensive, unethical or otherwise impractical to run. Approximations of experimental results can be obtained, in principle, by simulating the behavior of subjects using computer models of human mental behavior. Computer simulation technology has been developed for this purpose. Our goal is to produce a cognitive model suitable to guide the simulation machinery and enable it to closely approximate a human subject's performance in experimental conditions. The described model is designed to simulate a variety of cognitive behaviors involved in routine air traffic control. As the model is elaborated, our ability to predict the effects of novel circumstances on controller error rates and other performance characteristics should increase. This will enable the system to project the impact of proposed changes to air traffic control procedures and equipment on controller performance.

  7. Synchronized traffic flow simulating with cellular automata model

    NASA Astrophysics Data System (ADS)

    Tian, Jun-fang; Jia, Bin; Li, Xin-gang; Jiang, Rui; Zhao, Xiao-mei; Gao, Zi-you

    2009-12-01

    The synchronized flow traffic phase of Kerner’s three-phase traffic theory can be well reproduced by the model proposed by Jiang and Wu [R. Jiang, Q.S. Wu, J. Phys. A: Math. Gen. 36 (2003) 381]. But in the Jiang and Wu model, the rule for brake light-after switching on, the brake light will not set off until the vehicle accelerates-is obviously unrealistic. Thus we improved the model by considering the difference in accelerating and decelerating performance under different driving conditions. The fundamental diagram and spatial-temporal diagrams are analyzed. We confirmed that the new model could reproduce the synchronized flow by two methods, i.e. the traffic flow interruption effect and performing microscopic analysis of time series data. Simulation results show that the decelerating difference is an important factor to reproduce the synchronized flow. We expect that our work could make contributions to understanding the mechanism of the synchronized flow.

  8. Governors Highway Safety Association

    MedlinePlus

    ... Safety Distracted Driving Drowsy Driving Drug Impaired Driving Law Enforcement Mature Drivers Motorcyclists Seat Belts Speed and ... Driving Teen and Novice Drivers Traffic Records State Laws By Issue By State Resources Publications State Highway ...

  9. Traffic-related heavy metals uptake by wild plants grow along two main highways in Hunan Province, China: effects of soil factors, accumulation ability, and biological indication potential.

    PubMed

    Zhai, Yunbo; Dai, Qingyun; Jiang, Kang; Zhu, Yun; Xu, Bibo; Peng, Chuan; Wang, Tengfei; Zeng, Guangming

    2016-07-01

    This study was performed to investigate pollution of traffic-related heavy metals (HMs-Zn, Pb, Cu, Cr, and Cd) in roadside soils and their uptake by wild plants growing along highways in Hunan Province, China. For this, we analyzed the concentration and chemical fractionation of HMs in soils and plants. Soil samples were collected with different depths in the profile and different distances from highway edge. And leaves and barks of six high-frequency plants were collected. Results of the modified European Community Bureau of Reference (BCR) showed that the mobile fraction of these HMs was in the order of Cd > Pb > Zn > Cu > Cr. A high percentage of the mobile fraction indicates Cd, Pb, and Zn were labile and available for uptake by wild plants. The total concentration and values of risk assessment code (RAC) showed that Cd was the main risk factor, which were in the range high to very high risk. The accumulation ability of HMs in plants was evaluated by the biological accumulation factor (BAF) and the metal accumulation index (MAI), and the results showed that all those plant species have good phyto-extraction ability, while accumulation capacity for most HMs plants tissues was bark > leaf. The highest MAI value (5.99) in Cinnamomum camphora (L) Presl indicates the potential for bio-monitoring and a good choice for planting along highways where there is contamination with HMs.

  10. Temporal variation of traffic on highways and the development of accurate temporal allocation factors for air pollution analyses

    PubMed Central

    Batterman, Stuart; Cook, Richard; Justin, Thomas

    2015-01-01

    Traffic activity encompasses the number, mix, speed and acceleration of vehicles on roadways. The temporal pattern and variation of traffic activity reflects vehicle use, congestion and safety issues, and it represents a major influence on emissions and concentrations of traffic-related air pollutants. Accurate characterization of vehicle flows is critical in analyzing and modeling urban and local-scale pollutants, especially in near-road environments and traffic corridors. This study describes methods to improve the characterization of temporal variation of traffic activity. Annual, monthly, daily and hourly temporal allocation factors (TAFs), which describe the expected temporal variation in traffic activity, were developed using four years of hourly traffic activity data recorded at 14 continuous counting stations across the Detroit, Michigan, U.S. region. Five sites also provided vehicle classification. TAF-based models provide a simple means to apportion annual average estimates of traffic volume to hourly estimates. The analysis shows the need to separate TAFs for total and commercial vehicles, and weekdays, Saturdays, Sundays and observed holidays. Using either site-specific or urban-wide TAFs, nearly all of the variation in historical traffic activity at the street scale could be explained; unexplained variation was attributed to adverse weather, traffic accidents and construction. The methods and results presented in this paper can improve air quality dispersion modeling of mobile sources, and can be used to evaluate and model temporal variation in ambient air quality monitoring data and exposure estimates. PMID:25844042

  11. Temporal variation of traffic on highways and the development of accurate temporal allocation factors for air pollution analyses

    NASA Astrophysics Data System (ADS)

    Batterman, Stuart; Cook, Richard; Justin, Thomas

    2015-04-01

    Traffic activity encompasses the number, mix, speed and acceleration of vehicles on roadways. The temporal pattern and variation of traffic activity reflects vehicle use, congestion and safety issues, and it represents a major influence on emissions and concentrations of traffic-related air pollutants. Accurate characterization of vehicle flows is critical in analyzing and modeling urban and local-scale pollutants, especially in near-road environments and traffic corridors. This study describes methods to improve the characterization of temporal variation of traffic activity. Annual, monthly, daily and hourly temporal allocation factors (TAFs), which describe the expected temporal variation in traffic activity, were developed using four years of hourly traffic activity data recorded at 14 continuous counting stations across the Detroit, Michigan, U.S. region. Five sites also provided vehicle classification. TAF-based models provide a simple means to apportion annual average estimates of traffic volume to hourly estimates. The analysis shows the need to separate TAFs for total and commercial vehicles, and weekdays, Saturdays, Sundays and observed holidays. Using either site-specific or urban-wide TAFs, nearly all of the variation in historical traffic activity at the street scale could be explained; unexplained variation was attributed to adverse weather, traffic accidents and construction. The methods and results presented in this paper can improve air quality dispersion modeling of mobile sources, and can be used to evaluate and model temporal variation in ambient air quality monitoring data and exposure estimates.

  12. Temporal variation of traffic on highways and the development of accurate temporal allocation factors for air pollution analyses.

    PubMed

    Batterman, Stuart; Cook, Richard; Justin, Thomas

    2015-04-01

    Traffic activity encompasses the number, mix, speed and acceleration of vehicles on roadways. The temporal pattern and variation of traffic activity reflects vehicle use, congestion and safety issues, and it represents a major influence on emissions and concentrations of traffic-related air pollutants. Accurate characterization of vehicle flows is critical in analyzing and modeling urban and local-scale pollutants, especially in near-road environments and traffic corridors. This study describes methods to improve the characterization of temporal variation of traffic activity. Annual, monthly, daily and hourly temporal allocation factors (TAFs), which describe the expected temporal variation in traffic activity, were developed using four years of hourly traffic activity data recorded at 14 continuous counting stations across the Detroit, Michigan, U.S. region. Five sites also provided vehicle classification. TAF-based models provide a simple means to apportion annual average estimates of traffic volume to hourly estimates. The analysis shows the need to separate TAFs for total and commercial vehicles, and weekdays, Saturdays, Sundays and observed holidays. Using either site-specific or urban-wide TAFs, nearly all of the variation in historical traffic activity at the street scale could be explained; unexplained variation was attributed to adverse weather, traffic accidents and construction. The methods and results presented in this paper can improve air quality dispersion modeling of mobile sources, and can be used to evaluate and model temporal variation in ambient air quality monitoring data and exposure estimates.

  13. Generic vehicle speed models based on traffic simulation: Development and application

    SciTech Connect

    Margiotta, R.; Cohen, H.; Elkins, G.; Rathi, A.; Venigalla, M.

    1994-12-15

    This paper summarizes the findings of a research project to develop new methods of estimating speeds for inclusion in the Highway Performance Monitoring System (HPMS) Analytical Process. The paper focuses on the effects of traffic conditions excluding incidents (recurring congestion) on daily average ed and excess fuel consumption. A review of the literature revealed that many techniques have been used to predict speeds as a function of congestion but most fail to address the effects of queuing. However, the method of Dowling and Skabardonis avoids this limitation and was adapted to the research. The methodology used the FRESIM and NETSIM microscopic traffic simulation models to develop uncongested speed functions and as a calibration base for the congested flow functions. The chief contributions of the new speed models are the simplicity of application and their explicit accounting for the effects of queuing. Specific enhancements include: (1) the inclusion of a queue discharge rate for freeways; (2) use of newly defined uncongested flow speed functions; (3) use of generic temporal distributions that account for peak spreading; and (4) a final model form that allows incorporation of other factors that influence speed, such as grades and curves. The main limitation of the new speed models is the fact that they are based on simulation results and not on field observations. They also do not account for the effect of incidents on speed. While appropriate for estimating average national conditions, the use of fixed temporal distributions may not be suitable for analyzing specific facilities, depending on observed traffic patterns. Finally, it is recommended that these and all future speed models be validated against field data where incidents can be adequately identified in the data.

  14. Parallel Vehicular Traffic Simulation using Reverse Computation-based Optimistic Execution

    SciTech Connect

    Yoginath, Srikanth B; Perumalla, Kalyan S

    2008-01-01

    Vehicular traffic simulations are useful in applications such as emergency management and homeland security planning tools. High speed of traffic simulations translates directly to speed of response and level of resilience in those applications. Here, a parallel traffic simulation approach is presented that is aimed at reducing the time for simulating emergency vehicular traffic scenarios. Three unique aspects of this effort are: (1) exploration of optimistic simulation applied to vehicular traffic simulation (2) addressing reverse computation challenges specific to optimistic vehicular traffic simulation (3) achieving absolute (as opposed to self-relative) speedup with a sequential speed equal to that of a fast, de facto standard sequential simulator for emergency traffic. The design and development of the parallel simulation system is presented, along with a performance study that demonstrates excellent sequential performance as well as parallel performance.

  15. Upgrades to the Probabilistic NAS Platform Air Traffic Simulation Software

    NASA Technical Reports Server (NTRS)

    Hunter, George; Boisvert, Benjamin

    2013-01-01

    This document is the final report for the project entitled "Upgrades to the Probabilistic NAS Platform Air Traffic Simulation Software." This report consists of 17 sections which document the results of the several subtasks of this effort. The Probabilistic NAS Platform (PNP) is an air operations simulation platform developed and maintained by the Saab Sensis Corporation. The improvements made to the PNP simulation include the following: an airborne distributed separation assurance capability, a required time of arrival assignment and conformance capability, and a tactical and strategic weather avoidance capability.

  16. Identification of traffic-related metals and the effects of different environments on their enrichment in roadside soils along the Qinghai-Tibet highway.

    PubMed

    Zhang, Hua; Wang, Zhaofeng; Zhang, Yili; Ding, Mingjun; Li, Lanhui

    2015-07-15

    The road transportation could affect roadside soils environment detrimentally, including heavy metal enrichment. In order to identify and evaluate the enrichment of heavy metals resulted from road transportation on the Tibetan Plateau, the 11 heavy metals (V, Cr, Co, Ni, Cu, Zn, As, Cd, Rb, Pb and Tl) in the topsoil (0-10 cm depth) from four sites along the Qinghai-Tibet highway were discussed in this study. Our results indicate that heavy metals such as Cr, Cu, Zn, As, Cd and Pb are related to road transportation. The content of most of these heavy metals in roadside soils decreased exponentially with the distance from the road, as did some of the Nemero Synthesis Indexes (PN values). The contamination factor for the traffic-related metals ranged from 0.56 (no pollution) to 5.67 (considerable pollution) and the Nemero Synthesis Indexes of these heavy metals ranged from 0.80 (no pollution) to 4.49 (severe pollution). Cd was of priority concern as it had the highest contamination factor. The highest PN value for these traffic-related heavy metals was found in soils at site TTH (alpine steppe). Although transportation contributed to the high contents of these traffic-related metals in roadside environments, regional differences such as wind and the terrain also had significant relationship with their enrichment in these roadside soils. The roadside distance at which there is a potential risk to livestock and wildlife from the contamination of soils by heavy metals should be determined scientifically along the Qinghai-Tibet highway, based on the different natural environments found in the region.

  17. Study and Simulation of Traffic Behavior in Cellular Network

    NASA Astrophysics Data System (ADS)

    Madhup, D. K.; Shrestha, C. L.; Sharma, R. K.

    2007-07-01

    Cellular radio systems accommodate a large number of users with a limited radio spectrum. The concept of trunking allows a large number of users to share the relatively small number of channels in a cell by providing access to each user, on demand, from a pool of available channels. Traffic engineering deals with provisioning of communication circuits in a given area for a number of subscribers with a required grade of service. Traffic in any cell depends upon the number of users, the average request rate and average call duration. Certain number of channels is required for the required GOS. To design an optimum capacity cellular system, traffic behavior on that system is important. The number of channel required can be estimated by using Erlang formula and Erlang table. Erlang table is not always useful to calculate the probability of blocking in various complex scenarios such as channel borrowing strategies. When the total number of channel available in a given cell are divided to serve partly for newly generated calls and partly for handover calls, and if they use dynamic channel assignment strategies like channel borrowing, then the probability of blocking can't be calculated from Erlang table. Simulation model of the behavior help us to determine the blocking and the channel utilization while using various channel assignment strategies. The title "Study and Simulation of Traffic Behavior in Cellular Network" entail the study of the blocking probability of traffic in cellular network for static channel assignment strategies and dynamic channel borrowing strategies through MATLAB programming language and graphic user interface (GUI). The result shows that the dynamic scheme can perform better than static maximizing the overall utilization of the circuits and minimizing the overall blocking.

  18. Interaction Behavior between Thrust Faulting and the National Highway No. 3 - Tianliao III bridge as Determined using Numerical Simulation

    NASA Astrophysics Data System (ADS)

    Li, C. H.; Wu, L. C.; Chan, P. C.; Lin, M. L.

    2016-12-01

    The National Highway No. 3 - Tianliao III Bridge is located in the southwestern Taiwan mudstone area and crosses the Chekualin fault. Since the bridge was opened to traffic, it has been repaired 11 times. To understand the interaction behavior between thrust faulting and the bridge, a discrete element method-based software program, PFC, was applied to conduct a numerical analysis. A 3D model for simulating the thrust faulting and bridge was established, as shown in Fig. 1. In this conceptual model, the length and width were 50 and 10 m, respectively. Part of the box bottom was moveable, simulating the displacement of the thrust fault. The overburden stratum had a height of 5 m with fault dip angles of 20° (Fig. 2). The bottom-up strata were mudstone, clay, and sand, separately. The uplift was 1 m, which was 20% of the stratum thickness. In accordance with the investigation, the position of the fault tip was set, depending on the fault zone, and the bridge deformation was observed (Fig. 3). By setting "Monitoring Balls" in the numerical model to analyzes bridge displacement, we determined that the bridge deck deflection increased as the uplift distance increased. Furthermore, the force caused by the loading of the bridge deck and fault dislocation was determined to cause a down deflection of the P1 and P2 bridge piers. Finally, the fault deflection trajectory of the P4 pier displayed the maximum displacement (Fig. 4). Similar behavior has been observed through numerical simulation as well as field monitoring data. Usage of the discrete element model (PFC3D) to simulate the deformation behavior between thrust faulting and the bridge provided feedback for the design and improved planning of the bridge.

  19. A Cooperative Human-Adaptive Traffic Simulation (CHATS)

    NASA Technical Reports Server (NTRS)

    Phillips, Charles T.; Ballin, Mark G.

    1999-01-01

    NASA is considering the development of a Cooperative Human-Adaptive Traffic Simulation (CHATS), to examine and evaluate performance of the National Airspace System (NAS) as the aviation community moves toward free flight. CHATS will be specifically oriented toward simulating strategic decision-making by airspace users and by the service provider s traffic management personnel, within the context of different airspace and rules assumptions. It will use human teams to represent these interests and make decisions, and will rely on computer modeling and simulation to calculate the impacts of these decisions. The simulation objectives will be to examine: 1. evolution of airspace users and the service provider s strategies, through adaptation to new operational environments; 2. air carriers competitive and cooperative behavior; 3. expected benefits to airspace users and the service provider as compared to the current NAS; 4. operational limitations of free flight concepts due to congestion and safety concerns. This paper describes an operational concept for CHATS, and presents a high-level functional design which would utilize a combination of existing and new models and simulation capabilities.

  20. Numerical simulation of vehicular traffic for non-ideal drivers.

    NASA Astrophysics Data System (ADS)

    Domínguez, Laura; Amador, Carlos

    2004-03-01

    Numerical simulations of vehicular traffic based on cellular automatae have provided a description of the more relevant experimentally observed properties of the system. Rules for drivers behaviour, though, are highly idealized. In this work we have included rules to mimic the different personalities of drivers: lane changers, passers, over-cautious drivers, tail-gaters, etc. Also we have adopted rules specific to the behaviour of drivers in Mexico City. The whole space of parameters is studied and conclusions are drawn for the effect of this variability on overall vehicular flow. As a further application of the model we study the effect of "shoulder of the road" drivers (who pass congested traffic and return to the main road afterwards) on overall vehicular flow.

  1. On the required complexity of vehicle dynamic models for use in simulation-based highway design.

    PubMed

    Brown, Alexander; Brennan, Sean

    2014-06-01

    This paper presents the results of a comprehensive project whose goal is to identify roadway design practices that maximize the margin of safety between the friction supply and friction demand. This study is motivated by the concern for increased accident rates on curves with steep downgrades, geometries that contain features that interact in all three dimensions - planar curves, grade, and superelevation. This complexity makes the prediction of vehicle skidding quite difficult, particularly for simple simulation models that have historically been used for road geometry design guidance. To obtain estimates of friction margin, this study considers a range of vehicle models, including: a point-mass model used by the American Association of State Highway Transportation Officials (AASHTO) design policy, a steady-state "bicycle model" formulation that considers only per-axle forces, a transient formulation of the bicycle model commonly used in vehicle stability control systems, and finally, a full multi-body simulation (CarSim and TruckSim) regularly used in the automotive industry for high-fidelity vehicle behavior prediction. The presence of skidding--the friction demand exceeding supply--was calculated for each model considering a wide range of vehicles and road situations. The results indicate that the most complicated vehicle models are generally unnecessary for predicting skidding events. However, there are specific maneuvers, namely braking events within lane changes and curves, which consistently predict the worst-case friction margins across all models. This suggests that any vehicle model used for roadway safety analysis should include the effects of combined cornering and braking. The point-mass model typically used by highway design professionals may not be appropriate to predict vehicle behavior on high-speed curves during braking in low-friction situations. However, engineers can use the results of this study to help select the appropriate vehicle dynamic

  2. IMPROVEMENT OF BUSINESS EFFICIENCY USING A MULTI-AGENT SIMULATION FOR HIGHWAY PATROL ON URBAN EXPRESSWAY

    NASA Astrophysics Data System (ADS)

    Okamoto, Taro; Taniguchi, Eiichi; Yamada, Tadashi

    In Japan, the network of urban expressway has been expanding with the development of urban areas. However, the patrol systems in the urban expressway has not been operated on the basis of scientific evidence, but of conformity and experience. It is therefore crucial to efficiently operate such systems, not only to facilitate the rapid recovery of decreased expressway functionality, but also to acquire the income that supports the operation of privatized expressway companies. Therefore, we develop a multiagent simulation model consisting of the decision-making of four agents, including expressway company, highway patol company, road network users and road authority. These agents determines their schemes depending on their profit obtained. Results of the simulation identyfies the schemes that could offer the profits to the expressway companies in terms of the convenience of the users and the improvement of their operation.

  3. A new simulation system of traffic flow based on cellular automata principle

    NASA Astrophysics Data System (ADS)

    Shan, Junru

    2017-05-01

    Traffic flow is a complex system of multi-behavior so it is difficult to give a specific mathematical equation to express it. With the rapid development of computer technology, it is an important method to study the complex traffic behavior by simulating the interaction mechanism between vehicles and reproduce complex traffic behavior. Using the preset of multiple operating rules, cellular automata is a kind of power system which has discrete time and space. It can be a good simulation of the real traffic process and a good way to solve the traffic problems.

  4. Simulations of flooding on Tchoutacabouffa River at State Highways 15 and 67 at D'Iberville, Mississippi

    USGS Publications Warehouse

    Winters, Karl E.

    2000-01-01

    A two-dimensional finite-element surface-water model was used to simulate the effects of the proposed State Highways 15 and 67 relocation on water-surface elevations and flow distributions for the 100-year flood on the Tchoutacabouffa River at D?Iberville, Mississippi. The Mississippi Department of Transportation plans to relocate State Highways 15 and 67 by removing a portion of the existing four-lane highway and constructing a four-lane facility upstream of the existing alignment. The proposed alignment is located on the northern floodplain and will tie into the existing highway about 1,000 feet north of the dual State Highways 15 and 67 bridges. The proposed alignment will intercept flows that cross the existing highway during large floods. Seven scenarios were simulated for the 100-year flood, including four proposed alternative configurations for drainage structures. The model grid was developed by using surveyed floodplain cross sections and channel bathymetry data obtained by using an Acoustic Doppler Current Profiler, in combination with a global positioning system. The model was calibrated and verified by using surveyed flood profiles through the study reach and flood discharge measurements obtained at the State Highways 15 and 67 crossing. Model parameters were adjusted so that the computed water-surface profiles agreed closely with the surveyed flood profiles. Computed water-surface differentials across the proposed alignment near the northern edge of the floodplain for the four alternatives proposed by the Mississippi Department of Transportation ranged from 1.4 to 2.6 feet. Much lower differentials were computed in the vicinity of the main-channel bridge. The computed water-surface elevation at McCully Drive, upstream of the proposed alignment, was 17.3 feet for existing conditions. Computed water-surface elevations at McCully Drive for the proposed alternatives ranged from 17.3 to 17.8 feet.

  5. A method for simplifying the analysis of traffic accidents injury severity on two-lane highways using Bayesian networks.

    PubMed

    Mujalli, Randa Oqab; de Oña, Juan

    2011-10-01

    This study describes a method for reducing the number of variables frequently considered in modeling the severity of traffic accidents. The method's efficiency is assessed by constructing Bayesian networks (BN). It is based on a two stage selection process. Several variable selection algorithms, commonly used in data mining, are applied in order to select subsets of variables. BNs are built using the selected subsets and their performance is compared with the original BN (with all the variables) using five indicators. The BNs that improve the indicators' values are further analyzed for identifying the most significant variables (accident type, age, atmospheric factors, gender, lighting, number of injured, and occupant involved). A new BN is built using these variables, where the results of the indicators indicate, in most of the cases, a statistically significant improvement with respect to the original BN. It is possible to reduce the number of variables used to model traffic accidents injury severity through BNs without reducing the performance of the model. The study provides the safety analysts a methodology that could be used to minimize the number of variables used in order to determine efficiently the injury severity of traffic accidents without reducing the performance of the model. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. Application of environmental magnetism on crime detection in a highway traffic accident from Yangzhou to Guazhou, Jiangsu Province, China.

    PubMed

    Manrong, Chen; Lizhong, Yu; Xiangfeng, Niu; Bin, Chen

    2009-05-30

    Both elemental composition analysis and mineral magnetic measurements were used to infer the source of the earth dumped on a highway in China, which resulted in human life loss and injury in 2002. The results indicate that the earth and the samples from the potential two sources are very similar in geochemical compositions. However, magnetic properties show stronger difference among the samples. A plot of magnetic susceptibility (chi) vs. Anhysteretic Remanent Magnetization (ARM) clearly show that the earth at the accident site (sample No. 1) is closely matched with one sample (No. 4) from the source site B. Such a difference in geochemical and magnetic signatures among the samples is ascribed to the nature of the earth, which is derived from the Xiashu Loess in southern China. Our results indicate that environmental magnetic method can help to crime investigation by aiding in the provenance tracing of soils/sediments evidences in a simple, economic and non-destructive way.

  7. Distribution of platinum group elements and other traffic related elements among different plants along some highways in Germany.

    PubMed

    Djingova, Rumiana; Kovacheva, Petya; Wagner, Gerhard; Markert, Bernd

    2003-06-01

    Using ICP-MS and ICP-AES platinum group elements (Pt, Pd, Rh, Ru and Ir) and Ce, La, Nd, Pb and Zr have been determined in street dust, Taraxacum officinale (dandelion), Plantago lanceolata (plantain), Lolium multiflorum (annual ryegrass), Rhytidiadelphus squarrosus (moss) and Vascellum pratense (mushrooms) collected along highways and streets in Germany during 1999. Among the plants Taraxacum officinale (dandelion) reflects most adequately the pollution with the investigated elements matching the results from street dust. A strong positive correlation between all elements determined in the plants is established. Transfer factor for Pt between soil and plants has been determined in an agricultural experiment ranging between 0.004 and 0.008 for two types of soils.

  8. Hydrological modeling using high resolution dem to level control on highways

    NASA Astrophysics Data System (ADS)

    Akbulut, Zeynep; Cömert, Çetin

    2016-04-01

    Floods are natural disasters that must be managed, controlled and taken precautions before it happens considering the damage they inflicted to environment and human lives. As to highways, the main vein of urban life flow, must be taken into consideration as a different entity that affected by excessive rainfalls and floods. Due to inadequate drainage that allow rainfall to form water ponds on highways cause vehicles to lose control and that lead vehicles to have traffic accidents. To reduce the traffic accidents caused by ponding waters on highways we need to know area of inundation and water depths. In this context we used FLO-2D Basic Model (2009) to hydrological modeling of Black Sea Coastal Highway with meteorological and hydrological data using a Digital Elevation Model (DEM). In this study, ponding areas on highways determined by simulating the rainfall with a high resolution DEM that can represent the actual road surface correctly. With this information, General Directorate of Highways (GDH) in Turkey can adjust the cross-sectional and longitudinal slope or build better and bigger drainage structures where water accumulated to prevent ponding. With the results obtained from Hydrological Model, GDH can rapidly control highways conformity to regulations before highways come into service. Also these ponding areas acquired by reveals where to prioritize in flood risk managements. Key Words: Area of Inundation, Digital Elevation Model, FLO-2D, Hydrological Modeling, Highway, Rainfall-Runoff Simulation, Water Depth.

  9. 23 CFR 772.9 - Traffic noise prediction.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 23 Highways 1 2012-04-01 2012-04-01 false Traffic noise prediction. 772.9 Section 772.9 Highways... ABATEMENT OF HIGHWAY TRAFFIC NOISE AND CONSTRUCTION NOISE § 772.9 Traffic noise prediction. (a) Any analysis required by this subpart must use the FHWA Traffic Noise Model (TNM), which is described in “FHWA Traffic...

  10. 23 CFR 772.9 - Traffic noise prediction.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 23 Highways 1 2013-04-01 2013-04-01 false Traffic noise prediction. 772.9 Section 772.9 Highways... ABATEMENT OF HIGHWAY TRAFFIC NOISE AND CONSTRUCTION NOISE § 772.9 Traffic noise prediction. (a) Any analysis required by this subpart must use the FHWA Traffic Noise Model (TNM), which is described in “FHWA Traffic...

  11. 23 CFR 772.9 - Traffic noise prediction.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 23 Highways 1 2014-04-01 2014-04-01 false Traffic noise prediction. 772.9 Section 772.9 Highways... ABATEMENT OF HIGHWAY TRAFFIC NOISE AND CONSTRUCTION NOISE § 772.9 Traffic noise prediction. (a) Any analysis required by this subpart must use the FHWA Traffic Noise Model (TNM), which is described in “FHWA Traffic...

  12. Implementing and Simulating Dynamic Traffic Assignment with Intelligent Transportation Systems in Cube Avenue

    NASA Technical Reports Server (NTRS)

    Foytik, Peter; Robinson, Mike

    2010-01-01

    As urban populations and traffic congestion levels increase, effective use of information and communication tools and intelligent transportation systems as becoming increasingly important in order to maximize the efficiency of transportation networks. The appropriate placement and employment of these tools within a network is critical to their effectiveness. This presentation proposes and demonstrates the use of a commercial transportation simulation tool to simulate dynamic traffic assignment and rerouting to model route modifications as a result of traffic information.

  13. Simulation of traffic flow and control using conventional, fuzzy, and adaptive methods

    SciTech Connect

    Bisset, K.R.; Kelsey, R.L.

    1992-01-01

    This paper describes the graphical simulation of a traffic environment. The environment includes streets leading to an intersection, the intersection, vehicle traffic, and signal lights in the intersection controlled by different methods. The simulation allows for the study of parameters affecting traffic environments and the study of different control strategies for traffic signal lights, including conventional, fuzzy, and adaptive control methods. Realistic traffic environments are simulated including a cross intersection, with one or more lanes of traffic in each direction, with and without turn lanes. Vehicle traffic patterns are a mixture of cars going straight and making right or left turns. The free velocities of vehicles follow a normal distribution with a mean of the posted'' speed limit. Actual velocities depend on such factors as the proximity and velocity of surrounding traffic, approaches to intersections, and human response time. The simulation proves the be a useful tool for evaluating controller methods. Preliminary results show that larger quantities of traffic are handled'' by fuzzy control methods then by conventional control methods. Also, the average time spent waiting in traffic decreases with the use of fuzzy control versus conventional control.

  14. Simulation of traffic flow and control using conventional, fuzzy, and adaptive methods

    SciTech Connect

    Bisset, K.R.; Kelsey, R.L.

    1992-06-01

    This paper describes the graphical simulation of a traffic environment. The environment includes streets leading to an intersection, the intersection, vehicle traffic, and signal lights in the intersection controlled by different methods. The simulation allows for the study of parameters affecting traffic environments and the study of different control strategies for traffic signal lights, including conventional, fuzzy, and adaptive control methods. Realistic traffic environments are simulated including a cross intersection, with one or more lanes of traffic in each direction, with and without turn lanes. Vehicle traffic patterns are a mixture of cars going straight and making right or left turns. The free velocities of vehicles follow a normal distribution with a mean of the ``posted`` speed limit. Actual velocities depend on such factors as the proximity and velocity of surrounding traffic, approaches to intersections, and human response time. The simulation proves the be a useful tool for evaluating controller methods. Preliminary results show that larger quantities of traffic are ``handled`` by fuzzy control methods then by conventional control methods. Also, the average time spent waiting in traffic decreases with the use of fuzzy control versus conventional control.

  15. Rock fall analysis of slope along state highway in Uttarakhand Himalaya, India using numerical simulation

    NASA Astrophysics Data System (ADS)

    Vishal, V.; Phophliya, M. K.; Purohit, R.

    2014-12-01

    With almost 1% of the reported accidents being associated with slope stability problems, landslides and rock fall have been responsible for nearly 25% of fatalities in hill slopes and surface mines over past few decades. Morpho-dynamic terrain of Himalaya is continually facing challenges in stability of rock/slopes, which are aggravated due to increased disturbance level in rock/soil mass due to human intervention. The lithological and structural variations, orientations and patterns of different water bodies and vegetation are varied along the slopes which indicate site-specific studies of rock fall prone areas in Uttarakhand. Lack of sufficient knowledge and understanding of the phenomenon, frequent occurrences of rock fall along state and national highways, the consequent inconveniences and loss of lives highlight the importance of addressing the subject on a priority basis. Rock fall simulation of the hill cut face along state highway in India was performed to replicate the effects of the falling rock blocks in the valley. The energy, velocity, bounce height and the trajectory of possible rock failures were determined. The slopes were optimised with respect to the intermediate benches to reduce the impact of falling rock blocks on the adjoining road. It was observed that introducing benches near the top did not reduce the impact of falling boulders much, however, the number of rocks crossing the ditch was less. On the contrary, benches at intermediate height reduced the energy of falling blocks but could not restrict the blocks to cross over the ditch on to the road. An optimisation of the angle of inclination of the ditch angle was also carried out. A ditch angle of 15o could restrict the passage of boulders from ditch over to the adjoining road. The study will be very useful for safe design of structures for prevention and mitigation of hazards due to rock failures along these slopes.

  16. A Fast-Time Simulation Tool for Analysis of Airport Arrival Traffic

    NASA Technical Reports Server (NTRS)

    Erzberger, Heinz; Meyn, Larry A.; Neuman, Frank

    2004-01-01

    The basic objective of arrival sequencing in air traffic control automation is to match traffic demand and airport capacity while minimizing delays. The performance of an automated arrival scheduling system, such as the Traffic Management Advisor developed by NASA for the FAA, can be studied by a fast-time simulation that does not involve running expensive and time-consuming real-time simulations. The fast-time simulation models runway configurations, the characteristics of arrival traffic, deviations from predicted arrival times, as well as the arrival sequencing and scheduling algorithm. This report reviews the development of the fast-time simulation method used originally by NASA in the design of the sequencing and scheduling algorithm for the Traffic Management Advisor. The utility of this method of simulation is demonstrated by examining the effect on delays of altering arrival schedules at a hub airport.

  17. A Multi-Operator Simulation for Investigation of Distributed Air Traffic Management Concepts

    NASA Technical Reports Server (NTRS)

    Peters, Mark E.; Ballin, Mark G.; Sakosky, John S.

    2002-01-01

    This paper discusses the current development of an air traffic operations simulation that supports feasibility research for advanced air traffic management concepts. The Air Traffic Operations Simulation (ATOS) supports the research of future concepts that provide a much greater role for the flight crew in traffic management decision-making. ATOS provides representations of the future communications, navigation, and surveillance (CNS) infrastructure, a future flight deck systems architecture, and advanced crew interfaces. ATOS also provides a platform for the development of advanced flight guidance and decision support systems that may be required for autonomous operations.

  18. Percolation properties in a traffic model

    NASA Astrophysics Data System (ADS)

    Wang, Feilong; Li, Daqing; Xu, Xiaoyun; Wu, Ruoqian; Havlin, Shlomo

    2015-11-01

    As a dynamical complex system, traffic is characterized by a transition from free flow to congestions, which is mostly studied in highways. However, despite its importance in developing congestion mitigation strategies, the understanding of this common traffic phenomenon in a city scale is still missing. An open question is how the traffic in the network collapses from a global efficient traffic to isolated local flows in small clusters, i.e. the question of traffic percolation. Here we study the traffic percolation properties on a lattice by simulation of an agent-based model for traffic. A critical traffic volume in this model distinguishes the free state from the congested state of traffic. Our results show that the threshold of traffic percolation decreases with increasing traffic volume and reaches a minimum value at the critical traffic volume. We show that this minimal threshold is the result of longest spatial correlation between traffic flows at the critical traffic volume. These findings may help to develop congestion mitigation strategies in a network view.

  19. Simulation of three lanes one-way freeway in low visibility weather by possible traffic accidents

    NASA Astrophysics Data System (ADS)

    Pang, Ming-bao; Zheng, Sha-sha; Cai, Zhang-hui

    2015-09-01

    The aim of this work is to investigate the traffic impact of low visibility weather on a freeway including the fraction of real vehicle rear-end accidents and road traffic capacity. Based on symmetric two-lane Nagel-Schreckenberg (STNS) model, a cellular automaton model of three-lane freeway mainline with the real occurrence of rear-end accidents in low visibility weather, which considers delayed reaction time and deceleration restriction, was established with access to real-time traffic information of intelligent transportation system (ITS). The characteristics of traffic flow in different visibility weather were discussed via the simulation experiments. The results indicate that incoming flow control (decreasing upstream traffic volume) and inputting variable speed limits (VSL) signal are effective in accident reducing and road actual traffic volume's enhancing. According to different visibility and traffic demand the appropriate control strategies should be adopted in order to not only decrease the probability of vehicle accidents but also avoid congestion.

  20. Simulation model for urban ternary mix-traffic flow

    NASA Astrophysics Data System (ADS)

    Deo, Lalit; Akkawi, Faisal; Deo, Puspita

    2007-12-01

    A two-lane two-way traffic light controlled X-intersection for ternary mix traffic (cars + buses (equivalent vehicles) + very large trucks/ buses) is developed based on cellular automata model. This model can provide different matrices such as throughput, queue length and delay time. This paper will describe how the model works and how composition of traffic mix effects the throughput (numbers of vehicles navigate through the intersection per unit of time (vph)) and also compare the result with homogeneous counterpart.

  1. The Effect of Stereoscopic Presentation on a Simulated Air Traffic Control Task

    DTIC Science & Technology

    1989-12-01

    B87-17 No. in Program of Work : 731.3 SUMMARY Collision prediction in a simulated Air Traffic Control (ATC) task was compared for conditions in...increasing density and complexity of air traffic, the work load in Air Traffic Control (ATC) has become a matter of great concern. One of the factors that...three-dimensional space he is working in, should be welcome. One possibility would be colour coding, an application that has finally become well

  2. 23 CFR 1200.40 - Expiration of the Highway Safety Plan.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 23 Highways 1 2013-04-01 2013-04-01 false Expiration of the Highway Safety Plan. 1200.40 Section 1200.40 Highways NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION AND FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PROCEDURES FOR STATE HIGHWAY SAFETY PROGRAMS UNIFORM PROCEDURES FOR STATE...

  3. 23 CFR 1200.40 - Expiration of the Highway Safety Plan.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 23 Highways 1 2014-04-01 2014-04-01 false Expiration of the Highway Safety Plan. 1200.40 Section 1200.40 Highways NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION AND FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PROCEDURES FOR STATE HIGHWAY SAFETY PROGRAMS UNIFORM PROCEDURES FOR STATE...

  4. 23 CFR Appendix B to Part 1200 - Highway Safety Program Cost Summary (HS-217)

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 23 Highways 1 2014-04-01 2014-04-01 false Highway Safety Program Cost Summary (HS-217) B Appendix B to Part 1200 Highways NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION AND FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PROCEDURES FOR STATE HIGHWAY SAFETY PROGRAMS UNIFORM PROCEDURES FOR...

  5. 23 CFR Appendix B to Part 1200 - HIGHWAY SAFETY PROGRAM COST SUMMARY (HS-217)

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 23 Highways 1 2013-04-01 2013-04-01 false HIGHWAY SAFETY PROGRAM COST SUMMARY (HS-217) B APPENDIX B TO PART 1200 Highways NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION AND FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PROCEDURES FOR STATE HIGHWAY SAFETY PROGRAMS UNIFORM PROCEDURES FOR...

  6. [Simulation study on the bicyclist involved traffic accident and analysis of the injury].

    PubMed

    Zou, Dong-hua; Liu, Ning-guo; Chen, Jian-guo; Zhang, Jian-hua; Jin, Xian-long; Zhang, Xiao-yun; Chen, Yi-jiu

    2007-08-01

    This study aimed at computer simulation of reconstruction of vehicle-bicyclist traffic accidents and investigation of the injury characteristics. To use the model established by high performance computer and PC-Crash software to study the bicyclists and vehicles and to reconstruct the accident. The model of computer simulation response perfectly reconstructed phases of the traffic collision and explained the mechanisms of the injuries of the bicyclists, which correlated with details found in forensic investigation. Computer simulation is feasible for forensic analysis on the injury mechanism of bicyclists in traffic related accidents.

  7. Enhanced TCAS 2/CDTI traffic Sensor digital simulation model and program description

    NASA Technical Reports Server (NTRS)

    Goka, T.

    1984-01-01

    Digital simulation models of enhanced TCAS 2/CDTI traffic sensors are developed, based on actual or projected operational and performance characteristics. Two enhanced Traffic (or Threat) Alert and Collision Avoidance Systems are considered. A digital simulation program is developed in FORTRAN. The program contains an executive with a semireal time batch processing capability. The simulation program can be interfaced with other modules with a minimum requirement. Both the traffic sensor and CAS logic modules are validated by means of extensive simulation runs. Selected validation cases are discussed in detail, and capabilities and limitations of the actual and simulated systems are noted. The TCAS systems are not specifically intended for Cockpit Display of Traffic Information (CDTI) applications. These systems are sufficiently general to allow implementation of CDTI functions within the real systems' constraints.

  8. Satellite Network Performance Measurements Using Simulated Multi-User Internet Traffic

    NASA Technical Reports Server (NTRS)

    Kruse, Hans; Allman, Mark; Griner, Jim; Ostermann, Shawn; Helvey, Eric

    1999-01-01

    As a number of diverse satellite systems (both Low Earth Orbit and Geostationary systems) are being designed and deployed, it becomes increasingly important to be able to test these systems under realistic traffic loads. While software simulations can provide valuable input into the system design process, it is crucial that the physical system be tested so that actual network devices can be employed and tuned. These tests need to utilize traffic patterns that closely mirror the expected user load, without the need to actually deploy an end-user network for the test. In this paper, we present trafgen. trafgen uses statistical information about the characteristics of sampled network traffic to emulate the same type of traffic over the test network. This paper compares sampled terrestrial network traffic with emulated satellite network traffic over the NASA ACTS satellite.

  9. Synchronized flow in oversaturated city traffic

    NASA Astrophysics Data System (ADS)

    Kerner, Boris S.; Klenov, Sergey L.; Hermanns, Gerhard; Hemmerle, Peter; Rehborn, Hubert; Schreckenberg, Michael

    2013-11-01

    Based on numerical simulations with a stochastic three-phase traffic flow model, we reveal that moving queues (moving jams) in oversaturated city traffic dissolve at some distance upstream of the traffic signal while transforming into synchronized flow. It is found that, as in highway traffic [Kerner, Phys. Rev. EPLEEE81539-375510.1103/PhysRevE.85.036110 85, 036110 (2012)], such a jam-absorption effect in city traffic is explained by a strong driver's speed adaptation: Time headways (space gaps) between vehicles increase upstream of a moving queue (moving jam), resulting in moving queue dissolution. It turns out that at given traffic signal parameters, the stronger the speed adaptation effect, the shorter the mean distance between the signal location and the road location at which moving queues dissolve fully and oversaturated traffic consists of synchronized flow only. A comparison of the synchronized flow in city traffic found in this Brief Report with synchronized flow in highway traffic is made.

  10. 23 CFR 772.11 - Analysis of traffic noise impacts.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 23 Highways 1 2013-04-01 2013-04-01 false Analysis of traffic noise impacts. 772.11 Section 772.11... PROCEDURES FOR ABATEMENT OF HIGHWAY TRAFFIC NOISE AND CONSTRUCTION NOISE § 772.11 Analysis of traffic noise impacts. (a) The highway agency shall determine and analyze expected traffic noise impacts. (1) For...

  11. 23 CFR 772.11 - Analysis of traffic noise impacts.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 23 Highways 1 2014-04-01 2014-04-01 false Analysis of traffic noise impacts. 772.11 Section 772.11... PROCEDURES FOR ABATEMENT OF HIGHWAY TRAFFIC NOISE AND CONSTRUCTION NOISE § 772.11 Analysis of traffic noise impacts. (a) The highway agency shall determine and analyze expected traffic noise impacts. (1) For...

  12. 23 CFR 772.11 - Analysis of traffic noise impacts.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 23 Highways 1 2012-04-01 2012-04-01 false Analysis of traffic noise impacts. 772.11 Section 772.11... PROCEDURES FOR ABATEMENT OF HIGHWAY TRAFFIC NOISE AND CONSTRUCTION NOISE § 772.11 Analysis of traffic noise impacts. (a) The highway agency shall determine and analyze expected traffic noise impacts. (1)...

  13. Traffic Monitor

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Mestech's X-15 "Eye in the Sky," a traffic monitoring system, incorporates NASA imaging and robotic vision technology. A camera or "sensor box" is mounted in a housing. The sensor detects vehicles approaching an intersection and sends the information to a computer, which controls the traffic light according to the traffic rate. Jet Propulsion Laboratory technical support packages aided in the company's development of the system. The X-15's "smart highway" can also be used to count vehicles on a highway and compute the number in each lane and their speeds, important information for freeway control engineers. Additional applications are in airport and railroad operations. The system is intended to replace loop-type traffic detectors.

  14. Evaluation of the efficacy of simulation games in traffic safety education of kindergarten children.

    PubMed Central

    Renaud, L; Suissa, S

    1989-01-01

    Using a simulation game designed to teach children to obey certain traffic safety rules, an experimental study was conducted with 136 five-year-old children in four Quebec schools. Within each classroom, subjects were randomly divided into four groups: three intervention groups and one control group. Each of the experimental groups was subjected to a different intervention with outcome measured using three instruments related to attitudes, behavior, and transfer of learning of pedestrian traffic safety. Results suggest that simulation games including role-playing/group dynamics and modeling/training can change attitudes and modify behavior in the area of pedestrian traffic safety in children of this age. PMID:2916716

  15. Development of a Prototype Automation Simulation Scenario Generator for Air Traffic Management Software Simulations

    NASA Technical Reports Server (NTRS)

    Khambatta, Cyrus F.

    2007-01-01

    A technique for automated development of scenarios for use in the Multi-Center Traffic Management Advisor (McTMA) software simulations is described. The resulting software is designed and implemented to automate the generation of simulation scenarios with the intent of reducing the time it currently takes using an observational approach. The software program is effective in achieving this goal. The scenarios created for use in the McTMA simulations are based on data taken from data files from the McTMA system, and were manually edited before incorporation into the simulations to ensure accuracy. Despite the software s overall favorable performance, several key software issues are identified. Proposed solutions to these issues are discussed. Future enhancements to the scenario generator software may address the limitations identified in this paper.

  16. Computerized methods for trafficability analysis

    NASA Technical Reports Server (NTRS)

    Lewandowski, G. M.; Mc Adams, H. T.; Reese, P. A.

    1971-01-01

    Computer program produces trafficability maps displaying terrain characteristics in digital form for computer analysis. Maps serve as aid to vehicular operation and highway planning based on maneuverability parameters.

  17. Designing Scenarios for Controller-in-the-Loop Air Traffic Simulations

    NASA Technical Reports Server (NTRS)

    Kupfer, Michael; Mercer, Joey S.; Cabrall, Christopher; Callantine, Todd

    2013-01-01

    Well prepared traffic scenarios contribute greatly to the success of controller-in-the-loop simulations. This paper describes each stage in the design process of realistic scenarios based on real-world traffic, to be used in the Airspace Operations Laboratory for simulations within the Air Traffic Management Technology Demonstration 1 effort. The steps from the initial analysis of real-world traffic, to the editing of individual aircraft records in the scenario file, until the final testing of the scenarios before the simulation conduct, are all described. The iterative nature of the design process and the various efforts necessary to reach the required fidelity, as well as the applied design strategies, challenges, and tools used during this process are also discussed.

  18. Cellular automaton simulations for mixed traffic with erratic motorcycles’ behaviours

    NASA Astrophysics Data System (ADS)

    Lan, Lawrence W.; Chiou, Yu-Chiun; Lin, Zih-Shin; Hsu, Chih-Cheng

    2010-05-01

    Modeling mixed traffic composed of motorcycles can be a challenging issue because many erratic motorcyclists may not follow the lane disciplines, particularly when traffic is congested. Based upon the refined cellular automaton (CA) model recently developed by the authors [L.W. Lan, Y.C. Chiou, Z.S. Lin, C.C. Hsu, Physica A 388 (2009) 3917-3930], this paper further proposed a sophisticated CA model to elucidate the erratic motorcycle behaviours in mixed traffic contexts. In addition to the conventional moving forward and lane-change rules, the sophisticated CA model also explicated the lateral drift behaviour for cars moving in the same lane, the lateral drift behaviour for motorcycles breaking into two moving cars, and the transverse crossing behaviour for motorcycles through the gap between two stationary cars in the same lane. Fundamental diagrams and space-time trajectories for vehicles with various car-motorcycle mixed ratios are demonstrated.

  19. Traffic Emissions of Radical Precursors and Related Species as Observed and Modeled at an Urban Highway Junction in Houston/Texas

    NASA Astrophysics Data System (ADS)

    Rappenglück, Bernhard; Lubertino, Graciela

    2016-04-01

    Nitrous acid (HONO) and formaldehyde (HCHO) are important precursors for radicals and are believed to favor ozone formation significantly. Traffic emissions data for both compounds is scarce. Here we report results from continuous ambient air measurements of HONO, HCHO, carbon monoxide (CO), carbon dioxide (CO2), nitrogen oxides (NO/NO2/NOx), and peroxyacyl nitrates (PANs) taken at an Highway Junction in Houston/Texas from July 15 - October 15, 2009. The observational data was compared to emission estimates from currently available mobile emissions models (MOBILE6; MOVES). Observations indicated a molar CO versus NOx ratio of 6.01±0.15 (r2 = 0.91), which is in agreement with other field studies. Both, MOBILE6 and MOVES, overestimate this emission ratio by 92% and 24%, respectively. For HCHO/CO an overall slope of 3.14±0.14 g HCHO / kg CO was observed. While MOBILE6 largely underestimates this ratio by 77%, MOVES calculates somewhat higher HCHO/CO ratios (1.87) than MOBILE6, but is still significantly lower than the observed ratio. MOVES shows high HCHO/CO ratios during the early morning hours due to heavy duty diesel off-network emissions. The differences of the modeled CO/NOx and HCHO/CO ratios are largely due to higher NOx and HCHO emissions in MOVES (30% and 57%, respectively, increased from MOBILE6 for 2009), as CO emissions were about the same in both models. The observed HONO/NOx emission ratio is around 0.017±0.0009 kg HONO / kg NOx which is twice as high as in MOVES. The observed NO2/NOx emission ratio is around 0.16±0.01 kg NO2 / kg NOx, which is a bit more than 50% higher than in MOVES. MOVES overestimates the CO/CO2 emission ratio by a factor of 3 compared with the observations, which is 0.0033±0.0002 kg CO / kg CO2. This as well as CO/NOx overestimation is coming from light duty gasoline vehicles.

  20. Hydrologic Analysis and Two-Dimensional Simulation of Flow at State Highway 17 crossing the Gasconade River near Waynesville, Missouri

    USGS Publications Warehouse

    Huizinga, Richard J.

    2008-01-01

    In cooperation with the Missouri Department of Transportation, the U.S. Geological Survey determined hydrologic and hydraulic parameters for the Gasconade River at the site of a proposed bridge replacement and highway realignment of State Highway 17 near Waynesville, Missouri. Information from a discontinued streamflow-gaging station on the Gasconade River near Waynesville was used to determine streamflow statistics for analysis of the 25-, 50-, 100-, and 500-year floods at the site. Analysis of the streamflow-gaging stations on the Gasconade River upstream and downstream from Waynesville indicate that flood peaks attenuate between the upstream gaging station near Hazelgreen and the Waynesville gaging station, such that the peak discharge observed on the Gasconade River near Waynesville will be equal to or only slightly greater (7 percent or less) than that observed near Hazelgreen. A flood event occurred on the Gasconade River in March 2008, and a flood measurement was obtained near the peak at State Highway 17. The elevation of high-water marks from that event indicated it was the highest measured flood on record with a measured discharge of 95,400 cubic feet per second, and a water-surface elevation of 766.18 feet near the location of the Waynesville gaging station. The measurements obtained for the March flood resulted in a shift of the original stage-discharge relation for the Waynesville gaging station, and the streamflow statistics were modified based on the new data. A two-dimensional hydrodynamic flow model was used to simulate flow conditions on the Gasconade River in the vicinity of State Highway 17. A model was developed that represents existing (2008) conditions on State Highway 17 (the 'model of existing conditions'), and was calibrated to the floods of March 20, 2008, December 4, 1982, and April 14, 1945. Modifications were made to the model of existing conditions to create a model that represents conditions along the same reach of the Gasconade

  1. National Highway Traffic Safety Administration

    MedlinePlus

    ... your vehicle be affected by this recall. Federal vehicle cybersecurity guidance issued Covers best practices for all ... designing vehicle systems and software Read More Automated Vehicles Policy announced Industry leaders, experts in the field, ...

  2. National Highway Traffic Safety Administration

    MedlinePlus

    ... working to support the development of automated vehicle safety technologies because of their potential to save lives. September ... Drunk Driving Vehicle to Vehicle Communications Featured Topic Safety Technologies Recalls Update Takata Air Bags January 19, 2017 : ...

  3. Piloted simulation of a ground-based time-control concept for air traffic control

    NASA Technical Reports Server (NTRS)

    Davis, Thomas J.; Green, Steven M.

    1989-01-01

    A concept for aiding air traffic controllers in efficiently spacing traffic and meeting scheduled arrival times at a metering fix was developed and tested in a real time simulation. The automation aid, referred to as the ground based 4-D descent advisor (DA), is based on accurate models of aircraft performance and weather conditions. The DA generates suggested clearances, including both top-of-descent-point and speed-profile data, for one or more aircraft in order to achieve specific time or distance separation objectives. The DA algorithm is used by the air traffic controller to resolve conflicts and issue advisories to arrival aircraft. A joint simulation was conducted using a piloted simulator and an advanced concept air traffic control simulation to study the acceptability and accuracy of the DA automation aid from both the pilot's and the air traffic controller's perspectives. The results of the piloted simulation are examined. In the piloted simulation, airline crews executed controller issued descent advisories along standard curved path arrival routes, and were able to achieve an arrival time precision of + or - 20 sec at the metering fix. An analysis of errors generated in turns resulted in further enhancements of the algorithm to improve the predictive accuracy. Evaluations by pilots indicate general support for the concept and provide specific recommendations for improvement.

  4. Cellular Automaton Model Simulating Traffic Flow at AN Uncontrolled T-Shaped Intersection

    NASA Astrophysics Data System (ADS)

    Li, Xiao-Bai; Jiang, Rui; Wu, Qing-Song

    Traffic flow at an uncontrolled T-shaped intersection is modelled by a cellular automaton model. A priority probability of the through car is introduced. The phase diagram of the system and the effect of the turning car on the whole traffic situation are investigated. Our simulation results suggest that priority should be given to either through cars or to turning cars according to the ratio of the turning cars in order to obtain the optimization of the system.

  5. Development of simulation techniques suitable for the analysis of air traffic control situations and instrumentation

    NASA Technical Reports Server (NTRS)

    1972-01-01

    A terminal area simulation is described which permits analysis and synthesis of current and advanced air traffic management system configurations including ground and airborne instrumentation and new and modified aircraft characteristics. Ground elements in the simulation include navigation aids, surveillance radars, communication links, air-route structuring, ATC procedures, airport geometries and runway handling constraints. Airborne elements include traffic samples with individual aircraft performance and operating characteristics and aircraft navigation equipment. The simulation also contains algorithms for conflict detection, conflict resolution, sequencing and pilot-controller data links. The simulation model is used to determine the sensitivities of terminal area traffic flow, safety and congestion to aircraft performance characteristics, avionics systems, and other ATC elements.

  6. Traffic Cellular Automata Simulation of a Congested Round-About in Mauritius

    NASA Astrophysics Data System (ADS)

    Fowdur, S. C.; Rughooputh, S. D. D. V.

    In this paper a Traffic Cellular Automata (TCA) simulation of a highly congested round-about in Mauritius is performed. The simulations are performed using a multi-cell model that includes anticipation and probability randomization. The simulation model is first calibrated to match actual traffic count statistics taken at the round-about. The topology of the round-about is then modified and the TCA model is used to predict the impact on the congestion level of different changes made. The simulation results enable the assessment of the impact on the traffic density and travel time of the different modifications made. It has been found that the construction of a flyover bridge at the round-about will be the most convenient solution to alleviate congestion and improve the flux significantly.

  7. Microscale traffic simulation and emission estimation in a heavily trafficked roundabout in Madrid (Spain).

    PubMed

    Quaassdorff, Christina; Borge, Rafael; Pérez, Javier; Lumbreras, Julio; de la Paz, David; de Andrés, Juan Manuel

    2016-10-01

    This paper presents the evaluation of emissions from vehicle operations in a domain of 300m×300m covering a complex urban roundabout with high traffic density in Madrid. Micro-level simulation was successfully applied to estimate the emissions on a scale of meters. Two programs were used: i) VISSIM to simulate the traffic on the square and to compute velocity-time profiles; and ii) VERSIT+micro through ENVIVER that uses VISSIM outputs to compute the related emissions at vehicle level. Data collection was achieved by a measurement campaign obtaining empirical data of vehicle flows and traffic intensities. Twelve simulations of different traffic situations (scenarios) were conducted, representing different hours from several days in a week and the corresponding NOX and PM10 emissions were estimated. The results show a general reduction on average speeds for higher intensities due to braking-acceleration patterns that contribute to increase the average emission factor and, therefore, the total emissions in the domain, especially on weekdays. The emissions are clearly related to traffic volume, although maximum emission scenario does not correspond to the highest traffic intensity due to congestion and variations in fleet composition throughout the day. These results evidence the potential that local measures aimed at alleviating congestion may have in urban areas to reduce emissions. In general, scenario-averaged emission factors estimated with the VISSIM-VERSIT+micro modelling system fitted well those from the average-speed model COPERT, used as a preliminary validation of the results. The largest deviations between these two models occur in those scenarios with more congestion. The design and resolution of the microscale modelling system allow to reflect the impact of actual traffic conditions on driving patterns and related emissions, making it useful for the design of mitigation measures for specific traffic hot-spots.

  8. Multiclass first-order simulation model to explain non-linear traffic phenomena

    NASA Astrophysics Data System (ADS)

    Ngoduy, D.; Liu, R.

    2007-11-01

    With the first-order traffic model of Lighthill, Whitham and Richard (LWR), many simple traffic problems can be represented analytically such as a shock formation. However, the LWR model has some deficiencies. For example, among the other things, it fails to replicate interesting non-linear phenomena such as hysteresis and capacity drop as well as the dispersion of traffic platoon when there exists a distribution of desired speeds in heterogeneous traffic. To this end, in this paper, we propose a novel multiclass first-order simulation model based on an approximation of Riemann solver. In the developed model, each vehicle class is only characterized by their desired speeds in a free-flow traffic state where overtaking is allowed. However, when traffic is congested, all vehicle classes must travel at the same congested speed and overtaking is not possible. Numerical results show that the proposed model is not only more accurate and reliable than the existing models but also able to explain non-linear traffic phenomena on freeways.

  9. Jet transport flight operations using cockpit display of traffic information during instrument meteorological conditions: Simulation evaluation

    NASA Technical Reports Server (NTRS)

    Williams, David H.; Wells, Douglas C.

    1986-01-01

    A simulation study was undertaken to evaluate flight operations using cockpit display of traffic information (CDTI) in a conventional jet transport aircraft. Eight two-person airline flight crews participated as test subjects flying simulated terminal area approach and departure operations under instrument meteorological conditions (IMC). A fixed-base cockpit simulator configured with a full complement of conventional electromechanical instrumentation to permit full workload operations was utilized. Traffic information was displayed on a color cathode-ray tube (CRT) mounted above the throttle quadrant in the typical weather radar location. A transparent touchpanel overlay was utilized for pilot interface with the display. Air traffic control (ATC) simulation included an experienced controller and full partyline radio environment for evaluation of pilot-controlled self-separation and traffic situation monitoring tasks. Results of the study revealed the CDTI to be well received by the test subjects as a useful system which could be incorporated into an existing jet transport cockpit. Crew coordination and consistent operating procedures were identified as important considerations in operational implementation of traffic displays. Cockpit workload was increased with active CDTI tasks. However, all test subjects rated the increase to be acceptable.

  10. Improving Highway Safety Manpower: Traffic Engineering Technician Project at Longview Community College and Community College of Denver. Phase 2. Final Report.

    ERIC Educational Resources Information Center

    Korim, Andrew S.

    In Phase 2, materials on traffic accident investigation were introduced into the curriculum to determine the appropriateness of such materials in preparing traffic engineering technicians. This report gives findings, conclusions, and recommendations based on the testing efforts. The primary conclusion is that the curriculum being tested was…

  11. Design of an air traffic computer simulation system to support investigation of civil tiltrotor aircraft operations

    NASA Technical Reports Server (NTRS)

    Rogers, Ralph V.

    1993-01-01

    The TATSS Project's goal was to develop a design for computer software that would support the attainment of the following objectives for the air traffic simulation model: (1) Full freedom of movement for each aircraft object in the simulation model. Each aircraft object may follow any designated flight plan or flight path necessary as required by the experiment under consideration. (2) Object position precision up to +/- 3 meters vertically and +/- 15 meters horizontally. (3) Aircraft maneuvering in three space with the object position precision identified above. (4) Air traffic control operations and procedures. (5) Radar, communication, navaid, and landing aid performance. (6) Weather. (7) Ground obstructions and terrain. (8) Detection and recording of separation violations. (9) Measures of performance including deviations from flight plans, air space violations, air traffic control messages per aircraft, and traditional temporal based measures.

  12. Highway Safety Occupational Program Development Guide.

    ERIC Educational Resources Information Center

    Daugherty, Ronald D.; And Others

    As part of a national project conducted for the National Highway Traffic Safety Administration, U.S. Department of Transportation, The Center for Vocational and Technical Education conducted a nationwide search for curriculum materials related to highway safety occupations. These materials were then screened and synthesized to provide training…

  13. Highway Collision Investigation Training Program. Final Report.

    ERIC Educational Resources Information Center

    Garrett, John W.

    The report was prepared for the National Highway Traffic Safety Administration (NHTSA) of the U.S. Department of Transportation. The report briefly reviews the appropriate literature, then describes the one-year program which involved planning and organization of a Highway Collision Investigation Training Program, preparing a course syllabus, and…

  14. Risk assessment on an Argentinean road with a dynamic traffic simulator

    NASA Astrophysics Data System (ADS)

    Voumard, Jérémie; Baumann, Valérie; Jaboyedoff, Michel; Derron, Marc-Henri; Penna, Ivanna

    2014-05-01

    The National Route 7 in Argentina is one of the most important corridors crossing the Andean Cordillera. It concentrates most of the traffic related to the Southern Common Market (MERCOSUR), it also connects Mendoza city (the fourth most populated in Argentina) with Santiago de Chile (the Chile capital city), and is used by tourists to access to the Aconcagua National park, Puente del Inca natural monument, skiing resorts, and to local displacements for the villages along the Mendoza valley. The road crosses the Andes through the Mendoza river valley at an elevation between 2'000 and 3'000 m. The traffic (2500 vehicles/day) is composed of motorcycles, cars and pickup trucks, trucks without trailer, buses, and semi-trailer trucks. Debris flows developed along tributaries of the Mendoza River, and due to remobilization of talus materials, impact frequently the road, causing traffic disruptions, bridges damages, etc. Rock falls detached from highly fractured outcrops also impact frequently the road, causing sometimes casualties. The aim of this study is to evaluate risk along sections of the National Road 7 develop along the Mendoza river, using a dynamic traffic simulator based on MATLAB© routine. The dynamic traffic simulator developed for natural hazards events on roads consider different scenarios based on traffic speeds, vehicle types, interactions types, road properties and natural processes. Here we show that vehicle types and traffic variations may influence the risk estimation. The analyzed risk on several critical sections of the National Route 7 demonstrates that risk may significantly increase: 1) on sinuous sections, steep sections and because of road conditions changes (exit of tunnel, bridges, road width, etc.) because of decreasing vehicle speed, particularly with semi-trailer trucks; 2) when an event, such a debris flow, occurs and generates a vehicle tailback increasing their duration presence in the risk area.

  15. Integration of Linear Dynamic Emission and Climate Models with Air Traffic Simulations

    NASA Technical Reports Server (NTRS)

    Sridhar, Banavar; Ng, Hok K.; Chen, Neil Y.

    2012-01-01

    Future air traffic management systems are required to balance the conflicting objectives of maximizing safety and efficiency of traffic flows while minimizing the climate impact of aviation emissions and contrails. Integrating emission and climate models together with air traffic simulations improve the understanding of the complex interaction between the physical climate system, carbon and other greenhouse gas emissions and aviation activity. This paper integrates a national-level air traffic simulation and optimization capability with simple climate models and carbon cycle models, and climate metrics to assess the impact of aviation on climate. The capability can be used to make trade-offs between extra fuel cost and reduction in global surface temperature change. The parameters in the simulation can be used to evaluate the effect of various uncertainties in emission models and contrails and the impact of different decision horizons. Alternatively, the optimization results from the simulation can be used as inputs to other tools that monetize global climate impacts like the FAA s Aviation Environmental Portfolio Management Tool for Impacts.

  16. Platoon Interactions and Real-World Traffic Simulation and Validation Based on the LWR-IM

    PubMed Central

    Ng, Kok Mun; Reaz, Mamun Bin Ibne

    2016-01-01

    Platoon based traffic flow models form the underlying theoretical framework in traffic simulation tools. They are essentially important in facilitating efficient performance calculation and evaluation in urban traffic networks. For this purpose, a new platoon-based macroscopic model called the LWR-IM has been developed in [1]. Preliminary analytical validation conducted previously has proven the feasibility of the model. In this paper, the LWR-IM is further enhanced with algorithms that describe platoon interactions in urban arterials. The LWR-IM and the proposed platoon interaction algorithms are implemented in the real-world class I and class II urban arterials. Another purpose of the work is to perform quantitative validation to investigate the validity and ability of the LWR-IM and its underlying algorithms to describe platoon interactions and simulate performance indices that closely resemble the real traffic situations. The quantitative validation of the LWR-IM is achieved by performing a two-sampled t-test on queues simulated by the LWR-IM and real queues observed at these real-world locations. The results reveal insignificant differences of simulated queues with real queues where the p-values produced concluded that the null hypothesis cannot be rejected. Thus, the quantitative validation further proved the validity of the LWR-IM and the embedded platoon interactions algorithm for the intended purpose. PMID:26731745

  17. Platoon Interactions and Real-World Traffic Simulation and Validation Based on the LWR-IM.

    PubMed

    Ng, Kok Mun; Reaz, Mamun Bin Ibne

    2016-01-01

    Platoon based traffic flow models form the underlying theoretical framework in traffic simulation tools. They are essentially important in facilitating efficient performance calculation and evaluation in urban traffic networks. For this purpose, a new platoon-based macroscopic model called the LWR-IM has been developed in [1]. Preliminary analytical validation conducted previously has proven the feasibility of the model. In this paper, the LWR-IM is further enhanced with algorithms that describe platoon interactions in urban arterials. The LWR-IM and the proposed platoon interaction algorithms are implemented in the real-world class I and class II urban arterials. Another purpose of the work is to perform quantitative validation to investigate the validity and ability of the LWR-IM and its underlying algorithms to describe platoon interactions and simulate performance indices that closely resemble the real traffic situations. The quantitative validation of the LWR-IM is achieved by performing a two-sampled t-test on queues simulated by the LWR-IM and real queues observed at these real-world locations. The results reveal insignificant differences of simulated queues with real queues where the p-values produced concluded that the null hypothesis cannot be rejected. Thus, the quantitative validation further proved the validity of the LWR-IM and the embedded platoon interactions algorithm for the intended purpose.

  18. Simulations of floodflows on the White River in the vicinity of U.S. Highway 79 near Clarendon, Arkansas

    USGS Publications Warehouse

    Funkhouser, Jaysson E.; Barks, C. Shane

    2003-01-01

    A two-dimensional finite-element surface-water model was used to study the effects of the proposed modification to the U.S. Highway 79 corridor on flooding on the White River near Clarendon, Arkansas. The effects of floodflows were simulated for the following scenarios: existing, natural, and four proposed bridging alternatives. All of the scenarios were modeled with floods having the 5- and 100-year recurrence intervals (115,100 and 216,000 cubic feet per second). The simulated existing conditions included a 3,200-foot White River bridge located on the east side of the study area near Clarendon, Arkansas; a 3,700-foot First Old River bridge located 0.5 mile west of the White River bridge opening; and a 1,430-foot Roc Roe Bayou bridge located 1.6 mile west of the First Old River bridge. The simulated hypothetical natural conditions involved removing the U.S. Highway 79 and the Union Pacific Railroad embankments along the entire length of the flood plain. The primary purpose of model simulations for natural conditions was to calculate backwater data for the existing and proposed conditions. The four simulated hypothetical proposed alternatives involved a 1.8-mile White River bridge located on the east side of the study area near Clarendon, Arkansas, either a 1,400-foot relief bridge (Alternative 1) or a 1,545 relief bridge (Alternatives 2-4) located 0.25 mile west of the White River bridge opening, and three different Roc Roe Bayou bridge openings ranging from 1,540-3,475 feet in length located 0.9 mile west of the relief bridge (Alternatives 1-4). Simulation of the 5-year floodflow for the existing bridge openings indicates that about 57 percent (65,600 cubic feet per second) of flow was conveyed by the White River bridge, about 26 percent (29,900 cubic feet per second) by the First Old River bridge, and about 17 percent (19,600 cubic feet per second) by the Roc Roe Bayou bridge. Maximum depth-averaged point velocities for the White River, First Old River, and Roc

  19. Groundwater and highways interaction: past and present experiences of highway construction in Slovenia

    NASA Astrophysics Data System (ADS)

    Brencic, Mihael

    2006-03-01

    During the planning, designing, construction, operation and maintenance of highways, groundwater can be of important environmental and constructional constraint that can significantly influence the safety operation of traffic and of big influence on the operational costs of highways. To classify and conceptualize the relation between groundwater and highways, three important groups of problems can be determined: groundwater protection from highway influences, protection of highway from groundwater and economic use of groundwater for highway operation. In the present study, groundwater management strategies are represented during all life cycles of highways. Greater emphasis is given to groundwater protection and field hydrogeological investigations for proper groundwater management related to the highway. The approach adopted in Slovenia and the role of hydrogeology is given as an illustration.

  20. Neural network system for traffic flow management

    NASA Astrophysics Data System (ADS)

    Gilmore, John F.; Elibiary, Khalid J.; Petersson, L. E. Rickard

    1992-09-01

    Atlanta will be the home of several special events during the next five years ranging from the 1996 Olympics to the 1994 Super Bowl. When combined with the existing special events (Braves, Falcons, and Hawks games, concerts, festivals, etc.), the need to effectively manage traffic flow from surface streets to interstate highways is apparent. This paper describes a system for traffic event response and management for intelligent navigation utilizing signals (TERMINUS) developed at Georgia Tech for adaptively managing special event traffic flows in the Atlanta, Georgia area. TERMINUS (the original name given Atlanta, Georgia based upon its role as a rail line terminating center) is an intelligent surface street signal control system designed to manage traffic flow in Metro Atlanta. The system consists of three components. The first is a traffic simulation of the downtown Atlanta area around Fulton County Stadium that models the flow of traffic when a stadium event lets out. Parameters for the surrounding area include modeling for events during various times of day (such as rush hour). The second component is a computer graphics interface with the simulation that shows the traffic flows achieved based upon intelligent control system execution. The final component is the intelligent control system that manages surface street light signals based upon feedback from control sensors that dynamically adapt the intelligent controller's decision making process. The intelligent controller is a neural network model that allows TERMINUS to control the configuration of surface street signals to optimize the flow of traffic away from special events.

  1. Real-time highway pull-over vehicle monitoring using fiber microbending-loss reflectometry

    NASA Astrophysics Data System (ADS)

    Wang, Ke; Wei, ZhanXiong; Chen, Bingquan; Cui, Hong-Liang

    2005-05-01

    This paper introduces a novel application of fiber microbending sensor to monitor the highway vehicles, i.e. overtime pull-over vehicles. Precise locations and durations of the overtime pull-over vehicles can be detected and alarms can be sent to highway administrators. Highway administrators can use these data to maintain the traffic order, secure the passengers and enforce the law. The sensor is designed based on fiber microbending effect and optical time-domain reflectometry method is utilized to generate, collect and process the optical signals. The experiment is designed to simulate the highway shoulder with vehicle parking on it. Different vehicle weight-induced fiber microbending losses are detected and measured. By the optical time domain reflectometry technique, the precise locations of pull-over vehicles have been obtained.

  2. In-Trail Procedure Air Traffic Control Procedures Validation Simulation Study

    NASA Technical Reports Server (NTRS)

    Chartrand, Ryan C.; Hewitt, Katrin P.; Sweeney, Peter B.; Graff, Thomas J.; Jones, Kenneth M.

    2012-01-01

    In August 2007, Airservices Australia (Airservices) and the United States National Aeronautics and Space Administration (NASA) conducted a validation experiment of the air traffic control (ATC) procedures associated with the Automatic Dependant Surveillance-Broadcast (ADS-B) In-Trail Procedure (ITP). ITP is an Airborne Traffic Situation Awareness (ATSA) application designed for near-term use in procedural airspace in which ADS-B data are used to facilitate climb and descent maneuvers. NASA and Airservices conducted the experiment in Airservices simulator in Melbourne, Australia. Twelve current operational air traffic controllers participated in the experiment, which identified aspects of the ITP that could be improved (mainly in the communication and controller approval process). Results showed that controllers viewed the ITP as valid and acceptable. This paper describes the experiment design and results.

  3. An original traffic additional emission model and numerical simulation on a signalized road

    NASA Astrophysics Data System (ADS)

    Zhu, Wen-Xing; Zhang, Jing-Yu

    2017-02-01

    Based on VSP (Vehicle Specific Power) model traffic real emissions were theoretically classified into two parts: basic emission and additional emission. An original additional emission model was presented to calculate the vehicle's emission due to the signal control effects. Car-following model was developed and used to describe the traffic behavior including cruising, accelerating, decelerating and idling at a signalized intersection. Simulations were conducted under two situations: single intersection and two adjacent intersections with their respective control policy. Results are in good agreement with the theoretical analysis. It is also proved that additional emission model may be used to design the signal control policy in our modern traffic system to solve the serious environmental problems.

  4. Piloted simulation of a ground-based time-control concept for air traffic control

    NASA Technical Reports Server (NTRS)

    Davis, Thomas J.; Green, Steven M.

    1989-01-01

    A joint simulation was carried out using a piloted simulator and an advanced-concept air traffic control simulation to study the acceptability and accuracy of the ground-based four-dimensional descent advisor (DA), an automation aid based on accurate models of aircraft performance and weather conditions. In the piloted simulation, airline crews executed controller-issued descent advisories along standard curved-path arrival routes and were able to achieve an arrival-time precision of plus or minus 20 s at the metering fix. An analysis of errors generated in turns resulted in a further enhancement of the DA algorithm.

  5. Designing Scenarios for Controller-in-the-Loop Air Traffic Simulations

    NASA Technical Reports Server (NTRS)

    Kupfer, Michael; Mercer, Joey; Cabrall, Chris; Homola, Jeff; Callantine, Todd

    2013-01-01

    Within the Human Factors Division at NASA Ames Research Center the Airspace Operations Laboratory (AOL) is developing advanced automation concepts that help to transform the National Airspace System into NextGen, the Next Generation Air Transportation System. High-fidelity human-in-the-loop (HITL) simulations are used as a means to investigate and develop roles, responsibilities, support tools, and requirements for human operators and automation. This paper describes the traffic scenario design process and strategies as used by AOL researchers. Details are presented on building scenarios for specific simulation objectives using various design strategies. A focus is set on creating scenarios based on recorded real world traffic for terminal-area simulations.

  6. Simulating synchronized traffic flow and wide moving jam based on the brake light rule

    NASA Astrophysics Data System (ADS)

    Xiang, Zheng-Tao; Li, Yu-Jin; Chen, Yu-Feng; Xiong, Li

    2013-11-01

    A new cellular automaton (CA) model based on brake light rules is proposed, which considers the influence of deterministic deceleration on randomization probability and deceleration extent. To describe the synchronized flow phase of Kerner’s three-phase theory in accordance with empirical data, we have changed some rules of vehicle motion with the aim to improve speed and acceleration vehicle behavior in synchronized flow simulated with earlier cellular automaton models with brake lights. The fundamental diagrams and spatial-temporal diagrams are analyzed, as well as the complexity of the traffic evolution, the emergence process of wide moving jam. Simulation results show that our new model can reproduce the three traffic phases: free flow, synchronized flow and wide moving jam. In addition, our new model can well describe the complexity of traffic evolution: (1) with initial homogeneous distribution and large densities, the traffic will evolve into multiple steady states, in which the numbers of wide moving jams are not invariable. (2) With initial homogeneous distribution and the middle range of density, the wide moving jam will emerge stochastically. (3) With initial mega-jam distribution and the density close to a point with the low value, the initial mega-jam will disappear stochastically. (4) For the cases with multiple wide moving jams, the process is analyzed involving the generation of narrow moving jam due to “pinch effect”, which leads to wide moving jam emergence.

  7. Intelligent Vehicle Highway Systems (IVHS). (Latest citations from the INSPEC database). Published Search

    SciTech Connect

    1995-02-01

    The bibliography contains citations concerning technology for the automation of highways to reduce congestion, energy consumption and the need for additional highways. Citations focus on communication, guidance, and traffic management systems. The citations also examine human factors, traffic modeling, and highway safety. (Contains a minimum of 144 citations and includes a subject term index and title list.)

  8. Intelligent Vehicle Highway Systems (IVHS). (Latest citations from the INSPEC database). Published Search

    SciTech Connect

    1996-10-01

    The bibliography contains citations concerning technology for the automation of highways to reduce congestion, energy consumption and the need for additional highways. Citations focus on communication, guidance, and traffic management systems. The citations also examine human factors, traffic modeling, and highway safety. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  9. Intelligent vehicle highway systems (IVHS). (Latest citations from the INSPEC database). Published Search

    SciTech Connect

    1995-11-01

    The bibliography contains citations concerning technology for the automation of highways to reduce congestion, energy consumption and the need for additional highways. Citations focus on communication, guidance, and traffic management systems. The citations also examine human factors, traffic modeling, and highway safety. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  10. Traffic Alert and Collision Avoidance System. Developmental Simulation.

    DTIC Science & Technology

    1982-07-01

    TRAINTNCn CHECKLIST 1 APPENDIX C POST FLIG4T nilESTIONNAIRE C.lI APPENPIy nl nERRIEFTNG OINIESTIONNAIRF v LIST OF FIGURES FIGURE NO: TITLE PAGE 1.n-1...A-6 A.9.1-7 Internal View of Blue Cah A-7 A.7-1 CAS Simulation Equipment Layout A- c A.2.1-1 Advisory Messaqn Byte Definition A-il A.?.3-1 TCAS Audio...the TCAS criteria and represents a potential threat. Non-mode C Aircraft An aircraft that has a transponder but has no altitude reportinq from the

  11. Simulation studies of STOL airplane operations in metropolitan downtown and airport air traffic control environments

    NASA Technical Reports Server (NTRS)

    Sawyer, R. H.; Mclaughlin, M. D.

    1974-01-01

    The operating problems and equipment requirements for STOL airplanes in terminal area operations in simulated air traffic control (ATC) environments were studied. These studies consisted of Instrument Flight Rules (IFR) arrivals and departures in the New York area to and from a downtown STOL port, STOL runways at John F. Kennedy International Airport, or STOL runways at a hypothetical international airport. The studies were accomplished in real time by using a STOL airplane flight simulator. An experimental powered lift STOL airplane and two in-service airplanes having high aerodynamic lift (i.e., STOL) capability were used in the simulations.

  12. Using spatial context to support prospective memory in simulated air traffic control.

    PubMed

    Loft, Shayne; Finnerty, Dannielle; Remington, Roger W

    2011-12-01

    The aim was to examine whether prospective memory error and response costs to ongoing tasks in an air traffic control simulation could be reduced by providing spatial context. Prospective memory refers to remembering to perform an intended action at an appropriate point in the future. Failures of prospective memory can occur in air traffic control. For this study, three conditions of participants performed an air traffic control task that required them to accept and hand off aircraft and to prevent conflicts. The prospective memory task required participants to remember to press an alternative key rather than the routine key when accepting target aircraft. A red line separated the display into upper and lower regions. Participants in the context condition were told that the prospective memory instruction would apply only to aircraft approaching from one region (upper or lower). Those in the standard condition were not provided this information. In the control condition, participants did not have to perform the prospective memory task. In the context condition, participants made fewer prospective memory errors than did those in the standard condition and made faster acceptance decisions for aircraft approaching from irrelevant compared with relevant regions. Costs to hand-off decision time were also reduced in the context condition. Spatial context provided no benefit to conflict detection. Participants could partially localize their allocation of attentional resources to the prospective memory task to relevant display regions. The findings are potentially applicable to air traffic control, whereby regularities in airspace structure and standard traffic flows allow controllers to anticipate the location of specific air traffic events.

  13. Simulator of Road Tunnel

    NASA Astrophysics Data System (ADS)

    Danišovič, Peter; Schlosser, František; Šrámek, Juraj; Rázga, Martin

    2015-05-01

    A Tunnel Traffic & Operation Simulator is a device of the Centre of Transport Research at the University of Žilina. The Simulator allows managing technological equipment of virtual two-tube highway tunnel, which is interconnected with simulation of vehicle traffic in tunnel. Changes of the traffic-operation states and other equipment are reflecting at the simulated traffic, as well as simulations of various emergency events in traffic initiate changes in tunnel detecting and measuring devices. It is thus possible to simulate emergency states, which can be affected by various faults of technology as well as by climatic conditions. The solutions can be found in irreplaceable experiences of Slovak road tunnel operators, changes of trafficoperation states, visualizations of operator technological display screens, technological devices labelling in order to increase operational safety of road tunnels.

  14. Urban traffic simulated from the dual representation: Flow, crisis and congestion

    NASA Astrophysics Data System (ADS)

    Hu, Mao-Bin; Jiang, Rui; Wang, Ruili; Wu, Qing-Song

    2009-05-01

    We propose a traffic simulation model for urban system based on the dual graph representation of a urban road network and with a random entering vehicle rate. To avoid the shortcoming of “Space Syntax” of ignoring the road's metric distance, we consider both the motion of the vehicles along roads and the navigation of the vehicles in the network. Simulations have shown some basic properties of urban traffic system, such as flux fluctuation, crisis and dissipation, phase transition from a free flow to jams, overall capacity, the distribution of traveling time, and the fundamental diagram. The system's behavior greatly depends on the topology of the transportation network. A well-planned lattice grid can keep more vehicles travelling. The critical entering vehicle rate is much greater in lattice grid than in a self-organized network. The vehicles have to travel longer time in a self-organized urban system due to the navigation cost.

  15. Comparison between three different traffic micro-simulations and reality in Dallas

    SciTech Connect

    Nagel, K.; Pieck, M.; Simon, P.M.; Rickert, M.

    1998-06-18

    It is certainly desirable that transportation forecasting models are correct in the sense that the traffic patterns they predict correspond to what would happen in reality under the circumstances assumed in the forecasting model. Unfortunately, it is notoriously difficult to transform the above common sense statement into a technical specification. Since one cannot run controlled experiments in socio-economic systems, it is usually impossible to check the forecasts. The authors describe three traffic microsimulations which operate at different levels of fidelity. They are used to iteratively generate a self-consistent route-set based upon microsimulation feedback. They compare the simulation results of all three simulations to aggregated turn count data of actual field measurements.

  16. UAS Air Traffic Controller Acceptability Study-2: Effects of Communications Delays and Winds in Simulation

    NASA Technical Reports Server (NTRS)

    Comstock, James R., Jr.; Ghatas, Rania W.; Consiglio, Maria C.; Chamberlain, James P.; Hoffler, Keith D.

    2016-01-01

    This study evaluated the effects of Communications Delays and Winds on Air Traffic Controller ratings of acceptability of horizontal miss distances (HMDs) for encounters between UAS and manned aircraft in a simulation of the Dallas-Ft. Worth East-side airspace. Fourteen encounters per hour were staged in the presence of moderate background traffic. Seven recently retired controllers with experience at DFW served as subjects. Guidance provided to the UAS pilots for maintaining a given HMD was provided by information from self-separation algorithms displayed on the Multi-Aircraft Simulation System. Winds tested did not affect the acceptability ratings. Communications delays tested included 0, 400, 1200, and 1800 msec. For longer communications delays, there were changes in strategy and communications flow that were observed and reported by the controllers. The aim of this work is to provide useful information for guiding future rules and regulations applicable to flying UAS in the NAS.

  17. ADS-B within a Multi-Aircraft Simulation for Distributed Air-Ground Traffic Management

    NASA Technical Reports Server (NTRS)

    Barhydt, Richard; Palmer, Michael T.; Chung, William W.; Loveness, Ghyrn W.

    2004-01-01

    Automatic Dependent Surveillance Broadcast (ADS-B) is an enabling technology for NASA s Distributed Air-Ground Traffic Management (DAG-TM) concept. DAG-TM has the goal of significantly increasing capacity within the National Airspace System, while maintaining or improving safety. Under DAG-TM, aircraft exchange state and intent information over ADS-B with other aircraft and ground stations. This information supports various surveillance functions including conflict detection and resolution, scheduling, and conformance monitoring. To conduct more rigorous concept feasibility studies, NASA Langley Research Center s PC-based Air Traffic Operations Simulation models a 1090 MHz ADS-B communication structure, based on industry standards for message content, range, and reception probability. The current ADS-B model reflects a mature operating environment and message interference effects are limited to Mode S transponder replies and ADS-B squitters. This model was recently evaluated in a Joint DAG-TM Air/Ground Coordination Experiment with NASA Ames Research Center. Message probability of reception vs. range was lower at higher traffic levels. The highest message collision probability occurred near the meter fix serving as the confluence for two arrival streams. Even the highest traffic level encountered in the experiment was significantly less than the industry standard "LA Basin 2020" scenario. Future studies will account for Mode A and C message interference (a major effect in several industry studies) and will include Mode A and C aircraft in the simulation, thereby increasing the total traffic level. These changes will support ongoing enhancements to separation assurance functions that focus on accommodating longer ADS-B information update intervals.

  18. Fiberglass-Reinforced Rigid Polyurethane Expedient Pavement Subject to Simulated F-4 Aircraft Traffic.

    DTIC Science & Technology

    1980-05-01

    AD-AGa9 266 CIVIL ENGINEERING LAB (NAVY) PORT HUENEWE CA F/B 11/2 FIBERGLASS-REIFORCED RIGID POLYURETHANE EXPEDIFNT PAVEWWNT SUB--ETC(U) MAY 80 P S...FIBERGLASS-REINFORCED RIGID POLYURETHANE ~EXPEDIENT PAVEMENT SUBJECT TO SIMULATED F-4 AIRCRAFT TRAFFIC author: P. S. Sprngston . , date: May 1980oE 18...CATALOG NUMBER TN- 15 78DN412 h A J ........................................~ S. TYPE OF REPORT &PRO OEE B 1ERG LASS.-REIN FORCED -RIGID POLYURETHANE

  19. Traffic congestion forecasting model for the INFORM System. Final report

    SciTech Connect

    Azarm, A.; Mughabghab, S.; Stock, D.

    1995-05-01

    This report describes a computerized traffic forecasting model, developed by Brookhaven National Laboratory (BNL) for a portion of the Long Island INFORM Traffic Corridor. The model has gone through a testing phase, and currently is able to make accurate traffic predictions up to one hour forward in time. The model will eventually take on-line traffic data from the INFORM system roadway sensors and make projections as to future traffic patterns, thus allowing operators at the New York State Department of Transportation (D.O.T.) INFORM Traffic Management Center to more optimally manage traffic. It can also form the basis of a travel information system. The BNL computer model developed for this project is called ATOP for Advanced Traffic Occupancy Prediction. The various modules of the ATOP computer code are currently written in Fortran and run on PC computers (pentium machine) faster than real time for the section of the INFORM corridor under study. The following summarizes the various routines currently contained in the ATOP code: Statistical forecasting of traffic flow and occupancy using historical data for similar days and time (long term knowledge), and the recent information from the past hour (short term knowledge). Estimation of the empirical relationships between traffic flow and occupancy using long and short term information. Mechanistic interpolation using macroscopic traffic models and based on the traffic flow and occupancy forecasted (item-1), and the empirical relationships (item-2) for the specific highway configuration at the time of simulation (construction, lane closure, etc.). Statistical routine for detection and classification of anomalies and their impact on the highway capacity which are fed back to previous items.

  20. The smart highway project: Smart highways, smart vehicles, smart engineering

    NASA Technical Reports Server (NTRS)

    Pethtel, Ray D.

    1996-01-01

    The Smart Highway project is a six mile, limited access roadway being built between Interstate 81 and Blacksburg, Virginia. The initial construction segment will be two miles long and is designed to serve as a test bed and test track for Intelligent Transportation Systems (ITS) research. The Center for Transportation Research (CTR) at Virginia Tech is developing three evaluation tools for its ITS research including DYNAVIMTS (a software framework), and the FLASH Lab (a 1/15th scale model highway and vehicle system). The Smart Highway rounds out the Center's evaluation methodology by allowing full scale operational tests, evaluations, and research under both experimental and conventional traffic conditions. Currently under development is a concept for a fully automated highway using a 'Cooperative Infrastructure Managed System' which involves ultra wide band communication beacons installed in the infrastructure with appropriate sensors, receivers and processors on board the vehicles. The project is part of the research program funded by the National Automated Highway System Consortium. The CTR hopes to develop the automated concept to prototype status by 1997. Other smart transportation and smart engineering concepts are proposed. This presentation will address the goals and objectives of the Smart Highway project, overview its status and importance to the region, and identify some of the transportation technology now under development and planned in the future.

  1. Minimizing the Disruptive Effects of Prospective Memory in Simulated Air Traffic Control

    PubMed Central

    Loft, Shayne; Smith, Rebekah E.; Remington, Roger

    2015-01-01

    Prospective memory refers to remembering to perform an intended action in the future. Failures of prospective memory can occur in air traffic control. In two experiments, we examined the utility of external aids for facilitating air traffic management in a simulated air traffic control task with prospective memory requirements. Participants accepted and handed-off aircraft and detected aircraft conflicts. The prospective memory task involved remembering to deviate from a routine operating procedure when accepting target aircraft. External aids that contained details of the prospective memory task appeared and flashed when target aircraft needed acceptance. In Experiment 1, external aids presented either adjacent or non-adjacent to each of the 20 target aircraft presented over the 40min test phase reduced prospective memory error by 11% compared to a condition without external aids. In Experiment 2, only a single target aircraft was presented a significant time (39min–42min) after presentation of the prospective memory instruction, and the external aids reduced prospective memory error by 34%. In both experiments, costs to the efficiency of non-prospective memory air traffic management (non-target aircraft acceptance response time, conflict detection response time) were reduced by non-adjacent aids compared to no aids or adjacent aids. In contrast, in both experiments, the efficiency of the prospective memory air traffic management (target aircraft acceptance response time) was facilitated by adjacent aids compared to non-adjacent aids. Together, these findings have potential implications for the design of automated alerting systems to maximize multi-task performance in work settings where operators monitor and control demanding perceptual displays. PMID:24059825

  2. Minimizing the disruptive effects of prospective memory in simulated air traffic control.

    PubMed

    Loft, Shayne; Smith, Rebekah E; Remington, Roger W

    2013-09-01

    Prospective memory refers to remembering to perform an intended action in the future. Failures of prospective memory can occur in air traffic control. In two experiments, we examined the utility of external aids for facilitating air traffic management in a simulated air traffic control task with prospective memory requirements. Participants accepted and handed-off aircraft and detected aircraft conflicts. The prospective memory task involved remembering to deviate from a routine operating procedure when accepting target aircraft. External aids that contained details of the prospective memory task appeared and flashed when target aircraft needed acceptance. In Experiment 1, external aids presented either adjacent or nonadjacent to each of the 20 target aircraft presented over the 40-min test phase reduced prospective memory error by 11% compared with a condition without external aids. In Experiment 2, only a single target aircraft was presented a significant time (39-42 min) after presentation of the prospective memory instruction, and the external aids reduced prospective memory error by 34%. In both experiments, costs to the efficiency of nonprospective memory air traffic management (nontarget aircraft acceptance response time, conflict detection response time) were reduced by nonadjacent aids compared with no aids or adjacent aids. In contrast, in both experiments, the efficiency of the prospective memory air traffic management (target aircraft acceptance response time) was facilitated by adjacent aids compared with nonadjacent aids. Together, these findings have potential implications for the design of automated alerting systems to maximize multitask performance in work settings where operators monitor and control demanding perceptual displays. PsycINFO Database Record (c) 2013 APA, all rights reserved.

  3. Highway development

    Treesearch

    Peter M. Harvard; Bernard L. Chaplin

    1979-01-01

    Highways are something we see, and some-thing we see the landscape from. They exert tremendous visual influence on our national landscape and will continue to do so. While most interstate mileage is in place, major unbuilt urban segments remain, and rural and suburban trunk roads are receiving renewed emphasis. Nationwide programs of bridge replacement, safety and...

  4. Self-organized criticality and 1/f noise in traffic

    SciTech Connect

    Paczuski, M.; Nagel, K.

    1995-12-31

    Phantom traffic jams may emerge ``out of nowhere`` from small fluctuations rather than being triggered by large, exceptional events. We show how phantom jams arise in a model of single lane highway traffic, which mimics human driving behavior. Surprisingly, the optimal state of highest efficiency, with the largest throughput, is a critical state with traffic jams of all sizes. We demonstrate that open systems self-organize to the most efficient state. In the model we study, this critical state is a percolation transition for the phantom traffic jams. At criticality, the individual jams have a complicated fractal structure where cars follow an intermittent stop and go pattern. We analytically derive the form of the corresponding power spectrum to be 1/f{sup {alpha}} with {alpha} = 1 exactly. This theoretical prediction agrees with our numerical simulations and with observations of 1/f noise in real traffic.

  5. Field Measurements and Numerical Simulations of Temperature and Moisture in Highway Engineering Using a Frequency Domain Reflectometry Sensor.

    PubMed

    Yao, Yong-Sheng; Zheng, Jian-Long; Chen, Zeng-Shun; Zhang, Jun-Hui; Li, Yong

    2016-06-10

    This paper presents a systematic pioneering study on the use of agricultural-purpose frequency domain reflectometry (FDR) sensors to monitor temperature and moisture of a subgrade in highway extension and reconstruction engineering. The principle of agricultural-purpose FDR sensors and the process for embedding this kind of sensors for subgrade engineering purposes are introduced. Based on field measured weather data, a numerical analysis model for temperature and moisture content in the subgrade's soil is built. Comparisons of the temperature and moisture data obtained from numerical simulation and FDR-based measurements are conducted. The results show that: (1) the embedding method and process, data acquisition, and remote transmission presented are reasonable; (2) the temperature and moisture changes are coordinated with the atmospheric environment and they are also in close agreement with numerical calculations; (3) the change laws of both are consistent at positions where the subgrade is compacted uniformly. These results suggest that the data measured by the agricultural-purpose FDR sensors are reliable. The findings of this paper enable a new and effective real-time monitoring method for a subgrade's temperature and moisture changes, and thus broaden the application of agricultural-purpose FDR sensors.

  6. Field Measurements and Numerical Simulations of Temperature and Moisture in Highway Engineering Using a Frequency Domain Reflectometry Sensor

    PubMed Central

    Yao, Yong-Sheng; Zheng, Jian-Long; Chen, Zeng-Shun; Zhang, Jun-Hui; Li, Yong

    2016-01-01

    This paper presents a systematic pioneering study on the use of agricultural-purpose frequency domain reflectometry (FDR) sensors to monitor temperature and moisture of a subgrade in highway extension and reconstruction engineering. The principle of agricultural-purpose FDR sensors and the process for embedding this kind of sensors for subgrade engineering purposes are introduced. Based on field measured weather data, a numerical analysis model for temperature and moisture content in the subgrade’s soil is built. Comparisons of the temperature and moisture data obtained from numerical simulation and FDR-based measurements are conducted. The results show that: (1) the embedding method and process, data acquisition, and remote transmission presented are reasonable; (2) the temperature and moisture changes are coordinated with the atmospheric environment and they are also in close agreement with numerical calculations; (3) the change laws of both are consistent at positions where the subgrade is compacted uniformly. These results suggest that the data measured by the agricultural-purpose FDR sensors are reliable. The findings of this paper enable a new and effective real-time monitoring method for a subgrade’s temperature and moisture changes, and thus broaden the application of agricultural-purpose FDR sensors. PMID:27294935

  7. Modeling and Simulation for Urban Rail Traffic Problem Based on Cellular Automata

    NASA Astrophysics Data System (ADS)

    Xu, Yan; Cao, Cheng-Xun; Li, Ming-Hua; Luo, Jin-Long

    2012-12-01

    Based on the Nagel-Schreckenberg model, we propose a new cellular automata model to simulate the urban rail traffic flow under moving block system and present a new minimum instantaneous distance formula under pure moving block. We also analyze the characteristics of the urban rail traffic flow under the influence of train density, station dwell times, the length of train, and the train velocity. Train delays can be decreased effectively through flexible departure intervals according to the preceding train type before its departure. The results demonstrate that a suitable adjustment of the current train velocity based on the following train velocity can greatly shorten the minimum departure intervals and then increase the capacity of rail transit.

  8. Information Presentation and Control in a Modern Air Traffic Control Tower Simulator

    NASA Technical Reports Server (NTRS)

    Haines, Richard F.; Doubek, Sharon; Rabin, Boris; Harke, Stanton

    1996-01-01

    The proper presentation and management of information in America's largest and busiest (Level V) air traffic control towers calls for an in-depth understanding of many different human-computer considerations: user interface design for graphical, radar, and text; manual and automated data input hardware; information/display output technology; reconfigurable workstations; workload assessment; and many other related subjects. This paper discusses these subjects in the context of the Surface Development and Test Facility (SDTF) currently under construction at NASA's Ames Research Center, a full scale, multi-manned, air traffic control simulator which will provide the "look and feel" of an actual airport tower cab. Special emphasis will be given to the human-computer interfaces required for the different kinds of information displayed at the various controller and supervisory positions and to the computer-aided design (CAD) and other analytic, computer-based tools used to develop the facility.

  9. 23 CFR 772.9 - Analysis of traffic noise impacts and abatement measures.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... AND ENVIRONMENT PROCEDURES FOR ABATEMENT OF HIGHWAY TRAFFIC NOISE AND CONSTRUCTION NOISE § 772.9 Analysis of traffic noise impacts and abatement measures. (a) The highway agency shall determine and... 23 Highways 1 2011-04-01 2011-04-01 false Analysis of traffic noise impacts and abatement measures...

  10. 23 CFR 772.9 - Analysis of traffic noise impacts and abatement measures.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... AND ENVIRONMENT PROCEDURES FOR ABATEMENT OF HIGHWAY TRAFFIC NOISE AND CONSTRUCTION NOISE § 772.9 Analysis of traffic noise impacts and abatement measures. (a) The highway agency shall determine and... 23 Highways 1 2010-04-01 2010-04-01 false Analysis of traffic noise impacts and abatement measures...

  11. Economical Video Monitoring of Traffic

    NASA Technical Reports Server (NTRS)

    Houser, B. C.; Paine, G.; Rubenstein, L. D.; Parham, O. Bruce, Jr.; Graves, W.; Bradley, C.

    1986-01-01

    Data compression allows video signals to be transmitted economically on telephone circuits. Telephone lines transmit television signals to remote traffic-control center. Lines also carry command signals from center to TV camera and compressor at highway site. Video system with television cameras positioned at critical points on highways allows traffic controllers to determine visually, almost immediately, exact cause of traffic-flow disruption; e.g., accidents, breakdowns, or spills, almost immediately. Controllers can then dispatch appropriate emergency services and alert motorists to minimize traffic backups.

  12. Economical Video Monitoring of Traffic

    NASA Technical Reports Server (NTRS)

    Houser, B. C.; Paine, G.; Rubenstein, L. D.; Parham, O. Bruce, Jr.; Graves, W.; Bradley, C.

    1986-01-01

    Data compression allows video signals to be transmitted economically on telephone circuits. Telephone lines transmit television signals to remote traffic-control center. Lines also carry command signals from center to TV camera and compressor at highway site. Video system with television cameras positioned at critical points on highways allows traffic controllers to determine visually, almost immediately, exact cause of traffic-flow disruption; e.g., accidents, breakdowns, or spills, almost immediately. Controllers can then dispatch appropriate emergency services and alert motorists to minimize traffic backups.

  13. Fine-Tuning ADAS Algorithm Parameters for Optimizing Traffic ...

    EPA Pesticide Factsheets

    With the development of the Connected Vehicle technology that facilitates wirelessly communication among vehicles and road-side infrastructure, the Advanced Driver Assistance Systems (ADAS) can be adopted as an effective tool for accelerating traffic safety and mobility optimization at various highway facilities. To this end, the traffic management centers identify the optimal ADAS algorithm parameter set that enables the maximum improvement of the traffic safety and mobility performance, and broadcast the optimal parameter set wirelessly to individual ADAS-equipped vehicles. After adopting the optimal parameter set, the ADAS-equipped drivers become active agents in the traffic stream that work collectively and consistently to prevent traffic conflicts, lower the intensity of traffic disturbances, and suppress the development of traffic oscillations into heavy traffic jams. Successful implementation of this objective requires the analysis capability of capturing the impact of the ADAS on driving behaviors, and measuring traffic safety and mobility performance under the influence of the ADAS. To address this challenge, this research proposes a synthetic methodology that incorporates the ADAS-affected driving behavior modeling and state-of-the-art microscopic traffic flow modeling into a virtually simulated environment. Building on such an environment, the optimal ADAS algorithm parameter set is identified through an optimization programming framework to enable th

  14. Fine-Tuning ADAS Algorithm Parameters for Optimizing Traffic ...

    EPA Pesticide Factsheets

    With the development of the Connected Vehicle technology that facilitates wirelessly communication among vehicles and road-side infrastructure, the Advanced Driver Assistance Systems (ADAS) can be adopted as an effective tool for accelerating traffic safety and mobility optimization at various highway facilities. To this end, the traffic management centers identify the optimal ADAS algorithm parameter set that enables the maximum improvement of the traffic safety and mobility performance, and broadcast the optimal parameter set wirelessly to individual ADAS-equipped vehicles. After adopting the optimal parameter set, the ADAS-equipped drivers become active agents in the traffic stream that work collectively and consistently to prevent traffic conflicts, lower the intensity of traffic disturbances, and suppress the development of traffic oscillations into heavy traffic jams. Successful implementation of this objective requires the analysis capability of capturing the impact of the ADAS on driving behaviors, and measuring traffic safety and mobility performance under the influence of the ADAS. To address this challenge, this research proposes a synthetic methodology that incorporates the ADAS-affected driving behavior modeling and state-of-the-art microscopic traffic flow modeling into a virtually simulated environment. Building on such an environment, the optimal ADAS algorithm parameter set is identified through an optimization programming framework to enable th

  15. Initial Study of an Effective Fast-Time Simulation Platform for Unmanned Aircraft System Traffic Management

    NASA Technical Reports Server (NTRS)

    Xue, Min; Rios, Joseph

    2017-01-01

    Small Unmanned Aerial Vehicles (sUAVs), typically 55 lbs and below, are envisioned to play a major role in surveilling critical assets, collecting important information, and delivering goods. Large scale small UAV operations are expected to happen in low altitude airspace in the near future. Many static and dynamic constraints exist in low altitude airspace because of manned aircraft or helicopter activities, various wind conditions, restricted airspace, terrain and man-made buildings, and conflict-avoidance among sUAVs. High sensitivity and high maneuverability are unique characteristics of sUAVs that bring challenges to effective system evaluations and mandate such a simulation platform different from existing simulations that were built for manned air traffic system and large unmanned fixed aircraft. NASA's Unmanned aircraft system Traffic Management (UTM) research initiative focuses on enabling safe and efficient sUAV operations in the future. In order to help define requirements and policies for a safe and efficient UTM system to accommodate a large amount of sUAV operations, it is necessary to develop a fast-time simulation platform that can effectively evaluate requirements, policies, and concepts in a close-to-reality environment. This work analyzed the impacts of some key factors including aforementioned sUAV's characteristics and demonstrated the importance of these factors in a successful UTM fast-time simulation platform.

  16. Traffic signal design and simulation for vulnerable road users safety and bus preemption

    NASA Astrophysics Data System (ADS)

    Lo, Shih-Ching; Huang, Hsieh-Chu

    2015-01-01

    Mostly, pedestrian car accidents occurred at a signalized interaction is because pedestrians cannot across the intersection safely within the green light. From the viewpoint of pedestrian, there might have two reasons. The first one is pedestrians cannot speed up to across the intersection, such as the elders. The other reason is pedestrians do not sense that the signal phase is going to change and their right-of-way is going to be lost. Developing signal logic to protect pedestrian, who is crossing an intersection is the first purpose of this study. In addition, to improve the reliability and reduce delay of public transportation service is the second purpose. Therefore, bus preemption is also considered in the designed signal logic. In this study, the traffic data of the intersection of Chong-Qing North Road and Min-Zu West Road, Taipei, Taiwan, is employed to calibrate and validate the signal logic by simulation. VISSIM 5.20, which is a microscopic traffic simulation software, is employed to simulate the signal logic. From the simulated results, the signal logic presented in this study can protect pedestrians crossing the intersection successfully. The design of bus preemption can reduce the average delay. However, the pedestrian safety and bus preemption signal will influence the average delay of cars largely. Thus, whether applying the pedestrian safety and bus preemption signal logic to an intersection or not should be evaluated carefully.

  17. Traffic signal design and simulation for vulnerable road users safety and bus preemption

    SciTech Connect

    Lo, Shih-Ching; Huang, Hsieh-Chu

    2015-01-22

    Mostly, pedestrian car accidents occurred at a signalized interaction is because pedestrians cannot across the intersection safely within the green light. From the viewpoint of pedestrian, there might have two reasons. The first one is pedestrians cannot speed up to across the intersection, such as the elders. The other reason is pedestrians do not sense that the signal phase is going to change and their right-of-way is going to be lost. Developing signal logic to protect pedestrian, who is crossing an intersection is the first purpose of this study. In addition, to improve the reliability and reduce delay of public transportation service is the second purpose. Therefore, bus preemption is also considered in the designed signal logic. In this study, the traffic data of the intersection of Chong-Qing North Road and Min-Zu West Road, Taipei, Taiwan, is employed to calibrate and validate the signal logic by simulation. VISSIM 5.20, which is a microscopic traffic simulation software, is employed to simulate the signal logic. From the simulated results, the signal logic presented in this study can protect pedestrians crossing the intersection successfully. The design of bus preemption can reduce the average delay. However, the pedestrian safety and bus preemption signal will influence the average delay of cars largely. Thus, whether applying the pedestrian safety and bus preemption signal logic to an intersection or not should be evaluated carefully.

  18. Effect of damaged car evacuation on traffic flow behavior after perpendicular collisions in a bidirectional-lane highway with open boundaries

    NASA Astrophysics Data System (ADS)

    Mhirech, Abdelaziz

    2010-10-01

    A new model of the perpendicular accident probability of cars in a bidirectional-lane highway with open boundaries is proposed. The numerical study is done using the Nagel-Schreckenberg (NS) model in parallel dynamics. Indeed, in addition to parallel collisions that occur in the same lane, we also take into account perpendicular accidents between cars moving in opposite directions. To be consistent with reality, we assume that those cars involved in perpendicular collision with a sufficient impact speed, V12, get damaged and must then be removed from the road. It is found that the final density of cars in lane 1 depends strongly on the threshold value V12. Besides, both the perpendicular, Pacper, and parallel, Pacpar, accident probabilities per car and per time step depend largely on the injecting rate α1, the extracting rate β1 in lane 1 and the fractions r1 and r2 in lane 2 of the injecting and extracting rates, respectively. In fact, Pacpar and Pacper show abrupt jumps that increase with increasing α1 and β1. Furthermore, Pacper increases with increasing fractions r1 and/or r2. Taking into account the braking probability P1 of the NS model, both Pacpar and Pacper decrease.

  19. Simulating deforestation and carbon loss in Amazonia: impacts in Brazil's Roraima state from reconstructing Highway BR-319 (Manaus-Porto Velho).

    PubMed

    Barni, Paulo Eduardo; Fearnside, Philip Martin; Graça, Paulo Maurício Lima de Alencastro

    2015-02-01

    Reconstruction of Highway BR-319 (Manaus-Porto Velho) would allow for access from the "arc of deforestation" in the southern part of Brazil's Amazon region to vast blocks of forests in central and northern Amazonia. Building roads is known to be a major driver of deforestation, allowing entry of squatters, and other actors. Rather than deforestation along the highway route, here we consider the road's potential for stimulating deforestation in a separate location, approximately 550 km north of BR-319's endpoint in Manaus. Reconstructing BR-319 has great potential impact to start a new wave of migration to this remote region. The southern portion of the state of Roraima, the focus of our study, is already connected to Manaus by Highway BR-174. We modeled deforestation in southern Roraima and simulated carbon emissions between 2007 and 2030 under four scenarios. Simulations used the AGROECO model in DINAMICA-EGO © software. Two scenarios were considered with reconstruction of BR-319 and two without this road connection. For each of the two possibilities regarding BR-319, simulations were developed for (1) a "conservation" (CONSERV) scenario that assumes the creation of a series of protected areas, and (2) a "business-as-usual" (BAU) scenario that assumes no additional protected areas. Results show that by 2030, with BR-319 rebuilt, deforestation carbon emissions would increase between 19% (CONSERV) and 42% (BAU) over and above those corresponding to no-road scenarios.

  20. Simulating Deforestation and Carbon Loss in Amazonia: Impacts in Brazil's Roraima State from Reconstructing Highway BR-319 (Manaus-Porto Velho)

    NASA Astrophysics Data System (ADS)

    Barni, Paulo Eduardo; Fearnside, Philip Martin; Graça, Paulo Maurício Lima de Alencastro

    2015-02-01

    Reconstruction of Highway BR-319 (Manaus-Porto Velho) would allow for access from the "arc of deforestation" in the southern part of Brazil's Amazon region to vast blocks of forests in central and northern Amazonia. Building roads is known to be a major driver of deforestation, allowing entry of squatters, and other actors. Rather than deforestation along the highway route, here we consider the road's potential for stimulating deforestation in a separate location, approximately 550 km north of BR-319's endpoint in Manaus. Reconstructing BR-319 has great potential impact to start a new wave of migration to this remote region. The southern portion of the state of Roraima, the focus of our study, is already connected to Manaus by Highway BR-174. We modeled deforestation in southern Roraima and simulated carbon emissions between 2007 and 2030 under four scenarios. Simulations used the AGROECO model in DINAMICA-EGO software. Two scenarios were considered with reconstruction of BR-319 and two without this road connection. For each of the two possibilities regarding BR-319, simulations were developed for (1) a "conservation" (CONSERV) scenario that assumes the creation of a series of protected areas, and (2) a "business-as-usual" (BAU) scenario that assumes no additional protected areas. Results show that by 2030, with BR-319 rebuilt, deforestation carbon emissions would increase between 19 % (CONSERV) and 42 % (BAU) over and above those corresponding to no-road scenarios.

  1. Polymer delineation system. [Patent application: traffic lane lines

    DOEpatents

    Woolman, S.; Steinberg, M.

    1975-06-24

    A delineation system (traffic lane lines) for highways is described in which polymerizable substances are applied to existing or newly prepared highway pavements. The substances would contain a suitable pigment and may incorporate reflective elements.

  2. A STUDY ON IMPLEMENTATION POLICY OF AUXILIARY PASSING LANE ON TWO-WAY TWO-LANE HIGHWAYS CONSIDERING FOLLOWER DENSITY

    NASA Astrophysics Data System (ADS)

    Nakamura, Hideki; Kobayashi, Masato; Catbagan, Jerome L.

    In this paper, a methodology to evaluate impacts of implementing auxiliary passing lanes on the qulity of service of two-way two-lane (TWTL) highways is developed, by adopting follower density as a measure of effectiveness. It aims to quantitatively esti mate the performance of traffic flows to be realized dependent on the passing lane length and its spacing and to provide suggestions as a design guide. Relationships between passing lane length, one-lane section length and follower density are formulated by modeling the simulation results based on traffic fl ow surveys. And possible combinations of minimum required passing lane length and its spacing required for achieving the target performance are indicated. Furthermore, the expected qulity of service of traffic flow under seve ral typical design policies of 2+1 lane highways are evaluated by applying this concept.

  3. Simulation of the introduction of new technologies in air traffic management

    NASA Astrophysics Data System (ADS)

    Yliniemi, Logan; Agogino, Adrian K.; Tumer, Kagan

    2015-07-01

    Accurate simulation of the effects of integrating new technologies into a complex system is critical to the modernisation of large infrastructure problems. This is especially true in the modernisation of our antiquated air traffic system, where there exist many layers of interacting procedures, controls, and automation all designed to cooperate with human operators. Additions of even simple new technologies may result in unexpected emergent behaviour due to complex human/machine interactions. One approach is to create high-fidelity human models coming from the field of human factors that can simulate a rich set of behaviours. However, such models are difficult to produce, especially to show unexpected emergent behaviour coming from many human operators interacting simultaneously within a complex system. Instead, we introduce an alternate approach. Instead of engineering complex human models, we directly model the emergent behaviour with relatively simple goal-directed agents. In this model, each autonomous agent in a system pursues individual goals, and the high-level behaviour of the system emerges from the interactions, foreseen or unforeseen, between the agents/actors. We show that this method is capable of reflecting the integration of new technologies in a historical case, and apply the same methodology for a possible future technology. Finally, we show how these high-level simulated behaviours compare to actual deployed air traffic control mechanisms in use today.

  4. A digital simulation of message traffic for natural disaster warning communications satellite

    NASA Technical Reports Server (NTRS)

    Hein, G. F.; Stevenson, S. M.

    1972-01-01

    Various types of weather communications are required to alert industries and the general public about the impending occurrence of tornados, hurricanes, snowstorms, floods, etc. A natural disaster warning satellite system has been proposed for meeting the communications requirements of the National Oceanic and Atmospheric Administration. Message traffic for a communications satellite was simulated with a digital computer in order to determine the number of communications channels to meet system requirements. Poisson inputs are used for arrivals and an exponential distribution is used for service.

  5. Controlling Air Traffic (Simulated) in the Presence of Automation (CATS PAu) 1995: A Study of Measurement Techniques for Situation Awareness in Air Traffic Control

    NASA Technical Reports Server (NTRS)

    French, Jennifer R.

    1995-01-01

    As automated systems proliferate in aviation systems, human operators are taking on less and less of an active role in the jobs they once performed, often reducing what should be important jobs to tasks barely more complex than monitoring machines. When operators are forced into these roles, they risk slipping into hazardous states of awareness, which can lead to reduced skills, lack of vigilance, and the inability to react quickly and competently when there is a machine failure. Using Air Traffic Control (ATC) as a model, the present study developed tools for conducting tests focusing on levels of automation as they relate to situation awareness. Subjects participated in a two-and-a-half hour experiment that consisted of a training period followed by a simulation of air traffic control similar to the system presently used by the FAA, then an additional simulation employing automated assistance. Through an iterative design process utilizing numerous revisions and three experimental sessions, several measures for situational awareness in a simulated Air Traffic Control System were developed and are prepared for use in future experiments.

  6. Long-term trends in United States highway emissions, ambient concentrations, and in-vehicle exposure to carbon monoxide in traffic.

    PubMed

    Flachsbart, P G

    1995-01-01

    This paper reviews 16 published studies conducted between 1965 and 1992 of in-vehicle exposure to carbon monoxide (CO) in traffic on urban roadways in the United States. Analysis of these studies shows a downward trend in CO exposure, which corresponds to similar trends for CO in motor vehicle emission factors and ambient concentrations. The analysis demonstrates that emission controls on motor vehicles sold in the United States have been very effective in reducing commuter CO exposure. It is recommended that future studies of this kind be done routinely in cities nationwide to provide a more robust database for accurate estimates of commuter exposure. Such studies should relate human exposure measurements to estimates of emissions at study sites to document the progress of motor vehicle emission control programs. In addition, future studies should use standard protocols to enable comparisons of results in time and space. Previous studies have shown that typical in-vehicle exposures vary by study approach (direct versus indirect), city, season, roadway type and location, travel mode, and vehicular ventilation. Future studies should carefully account for these factors.

  7. Crash Risk Prediction Modeling Based on the Traffic Conflict Technique and a Microscopic Simulation for Freeway Interchange Merging Areas.

    PubMed

    Li, Shen; Xiang, Qiaojun; Ma, Yongfeng; Gu, Xin; Li, Han

    2016-11-19

    This paper evaluates the traffic safety of freeway interchange merging areas based on the traffic conflict technique. The hourly composite risk indexes (HCRI) was defined. By the use of unmanned aerial vehicle (UAV) photography and video processing techniques, the conflict type and severity was judged. Time to collision (TTC) was determined with the traffic conflict evaluation index. Then, the TTC severity threshold was determined. Quantizing the weight of the conflict by direct losses of different severities of freeway traffic accidents, the calculated weight of the HCRI can be obtained. Calibration of the relevant parameters of the micro-simulation simulator VISSIM is conducted by the travel time according to the field data. Variables are placed into orthogonal tables at different levels. On the basis of this table, the trajectory file of every traffic condition is simulated, and then submitted into a surrogate safety assessment model (SSAM), identifying the number of hourly traffic conflicts in the merging area, a statistic of HCRI. Moreover, the multivariate linear regression model was presented and validated to study the relationship between HCRI and the influencing variables. A comparison between the HCRI model and the hourly conflicts ratio (HCR), without weight, shows that the HCRI model fitting degree was obviously higher than the HCR. This will be a reference to design and implement operational planners.

  8. Crash Risk Prediction Modeling Based on the Traffic Conflict Technique and a Microscopic Simulation for Freeway Interchange Merging Areas

    PubMed Central

    Li, Shen; Xiang, Qiaojun; Ma, Yongfeng; Gu, Xin; Li, Han

    2016-01-01

    This paper evaluates the traffic safety of freeway interchange merging areas based on the traffic conflict technique. The hourly composite risk indexes (HCRI) was defined. By the use of unmanned aerial vehicle (UAV) photography and video processing techniques, the conflict type and severity was judged. Time to collision (TTC) was determined with the traffic conflict evaluation index. Then, the TTC severity threshold was determined. Quantizing the weight of the conflict by direct losses of different severities of freeway traffic accidents, the calculated weight of the HCRI can be obtained. Calibration of the relevant parameters of the micro-simulation simulator VISSIM is conducted by the travel time according to the field data. Variables are placed into orthogonal tables at different levels. On the basis of this table, the trajectory file of every traffic condition is simulated, and then submitted into a surrogate safety assessment model (SSAM), identifying the number of hourly traffic conflicts in the merging area, a statistic of HCRI. Moreover, the multivariate linear regression model was presented and validated to study the relationship between HCRI and the influencing variables. A comparison between the HCRI model and the hourly conflicts ratio (HCR), without weight, shows that the HCRI model fitting degree was obviously higher than the HCR. This will be a reference to design and implement operational planners. PMID:27869763

  9. Physics of Traffic Flow

    NASA Astrophysics Data System (ADS)

    Davis, L. C.

    2015-03-01

    The Texas A&M Transportation Institute estimated that traffic congestion cost the United States 121 billion in 2011 (the latest data available). The cost is due to wasted time and fuel. In addition to accidents and road construction, factors contributing to congestion include large demand, instability of high-density free flow and selfish behavior of drivers, which produces self-organized traffic bottlenecks. Extensive data collected on instrumented highways in various countries have led to a better understanding of traffic dynamics. From these measurements, Boris Kerner and colleagues developed a new theory called three-phase theory. They identified three major phases of flow observed in the data: free flow, synchronous flow and wide moving jams. The intermediate phase is called synchronous because vehicles in different lanes tend to have similar velocities. This congested phase, characterized by lower velocities yet modestly high throughput, frequently occurs near on-ramps and lane reductions. At present there are only two widely used methods of congestion mitigation: ramp metering and the display of current travel-time information to drivers. To find more effective methods to reduce congestion, researchers perform large-scale simulations using models based on the new theories. An algorithm has been proposed to realize Wardrop equilibria with real-time route information. Such equilibria have equal travel time on alternative routes between a given origin and destination. An active area of current research is the dynamics of connected vehicles, which communicate wirelessly with other vehicles and the surrounding infrastructure. These systems show great promise for improving traffic flow and safety.

  10. 78 FR 36132 - National Standards for Traffic Control Devices; Manual on Uniform Traffic Control Devices for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-17

    ...; Manual on Uniform Traffic Control Devices for Streets and Highways AGENCY: Federal Highway Administration (FHWA), DOT. ACTION: Notification; response to comments. SUMMARY: The Manual on Uniform Traffic Control... all components that are under consideration as the FHWA develops ideas for the next edition of...

  11. Simulation of traffic flow during emergency evacuations: A microcomputer based modeling system

    SciTech Connect

    Rathi, A.K.; Solanki, R.S.

    1993-09-01

    Evacuation is one of the major and often preferred protective action options available for emergency management in times of threat to the general public. One of the key factors used in evaluating the effectiveness of evacuation as a protective action option is the estimate of time required for evacuation. The time required for evacuation is the time associated with clearing an area at risk to areas far enough away to be considered safe. Computer simulation models of traffic flow are used to estimate the time it takes to evacuate or ``clear`` an at-risk region by means of vehicular evacuation. This paper provides a brief description of the Oak Ridge Evacuation Modeling System (OREMS), a prototype under development at the Oak Ridge National Laboratory. OREMS consists of a set of computer programs and models which can be used to simulate traffic flow during regional population evacuations and to develop evacuation plans for different events and scenarios (e.g. good vs. bad weather and nighttime vs. daytime evacuations) for user-defined spatial boundaries.

  12. The effect of interruption probability in lattice model of two-lane traffic flow with passing

    NASA Astrophysics Data System (ADS)

    Peng, Guanghan

    2016-11-01

    A new lattice model is proposed by taking into account the interruption probability with passing for two-lane freeway. The effect of interruption probability with passing is investigated about the linear stability condition and the mKdV equation through linear stability analysis and nonlinear analysis, respectively. Furthermore, numerical simulation is carried out to study traffic phenomena resulted from the interruption probability with passing in two-lane system. The results show that the interruption probability with passing can improve the stability of traffic flow for low reaction coefficient while the interruption probability with passing can destroy the stability of traffic flow for high reaction coefficient on two-lane highway.

  13. 77 FR 28455 - National Standards for Traffic Control Devices; the Manual on Uniform Traffic Control Devices for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-14

    ... Management and Budget for each collection of information they conduct, sponsor, or require through...--Transportation, Highways and roads, Incorporation by reference, Pavement Markings, Traffic regulations. Issued...

  14. Highway Safety Program Manual: Volume 6: Codes and Laws.

    ERIC Educational Resources Information Center

    National Highway Traffic Safety Administration (DOT), Washington, DC.

    Volume 6 of the 19-volume Highway Safety Program Manual (which provides guidance to State and local governments on preferred safety practices) concentrates on codes and laws. The purpose and specific objectives of the Codes and Laws Program, Federal authority in the area of highway safety, and policies regarding traffic regulation are described.…

  15. Simulation of multilane freeway traffic with detailed rules deduced from microscopic driving behavior

    PubMed

    Goldbach; Eidmann; Kittel

    2000-02-01

    A simulation to model traffic on a multilane freeway is introduced starting from microscopic driving rules. The model takes each individual car into account with its individual features and actual situations, so that a distribution of parameters as well as different behaviors can easily be analyzed. Therefore, a detailed study of certain situations, driving tactics, vehicle properties, and their influence on the global traffic flow can be performed. The model is discussed, as are first results such as the influence of driver behavior on the fundamental diagram and, in addition, the dynamics of microscopic, individual quantities like separation and difference in speed between successive cars. It turns out that a hysteresis in the reaction of the driver for speeding up and slowing down plays an important role, and effects macroscopic quantities like the shape of the fundamental diagram, e.g., the metastable behavior around the maximum flow and on the speed of observed jams running backward. Furthermore, microscopic time resolved characteristics are strongly influenced, e.g., oscillations in the distance and relative speed between successive cars.

  16. Pseudo Aircraft Systems - A multi-aircraft simulation system for air traffic control research

    NASA Technical Reports Server (NTRS)

    Weske, Reid A.; Danek, George L.

    1993-01-01

    Pseudo Aircraft Systems (PAS) is a computerized flight dynamics and piloting system designed to provide a high fidelity multi-aircraft real-time simulation environment to support Air Traffic Control research. PAS is composed of three major software components that run on a network of computer workstations. Functionality is distributed among these components to allow the system to execute fast enough to support real-time operation. PAS workstations are linked by an Ethernet Local Area Network, and standard UNIX socket protocol is used for data transfer. Each component of PAS is controlled and operated using a custom designed Graphical User Interface. Each of these is composed of multiple windows, and many of the windows and sub-windows are used in several of the components. Aircraft models and piloting logic are sophisticated and realistic and provide complex maneuvering and navigational capabilities. PAS will continually be enhanced with new features and improved capabilities to support ongoing and future Air Traffic Control system development.

  17. Pseudo Aircraft Systems - A multi-aircraft simulation system for air traffic control research

    NASA Technical Reports Server (NTRS)

    Weske, Reid A.; Danek, George L.

    1993-01-01

    Pseudo Aircraft Systems (PAS) is a computerized flight dynamics and piloting system designed to provide a high fidelity multi-aircraft real-time simulation environment to support Air Traffic Control research. PAS is composed of three major software components that run on a network of computer workstations. Functionality is distributed among these components to allow the system to execute fast enough to support real-time operation. PAS workstations are linked by an Ethernet Local Area Network, and standard UNIX socket protocol is used for data transfer. Each component of PAS is controlled and operated using a custom designed Graphical User Interface. Each of these is composed of multiple windows, and many of the windows and sub-windows are used in several of the components. Aircraft models and piloting logic are sophisticated and realistic and provide complex maneuvering and navigational capabilities. PAS will continually be enhanced with new features and improved capabilities to support ongoing and future Air Traffic Control system development.

  18. Air Traffic Controller Performance and Acceptability of Multiple UAS in a Simulated NAS Environment

    NASA Technical Reports Server (NTRS)

    Vu, Kim-Phuong L.; Strybel, Thomas; Chiappe, Dan; Morales, Greg; Battiste, Vernol; Shively, Robert Jay

    2014-01-01

    Previously, we showed that air traffic controllers (ATCos) rated UAS pilot verbal response latencies as acceptable when a 1.5 s delay was added to the UAS pilot responses, but a 5 s delay was rated as mostly unacceptable. In the present study we determined whether a 1.5 s added delay in the UAS pilots' verbal communications would affect ATCos interactions with UAS and other conventional aircraft when the number and speed of the UAS were manipulated. Eight radar-certified ATCos participated in this simulation. The ATCos managed a medium altitude sector containing arrival aircraft, en route aircraft, and one to four UAS. The UAS were conducting a surveillance mission and flew at either a "slow" or "fast" speed. We measured both UAS and conventional pilots' verbal communication latencies, and obtained ATCos' acceptability ratings for these latencies. Although the UAS pilot response latencies were longer than those of conventional pilots, the ATCos rated UAS pilot verbal communication latencies to be as acceptable as those of conventional pilots. Because the overall traffic load within the sector was held constant, ATCos only performed slightly worse when multiple UAS were in their sector compared to when only one UAS was in the sector. Implications of these findings for UAS integration in the NAS are discussed.

  19. Simulation studies of time-control procedures for the advanced air traffic control system

    NASA Technical Reports Server (NTRS)

    Tobias, L.; Alcabin, M.; Erzberger, H.; Obrien, P. J.

    1985-01-01

    The problem of mixing aircraft equipped with time-controlled guidance systems and unequipped aircraft in the terminal area has been investigated via a real-time air traffic control simulation. These four-dimensional (4D) guidance systems can predict and control the touchdown time of an aircraft to an accuracy of a few seconds throughout the descent. The objectives of this investigation were to (1) develop scheduling algorithms and operational procedures for various traffic mixes that ranged from 25% to 75% 4D-equipped aircraft; (2) examine the effect of time errors at 120 n. mi. from touchdown on touchdown time scheduling of the various mix conditions; and (3) develop efficient algorithms and procedures to null the initial time errors prior to reaching the final control sector, 30 n. mi. from touchdown. Results indicate substantial reduction in controller workload and an increase in orderliness when more than 25% of the aircraft are equipped with 4D guidance systems; initial random errors of up to + or - 2 min can be handled via a single speed advisory issued in the arrival control sector, thus avoiding disruption of the time schedule.

  20. Suitability of Synthetic Driving Profiles from Traffic Micro-Simulation for Real-World Energy Analysis: Preprint

    SciTech Connect

    Hou, Yunfei; Wood, Eric; Burton, Evan; Gonder, Jeffrey

    2015-10-14

    A shift towards increased levels of driving automation is generally expected to result in improved safety and traffic congestion outcomes. However, little empirical data exists to estimate the impact that automated driving could have on energy consumption and greenhouse gas emissions. In the absence of empirical data on differences between drive cycles from present day vehicles (primarily operated by humans) and future vehicles (partially or fully operated by computers) one approach is to model both situations over identical traffic conditions. Such an exercise requires traffic micro-simulation to not only accurately model vehicle operation under high levels of automation, but also (and potentially more challenging) vehicle operation under present day human drivers. This work seeks to quantify the ability of a commercial traffic micro-simulation program to accurately model real-world drive cycles in vehicles operated primarily by humans in terms of driving speed, acceleration, and simulated fuel economy. Synthetic profiles from models of freeway and arterial facilities near Atlanta, Georgia, are compared to empirical data collected from real-world drivers on the same facilities. Empirical and synthetic drive cycles are then simulated in a powertrain efficiency model to enable comparison on the basis of fuel economy. Synthetic profiles from traffic micro-simulation were found to exhibit low levels of transient behavior relative to the empirical data. Even with these differences, the synthetic and empirical data in this study agree well in terms of driving speed and simulated fuel economy. The differences in transient behavior between simulated and empirical data suggest that larger stochastic contributions in traffic micro-simulation (relative to those present in the traffic micro-simulation tool used in this study) are required to fully capture the arbitrary elements of human driving. Interestingly, the lack of stochastic contributions from models of human drivers

  1. Analysis of road traffic obstructions caused by the central European flood in June 2013 in Germany

    NASA Astrophysics Data System (ADS)

    Bessel, Tina

    2014-05-01

    The flood in June 2013 caused in Germany severe damage to infrastructure and has had a great impact on transportation. Traffic was disrupted in the interregional transportation network including federal highways and long distance railways. Researchers from the Center for Disaster Management and Risk Reduction Technology (CEDIM) aim to develop rapid assessment tools which allow a science based estimation of disaster impacts. This is part of a larger project called Forensic Disaster Analysis (FDA). During the flood event, the CEDIM FDA group on transportation disruptions monitored and recorded traffic reports in Germany to obtain accurate information on road traffic obstructions due to the flood. A rapid initial evaluation of the data was carried out for federal and interstate highways on a district level for the period of May 31 till June 4 2013. In this evaluation, the causes and types of traffic obstruction, as well as the number and duration of flood-caused disruptions are considered. In the evaluated time period of five days, an amount of more than 4,800 hours of flood-related traffic obstructions could be observed in a total of 89 districts. Major traffic disruptions were located in the districts along the Mulde and in the foothills of the Alps. This first initial evaluation will be followed by a detailed statistical analysis including all data collected during the flood event. To assess the impacts of the flood on traffic, a simple traffic simulation considering the disruptions will be carried out using a gravity model.

  2. 32 CFR 634.24 - Traffic planning and codes.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... engineering representatives from adjacent civil communities must be consulted to ensure the installation plan... and minor routes, location of traffic control devices, and conditions requiring engineering or... Engineering Agency (SDDCTEA) will help installation commanders solve complex highway traffic engineering...

  3. New Algorithms for Computing the Time-to-Collision in Freeway Traffic Simulation Models

    PubMed Central

    Hou, Jia; List, George F.; Guo, Xiucheng

    2014-01-01

    Ways to estimate the time-to-collision are explored. In the context of traffic simulation models, classical lane-based notions of vehicle location are relaxed and new, fast, and efficient algorithms are examined. With trajectory conflicts being the main focus, computational procedures are explored which use a two-dimensional coordinate system to track the vehicle trajectories and assess conflicts. Vector-based kinematic variables are used to support the calculations. Algorithms based on boxes, circles, and ellipses are considered. Their performance is evaluated in the context of computational complexity and solution time. Results from these analyses suggest promise for effective and efficient analyses. A combined computation process is found to be very effective. PMID:25628650

  4. Simulation evaluation of TIMER, a time-based, terminal air traffic, flow-management concept

    NASA Technical Reports Server (NTRS)

    Credeur, Leonard; Capron, William R.

    1989-01-01

    A description of a time-based, extended terminal area ATC concept called Traffic Intelligence for the Management of Efficient Runway scheduling (TIMER) and the results of a fast-time evaluation are presented. The TIMER concept is intended to bridge the gap between today's ATC system and a future automated time-based ATC system. The TIMER concept integrates en route metering, fuel-efficient cruise and profile descents, terminal time-based sequencing and spacing together with computer-generated controller aids, to improve delivery precision for fuller use of runway capacity. Simulation results identify and show the effects and interactions of such key variables as horizon of control location, delivery time error at both the metering fix and runway threshold, aircraft separation requirements, delay discounting, wind, aircraft heading and speed errors, and knowledge of final approach speed.

  5. Simulation of time-control procedures for the advanced air traffic control system

    NASA Technical Reports Server (NTRS)

    Tobias, L.; Obrien, P. J.

    1984-01-01

    The problem of mixing four-dimensional (4D) equipped aircraft - aircraft equipped with on-board guidance systems that can predict and control the touchdown time of an aircraft to an accuracy of a few seconds throughout the descent - with unequipped aircraft in the terminal area has been investigated via a real-time air traffic control simulation study. The objective of this study was to examine the effect of time errors (at 120 n. mi. from touchdown) on touchdown time scheduling, and to develop efficient algorithms and procedures to null the initial time errors prior to reaching the final control sector (30 n. mi. from touchdown). Results indicate that initial random errors of up to + or - 2 min can be handled via a single speed advisory issued in the arrival control sector, and thus the time schedule is not disrupted.

  6. Interstate Highway Interchanges Reshape Rural Communities.

    ERIC Educational Resources Information Center

    Moon, Henry E., Jr.

    1987-01-01

    Highway interchanges offer rural counties practically ready-made sites for development, but some interchanges offer better development opportunities than others. A study of a Kentucky interchange identified seven factors that make a difference in development, including traffic volume, distance to an urban area, ruggedness of terrain, and sale of…

  7. Interstate Highway Interchanges Reshape Rural Communities.

    ERIC Educational Resources Information Center

    Moon, Henry E., Jr.

    1987-01-01

    Highway interchanges offer rural counties practically ready-made sites for development, but some interchanges offer better development opportunities than others. A study of a Kentucky interchange identified seven factors that make a difference in development, including traffic volume, distance to an urban area, ruggedness of terrain, and sale of…

  8. Evaluation of average travel delay caused by moving bottlenecks on highways

    PubMed Central

    Xu, Chengcheng; Wang, Wei; Yang, Menglin; Ren, Xiaoma

    2017-01-01

    This paper presents a modelling framework to evaluate travel delay of all vehicles influenced by moving bottlenecks on highways. During the derivation of analytical formulas, the arrival of slow vehicles was approximated by a Poisson process based on the assumption that they occupied a constant low proportion of the traffic stream. The mathematical analysis process was developed from moving bottlenecks with the same velocity to those with multiple different velocities, and the closed-form expression of expected average travel delay was obtained by utilizing kinematic-wave moving bottleneck theory, gap acceptance theory, probability theory and renewal theory. Model validation and parameters sensitive analysis were conducted by simulation relying on the open source database of US highway 10. The maximum passing rate and the macroscopic parameters of initial traffic state with maximum delay could be found by means of approximate formulas. The proposed modeling framework can be applied for evaluating impacts of slow vehicles on highway operation quantifiably, based on which traffic managements like truck prohibited period decision and speed or lane restriction could be made more scientifically. PMID:28854213

  9. Evaluation of average travel delay caused by moving bottlenecks on highways.

    PubMed

    Wei, Xueyan; Xu, Chengcheng; Wang, Wei; Yang, Menglin; Ren, Xiaoma

    2017-01-01

    This paper presents a modelling framework to evaluate travel delay of all vehicles influenced by moving bottlenecks on highways. During the derivation of analytical formulas, the arrival of slow vehicles was approximated by a Poisson process based on the assumption that they occupied a constant low proportion of the traffic stream. The mathematical analysis process was developed from moving bottlenecks with the same velocity to those with multiple different velocities, and the closed-form expression of expected average travel delay was obtained by utilizing kinematic-wave moving bottleneck theory, gap acceptance theory, probability theory and renewal theory. Model validation and parameters sensitive analysis were conducted by simulation relying on the open source database of US highway 10. The maximum passing rate and the macroscopic parameters of initial traffic state with maximum delay could be found by means of approximate formulas. The proposed modeling framework can be applied for evaluating impacts of slow vehicles on highway operation quantifiably, based on which traffic managements like truck prohibited period decision and speed or lane restriction could be made more scientifically.

  10. Car accidents and number of stopped cars due to road blockage on a one-lane highway

    NASA Astrophysics Data System (ADS)

    Boccara, N.; Fuks, H.; Zeng, Q.

    1997-05-01

    Within the framework of a simple model of car traffic on a one-lane highway, we study the probability of the occurrence of car accidents when drivers do not respect the safety distance between cars, and, as a result of the blockage during the time T necessary to clear the road, we determine the number of stopped cars as a function of car density. We give a simple theory in good agreement with our numerical simulations.

  11. Uses of recycled rubber tires in highways: A synthesis of highway practice. Final report

    SciTech Connect

    Epps, J.A.; Mason, L.S.

    1994-01-01

    The synthesis on the use of recycled rubber tires in highways will be of interest to administrators and policymakers; pavement, materials, geotechnical, environmental, and traffic operations engineers; and research engineers involved with highway design and construction issues. Information is provided on the uses of rubber tires in asphalt paving materials as well as other uses, such as on fills and embankments, for erosion control and on railroad grade crossings. Specifically, information is included which identifies the highway agencies using or implementing applications for recycled rubber tires and defines the design parameters, technical and construction limitations, performance, costs, benefits, environmental limitations, specifications, and availability. This synthesis of information defines the use of recycled rubber tires in highways and is based on a review of nearly 500 references and on information recorded from state highway agency responses to a 1991 survey of practice.

  12. The comfortable driving model revisited: traffic phases and phase transitions

    NASA Astrophysics Data System (ADS)

    Knorr, Florian; Schreckenberg, Michael

    2013-07-01

    We study the spatiotemporal patterns resulting from different boundary conditions for a microscopic traffic model and contrast them with empirical results. By evaluating the time series of local measurements, the local traffic states are assigned to the different traffic phases of Kerner’s three-phase traffic theory. For this classification we use the rule-based FOTO-method, which provides ‘hard’ rules for this assignment. Using this approach, our analysis shows that the model is indeed able to reproduce three qualitatively different traffic phases: free flow (F), synchronized traffic (S), and wide moving jams (J). In addition, we investigate the likelihood of transitions between the three traffic phases. We show that a transition from free flow to a wide moving jam often involves an intermediate transition: first from free flow to synchronized flow and then from synchronized flow to a wide moving jam. This is supported by the fact that the so-called F → S transition (from free flow to synchronized traffic) is much more likely than a direct F → J transition. The model under consideration has a functional relationship between traffic flow and traffic density. The fundamental hypothesis of the three-phase traffic theory, however, postulates that the steady states of synchronized flow occupy a two-dimensional region in the flow-density plane. Due to the obvious discrepancy between the model investigated here and the postulate of the three-phase traffic theory, the good agreement that we found could not be expected. For a more detailed analysis, we also studied vehicle dynamics at a microscopic level and provide a comparison of real detector data with simulated data of the identical highway segment.

  13. Virginia's traffic management system

    SciTech Connect

    Morris, J.; Marber, S. )

    1992-07-01

    This paper reports that Northern Virginia, like most other urban areas, faces the challenge of moving more and more vehicles on roads that are already overloaded. Traffic in Northern Virginia is continually increasing, but the development surrounding Interstate 395, 495, and 66 makes little room available for roadway expansion. Even if land were unlimited, the strict requirement of the Clean Air Act make building roads difficult. This paper reports that ensuring the most efficient use of the interstate highways is the goal of the Virginia Department of Transportation's (VDOT's) traffic management system (TMS). TMS is a computerized highway surveillance and control system that monitors 30 interstate miles on I-395, I-495, and I-66. The system helps squeeze the most use from these interstates by detecting and helping clear accidents or disabled vehicles and by smoothing traffic flow. TMS spots and helps clear an average of two incidents a day and prevents accidents caused by erratic traffic flow from ramps onto the main line. For motorists, these TMS functions translate into decreased travel time, vehicle operating costs, and air pollution. VDOT's TMS is the foundation for the intelligent vehicle-highway systems of tomorrow. It employs several elements that work together to improve traffic flow.

  14. Reachability-Based Safety and Goal Satisfaction of Unmanned Aerial Platoons on Air Highways

    NASA Astrophysics Data System (ADS)

    Chen, Mo; Hu, Qie; Fisac, Jaime F.; Akametalu, Kene; Mackin, Casey; Tomlin, Claire J.

    2017-06-01

    Recently, there has been immense interest in using unmanned aerial vehicles (UAVs) for civilian operations. As a result, unmanned aerial systems traffic management is needed to ensure the safety and goal satisfaction of potentially thousands of UAVs flying simultaneously. Currently, the analysis of large multi-agent systems cannot tractably provide these guarantees if the agents' set of maneuvers is unrestricted. In this paper, platoons of UAVs flying on air highways is proposed to impose an airspace structure that allows for tractable analysis. For the air highway placement problem, the fast marching method is used to produce a sequence of air highways that minimizes the cost of flying from an origin to any destination. The placement of air highways can be updated in real-time to accommodate sudden airspace changes. Within platoons traveling on air highways, each vehicle is modeled as a hybrid system. Using Hamilton-Jacobi reachability, safety and goal satisfaction are guaranteed for all mode transitions. For a single altitude range, the proposed approach guarantees safety for one safety breach per vehicle, in the unlikely event of multiple safety breaches, safety can be guaranteed over multiple altitude ranges. We demonstrate the platooning concept through simulations of three representative scenarios.

  15. Indicate severe toxicity of highway runoff.

    PubMed

    Dorchin, Achik; Shanas, Uri

    2013-09-01

    Road runoff is recognized as a substantial nonpoint source of contamination to the aquatic environment. Highway seasonal first flushes contain particularly high concentrations of pollutants. To fully account for the toxicity potential of the runoff, the cumulative effects of the pollutants should be assessed, ideally by biological analyses. Acute toxicity tests with were used to measure the toxicity of runoff from three major highway sections in Israel for 2 yr. Highway first flushes resulted in the mortality of all tested individuals within 24 to 48 h. A first flush collected from Highway 4 (traffic volume: 81,200 cars d) remained toxic even after dilution to <5% (48 h EC <5%). Synthetic solutions with metal concentrations corresponding to highways' first flushes revealed a synergistic adverse effect on survival and a potential additive effect of nonmetal pollutants in the runoff. Because daphnids and other invertebrates constitute the base of the aquatic food chain, detrimental effects of highway runoff may propagate to higher levels of biological organization. The observed high potential of environmental contamination warrants the control of highway runoff in proximity to natural watercourses. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  16. Highway fuel economy study. Final report Sep 79-Mar 81

    SciTech Connect

    Mason, R.L.; Zub, R.W.

    1981-06-01

    In 1979, the National Highway Traffic Safety Administration (NHTSA) with support from the Federal Highway Administration (FHWA), convened a Task Force to develop a base of information on the effects of the 55 MPH speed limit. This report addresses the fuel consumption changes attributable to speed reduction and compliance with the 55 MPH speed limit. It also discusses the effects of vehicle size and type, and driver-controllable functions on vehicle fuel economy at highway speeds. Most of the analytical work in this report is related to passenger cars and light trucks. However, medium and heavy trucks, primarily commercial in application, have been included in the highway fuel economy analyses.

  17. Complexity Analysis of Traffic in Corridors-in-the-Sky

    NASA Technical Reports Server (NTRS)

    Xue, Min; Zelinski, Shannon Jean

    2010-01-01

    The corridors-in-the-sky concept imitates the highway system in ground transportation. The benefit expected from a corridor relies on its capability of handling high density traffic with negligible controller workload, the acceptance of extra fuel or distance, and the complexity reduction in underlying sectors. This work evaluates a selected corridor from these perspectives through simulations. To examine traffic inside the corridor, a corridor traffic simulation tool that can resolve conflicts is developed using C language. Prescribed conflict resolution maneuvers mimic corridor users behaviors and conflict resolution counts measure complexity. Different lane options and operational policies are proposed to examine their impacts on complexity. Fuel consumption is calculated and compared for corridor traffic. On the other hand, to investigate the complexity of non-corridor traffic in underlying sectors, the existing Airspace Concept Evaluation System tool is utilized along with the Automated Airspace Concept tool. The number of conflict resolutions is examined and treated as the complexity measurement. The results show heavy traffic can be managed with low complexity for a historical traffic schedule simulated with appropriate operational policies and lane options. For instance, with 608 flights and peak aircraft count of 100, only 84 actions need to be taken in a 24-hour period to resolve the conflicts for an 8-lane corridor. Compared with the fuel consumptions with great circle trajectories, the simulation of corridor traffic shows that the total extra fuel for corridor flights is 26,373 gallons, or 2.76%, which is 0.38% less than flying filed flight plans. Without taking climb and descent portions of corridor traffic, the complexity of underlying sectors is reduced by 17.71%. However the climb and descent portions will eliminate the reduction and the overall complexity of sectors is actually increased by 9.14%.

  18. 77 FR 49859 - Proposed Traffic Records Program Assessment Advisory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-17

    ... National Highway Traffic Safety Administration Proposed Traffic Records Program Assessment Advisory AGENCY.... SUMMARY: This notice announces the publication of the Traffic Records Program Assessment Advisory, DOT HS..., and data quality attributes of an effective traffic records system, and includes assessment questions...

  19. 23 CFR Appendix A to Part 1200 - CERTIFICATION AND ASSURANCES FOR HIGHWAY SAFETY GRANTS (23 U.S.C. CHAPTER 4)

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... (23 U.S.C. CHAPTER 4) A APPENDIX A TO PART 1200 Highways NATIONAL HIGHWAY TRAFFIC SAFETY... basis of sex; (c) Section 504 of the Rehabilitation Act of 1973, as amended (29 U.S.C. 794), and the... company-owned, rented, or personally-owned vehicles. The National Highway Traffic Safety...

  20. 23 CFR Appendix A to Part 1200 - Certification and Assurances for Highway Safety Grants (23 U.S.C. Chapter 4)

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... (23 U.S.C. Chapter 4) A Appendix A to Part 1200 Highways NATIONAL HIGHWAY TRAFFIC SAFETY... basis of sex; (c) Section 504 of the Rehabilitation Act of 1973, as amended (29 U.S.C. 794), and the... company-owned, rented, or personally-owned vehicles. The National Highway Traffic Safety...

  1. Evolutionary Agent-Based Simulation of the Introduction of New Technologies in Air Traffic Management

    NASA Technical Reports Server (NTRS)

    Yliniemi, Logan; Agogino, Adrian K.; Tumer, Kagan

    2014-01-01

    Accurate simulation of the effects of integrating new technologies into a complex system is critical to the modernization of our antiquated air traffic system, where there exist many layers of interacting procedures, controls, and automation all designed to cooperate with human operators. Additions of even simple new technologies may result in unexpected emergent behavior due to complex human/ machine interactions. One approach is to create high-fidelity human models coming from the field of human factors that can simulate a rich set of behaviors. However, such models are difficult to produce, especially to show unexpected emergent behavior coming from many human operators interacting simultaneously within a complex system. Instead of engineering complex human models, we directly model the emergent behavior by evolving goal directed agents, representing human users. Using evolution we can predict how the agent representing the human user reacts given his/her goals. In this paradigm, each autonomous agent in a system pursues individual goals, and the behavior of the system emerges from the interactions, foreseen or unforeseen, between the agents/actors. We show that this method reflects the integration of new technologies in a historical case, and apply the same methodology for a possible future technology.

  2. Effectiveness of traffic light vs. boom barrier controls at road-rail level crossings: a simulator study.

    PubMed

    Rudin-Brown, Christina M; Lenné, Michael G; Edquist, Jessica; Navarro, Jordan

    2012-03-01

    Although collisions at level crossings are relatively uncommon occurrences, the potential severity of their consequences make them a top priority among safety authorities. Twenty-five fully-licensed drivers aged between 20 and 50 years participated in a driving simulator study that compared the efficacy, and drivers' subjective perception, of two active level crossing traffic control devices: flashing lights with boom barriers and standard traffic lights. Because of its common usage in most states in Australia, a stop sign-controlled level crossing served as the passive referent. Although crossing violations were less likely at the level crossings controlled by active devices than at those controlled by stop signs, both kinds of active control were associated with a similar number of violations. Further, the majority (72%) of drivers reported preferring flashing lights to traffic lights. Collectively, results indicate that the installation of traffic lights at real-world level crossings would not be likely to offer safety benefits over and above those provided already by flashing lights with boom barriers. Furthermore, the high rate of violations at passively controlled crossings strongly supports the continued practice of upgrading level crossings with active traffic control devices. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Automatic speed control of highway traffic

    NASA Technical Reports Server (NTRS)

    Klingman, E. E.

    1973-01-01

    Vehicle control system monitors all vehicles in its range, and automatically slows down speeding vehicles by activating governor in vehicle. System determines only maximum speed; speeds below maximum are controlled by vehicle operator. Loss of transmitted signal or activation of emergency over-ride will open fuel line and return control to operator.

  4. Highway runoff quality in Ireland.

    PubMed

    Berhanu Desta, Mesfin; Bruen, Michael; Higgins, Neil; Johnston, Paul

    2007-04-01

    Highway runoff has been identified as a significant source of contaminants that impact on the receiving aquatic environment. Several studies have been completed documenting the characteristics of highway runoff and its implication to the receiving water in the UK and elsewhere. However, very little information is available for Ireland. The objective of this study was to determine the quality of highway runoff from major Irish roads under the current road drainage design and maintenance practice. Four sites were selected from the M4 and the M7 motorways outside Dublin. Automatic samplers and continuous monitoring devices were deployed to sample and monitor the runoff quality and quantity. More than 42 storm events were sampled and analysed for the heavy metals Cd, Cu, Pb, and Zn, 16 US EPA specified PAHs, volatile organic compounds including MTBE, and a number of conventional pollutants. All samples were analysed based on the Standard Methods. Significant quantities of solids and heavy metals were detected at all sites. PAHs were not detected very often, but when detected the values were different from quantities observed in UK highways. The heavy metal concentrations were strongly related to the total suspended solids concentrations, which has a useful implication for runoff management strategies. No strong relationship was discovered between pollutant concentrations and event characteristics such as rainfall intensity, antecedent dry days (ADD), or rainfall depth (volume). This study has demonstrated that runoff from Irish motorways was not any cleaner than in the UK although the traffic volume at the monitored sites was relatively smaller. This calls for a site specific investigation of highway runoff quality before adopting a given management strategy.

  5. Risk evaluation by modeling of passing behavior on two-lane rural highways.

    PubMed

    Farah, Haneen; Bekhor, Shlomo; Polus, Abishai

    2009-07-01

    Passing maneuver on rural two-lane highways is a complex task, which has a significant effect on capacity, level of service and safety. The maneuver is conditioned on the gap between two successive vehicles on the opposing lane. The minimum time to collision, defined as the remaining gap between the passing vehicle and the oncoming vehicle at the end of the passing process, expresses a measure of the risk involved in the passing maneuver. This paper develops a model that explains the minimum time to collision. The model formulation is based on the analysis of drivers' passing decisions on two-lane rural highways using an interactive driving simulator. The simulator enables the collection of vehicle speeds and positions for different road and traffic scenarios. In addition to the driver simulator, participants responded to a questionnaire which collected information about their socio-demographic characteristics. The composed dataset was analyzed and processed to develop a model that predicts the risk associated with the passing behavior. Tobit regression models were found to be more suitable, in comparison to ordinary least square models and Hazard-based Duration models. The explanatory variables tested represent road geometry, traffic conditions and drivers' characteristics. It was found that while the traffic related variables had the most important effect on the measure of risk chosen, factors related to the geometric design and the driver characteristics also had a significant contribution.

  6. Impact of updated traffic emissions on HONO mixing ratios simulated for urban site in Houston, Texas

    NASA Astrophysics Data System (ADS)

    Czader, B. H.; Choi, Y.; Li, X.; Alvarez, S.; Lefer, B.

    2014-08-01

    Recent measurements in Houston show that HONO traffic emissions are 1.7% of NOx emissions which is about twice the previously estimated value of 0.8% based on tunnel measurements in 2001. The 0.8% value is widely used to estimate mobile emissions of HONO for air quality modeling applications. This study applies the newly estimated HONO/NOx ratio in the WRF-SMOKE-CMAQ modeling system and estimates the impact of higher HONO traffic emissions on its mixing ratios. Since applied emission inventory resulted in overestimates of NOx mixing ratios and because HONO emissions and chemical formation depends on the magnitude of NOx, thus, before proceeding with HONO emission modifications emissions of NOx were adjusted to reflect current emission trends. The modeled mixing ratios of NOx were evaluated against measured data from a number of sites in the Houston area. Overall, the NOx mean value dropped from 11.11 ppbv in the base case to 7.59 ppbv in the NOx adjusted case becoming much closer to the observed mean of 7.76 ppbv. The Index of Agreement (IOA) is improved in the reduced NOx case (0.71 vs. 0.75) and the Absolute Mean Error (AME) is lowered from 6.76 to 4.94. The modeled mixing ratios of HONO were evaluated against the actual observed values attained at the Moody Tower in Houston. The model could not reproduce the morning HONO peaks when the low HONO/NOx ratio of 0.008 was used to estimate HONO emissions. Doubling HONO emissions from mobile sources resulted in higher mixing ratios, the mean value increased from 0.30 to 0.41 ppbv becoming closer to the observed mean concentrations of 0.69 but still low; AME was slightly reduced from 0.46 to 0.43. IOA for simulation that used the 2001 emission values is 0.63 while for simulation with higher HONO emission it increased to 0.70. Increased HONO emissions impacted OH mixing ratio, up to about 6% increase was found during morning and mid-day hours. The impact on ozone is marginal. This study results sheds light on the

  7. Impact of updated traffic emissions on HONO mixing ratios simulated for urban site in Houston, Texas

    NASA Astrophysics Data System (ADS)

    Czader, B. H.; Choi, Y.; Li, X.; Alvarez, S.; Lefer, B.

    2015-02-01

    Recent measurements in Houston show that HONO traffic emissions are 1.7% of NOx emissions, which is about twice the previously estimated value of 0.8% based on tunnel measurements in 2001. The 0.8% value is widely used to estimate mobile emissions of HONO for air quality modeling applications. This study applies the newly estimated HONO / NOx ratio in the WRF-SMOKE-CMAQ modeling system and estimates the impact of higher HONO traffic emissions on its mixing ratios. Since applied emission inventory resulted in overestimates of NOx mixing ratios and because HONO emissions and chemical formation depend on the magnitude of NOx, thus, before proceeding with HONO emission modifications emissions of NOx were adjusted to reflect current emission trends. The modeled mixing ratios of NOx were evaluated against measured data from a number of sites in the Houston area. Overall, the NOx mean value dropped from 11.11 ppbv in the base case to 7.59 ppbv in the NOx-adjusted case becoming much closer to the observed mean of 7.76 ppbv. The index of agreement (IOA) is improved in the reduced NOx case (0.71 vs. 0.75) and the absolute mean error (AME) is lowered from 6.76 to 4.94. The modeled mixing ratios of HONO were evaluated against the actual observed values attained at the Moody Tower in Houston. The model could not reproduce the morning HONO peaks when the low HONO / NOx ratio of 0.008 was used to estimate HONO emissions. Doubling HONO emissions from mobile sources resulted in higher mixing ratios, and the mean value increased from 0.30 to 0.41 ppbv becoming closer to the observed mean concentrations of 0.69 but still low; AME was slightly reduced from 0.46 to 0.43. IOA for simulation that used the 2001 emission values is 0.63 while for simulation with higher HONO emission it increased to 0.70. Increased HONO emissions from mobile sources resulted in a 14% increase in OH during morning time at the location of the Moody Tower and 3% when averaged over an urban area. The increase

  8. HOV on the information highway

    NASA Astrophysics Data System (ADS)

    Carlowicz, Michael

    Sick of rush-hour traffic jams? Tired of bottlenecks that keep you from getting where you want to go? Frustrated by sluggish drivers who tie you up on your way to work? The National Science Foundation (NSF) is hoping to put scientists back in the fast lane—of the Internet, that is.The recent boom in the popularity of the Internet has brought traffic on some parts of the information highway to a crawl. Since all packets of information sent across the Internet are treated equally, e-mail love letters and playful web browsing can interfere with scientific data transfers and high-performance on-line experiments and conferences.

  9. Relationship between obstructive sleep apnoea, driving simulator performance, and risk of road traffic accidents

    PubMed Central

    Turkington, P; Sircar, M; Allgar, V; Elliott, M

    2001-01-01

    BACKGROUND—Obstructive sleep apnoea (OSA) has been shown to be associated with an increased risk of road traffic accidents (RTAs). Predicting the driving ability and risk of RTAs in an individual with OSA is difficult. On-road testing is the gold standard, but this is time consuming, expensive, and potentially dangerous. Simple computer based driving simulators have been developed to help determine driving ability. Although patients with OSA have been shown to perform poorly compared with matched controls, it is not known whether these simulators can predict those at most risk of accidents. In this study we evaluated whether data derived from a simple driving simulator provided information over and above that obtained from the history and a sleep study that might be useful for advising patients about driving.
METHODS—We examined 150 patients admitted for routine sleep studies for investigation of OSA and snoring. Each patient performed a 20 minute driving simulation and completed a questionnaire regarding their driving history and experience.
RESULTS—Logistic regression analysis was used to investigate factors associated with patients' performance on the simulator. It was found that patient characteristics, older age (OR 1.05, 95% CI 1.01 to 1.09, p<0.01), female sex (OR 9.32, 95% CI 1.09 to 79.4,p<0.04), and self-reported alcohol consumption (OR 1.04, 95% CI 1.01 to 1.07, p<0.01) had the greatest influence; however, the number of self-reported near miss accidents was independently associated with a poor performance (OR 2.62, 95% CI 1.00 to 6.88,p<0.05). A further logistic regression was used to investigate whether clinical history, sleep study results, and data from the driving simulator were useful in classifying patients with OSA as having had an RTA. The number of off-road events per hour on the simulator was independently associated with a history of previous RTA (OR 1.004, 95% CI 1.0004 to 1.008, p<0.03). The Epworth score was independently

  10. Simulation Study of Traffic-Sensor Noise Effects on Utilization of Traffic Situation Display for Self-Spacing Task.

    DTIC Science & Technology

    1983-02-01

    airline-type operations and to avoid radical maneu- vers. Besides being NASA research pilots, the test subjects had attended an airline training school and...devised for this study. Two NASA research pilots flying 3 replications of each test condition resulted in a total of 108 simulator runs. Table I

  11. Simulating the impacts of on-street vehicle parking on traffic operations on urban streets using cellular automation

    NASA Astrophysics Data System (ADS)

    Chen, Jingxu; Li, Zhibin; Jiang, Hang; Zhu, Senlai; Wang, Wei

    2017-02-01

    In recent years, many bicycle lanes on urban streets are replaced with vehicle parking places. Spaces for bicycle riding are reduced, resulting in changes in bicycle and vehicle operational features. The objective of this study is to estimate the impacts of on-street parking on heterogeneous traffic operation on urban streets. A cellular automaton (CA) model is developed and calibrated to simulate bicycle lane-changing on streets with on-street parking. Two types of street segments with different bicycle lane width are considered. From the simulation, two types of conflicts between bicycles and vehicles are identified which are frictional conflicts and blocking conflicts. Factors affecting the frequency of conflicts are also identified. Based on the results, vehicle delay is estimated for various traffic situations considering the range of occupancy levels for on-street parking. Later, a numerical network example is analyzed to estimate the network impact of on-street parking on traffic assignment and operation. Findings of the study are helpful to policies and design regarding on-street vehicle parking to improve the efficiency of traffic operations.

  12. Fiber grating systems for traffic monitoring

    NASA Astrophysics Data System (ADS)

    Udd, Eric; Kunzler, Marley; Laylor, Harold M.; Schulz, Whitten L.; Kreger, Stephen T.; Corones, John C.; McMahon, Robert; Soltesz, Steven M.; Edgar, Robert

    2001-08-01

    Blue Road Research has designed, built, and installed fiber grating sensor systems onto bridges, and most recently into an asphalt and concrete highway test pad. The sensitivity levels of the fiber grating sensors are sufficiently high to enable detection of people standing on the bridge or highway. This paper briefly overviews the usage of these sensors for traffic monitoring.

  13. A Simulated Environment Experiment on Annoyance Due to Combined Road Traffic and Industrial Noises

    PubMed Central

    Marquis-Favre, Catherine; Morel, Julien

    2015-01-01

    Total annoyance due to combined noises is still difficult to predict adequately. This scientific gap is an obstacle for noise action planning, especially in urban areas where inhabitants are usually exposed to high noise levels from multiple sources. In this context, this work aims to highlight potential to enhance the prediction of total annoyance. The work is based on a simulated environment experiment where participants performed activities in a living room while exposed to combined road traffic and industrial noises. The first objective of the experiment presented in this paper was to gain further understanding of the effects on annoyance of some acoustical factors, non-acoustical factors and potential interactions between the combined noise sources. The second one was to assess total annoyance models constructed from the data collected during the experiment and tested using data gathered in situ. The results obtained in this work highlighted the superiority of perceptual models. In particular, perceptual models with an interaction term seemed to be the best predictors for the two combined noise sources under study, even with high differences in sound pressure level. Thus, these results reinforced the need to focus on perceptual models and to improve the prediction of partial annoyances. PMID:26197326

  14. Prospective memory in an air traffic control simulation: External aids that signal when to act

    PubMed Central

    Loft, Shayne; Smith, Rebekah E.; Bhaskara, Adella

    2011-01-01

    At work and in our personal life we often need to remember to perform intended actions at some point in the future, referred to as Prospective Memory. Individuals sometimes forget to perform intentions in safety-critical work contexts. Holding intentions can also interfere with ongoing tasks. We applied theories and methods from the experimental literature to test the effectiveness of external aids in reducing prospective memory error and costs to ongoing tasks in an air traffic control simulation. Participants were trained to accept and hand-off aircraft, and to detect aircraft conflicts. For the prospective memory task participants were required to substitute alternative actions for routine actions when accepting target aircraft. Across two experiments, external display aids were provided that presented the details of target aircraft and associated intended actions. We predicted that aids would only be effective if they provided information that was diagnostic of target occurrence and in this study we examined the utility of aids that directly cued participants when to allocate attention to the prospective memory task. When aids were set to flash when the prospective memory target aircraft needed to be accepted, prospective memory error and costs to ongoing tasks of aircraft acceptance and conflict detection were reduced. In contrast, aids that did not alert participants specifically when the target aircraft were present provided no advantage compared to when no aids we used. These findings have practical implications for the potential relative utility of automated external aids for occupations where individuals monitor multi-item dynamic displays. PMID:21443381

  15. Virtualized Traffic: reconstructing traffic flows from discrete spatiotemporal data.

    PubMed

    Sewall, Jason; van den Berg, Jur; Lin, Ming C; Manocha, Dinesh

    2011-01-01

    We present a novel concept, Virtualized Traffic, to reconstruct and visualize continuous traffic flows from discrete spatiotemporal data provided by traffic sensors or generated artificially to enhance a sense of immersion in a dynamic virtual world. Given the positions of each car at two recorded locations on a highway and the corresponding time instances, our approach can reconstruct the traffic flows (i.e., the dynamic motions of multiple cars over time) between the two locations along the highway for immersive visualization of virtual cities or other environments. Our algorithm is applicable to high-density traffic on highways with an arbitrary number of lanes and takes into account the geometric, kinematic, and dynamic constraints on the cars. Our method reconstructs the car motion that automatically minimizes the number of lane changes, respects safety distance to other cars, and computes the acceleration necessary to obtain a smooth traffic flow subject to the given constraints. Furthermore, our framework can process a continuous stream of input data in real time, enabling the users to view virtualized traffic events in a virtual world as they occur. We demonstrate our reconstruction technique with both synthetic and real-world input.

  16. 49 CFR 27.75 - Federal Highway Administration-highways.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Federal Highway Administration-highways. 27.75... Specific Operating Administration Programs: Airports, Railroads, and Highways § 27.75 Federal Highway Administration—highways. (a) New facilities—(1) Highway rest area facilities. All such facilities that will be...

  17. 49 CFR 27.75 - Federal Highway Administration-highways.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 1 2014-10-01 2014-10-01 false Federal Highway Administration-highways. 27.75... Specific Operating Administration Programs: Airports, Railroads, and Highways § 27.75 Federal Highway Administration—highways. (a) New facilities—(1) Highway rest area facilities. All such facilities that will be...

  18. Evaluation of countermeasures for red light running by traffic simulator-based surrogate safety measures.

    PubMed

    Lee, Changju; So, Jaehyun Jason; Ma, Jiaqi

    2017-06-21

    The conflicts among motorists entering a signalized intersection with the red light indication have become a national safety issue. Because of its sensitivity, efforts have been made to investigate the possible causes and effectiveness of countermeasures using comparison sites and/or before-and-after studies. Nevertheless, these approaches are ineffective when comparison sites cannot be found, or crash data sets are not readily available or not reliable for statistical analysis. Considering the random nature of red light running (RLR) crashes, an inventive approach regardless of data availability is necessary to evaluate the effectiveness of each countermeasure face to face. The aims of this research are to (1) review erstwhile literature related to red light running and traffic safety models; (2) propose a practical methodology for evaluation of RLR countermeasures with a microscopic traffic simulation model and surrogate safety assessment model (SSAM); (3) apply the proposed methodology to actual signalized intersection in Virginia, with the most prevalent scenarios-increasing the yellow signal interval duration, installing an advance warning sign, and an RLR camera; and (4) analyze the relative effectiveness by RLR frequency and the number of conflicts (rear-end and crossing). All scenarios show a reduction in RLR frequency (-7.8, -45.5, and -52.4%, respectively), but only increasing the yellow signal interval duration results in a reduced total number of conflicts (-11.3%; a surrogate safety measure of possible RLR-related crashes). An RLR camera makes the greatest reduction (-60.9%) in crossing conflicts (a surrogate safety measure of possible angle crashes), whereas increasing the yellow signal interval duration results in only a 12.8% reduction of rear-end conflicts (a surrogate safety measure of possible rear-end crash). Although increasing the yellow signal interval duration is advantageous because this reduces the total conflicts (a possibility of total

  19. Spontaneous density fluctuations in granular flow and traffic

    NASA Astrophysics Data System (ADS)

    Herrmann, Hans J.

    It is known that spontaneous density waves appear in granular material flowing through pipes or hoppers. A similar phenomenon is known from traffic jams on highways. Using numerical simulations we show that several types of waves exist and find that the density fluctuations follow a power law spectrum. We also investigate one-dimensional traffic models. If positions and velocities are continuous variables the model shows self-organized criticality driven by the slowest car. Lattice gas and lattice Boltzmann models reproduce the experimentally observed effects. Density waves are spontaneously generated when the viscosity has a non-linear dependence on density or shear rate as it is the case in traffic or granular flow.

  20. REVIEW AND PERSPECTIVE OF HIGHWAY CAPACITY AND QUALITY OF SERVICE RESEARCH IN JAPAN

    NASA Astrophysics Data System (ADS)

    Oguchi, Takashi; Nakamura, Hideki

    The highway traffic congestion is one of the most important social and technical issues from the early days of motorization in Japan. Accordingly, the highway capacity has long been a major concern of traffic engineers, not only in research but also in practice, in order to alleviate the traffic congestions. Also, the concept of the quality of service of traffic flow and its proper understanding according to diverse conditions are crucial for implementing the performance-oriented highway planning and design schemes. This article therefore overviews the recent research works regarding highway capacity and quality of service particularly in Japan, after reviewing the state of the arts in bottleneck phenomena observed on Japan motorways and highways. And the future perspective of these research fields is discussed.

  1. Highway corridor responsibility

    Treesearch

    Bonnie L. Harper-Lore

    1998-01-01

    As highways cross the nation they provide safe travel for the vacationers, commuters, truckers, the military, farmers, congressmen, our families, and friends. Highway corridors provide safe passage for many plant invaders as well. Highway vegetation managers manage millions of acres of rights-of-way that cross your land. It is imperative that we understand each other...

  2. Generalized Deterministic Traffic Rules

    NASA Astrophysics Data System (ADS)

    Fuks, Henryk; Boccara, Nino

    We study a family of deterministic models for highway traffic flow which generalize cellular automaton rule 184. This family is parameterized by the speed limit m and another parameter k that represents a "degree of aggressiveness" in driving, strictly related to the distance between two consecutive cars. We compare two driving strategies with identical maximum throughput: "conservative" driving with high speed limit and "aggressive" driving with low speed limit. Those two strategies are evaluated in terms of accident probability. We also discuss fundamental diagrams of generalized traffic rules and examine limitations of maximum achievable throughput. Possible modifications of the model are considered.

  3. 23 CFR 661.49 - Can IRRBP funds be spent on Interstate, State Highway, and Toll Road IRR bridges?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ..., and Toll Road IRR bridges? 661.49 Section 661.49 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS INDIAN RESERVATION ROAD BRIDGE PROGRAM § 661.49 Can IRRBP funds be spent on Interstate, State Highway, and Toll Road IRR bridges? Yes. Interstate...

  4. 23 CFR 661.49 - Can IRRBP funds be spent on Interstate, State Highway, and Toll Road IRR bridges?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ..., and Toll Road IRR bridges? 661.49 Section 661.49 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS INDIAN RESERVATION ROAD BRIDGE PROGRAM § 661.49 Can IRRBP funds be spent on Interstate, State Highway, and Toll Road IRR bridges? Yes. Interstate...

  5. 23 CFR 661.49 - Can IRRBP funds be spent on Interstate, State Highway, and Toll Road IRR bridges?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ..., and Toll Road IRR bridges? 661.49 Section 661.49 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS INDIAN RESERVATION ROAD BRIDGE PROGRAM § 661.49 Can IRRBP funds be spent on Interstate, State Highway, and Toll Road IRR bridges? Yes. Interstate...

  6. 23 CFR 661.49 - Can IRRBP funds be spent on Interstate, State Highway, and Toll Road IRR bridges?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ..., and Toll Road IRR bridges? 661.49 Section 661.49 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS INDIAN RESERVATION ROAD BRIDGE PROGRAM § 661.49 Can IRRBP funds be spent on Interstate, State Highway, and Toll Road IRR bridges? Yes. Interstate...

  7. 23 CFR 661.49 - Can IRRBP funds be spent on Interstate, State Highway, and Toll Road IRR bridges?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ..., and Toll Road IRR bridges? 661.49 Section 661.49 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS INDIAN RESERVATION ROAD BRIDGE PROGRAM § 661.49 Can IRRBP funds be spent on Interstate, State Highway, and Toll Road IRR bridges? Yes. Interstate...

  8. Techniques for the investigation of road traffic noise in regions of restricted flow by the use of digital computer simulation methods

    NASA Astrophysics Data System (ADS)

    Jones, R. R. K.; Hothersall, D. C.; Salter, R. J.

    1981-04-01

    Computer methods of calculating and predicting the noise from road traffic operating in restricted flow conditions are discussed. A method of calculating the noise from road traffic as a function of the manoeuvring parameters by means of a Monte Carlo digital computer simulation model is briefly described. The model is used in deriving correction contours for single streams of traffic which enable free flow L10 levels to be modified to allow for a flow restriction. Flow restrictions of the type encountered at traffic signals, priority intersections and pelican crossings are considered. The contours cover a stretch of road 600 m long and a distance of 60 m from the kerb line and in general show a reduction in L10 level in transferring from the free to the restricted flow situation. A method of applying the contours as a modification of the United Kingdom Department of the Environment prediction method for L10 is proposed and compared with experimental results. Computer simulation models of complete road intersections are discussed. Two types of intersection controls are considered, the traffic signal control and the roundabout. The results of the two types of simulation are compared and the L10 level adjacent to the accelerating traffic streams is generally found to be greater than that adjacent to decelerating streams. Experimental results for both types of intersection are compared with simulation runs in which the observed traffic parameters are used.

  9. Near real-time traffic routing

    NASA Technical Reports Server (NTRS)

    Yang, Chaowei (Inventor); Cao, Ying (Inventor); Xie, Jibo (Inventor); Zhou, Bin (Inventor)

    2012-01-01

    A near real-time physical transportation network routing system comprising: a traffic simulation computing grid and a dynamic traffic routing service computing grid. The traffic simulator produces traffic network travel time predictions for a physical transportation network using a traffic simulation model and common input data. The physical transportation network is divided into a multiple sections. Each section has a primary zone and a buffer zone. The traffic simulation computing grid includes multiple of traffic simulation computing nodes. The common input data includes static network characteristics, an origin-destination data table, dynamic traffic information data and historical traffic data. The dynamic traffic routing service computing grid includes multiple dynamic traffic routing computing nodes and generates traffic route(s) using the traffic network travel time predictions.

  10. Older People’s Perceptions of Pedestrian Friendliness and Traffic Safety: An Experiment Using Computer-Simulated Walking Environments

    PubMed Central

    Kahlert, Daniela; Schlicht, Wolfgang

    2015-01-01

    Traffic safety and pedestrian friendliness are considered to be important conditions for older people’s motivation to walk through their environment. This study uses an experimental study design with computer-simulated living environments to investigate the effect of micro-scale environmental factors (parking spaces and green verges with trees) on older people’s perceptions of both motivational antecedents (dependent variables). Seventy-four consecutively recruited older people were randomly assigned watching one of two scenarios (independent variable) on a computer screen. The scenarios simulated a stroll on a sidewalk, as it is ‘typical’ for a German city. In version ‘A,’ the subjects take a fictive walk on a sidewalk where a number of cars are parked partially on it. In version ‘B’, cars are in parking spaces separated from the sidewalk by grass verges and trees. Subjects assessed their impressions of both dependent variables. A multivariate analysis of covariance showed that subjects’ ratings on perceived traffic safety and pedestrian friendliness were higher for Version ‘B’ compared to version ‘A’. Cohen’s d indicates medium (d = 0.73) and large (d = 1.23) effect sizes for traffic safety and pedestrian friendliness, respectively. The study suggests that elements of the built environment might affect motivational antecedents of older people’s walking behavior. PMID:26308026

  11. Older People's Perceptions of Pedestrian Friendliness and Traffic Safety: An Experiment Using Computer-Simulated Walking Environments.

    PubMed

    Kahlert, Daniela; Schlicht, Wolfgang

    2015-08-21

    Traffic safety and pedestrian friendliness are considered to be important conditions for older people's motivation to walk through their environment. This study uses an experimental study design with computer-simulated living environments to investigate the effect of micro-scale environmental factors (parking spaces and green verges with trees) on older people's perceptions of both motivational antecedents (dependent variables). Seventy-four consecutively recruited older people were randomly assigned watching one of two scenarios (independent variable) on a computer screen. The scenarios simulated a stroll on a sidewalk, as it is 'typical' for a German city. In version 'A,' the subjects take a fictive walk on a sidewalk where a number of cars are parked partially on it. In version 'B', cars are in parking spaces separated from the sidewalk by grass verges and trees. Subjects assessed their impressions of both dependent variables. A multivariate analysis of covariance showed that subjects' ratings on perceived traffic safety and pedestrian friendliness were higher for Version 'B' compared to version 'A'. Cohen's d indicates medium (d = 0.73) and large (d = 1.23) effect sizes for traffic safety and pedestrian friendliness, respectively. The study suggests that elements of the built environment might affect motivational antecedents of older people's walking behavior.

  12. Case Study: Influences of Uncertainties and Traffic Scenario Difficulties in a Human-in-the-Loop Simulation

    NASA Technical Reports Server (NTRS)

    Bienert, Nancy; Mercer, Joey; Homola, Jeffrey; Morey, Susan; Prevot, Thomas

    2014-01-01

    This paper presents a case study of how factors such as wind prediction errors and metering delays can influence controller performance and workload in Human-In-The-Loop simulations. Retired air traffic controllers worked two arrival sectors adjacent to the terminal area. The main tasks were to provide safe air traffic operations and deliver the aircraft to the metering fix within +/- 25 seconds of the scheduled arrival time with the help of provided decision support tools. Analyses explore the potential impact of metering delays and system uncertainties on controller workload and performance. The results suggest that trajectory prediction uncertainties impact safety performance, while metering fix accuracy and workload appear subject to the scenario difficulty.

  13. STUDY ON SUPPORTING FOR DRAWING UP THE BCP FOR URBAN EXPRESSWAY NETWORK USING BY TRAFFIC SIMULATION SYSTEM

    NASA Astrophysics Data System (ADS)

    Yamawaki, Masashi; Shiraki, Wataru; Inomo, Hitoshi; Yasuda, Keiichi

    The urban expressway network is an important infrastructure to execute a disaster restoration. Therefore, it is necessary to draw up the BCP (Business Continuity Plan) to enable securing of road user's safety and restoration of facilities, etc. It is important that each urban expressway manager execute decision and improvement of effective BCP countermeasures when disaster occurs by assuming various disaster situations. Then, in this study, we develop the traffic simulation system that can reproduce various disaster situations and traffic actions, and examine some methods supporting for drawing up the BCP for an urban expressway network. For disaster outside assumption such as tsunami generated by a huge earthquake, we examine some approaches securing safety of users and cars on the Hanshin Expressway Network as well as on general roads. And, we aim to propose a tsunami countermeasure not considered in the current urban expressway BCP.

  14. Driver behaviour at rail level crossings: responses to flashing lights, traffic signals and stop signs in simulated rural driving.

    PubMed

    Lenné, Michael G; Rudin-Brown, Christina M; Navarro, Jordan; Edquist, Jessica; Trotter, Margaret; Tomasevic, Nebojsa

    2011-05-01

    Australian road and railway authorities have made a concerted effort to reduce the number of rail level crossings, particularly the higher risk passive crossings that are protected by devices such as 'give way' or 'stop' signs. To improve this situation, passive level crossings are often upgraded with active controls such as flashing red lights. Traffic signals may provide good safety outcomes at level crossings but remain untested. The primary purpose of this research was to compare driver behaviour at two railway level crossings with active controls, flashing red lights and traffic signals, to behaviour at the current standard passive level crossing control, a stop sign. Participants drove the MUARC advanced driving simulator for 30 min. During the simulated drive, participants were exposed to three level crossing scenarios. Each scenario consisted of one of three level crossing control types, and was associated with an oncoming train. Mean vehicle speed on approach to the level crossings decreased more rapidly in response to flashing lights than to traffic signals. While speed on approach was lowest for the stop-sign condition, the number of non-compliant drivers (i.e., those who did not stop) at the crossing was highest for this condition. While results indicate that traffic signals at rail level crossings do not appear to offer any safety benefits over and above flashing red lights, further avenues of research are proposed to reach more definitive conclusions. Compliance was lowest for the passive crossing control which provides further support for the ongoing passive crossing upgrades in Australia. Copyright © 2010 Elsevier Ltd and The Ergonomics Society. All rights reserved.

  15. Multimedia traffic monitoring system

    NASA Astrophysics Data System (ADS)

    Al-Sayegh, Osamah A.; Dashti, Ali E.

    2000-10-01

    Increasing congestion on roads and highways, and the problems associated with conventional traffic monitoring systems have generated an interest in new traffic surveillance systems, such as video image processing. These systems are expected to be more effective and more economical than conventional surveillance systems. In this paper, we describe the design of a traffic surveillance system, called Multimedia traffic Monitoring System. The system is based on a client/server model, with the following main modules: 1) video image capture module (VICM), 2) video image processing module (VIPM), and 3) database module (DBM). The VICM is used to capture the live feed from a digital camera. Depending on the mode of operation, VICM either: 1) sends the video images directly to the VIPM (on the same processing node), or 2) compresses the video images and sends them to the VIPM and/or the DBM on separate processing node(s). The main contribution of this paper is the design of a traffic monitoring system that uses image processing (VIPM) to estimate traffic flow. In the current implementation, VIPM estimates the number of vehicles per kilometer, while using 9 image sequences (at a rate of 4 frames per second). The VIPM algorithm generates a virtual grid and superimposes it on a part of the traffic scene. Motion and vehicle detection operators are carried out within each cell in the grid. Vehicle count is concluded based on the nine images of a sequence. The system is tested against a manual count of more than 40 image sequences (total of more than 365 traffic images) of various traffic situations. The results show that the system is able to determine the traffic flow with a precision of 1.5 vehicles per kilometer.

  16. Automated Air Traffic Control Operations with Weather and Time-Constraints: A First Look at (Simulated) Far-Term Control Room Operations

    NASA Technical Reports Server (NTRS)

    Prevot, Thomas; Homola, Jeffrey R.; Martin, Lynne H.; Mercer, Joey S.; Cabrall, Christopher C.

    2011-01-01

    In this paper we discuss results from a recent high fidelity simulation of air traffic control operations with automated separation assurance in the presence of weather and time-constraints. We report findings from a human-in-the-loop study conducted in the Airspace Operations Laboratory (AOL) at the NASA Ames Research Center. During four afternoons in early 2010, fifteen active and recently retired air traffic controllers and supervisors controlled high levels of traffic in a highly automated environment during three-hour long scenarios, For each scenario, twelve air traffic controllers operated eight sector positions in two air traffic control areas and were supervised by three front line managers, Controllers worked one-hour shifts, were relieved by other controllers, took a 3D-minute break, and worked another one-hour shift. On average, twice today's traffic density was simulated with more than 2200 aircraft per traffic scenario. The scenarios were designed to create peaks and valleys in traffic density, growing and decaying convective weather areas, and expose controllers to heavy and light metering conditions. This design enabled an initial look at a broad spectrum of workload, challenge, boredom, and fatigue in an otherwise uncharted territory of future operations. In this paper we report human/system integration aspects, safety and efficiency results as well as airspace throughput, workload, and operational acceptability. We conclude that, with further refinements. air traffic control operations with ground-based automated separation assurance can be an effective and acceptable means to routinely provide very high traffic throughput in the en route airspace.

  17. UAS Air Traffic Controller Acceptability Study. 2; Evaluating Detect and Avoid Technology and Communication Delays in Simulation

    NASA Technical Reports Server (NTRS)

    Comstock, James R., Jr.; Ghatas, Rania W.; Consiglio, Maria C.; Chamberlain, James P.; Hoffler, Keith D.

    2015-01-01

    This study evaluated the effects of communications delays and winds on air traffic controller ratings of acceptability of horizontal miss distances (HMDs) for encounters between Unmanned Aircraft Systems (UAS) and manned aircraft in a simulation of the Dallas-Ft. Worth (DFW) airspace. Fourteen encounters per hour were staged in the presence of moderate background traffic. Seven recently retired controllers with experience at DFW served as subjects. Guidance provided to the UAS pilots for maintaining a given HMD was provided by information from Detect and Avoid (DAA) self-separation algorithms (Stratway+) displayed on the Multi-Aircraft Control System. This guidance consisted of amber "bands" on the heading scale of the UAS navigation display indicating headings that would result in a loss of well clear between the UAS and nearby traffic. Winds tested were successfully handled by the DAA algorithms and did not affect the controller acceptability ratings of the HMDs. Voice communications delays for the UAS were also tested and included one-way delay times of 0, 400, 1200, and 1800 msec. For longer communications delays, there were changes in strategy and communications flow that were observed and reported by the controllers. The aim of this work is to provide useful information for guiding future rules and regulations applicable to flying UAS in the NAS. Information from this study will also be of value to the Radio Technical Commission for Aeronautics (RTCA) Special Committee 228 - Minimum Performance Standards for UAS.

  18. Lead Isotopes in Highway Runoff

    NASA Astrophysics Data System (ADS)

    Ferreira, M.; Lau, S.; Green, P. G.; Stenstrom, M. K.

    2011-12-01

    Lead (Pb) isotopes have been used extensively to study the provenance of lead pollution on air, water, and sediments. In this study, we measured Pb isotopes and Pb aqueous concentration in highway runoff in three west Los Angeles sites. Those three sites, part of a long-term study sponsored by the California Department of Transportation, represent small catchment areas, and host heavy traffic. In addition, there were no inputs of sand or salt to the highway because the sites are almost completely impervious and also due to the lack of snow to be controlled. Highway runoff from the three sites was collected for 7 storms during the 2004-2005 Winter. Grab samples were collected every 15 minutes during the first hour, and hourly afterwards. A total of 202 samples were collected and filtered into five size fractions (<0.45μm, 0.45-8μm, 8-20μm, 20-100μm, >100μm). Aqueous concentration of Pb range from 0.08μg/L to 46.95μg/L (7.98±10.89μg/L) and it is not correlated with any of the lead isotope ratios. The 208Pb/206Pb ratio ranges from 1.983 to 2.075 (2.024±0.026) and there is no statistical difference for the mean value of the 208Pb/206Pb ratio for the four particulate size fractions (0.45-8μm, 8-20μm, 20-100μm, >100μm). However, the 208Pb/206Pb ratio of nearby soils yield 2.060±0.021 and it is statistically different from the ratios obtained for the highway runoff. This hints that the lead present in highway runoff does not come from local soils. The 207Pb/206Pb ratio ranges from 0.804 to 0.847 (0.827±0.011) and there is no statistical difference for the mean value of the 207Pb/206Pb ratio for the four particulate size fractions (0.45-8μm, 8-20μm, 20-100μm, >100μm). Surprisingly, there is also no statistical difference with the 207Pb/206Pb ratio of nearby soils (0.833±0.009).

  19. A simulator study on the impact of traffic calming measures in urban areas on driving behavior and workload.

    PubMed

    Ariën, Caroline; Jongen, Ellen M M; Brijs, Kris; Brijs, Tom; Daniels, Stijn; Wets, Geert

    2013-12-01

    This study examined the impact of traffic calming measures (TCM) on major roads in rural and urban areas. More specifically we investigated the effect of gate constructions located at the entrance of the urban area and horizontal curves within the urban area on driving behavior and workload. Forty-six participants completed a 34km test-drive on a driving simulator with eight thoroughfare configurations, i.e., 2 (curves: present, absent)×2 (gates: present, absent)×2 (peripheral detection task (PDT): present, absent) in a within-subject design. PDT performance (mean response time (RT) and hit rate) indicated that drivers experienced the road outside the urban area as cognitively less demanding relative to the more complex road environment inside the urban area. Whereas curves induced a speed reduction that was sustained throughout the entire urban area, variability of acceleration/deceleration and lateral position were increased. In addition, PDT performance indicated higher workload when curves were present (versus absent). Gate constructions locally reduced speed (i.e., shortly before and after the entrance) and slightly increased variability of acceleration/deceleration and lateral position nearby the entrance. However, the effects on SDL-A/D and SDLP are too small to expect traffic safety problems. It can be concluded that both curves and gate constructions can improve traffic safety. Notwithstanding, the decision to implement these measures will depend on contextual factors such as whether the road serves a traffic-, rather than a residential function. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Highway Safety, Manpower, and Training: A Report on Highway Safety, Manpower, and Training Needed to Implement National Highway Safety Bureau Standards.

    ERIC Educational Resources Information Center

    National Safety Council, Chicago, IL. Traffic Education and Training Committee.

    This paper was developed by the Liaison Subcommittee of the Traffic Educational and Training Committee to: (1) delineate highway safety manpower and training problems, (2) propose activities to meet these problems, and (3) develop a proposed course of action to initate the activities. Included are: (1) a discussion of areas where manpower…

  1. RELATIVE TOXICITY OF SIZE-FRACTIONATED PARTICULATE MATTER OBTAINED AT DIFFERENT DISTANCES FROM A HIGHWAY

    EPA Science Inventory

    Epidemiological studies have reported an association between proximity to highway traffic and increased respiratory symptoms. This study was initiated to determine the contribution of ambient particulate matter (PM) to these observed effects. Ambient PM was collected for 2 weeks ...

  2. RELATIVE TOXICITY OF SIZE-FRACTIONATED PARTICULATE MATTER OBTAINED AT DIFFERENT DISTANCES FROM A HIGHWAY

    EPA Science Inventory

    Epidemiological studies have reported an association between proximity to highway traffic and increased respiratory symptoms. This study was initiated to determine the contribution of ambient particulate matter (PM) to these observed effects. Ambient PM was collected for 2 weeks ...

  3. 76 FR 51462 - Notice of Final Federal Agency Actions on Proposed Highway in Utah

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-18

    ... Midvalley Highway Project, To Address Traffic Congestion on UT-36 and at the I-80 Lake Point interchange... anticipated congestion on SR-36, and reduce anticipated congestion at the Lake Point interchange with...

  4. Traffic accidents on a single-lane road with multi-slowdown sections

    NASA Astrophysics Data System (ADS)

    Li, Xingli; Kuang, Hua; Fan, Yanhong; Zhang, Guoxin

    2014-02-01

    In this paper, an extended cellular automaton model is proposed to simulate the complex characteristics of traffic flow and the probability of the occurrence of traffic accidents by considering the modified conditions for determining whether traffic accidents happen and the effect of multi-slowdown sections on a highway. The simulation results show that the multi-slowdown sections can lead to multiphase coexistences (i.e. free flow phase, congestion phase and saturation phase) in traffic system. The fundamental diagram shows that the number of slowdown section does not influence the mean velocity and the mean flow under the periodic boundary condition, but the existence of slowdown sections can effectively reduce the occurrence of traffic accident. In particular, it is found that the probability of car accidents to occur is the largest at the joint of the normal-speed section and slowdown section, and the underlying mechanism is analyzed. In addition, to design the appropriate limited speed and reduce the differences between the normal speed and limited speed will alleviate traffic congestion and reduce the occurrence of traffic accidents obviously.

  5. Simulation study of interference of crossings pedestrian and vehicle traffic at a single lane roundabout

    NASA Astrophysics Data System (ADS)

    Echab, H.; Ez-Zahraouy, H.; Lakouari, N.

    2016-11-01

    This paper proposes a vehicle-pedestrian cellular automata model to investigate the characteristics of the mixed traffic at a single lane roundabout. The roundabout boundary is controlled by the injecting rates α1 ,α2 and the extracting rate β whereas pedestrians are generated with arrival probability Pcr. The pedestrian and vehicle flux are calculated in terms of rates. Also, the phase diagrams of the system in the (α1 ,Pcr) and (α1 , β) spaces are constructed. The results show that, the gridlock state is reached only when the pedestrians have the right of way over vehicles, while the maximum current state is reached when including a pedestrians' crossing decision rule. Likewise, we have found that the crosswalk location play a chief role in improving the dynamic characteristics of pedestrian and vehicle flux. Furthermore, it has turned out that the traffic is sensitive to the driver behavior.

  6. Air Traffic Control/Active Beacon Collision Avoidance System Knoxville Simulation.

    DTIC Science & Technology

    1980-05-01

    Traffic Conditions 3 Error and Response Models 5 Desensitization Methods 5 Data Collection Plan 6 Controller Questionnaires 6 RESULTS AND ANALYSIS 10 ...Operations Rates 10 Effect of Active BCAS on Controllers and Control Procedures 10 Conflict Analysis 10 Active BCAS Protection 13 Active BCAS Alert Rates...Altitude Desensitization 23 10 Encounter on Parallel Approach (Horizontal View) 27 (See Appendix H For Legend) 11 Encounter on Parallel Approach

  7. Highways and Population Change

    ERIC Educational Resources Information Center

    Voss, Paul R.; Chi, Guangqing

    2006-01-01

    In this paper we return to an issue often discussed in the literature regarding the relationship between highway expansion and population change. Typically it simply is assumed that this relationship is well established and understood. We argue, following a thorough review of the relevant literature, that the notion that highway expansion leads to…

  8. Highways and Population Change

    ERIC Educational Resources Information Center

    Voss, Paul R.; Chi, Guangqing

    2006-01-01

    In this paper we return to an issue often discussed in the literature regarding the relationship between highway expansion and population change. Typically it simply is assumed that this relationship is well established and understood. We argue, following a thorough review of the relevant literature, that the notion that highway expansion leads to…

  9. Simulation evaluation of combined 4D RNAV and airborne traffic situation displays and procedures applied to terminal aerial maneuvers

    NASA Technical Reports Server (NTRS)

    Athans, M.; Connelly, M. E.

    1979-01-01

    Simulation scenarios were developed in which subject pilots must simultaneously follow a 3D terminal airspace structure and arrive at fixed waypoints within the structure precisely at pre-scheduled times in the presence of a full range of wind conditions aloft, and monitor nearby traffic on an airborne traffic situation display, especially during merging and spacing operations, and detect blunders and resolve conflicts in a safe manner. Open-loop simulator tests of the single-stage 4D RNAV algorithm indicate that a descending pilot can comply quite closely with an assigned time of arrival at a 3D waypoint simply by tracking a pre-calculated speed profile. Initial experiments show that the aircraft arrives at the 3D waypoint within a few seconds of the anticipated time. The presence of headwinds or tailwinds does not affect the arrival time error as long as the wind is accurately modeled in the descent algorithm. Results all but quarantee that a 5 second standard deviation in arrival time error can be realized in closed-loop descents at very moderate pilot workload levels.

  10. Studies of vehicle lane-changing dynamics and its effect on traffic efficiency, safety and environmental impact

    NASA Astrophysics Data System (ADS)

    Li, Xiang; Sun, Jian-Qiao

    2017-02-01

    Drivers often change lanes on the road to maintain desired speed and to avoid slow vehicles, pedestrians, obstacles and lane closure. Understanding the effect of lane-changing on the traffic is an important topic in designing optimal traffic control systems. This paper presents a comprehensive study of this topic. We review the theory of microscopic dynamic car-following models and the lane-changing models, propose additional lane-changing rules to deal with moving bottleneck and lane reduction, and investigate the effects of lane-changing on the traffic efficiency, traffic safety and fuel consumption as a function of different variables including the distance of the emergency sign ahead of the lane closure, speed limit, traffic density, etc. Extensive simulations of the traffic system have been carried out in different scenarios. A number of important findings of the effect of various factors on the traffic are reported. These findings provide guidance on the traffic management and are important to the designers and engineers of modern highway or inner city roads to achieve high traffic efficiency and safety with minimum environmental impact.

  11. The 'go-between' study: a simulation study comparing the 'Traffic Lights' and 'SBAR' tools as a means of communication between anaesthetic staff.

    PubMed

    MacDougall-Davis, S R; Kettley, L; Cook, T M

    2016-07-01

    Communicating non-urgent, urgent and frank emergency requests for assistance between anaesthetists in theatre often requires a 'go-between' - frequently a non-anaesthetic healthcare professional - to transmit information. We compared the currently recommended situation, background, assessment, recommendation (SBAR) tool with a newly devised Traffic Lights tool ('red alert', 'amber assist' and 'green query') in a simulation study to assess communication quality using 12 validated clinical scenarios of varying urgency. Compared to SBAR, Traffic Lights was used more consistently ('very clear' or 'clear' Traffic Lights 94% vs SBAR 69%); transferred information better (two or three pieces of information correctly transferred Traffic Lights 85%, SBAR 44%; and was judged to lead to greater clarity (all p < 0.0001). Message delivery time was significantly reduced (Traffic Lights 20.5 s vs SBAR 45.5 s, median (95% CI) difference 25 (19-30) s, p < 0.001). Users rated the Traffic Lights system as significantly more useful than SBAR, with 96% of participants preferring the Traffic Lights tool. Results were independent of go-between training. We recommend the adoption of this communication tool as standard practice for anaesthetic teams.

  12. 23 CFR 630.1110 - Maintenance of temporary traffic control devices.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 23 Highways 1 2013-04-01 2013-04-01 false Maintenance of temporary traffic control devices. 630... AND TRAFFIC OPERATIONS PRECONSTRUCTION PROCEDURES Temporary Traffic Control Devices § 630.1110 Maintenance of temporary traffic control devices. To provide for the continued effectiveness of...

  13. 23 CFR 630.1110 - Maintenance of temporary traffic control devices.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 23 Highways 1 2011-04-01 2011-04-01 false Maintenance of temporary traffic control devices. 630... AND TRAFFIC OPERATIONS PRECONSTRUCTION PROCEDURES Temporary Traffic Control Devices § 630.1110 Maintenance of temporary traffic control devices. To provide for the continued effectiveness of...

  14. 23 CFR 630.1110 - Maintenance of temporary traffic control devices.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Maintenance of temporary traffic control devices. 630... AND TRAFFIC OPERATIONS PRECONSTRUCTION PROCEDURES Temporary Traffic Control Devices § 630.1110 Maintenance of temporary traffic control devices. To provide for the continued effectiveness of...

  15. 23 CFR 630.1110 - Maintenance of temporary traffic control devices.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 23 Highways 1 2012-04-01 2012-04-01 false Maintenance of temporary traffic control devices. 630... AND TRAFFIC OPERATIONS PRECONSTRUCTION PROCEDURES Temporary Traffic Control Devices § 630.1110 Maintenance of temporary traffic control devices. To provide for the continued effectiveness of...

  16. Triggering factor evolution and dynamic process simulation of the Formosa Highway dip-slope failure, northern Taiwan

    NASA Astrophysics Data System (ADS)

    Huang, Mei-Jen; Chiang, Yi-Lin; Chang, Ho-Shyang; Chang, Kuo-Jen

    2013-04-01

    Taiwan, due to the high seismicity and high annual rainfall, numerous landslides triggered every year and severe impacts affect the island. Accordingly, if the new-built construction does not take into account this threaten, tremendous disasters will occur. On April 25th 2010, Formosa Freeway dip-slope failure caused four deaths, resulted from artificial slope cutting and rock-bot supporting system weakening. This research integrates high resolution Digital Terrain Model (DTM) and numerical simulation to evaluate the triggering mechanism and dynamic process of the landslide. First of all, to access the landslide geometry, the morphology of the event before and after landslide is constructed from high resolution DTM by means of aerial photos. The slid and the deposit volumes of the landslide are thus estimated accordingly. Only part of the surface of separation between slide block and slide slope is exposed. Based on the exposed planar strata/sliding surface, situated on the upper part of the slope, by means of extrapolating part of the plane to mimic the entire slide surface. From DTMs, the slide block is approximately 0.15 million cubic meters. The extrapolated planar surface serves as sliding surface for the numerical models. For numerical model preparation, the particle clusters produced by isotropic stress and the porosity are take into account. To ensure the production range should cover the entire slid mass from the source area, the particle clusters represent the slid block is been rotated, scaled and translated to the source area. Then, part of the particles are been eliminated if it is situated outside the upper and lower surface from the DTM before and after landslide. According to the geological map, the model of the particles to mimic the slide block can be divided into two parts: 1) the underneath interbedded sandstone and shale which may soften by water 2) the supposed upper layer composed of sandstone. Furthermore, set up a layer of particles to

  17. Spatial variations in estimated chronic exposure to traffic-related air pollution in working populations: A simulation

    PubMed Central

    Setton, Eleanor M; Keller, C Peter; Cloutier-Fisher, Denise; Hystad, Perry W

    2008-01-01

    Background Chronic exposure to traffic-related air pollution is associated with a variety of health impacts in adults and recent studies show that exposure varies spatially, with some residents in a community more exposed than others. A spatial exposure simulation model (SESM) which incorporates six microenvironments (home indoor, work indoor, other indoor, outdoor, in-vehicle to work and in-vehicle other) is described and used to explore spatial variability in estimates of exposure to traffic-related nitrogen dioxide (not including indoor sources) for working people. The study models spatial variability in estimated exposure aggregated at the census tracts level for 382 census tracts in the Greater Vancouver Regional District of British Columbia, Canada. Summary statistics relating to the distributions of the estimated exposures are compared visually through mapping. Observed variations are explored through analyses of model inputs. Results Two sources of spatial variability in exposure to traffic-related nitrogen dioxide were identified. Median estimates of total exposure ranged from 8 μg/m3 to 35 μg/m3 of annual average hourly NO2 for workers in different census tracts in the study area. Exposure estimates are highest where ambient pollution levels are highest. This reflects the regional gradient of pollution in the study area and the relatively high percentage of time spent at home locations. However, for workers within the same census tract, variations were observed in the partial exposure estimates associated with time spent outside the residential census tract. Simulation modeling shows that some workers may have exposures 1.3 times higher than other workers residing in the same census tract because of time spent away from the residential census tract, and that time spent in work census tracts contributes most to the differences in exposure. Exposure estimates associated with the activity of commuting by vehicle to work were negligible, based on the

  18. Games for Traffic Education: An Experimental Study of a Game-Based Driving Simulator

    ERIC Educational Resources Information Center

    Backlund, Per; Engstrom, Henrik; Johannesson, Mikael; Lebram, Mikael

    2010-01-01

    In this article, the authors report on the construction and evaluation of a game-based driving simulator using a real car as a joystick. The simulator is constructed from off-the-shelf hardware and the simulation runs on open-source software. The feasibility of the simulator as a learning tool has been experimentally evaluated. Results are…

  19. Games for Traffic Education: An Experimental Study of a Game-Based Driving Simulator

    ERIC Educational Resources Information Center

    Backlund, Per; Engstrom, Henrik; Johannesson, Mikael; Lebram, Mikael

    2010-01-01

    In this article, the authors report on the construction and evaluation of a game-based driving simulator using a real car as a joystick. The simulator is constructed from off-the-shelf hardware and the simulation runs on open-source software. The feasibility of the simulator as a learning tool has been experimentally evaluated. Results are…

  20. Effective flow resistivity of highway pavements.

    PubMed

    Rochat, Judith L; Read, David R

    2013-12-01

    In the case of highway traffic noise, propagating sound is influenced by the ground over which it travels, whether it is the pavement itself or the ground between the highway and nearby communities. Properly accounting for ground type in modeling can increase accuracy in noise impact determinations and noise abatement design. Pavement-specific effective flow resistivity values are being investigated for inclusion in the Federal Highway Administration Traffic Noise Model, which uses these values in the sound propagation algorithms and currently applies a single effective flow resistivity value to all pavement. Pavement-specific effective flow resistivity values were obtained by applying a modified version of the American National Standards Institute S1.18 standard. The data analysis process was tailored to allow for increased sensitivity and extraction of effective flow resistivity values for a broad range of pavements (sound absorptive to reflective). For porous pavements (sound absorptive), it was determined that examination of the measured data can reveal influence from an underlying structure. Use of such techniques can aid in the design of quieter pavements.

  1. 49 CFR 325.33 - Site characteristics; highway operations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... MOTOR CARRIER NOISE EMISSION STANDARDS Measurement of Noise Emissions; Highway Operations § 325.33 Site... or utility poles. (2) Rural mailboxes. (3) Traffic railings of any type of construction except solid... irregular tire, body, or chassis impact noise; and (2) Loose material, such as gravel or sand. (f) The...

  2. 49 CFR 325.33 - Site characteristics; highway operations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... MOTOR CARRIER NOISE EMISSION STANDARDS Measurement of Noise Emissions; Highway Operations § 325.33 Site... or utility poles. (2) Rural mailboxes. (3) Traffic railings of any type of construction except solid... irregular tire, body, or chassis impact noise; and (2) Loose material, such as gravel or sand. (f) The...

  3. Program of Instruction for Highway Collision Investigation Training Program.

    ERIC Educational Resources Information Center

    Cornell Aeronautical Lab., Inc., Buffalo, NY.

    This program of instruction, reviewed and accepted by the National Highway Traffic Safety Administration, was prepared for Multidisciplinary Accident Investigation teams and others. It is intended to provide background information, a working knowledge of all of the pertinent factors, investigative techniques, tools, data requirements, and field…

  4. Program of Instruction for Highway Collision Investigation Training Program.

    ERIC Educational Resources Information Center

    Cornell Aeronautical Lab., Inc., Buffalo, NY.

    This program of instruction, reviewed and accepted by the National Highway Traffic Safety Administration, was prepared for Multidisciplinary Accident Investigation teams and others. It is intended to provide background information, a working knowledge of all of the pertinent factors, investigative techniques, tools, data requirements, and field…

  5. 78 FR 71715 - Amendments to Highway Safety Program Guidelines

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-29

    ... Highway & Auto Safety (Advocates), the American Automobile Association (AAA), American Traffic Safety... NHTSA received comments in response to the notice from several organizations or associations: AAA... as from one individual. General AAA offered general support for the guidelines and provided two...

  6. 32 CFR 634.24 - Traffic planning and codes.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... enforcement officer, engineer, safety officer, and other concerned staff agencies. Highway engineering representatives from adjacent civil communities must be consulted to ensure the installation plan is compatible... and minor routes, location of traffic control devices, and conditions requiring engineering or...

  7. Implementation of Controlled Traffic in the Canadian Prairies: Soil and Plant Dynamics under Simulated and Field Conditions

    NASA Astrophysics Data System (ADS)

    Guenette, Kris; Hernandez-Ramirez, Guillermo

    2017-04-01

    Achieving resiliency in agroecosystems may be accomplished through the incorporation of contemporary management systems and the diversification of crop rotations with pulse crops, such as controlled traffic farming (CTF) and faba beans (Vicia faba L.). As these practices become more common in the Canadian Prairies, it is imperative to have a well-rounded understanding of how faba beans interact with the soil-plant-atmosphere continuum in conditions found in contemporary management systems. Simulated field conditions emulated soil compaction found in both the trafficked and un-trafficked areas of a CTF system, in which the presence of high water availability was shown to offset the negative results of large applications of compactive effort. Furthermore, low water availability exacerbated differences in plant responses between compaction treatments. The simulated treatment of 1.2 gcm-3 coupled with high water content yielded the most optimal results for most measured parameters, with a contrasting detrimental treatment of 1.4 gcm-3 at low water availability. The simulated field conditions were further bridged through an analysis of two commercial sites in Alberta, Canada that compared both trafficked and un-trafficked soil properties. Soil properties such as available nitrogen (AN), pH, soil total nitrogen (STN), soil organic carbon (SOC), bulk density, macroporosity, soil quality S-Index, plant available water capacity (PAWC) and unsaturated hydraulic conductivity (Km) were analysed and compared among trafficked and un-trafficked areas. The measured soil physical and hydraulic properties of bulk density, macroporosity, S-Index, PAWC and Km were shown to be heavily influenced by the CTF traffic regime, while soil nutrient properties of AN, pH, STN SOC were determined to be dependent on both management and landscape features.

  8. Empirical Analysis of Crash Injury Severity on Mountainous and Nonmountainous Interstate Highways.

    PubMed

    Ma, Xiaoxiang; Chen, Feng; Chen, Suren

    2015-01-01

    Mountainous (MT) highways usually exhibit complex geometry features such as steep gradients or sharp curves, which can cause considerably different driver behavior and vehicle performance compared to nonmountainous (NM) ones. In addition, MT highways experience adverse weather conditions more often than NM counterparts. We examine different characteristics of crash injury severity from an MT highway and an NM highway. One major interstate highway with typical MT terrain and another one with NM terrain in Colorado were selected for this study. A comparative investigation about the impact on injury severity from MT and NM highways is conducted. Separate mixed logit models are estimated for both highways with 4-year detailed crash data. Incorporating 2 major interstate highways from the same region into the comparative study offers some unique strength on investigating the impacts from different causes. As a result, the study provides better insights about contributing factors and associated mechanism for injury severity on MT highways. Substantial differences in the magnitude and direction of the influence of some contributing factors between MT and NM models are observed. Some new findings about injury severity on MT highways are made possible for the first time. The findings in this study provide scientific guidance to potentially improve the current highway design and traffic management policy on thousands of miles of MT highways in the country.

  9. Impact of distracted driving on safety and traffic flow.

    PubMed

    Stavrinos, Despina; Jones, Jennifer L; Garner, Annie A; Griffin, Russell; Franklin, Crystal A; Ball, David; Welburn, Sharon C; Ball, Karlene K; Sisiopiku, Virginia P; Fine, Philip R

    2013-12-01

    Studies have documented a link between distracted driving and diminished safety; however, an association between distracted driving and traffic congestion has not been investigated in depth. The present study examined the behavior of teens and young adults operating a driving simulator while engaged in various distractions (i.e., cell phone, texting, and undistracted) and driving conditions (i.e., free flow, stable flow, and oversaturation). Seventy five participants 16-25 years of age (split into 2 groups: novice drivers and young adults) drove a STISIM simulator three times, each time with one of three randomly presented distractions. Each drive was designed to represent daytime scenery on a 4 lane divided roadway and included three equal roadway portions representing Levels of Service (LOS) A, C, and E as defined in the 2000 Highway Capacity Manual. Participants also completed questionnaires documenting demographics and driving history. Both safety and traffic flow related driving outcomes were considered. A Repeated Measures Multivariate Analysis of Variance was employed to analyze continuous outcome variables and a Generalized Estimate Equation (GEE) Poisson model was used to analyze count variables. Results revealed that, in general more lane deviations and crashes occurred during texting. Distraction (in most cases, text messaging) had a significantly negative impact on traffic flow, such that participants exhibited greater fluctuation in speed, changed lanes significantly fewer times, and took longer to complete the scenario. In turn, more simulated vehicles passed the participant drivers while they were texting or talking on a cell phone than while undistracted. The results indicate that distracted driving, particularly texting, may lead to reduced safety and traffic flow, thus having a negative impact on traffic operations. No significant differences were detected between age groups, suggesting that all drivers, regardless of age, may drive in a manner

  10. Impact of Distracted Driving on Safety and Traffic Flow

    PubMed Central

    Stavrinos, Despina; Jones, Jennifer L.; Garner, Annie A.; Griffin, Russell; Franklin, Crystal A.; Ball, David; Welburn, Sharon C.; Ball, Karlene K.; Sisiopiku, Virginia P.; Fine, Philip R.

    2015-01-01

    Studies have documented a link between distracted driving and diminished safety; however, an association between distracted driving and traffic congestion has not been investigated in depth. The present study examined the behavior of teens and young adults operating a driving simulator while engaged in various distractions (i.e., cell phone, texting, and undistracted) and driving conditions (i.e., free flow, stable flow, and oversaturation). Seventy five participants 16 to 25 years of age (split into 2 groups: novice drivers and young adults) drove a STISIM simulator three times, each time with one of three randomly presented distractions. Each drive was designed to represent daytime scenery on a 4 lane divided roadway and included three equal roadway portions representing Levels of Service (LOS) A, C, and E as defined in the 2000 Highway Capacity Manual. Participants also completed questionnaires documenting demographics and driving history. Both safety and traffic flow related driving outcomes were considered. A Repeated Measures Multivariate Analysis of Variance was employed to analyze continuous outcome variables and a Generalized Estimate Equation (GEE) poisson model was used to analyze count variables. Results revealed that, in general more lane deviations and crashes occurred during texting. Distraction (in most cases, text messaging) had a significantly negative impact on traffic flow, such that participants exhibited greater fluctuation in speed, changed lanes significantly fewer times, and took longer to complete the scenario. In turn, more simulated vehicles passed the participant drivers while they were texting or talking on a cell phone than while undistracted. The results indicate that distracted driving, particularly texting, may lead to reduced safety and traffic flow, thus having a negative impact on traffic operations. No significant differences were detected between age groups, suggesting that all drivers, regardless of age, may drive in a manner

  11. CONDENSED MATTER: STRUCTURE, THERMAL AND MECHANICAL PROPERTIES: Multiple car-following model of traffic flow and numerical simulation

    NASA Astrophysics Data System (ADS)

    Peng, Guang-Han; Sun, Di-Hua

    2009-12-01

    On the basis of the full velocity difference (FVD) model, an improved multiple car-following (MCF) model is proposed by taking into account multiple information inputs from preceding vehicles. The linear stability condition of the model is obtained by using the linear stability theory. Through nonlinear analysis, a modified Korteweg-de Vries equation is constructed and solved. The traffic jam can thus be described by the kink-antikink soliton solution for the mKdV equation. The improvement of this new model over the previous ones lies in the fact that it not only theoretically retains many strong points of the previous ones, but also performs more realistically than others in the dynamical evolution of congestion. Furthermore, numerical simulation of traffic dynamics shows that the proposed model can avoid the disadvantage of negative velocity that occurs at small sensitivity coefficients λ in the FVD model by adjusting the information on the multiple leading vehicles. No collision occurs and no unrealistic deceleration appears in the improved model.

  12. Traffic camera system development

    NASA Astrophysics Data System (ADS)

    Hori, Toshi

    1997-04-01

    The intelligent transportation system has generated a strong need for the development of intelligent camera systems to meet the requirements of sophisticated applications, such as electronic toll collection (ETC), traffic violation detection and automatic parking lot control. In order to achieve the highest levels of accuracy in detection, these cameras must have high speed electronic shutters, high resolution, high frame rate, and communication capabilities. A progressive scan interline transfer CCD camera, with its high speed electronic shutter and resolution capabilities, provides the basic functions to meet the requirements of a traffic camera system. Unlike most industrial video imaging applications, traffic cameras must deal with harsh environmental conditions and an extremely wide range of light. Optical character recognition is a critical function of a modern traffic camera system, with detection and accuracy heavily dependent on the camera function. In order to operate under demanding conditions, communication and functional optimization is implemented to control cameras from a roadside computer. The camera operates with a shutter speed faster than 1/2000 sec. to capture highway traffic both day and night. Consequently camera gain, pedestal level, shutter speed and gamma functions are controlled by a look-up table containing various parameters based on environmental conditions, particularly lighting. Lighting conditions are studied carefully, to focus only on the critical license plate surface. A unique light sensor permits accurate reading under a variety of conditions, such as a sunny day, evening, twilight, storms, etc. These camera systems are being deployed successfully in major ETC projects throughout the world.

  13. Short Course in Highway Lighting.

    ERIC Educational Resources Information Center

    Federal Highway Administration (DOT), Washington, DC.

    This course guide in highway lighting includes an overview of trends in highway lighting, illustrated information on three light sources for today's luminaires, a reference guide to lamp classification, specifications for highway lighting equipment, and instructions for calculating appropriate use. Maintenance notes on highway illumination and…

  14. Cellular automata model for traffic flow with safe driving conditions

    NASA Astrophysics Data System (ADS)

    María, Elena Lárraga; Luis, Alvarez-Icaza

    2014-05-01

    In this paper, a recently introduced cellular automata (CA) model is used for a statistical analysis of the inner microscopic structure of synchronized traffic flow. The analysis focuses on the formation and dissolution of clusters or platoons of vehicles, as the mechanism that causes the presence of this synchronized traffic state with a high flow. This platoon formation is one of the most interesting phenomena observed in traffic flows and plays an important role both in manual and automated highway systems (AHS). Simulation results, obtained from a single-lane system under periodic boundary conditions indicate that in the density region where the synchronized state is observed, most vehicles travel together in platoons with approximately the same speed and small spatial distances. The examination of velocity variations and individual vehicle gaps shows that the flow corresponding to the synchronized state is stable, safe and highly correlated. Moreover, results indicate that the observed platoon formation in real traffic is reproduced in simulations by the relation between vehicle headway and velocity that is embedded in the dynamics definition of the CA model.

  15. Analysis of traffic congestion induced by the work zone

    NASA Astrophysics Data System (ADS)

    Fei, L.; Zhu, H. B.; Han, X. L.

    2016-05-01

    Based on the cellular automata model, a meticulous two-lane cellular automata model is proposed, in which the driving behavior difference and the difference of vehicles' accelerations between the moving state and the starting state are taken into account. Furthermore the vehicles' motion is refined by using the small cell of one meter long. Then accompanied by coming up with a traffic management measure, a two-lane highway traffic model containing a work zone is presented, in which the road is divided into normal area, merging area and work zone. The vehicles in different areas move forward according to different lane changing rules and position updating rules. After simulation it is found that when the density is small the cluster length in front of the work zone increases with the decrease of the merging probability. Then the suitable merging length and the appropriate speed limit value are recommended. The simulation result in the form of the speed-flow diagram is in good agreement with the empirical data. It indicates that the presented model is efficient and can partially reflect the real traffic. The results may be meaningful for traffic optimization and road construction management.

  16. Real-Time Traffic Signal Control for Optimization of Traffic Jam Probability

    NASA Astrophysics Data System (ADS)

    Cui, Cheng-You; Shin, Ji-Sun; Miyazaki, Michio; Lee, Hee-Hyol

    Real-time traffic signal control is an integral part of urban traffic control system. It can control traffic signals online according to variation of traffic flow. In this paper, we propose a new method for the real-time traffic signal control system. The system uses a Cellular Automaton model and a Bayesian Network model to predict probabilistic distributions of standing vehicles, and uses a Particle Swarm Optimization method to calculate optimal traffic signals. A simulation based on real traffic data was carried out to show the effectiveness of the proposed real-time traffic signal control system CAPSOBN using a micro traffic simulator.

  17. 23 CFR 772.17 - Traffic noise prediction.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... “FHWA Traffic Noise Model” Report No. FHWA-PD-96-010, including Revision No. 1, dated April 14, 2004, or... 23 Highways 1 2011-04-01 2011-04-01 false Traffic noise prediction. 772.17 Section 772.17 Highways... publications are incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51 and are on...

  18. 23 CFR 772.17 - Traffic noise prediction.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... “FHWA Traffic Noise Model” Report No. FHWA-PD-96-010, including Revision No. 1, dated April 14, 2004, or... 23 Highways 1 2010-04-01 2010-04-01 false Traffic noise prediction. 772.17 Section 772.17 Highways... publications are incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51 and are on...

  19. Integration of Weather Data into Airspace and Traffic Operations Simulation (ATOS) for Trajectory- Based Operations Research

    NASA Technical Reports Server (NTRS)

    Peters, Mark; Boisvert, Ben; Escala, Diego

    2009-01-01

    Explicit integration of aviation weather forecasts with the National Airspace System (NAS) structure is needed to improve the development and execution of operationally effective weather impact mitigation plans and has become increasingly important due to NAS congestion and associated increases in delay. This article considers several contemporary weather-air traffic management (ATM) integration applications: the use of probabilistic forecasts of visibility at San Francisco, the Route Availability Planning Tool to facilitate departures from the New York airports during thunderstorms, the estimation of en route capacity in convective weather, and the application of mixed-integer optimization techniques to air traffic management when the en route and terminal capacities are varying with time because of convective weather impacts. Our operational experience at San Francisco and New York coupled with very promising initial results of traffic flow optimizations suggests that weather-ATM integrated systems warrant significant research and development investment. However, they will need to be refined through rapid prototyping at facilities with supportive operational users We have discussed key elements of an emerging aviation weather research area: the explicit integration of aviation weather forecasts with NAS structure to improve the effectiveness and timeliness of weather impact mitigation plans. Our insights are based on operational experiences with Lincoln Laboratory-developed integrated weather sensing and processing systems, and derivative early prototypes of explicit ATM decision support tools such as the RAPT in New York City. The technical components of this effort involve improving meteorological forecast skill, tailoring the forecast outputs to the problem of estimating airspace impacts, developing models to quantify airspace impacts, and prototyping automated tools that assist in the development of objective broad-area ATM strategies, given probabilistic

  20. Arizona Traffic Safety Education, K-8. Bicycle Safety, Grade 2.

    ERIC Educational Resources Information Center

    Mesa Public Schools, AZ.

    One in a series designed to assist Arizona elementary and junior high school teachers in developing children's traffic safety skills, this curriculum guide contains ten lessons on bicycles for use in grade 2. Introductory information provided for the teacher includes basic highway safety concepts, stressing communication methods for highway users,…

  1. Arizona Traffic Safety Education, K-8. Bicycle Safety, Grade 2.

    ERIC Educational Resources Information Center

    Mesa Public Schools, AZ.

    One in a series designed to assist Arizona elementary and junior high school teachers in developing children's traffic safety skills, this curriculum guide contains ten lessons on bicycles for use in grade 2. Introductory information provided for the teacher includes basic highway safety concepts, stressing communication methods for highway users,…

  2. Trunk Highway 169: Dynamic ramp metering evaluation. Final report

    SciTech Connect

    1998-03-01

    Peak period travel demand has exceed unmanaged road capacity on most of Twin Cities metropolitan area freeways for more than two decades. During this time, the Minnesota Department of Transportation (MN/DOT) has developed and implemented its freeway traffic management system (FTMS). MN/DOT continues to expand the FTMS, which includes ramp metering as one component. This report documents the impact of dynamic ramp metering on Trunk Highway 169 (TH 16) from Minnetonka Boulevard in Minnetonka to 77th Avenue in Brooklyn Park. The study examines changes in traffic performance with regard to traffic flow, congestion levels, travel times, and accident rates before and after implementation of dynamic ramp metering.

  3. Alternative Techniques for Testing A Highway Information Systems

    NASA Technical Reports Server (NTRS)

    Mast, Truman; Mast, Truman

    1974-01-01

    The highway transport system as contrasted with other modes of transportation is quite unique in that the users of the system are responsible for the guidance and control functions of the vehicle. Research has shown that improved forms of motorist information, such as highway signs and markings, can enhance the predictability and reliability of the driving task. Test and evaluation of promising new concepts in motorist information must preceed widespread endorsement and implementation on our highway system. This paper reviews the merits and limitations of presently available human factor research techniques--laboratory, instrumented vehicle and traffic performance studies on operational facilities--for evaluating the efficacy of motorist information concepts. Specific examples are given to demonstrate the utility and the interrelationships of the alternative research techniques and there is a discussion of the most pressing immediate and future needs for improved highway signing and road marking research methodology.

  4. Alternative Techniques for Testing A Highway Information Systems

    NASA Technical Reports Server (NTRS)

    Mast, Truman; Mast, Truman

    1974-01-01

    The highway transport system as contrasted with other modes of transportation is quite unique in that the users of the system are responsible for the guidance and control functions of the vehicle. Research has shown that improved forms of motorist information, such as highway signs and markings, can enhance the predictability and reliability of the driving task. Test and evaluation of promising new concepts in motorist information must preceed widespread endorsement and implementation on our highway system. This paper reviews the merits and limitations of presently available human factor research techniques--laboratory, instrumented vehicle and traffic performance studies on operational facilities--for evaluating the efficacy of motorist information concepts. Specific examples are given to demonstrate the utility and the interrelationships of the alternative research techniques and there is a discussion of the most pressing immediate and future needs for improved highway signing and road marking research methodology.

  5. Isochrones as Indicators of the Influence of Traffic in Public Health: A Visual Simulation Application in Ávila, Spain

    PubMed Central

    Otamendi, F. Javier; García-Heredia, David

    2015-01-01

    It is well known that excessive rescue times after traffic accidents negatively affect the health of those injured. There is a need to quantitatively measure the impact of unexpected events like ambulance availability, weather, floating population and congestion in those rescue times. A family of indicators based on isochrones is disguised and proposed to understand the risk of the whole population as the probability of not being assisted on time. Indicators of health risk for local towns are also defined. The indicators are calculated using a simulation model and visualized in web format. The framework of analysis is validated using Ávila (Spain) and the problem of the optimal deployment of ambulances as a test-bench. PMID:26473894

  6. Isochrones as Indicators of the Influence of Traffic in Public Health: A Visual Simulation Application in Ávila, Spain.

    PubMed

    Otamendi, F Javier; García-Heredia, David

    2015-10-09

    It is well known that excessive rescue times after traffic accidents negatively affect the health of those injured. There is a need to quantitatively measure the impact of unexpected events like ambulance availability, weather, floating population and congestion in those rescue times. A family of indicators based on isochrones is disguised and proposed to understand the risk of the whole population as the probability of not being assisted on time. Indicators of health risk for local towns are also defined. The indicators are calculated using a simulation model and visualized in web format. The framework of analysis is validated using Ávila (Spain) and the problem of the optimal deployment of ambulances as a test-bench.

  7. Life cycle optimisation for highway best management practices.

    PubMed

    Lee, J G; Heaney, J P; Rapp, D N; Pack, C A

    2006-01-01

    Highway runoff can cause a number of water quantity and quality problems. Stormwater management systems for highways have been developed based on a fast drainage for large storm situations. Non-point source pollution from highway runoff is a growing water quality concern. Stormwater quality control needs to be integrated into highway drainage design and operation to reduce the stormwater impacts on the receiving water. A continuous simulation/optimisation model for analysing integrated highway best management practices (BMPs) is presented. This model can evaluate the life cycle performance of infiltration and/or storage oriented highway BMPs. It can be directly integrated with spreadsheet optimisation tools to find the least cost options for implementing BMPs throughout a specified life cycle.

  8. The car following model considering traffic jerk

    NASA Astrophysics Data System (ADS)

    Ge, Hong-Xia; Zheng, Peng-jun; Wang, Wei; Cheng, Rong-Jun

    2015-09-01

    Based on optimal velocity car following model, a new model considering traffic jerk is proposed to describe the jamming transition in traffic flow on a highway. Traffic jerk means the sudden braking and acceleration of vehicles, which has a significant impact on traffic movement. The nature of the model is researched by using linear and nonlinear analysis method. A thermodynamic theory is formulated to describe the phase transition and critical phenomenon in traffic flow. The time-dependent Ginzburg-Landau (TDGL) equation and the modified Korteweg-de Vries (mKdV) equation are derived to describe the traffic flow near the critical point and the traffic jam. In addition, the connection between the TDGL and the mKdV equations are also given.

  9. A before-after control-impact assessment to understand the potential impacts of highway construction noise and activity on an endangered songbird.

    PubMed

    Long, Ashley M; Colón, Melanie R; Bosman, Jessica L; Robinson, Dianne H; Pruett, Hannah L; McFarland, Tiffany M; Mathewson, Heather A; Szewczak, Joseph M; Newnam, J Cal; Morrison, Michael L

    2017-01-01

    Anthropogenic noise associated with highway construction and operation can have individual- and population-level consequences for wildlife (e.g., reduced densities, decreased reproductive success, behavioral changes). We used a before-after control-impact study design to examine the potential impacts of highway construction and traffic noise on endangered golden-cheeked warblers (Setophaga chrysoparia; hereafter warbler) in urban Texas. We mapped and monitored warbler territories before (2009-2011), during (2012-2013), and after (2014) highway construction at three study sites: a treatment site exposed to highway construction and traffic noise, a control site exposed only to traffic noise, and a second control site exposed to neither highway construction or traffic noise. We measured noise levels at varying distances from the highway at sites exposed to construction and traffic noise. We examined how highway construction and traffic noise influenced warbler territory density, territory placement, productivity, and song characteristics. In addition, we conducted a playback experiment within study sites to evaluate acute behavioral responses to highway construction noises. Noise decreased with increasing distance from the highways. However, noise did not differ between the construction and traffic noise sites or across time. Warbler territory density increased over time at all study sites, and we found no differences in warbler territory placement, productivity, behavior, or song characteristics that we can attribute to highway construction or traffic noise. As such, we found no evidence to suggest that highway construction or traffic noise had a negative effect on warblers during our study. Because human population growth will require recurring improvements to transportation infrastructure, understanding wildlife responses to anthropogenic noise associated with the construction and operation of roads is essential for effective management and recovery of prioritized

  10. 25 CFR 170.144 - What are eligible highway safety projects?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... reduce traffic accidents and deaths, injuries, and property damage; (i) Collecting data on traffic-related deaths, injuries and accidents; (j) Impaired driver initiatives; (k) Child safety seat programs... management system; (g) Education and outreach highway safety programs, such as use of child safety...

  11. Application of the mechanical perturbation produced by traffic as a new approach of nonlinear acoustic technique for detecting microcracks in the concrete: A laboratory simulation

    NASA Astrophysics Data System (ADS)

    Moradi-Marani, F.; Kodjo, S. A.; Rivard, P.; Lamarche, C. P.

    2012-05-01

    Very few nonlinear acoustics techniques are currently applied on real structures because their large scale implementation is difficult. Recently, a new method based on nonlinear acoustics has been proposed at the Université de Sherbrooke for the characterization of the damage associated with Alkali-Silica Reaction (ASR). This method consists in quantifying the influence of an external mechanical disturbance on the propagation of a continual ultrasonic wave that probes the material. In this method, the mechanical perturbation produced by an impact causes sudden opening of microcracks and, consequently, the velocity of the probe ultrasonic wave is suddenly reduced. Then it slowly and gradually returns to its initial level as the microcracks are closing. The objective of this study is: using waves generated by traffics in infrastructures in order to monitor microdefects due to damage mechanisms like ASR. This type of mechanical disturbance (by traffic loadings) is used as a source of low frequency-high amplitude waves for opening/closing of the microdefects in the bulk of concrete. This paper presents a laboratory set-up made of three large deep concrete slabs used to study the nonlinear behavior of concrete using the disturbance caused by simulated traffic. The traffic is simulated with a controlled high accuracy jack to produce a wave similar to that produced by traffic. Results obtained from this study will be used in the future to design an in-situ protocol for assessing ASR-affected structures.

  12. The realistic consideration of human factors in model based simulation tools for the air traffic control domain.

    PubMed

    Duca, Gabriella; Attaianese, Erminia

    2012-01-01

    Advanced Air Traffic Management (ATM) concepts related to automation, airspace organization and operational procedures are driven by the overall goal to increase ATM system performance. Independently on the nature and/or impact of envisaged changes (e.g. from a short term procedure adjustment to a very long term operational concept or aid tools completion), the preliminary assessment of possible gains in airspace/airport capacity, safety and cost-effectiveness is done by running Model Based Simulations (MBSs, also known as Fast Time Simulations - FTS). Being a not human-in-the-loop technique, the reliability of a MBS results depend on the accuracy and significance of modeled human factors. Despite that, it can be observed in the practice that modeling tools commonly assume a generalized standardization of human behaviors and tasks and consider a very few range of work environment factors that, in the reality, affect the actual human-system performance. The present paper is aimed at opening a discussion about the possibility to keep task description and related weight at a high/general level, suitable for an efficient use of MBSs and, at the same time, increasing simulations reliability adopting some adjustment coming from the elaboration of further variables related to the human aspects of controllers workload.

  13. Managing Bandwidth and Traffic via Bundling and Filtration in Large-Scale Distributed Simulations

    DTIC Science & Technology

    2006-06-13

    the 2003 Winter Simulation Conference, 847–854. New Orleans, Louisiana, United States, 2003. 10. Gottlieb, Eric J., Michael J. McDonald, Fred J. Oppel ... Craig Goodyear and Jason Atkinson, July 14-15 2005. 24. Straßburger, Steffen, Thomas Schulze, and James O. Henrikson. “Internet- Based Simulation Using

  14. Self-Learning Intelligent Agents for Dynamic Traffic Routing on Transportation Networks

    NASA Astrophysics Data System (ADS)

    Sadek, Add; Basha, Nagi

    Intelligent Transportation Systems (ITS) are designed to take advantage of recent advances in communications, electronics, and Information Technology in improving the efficiency and safety of transportation systems. Among the several ITS applications is the notion of Dynamic Traffic Routing (DTR), which involves generating "optimal" routing recommendations to drivers with the aim of maximizing network utilizing. In this paper, we demonstrate the feasibility of using a self-learning intelligent agent to solve the DTR problem to achieve traffic user equilibrium in a transportation network. The core idea is to deploy an agent to a simulation model of a highway. The agent then learns by itself by interacting with the simulation model. Once the agent reaches a satisfactory level of performance, it can then be deployed to the real-world, where it would continue to learn how to refine its control policies over time. To test this concept in this paper, the Cell Transmission Model (CTM) developed by Carlos Daganzo of the University of California at Berkeley is used to simulate a simple highway with two main alternative routes. With the model developed, a Reinforcement Learning Agent (RLA) is developed to learn how to best dynamically route traffic, so as to maximize the utilization of existing capacity. Preliminary results obtained from our experiments are promising. RL, being an adaptive online learning technique, appears to have a great potential for controlling a stochastic dynamic systems such as a transportation system. Furthermore, the approach is highly scalable and applicable to a variety of networks and roadways.

  15. The green highway forum

    SciTech Connect

    2006-07-01

    In late 2004, as part of American Coal Ash Association's (ACAA) strategic planning process, a plan was approved by its Board of Directors implementing a 'green highways' concept which emphasized use of coal combustion products (CCPs) in highways in a variety of ways including being used alone, in combination with other forms of CCPs, and combined with non ash materials. The incentives behind the developed concept were the derived advantages from beneficial technical economic and environmental impacts. Although the primary use of fly ash is concrete, other forms of CCPs could be considered for more non-traditional highway applications. For example, these might include soils stabilization, binders for in-place pavement recycling, use in flowable fills, aggregates, source materials for structural fills and embankments, components in manufactured soils, and for granular base courses beneath pavements. At this same time, unknown to ACCA, EPA Region 3 in Philadelphia was working with the Wetlands and Watershed Work Group, a non-profit organization involved in wetlands policy and management along with the Federal Highway Administration (FHWA) on their own Green Highways initiative. These groups were planning a conference, the 'Green Highway Forum'. This was held in College Park, Maryland at the University of Maryland, Nov 8-10 2005. At the conference a draft 'roadmap' was presented as a guide to executive level participants bringing the diverse viewpoints of many agencies and interest groups together. Ten guiding principals were considered. The 'Green Highways' is a new effort to recognize the 'greenness' of many projects already completed and those to be initiated. 2 photos.

  16. Probabilistic description of traffic flow

    NASA Astrophysics Data System (ADS)

    Mahnke, R.; Kaupužs, J.; Lubashevsky, I.

    2005-03-01

    A stochastic description of traffic flow, called probabilistic traffic flow theory, is developed. The general master equation is applied to relatively simple models to describe the formation and dissolution of traffic congestions. Our approach is mainly based on spatially homogeneous systems like periodically closed circular rings without on- and off-ramps. We consider a stochastic one-step process of growth or shrinkage of a car cluster (jam). As generalization we discuss the coexistence of several car clusters of different sizes. The basic problem is to find a physically motivated ansatz for the transition rates of the attachment and detachment of individual cars to a car cluster consistent with the empirical observations in real traffic. The emphasis is put on the analogy with first-order phase transitions and nucleation phenomena in physical systems like supersaturated vapour. The results are summarized in the flux-density relation, the so-called fundamental diagram of traffic flow, and compared with empirical data. Different regimes of traffic flow are discussed: free flow, congested mode as stop-and-go regime, and heavy viscous traffic. The traffic breakdown is studied based on the master equation as well as the Fokker-Planck approximation to calculate mean first passage times or escape rates. Generalizations are developed to allow for on-ramp effects. The calculated flux-density relation and characteristic breakdown times coincide with empirical data measured on highways. Finally, a brief summary of the stochastic cellular automata approach is given.

  17. Cellular automata model simulating traffic car accidents in the on-ramp system

    NASA Astrophysics Data System (ADS)

    Echab, H.; Lakouari, N.; Ez-Zahraouy, H.; Benyoussef, A.

    2015-01-01

    In this paper, using Nagel-Schreckenberg model we study the on-ramp system under the expanded open boundary condition. The phase diagram of the two-lane on-ramp system is computed. It is found that the expanded left boundary insertion strategy enhances the flow in the on-ramp lane. Furthermore, we have studied the probability of the occurrence of car accidents. We distinguish two types of car accidents: the accident at the on-ramp site (Prc) and the rear-end accident in the main road (Pac). It is shown that car accidents at the on-ramp site are more likely to occur when traffic is free on road A. However, the rear-end accidents begin to occur above a critical injecting rate αc1. The influence of the on-ramp length (LB) and position (xC0) on the car accidents probabilities is studied. We found that large LB or xC0 causes an important decrease of the probability Prc. However, only large xC0 provokes an increase of the probability Pac. The effect of the stochastic randomization is also computed.

  18. Analysing the influence of different street vegetation on traffic-induced particle dispersion using microscale simulations.

    PubMed

    Wania, Annett; Bruse, Michael; Blond, Nadège; Weber, Christiane

    2012-02-01

    Urban vegetation can be viewed as compensation to the environmental drawbacks of urbanisation. However, its ecosystem function is not well-known and, for urban planning, vegetation is mainly considered as an element of urban design. This article argues that planning practice needs to re-examine the impact of vegetation cover in the urban fabric given our evaluation of vegetation's effects on air quality, including the dispersion of traffic-induced particles at street level. Using the three-dimensional microclimate model ENVI-met®, we evaluate these effects regarding the height-to-width ratio of streets flanked by buildings and the vertical and horizontal density of street vegetation. Our results reveal vegetation's effect on particle dispersion through its influence on street ventilation. In general, vegetation was found to reduce wind speed, causing inhibition of canyon ventilation and, consequently, an increase in particle concentrations. Vegetation was also found to reduce wind speed at crown-height and to disrupt the flow field in close vicinity to the canopy. With increasing height-to-width ratio of street canyons, wind speed reduction increases and the disturbance of the flow impacts across a canyon's entire width. We also found that the effect is more pronounced in configurations with poor ventilation, such as the low wind speed, perpendicular inflow direction, and in deep canyons cases.

  19. Visualizing Network Traffic to Understand the Performance of Massively Parallel Simulations.

    PubMed

    Landge, A G; Levine, J A; Bhatele, A; Isaacs, K E; Gamblin, T; Schulz, M; Langer, S H; Bremer, Peer-Timo; Pascucci, V

    2012-12-01

    The performance of massively parallel applications is often heavily impacted by the cost of communication among compute nodes. However, determining how to best use the network is a formidable task, made challenging by the ever increasing size and complexity of modern supercomputers. This paper applies visualization techniques to aid parallel application developers in understanding the network activity by enabling a detailed exploration of the flow of packets through the hardware interconnect. In order to visualize this large and complex data, we employ two linked views of the hardware network. The first is a 2D view, that represents the network structure as one of several simplified planar projections. This view is designed to allow a user to easily identify trends and patterns in the network traffic. The second is a 3D view that augments the 2D view by preserving the physical network topology and providing a context that is familiar to the application developers. Using the massively parallel multi-physics code pF3D as a case study, we demonstrate that our tool provides valuable insight that we use to explain and optimize pF3D's performance on an IBM Blue Gene/P system.

  20. Simulation study of satisfaction rate in the mixed traffic flow with open boundary conditions

    NASA Astrophysics Data System (ADS)

    Bentaleb, Khalid; Lakouari, Noureddine; Ez-Zahraouy, Hamid; Benyoussef, Abdelilah

    2016-08-01

    In this paper, we propose a single-lane cellular automata (CA) traffic model which takes into account the disorder in the length and the maximal speed of the vehicles (i.e. slow and fast) to study the satisfaction rate of the fast vehicles (i.e. the number of vehicles that run with their desired speed) with open boundary conditions in the case of a chain of one entry; where α is the injecting rate of vehicles independent of their nature and β is the extracting rate. The slow vehicles are injected with the conditional probability αs, where 0≤αs=χα≤α and χ is the concentration of the slow vehicles. It is found that for the low value of the injecting rate α and for the high extraction rate β, the satisfaction rate takes higher values. It also depends on the concentration of the slow vehicles injected on the road. Furthermore, we have shown that, in the case when α=β, the satisfaction rate undergoes a transition from the maximal value to the minimal one and it takes a value near to zero in the case of α>β. We have also found that the satisfaction rate depends strongly on the probability of overtaking, also the phase diagrams (α,β) are established for the different values of the slow vehicles concentrations χ.

  1. Air traffic simulation in chemistry-climate model EMAC 2.41: AirTraf 1.0

    NASA Astrophysics Data System (ADS)

    Yamashita, Hiroshi; Grewe, Volker; Jöckel, Patrick; Linke, Florian; Schaefer, Martin; Sasaki, Daisuke

    2016-09-01

    Mobility is becoming more and more important to society and hence air transportation is expected to grow further over the next decades. Reducing anthropogenic climate impact from aviation emissions and building a climate-friendly air transportation system are required for a sustainable development of commercial aviation. A climate optimized routing, which avoids climate-sensitive regions by re-routing horizontally and vertically, is an important measure for climate impact reduction. The idea includes a number of different routing strategies (routing options) and shows a great potential for the reduction. To evaluate this, the impact of not only CO2 but also non-CO2 emissions must be considered. CO2 is a long-lived gas, while non-CO2 emissions are short-lived and are inhomogeneously distributed. This study introduces AirTraf (version 1.0) that performs global air traffic simulations, including effects of local weather conditions on the emissions. AirTraf was developed as a new submodel of the ECHAM5/MESSy Atmospheric Chemistry (EMAC) model. Air traffic information comprises Eurocontrol's Base of Aircraft Data (BADA Revision 3.9) and International Civil Aviation Organization (ICAO) engine performance data. Fuel use and emissions are calculated by the total energy model based on the BADA methodology and Deutsches Zentrum für Luft- und Raumfahrt (DLR) fuel flow method. The flight trajectory optimization is performed by a genetic algorithm (GA) with respect to a selected routing option. In the model development phase, benchmark tests were performed for the great circle and flight time routing options. The first test showed that the great circle calculations were accurate to -0.004 %, compared to those calculated by the Movable Type script. The second test showed that the optimal solution found by the algorithm sufficiently converged to the theoretical true-optimal solution. The difference in flight time between the two solutions is less than 0.01 %. The dependence of

  2. Accident prediction model for public highway-rail grade crossings.

    PubMed

    Lu, Pan; Tolliver, Denver

    2016-05-01

    Considerable research has focused on roadway accident frequency analysis, but relatively little research has examined safety evaluation at highway-rail grade crossings. Highway-rail grade crossings are critical spatial locations of utmost importance for transportation safety because traffic crashes at highway-rail grade crossings are often catastrophic with serious consequences. The Poisson regression model has been employed to analyze vehicle accident frequency as a good starting point for many years. The most commonly applied variations of Poisson including negative binomial, and zero-inflated Poisson. These models are used to deal with common crash data issues such as over-dispersion (sample variance is larger than the sample mean) and preponderance of zeros (low sample mean and small sample size). On rare occasions traffic crash data have been shown to be under-dispersed (sample variance is smaller than the sample mean) and traditional distributions such as Poisson or negative binomial cannot handle under-dispersion well. The objective of this study is to investigate and compare various alternate highway-rail grade crossing accident frequency models that can handle the under-dispersion issue. The contributions of the paper are two-fold: (1) application of probability models to deal with under-dispersion issues and (2) obtain insights regarding to vehicle crashes at public highway-rail grade crossings.

  3. Assessment of highway pavements using GPR

    NASA Astrophysics Data System (ADS)

    Plati, Christina; Loizos, Andreas

    2015-04-01

    Highway infrastructure is a prerequisite for a functioning economy and social life. Highways, often prone to congestion and disruption, are one of the aspects of a modern transport network that require maximum efficiency if an integrated transport network, and sustainable mobility, is to be achieved. Assessing the condition of highway structures, to plan subsequent maintenance, is essential to allow the long-term functioning of a road network. Optimizing the methods used for such assessment will lead to better information being obtained about the road and underlying ground conditions. The condition of highway structures will be affected by a number of factors, including the properties of the highway pavement, the supporting sub-base and the subgrade (natural ground), and the ability to obtain good information about the entire road structure, from pavement to subgrade, allows appropriate maintenance programs to be planned. The maintenance of highway pavements causes considerable cost and in many cases obstruction to traffic flow. In this situation, methods that provide information on the present condition of pavement structure non-destructively and economically are of great interest. It has been shown that Ground-Penetrating-Radar (GPR), which is a Non Destructive Technique (NDT), can deliver information that is useful for the planning of pavement maintenance activities. More specifically GPR is used by pavement engineers in order to determine physical properties and characteristics of the pavement structure, information that is valuable for the assessment of pavement condition. This work gives an overview on the practical application of GPR using examples from highway asphalt pavements monitoring. The presented individual applications of GPR pavement diagnostics concern structure homogeneity, thickness of pavement layers, dielectric properties of asphalt materials etc. It is worthwhile mentioning that a number of applications are standard procedures, either

  4. Posted and free-flow speeds for rural multilane highways in Georgia

    SciTech Connect

    Dixon, K.K.; Wu, C.H.; Sarasua, W.; Daniel, J.

    1999-12-01

    The National Highway System Designation Act of 1995 repealed the national maximum speed limit. As a result, approximately 70% of the US has increased posted speed limits to 104.7 km/h (65 mi/h) for select multilane highways. This study evaluates the application of the Highway Capacity Manual multilane highway rules-of-thumb for free-flow speed to both an 88.6 and a 104.7 km/h (55 and 65 mi/h) posted speed limit condition. The paper further quantifies the observed relationship between the posted speed limit and observed free-flow speed on rural multilane highways in Georgia. Specific issues evaluated include heavy vehicle influence, traffic volumes, access point density, and vertical grade. The research indicates that the current Highway Capacity Manual rule-of-thumb free-flow estimation technique based on posted speed limit does not adequately estimate free-flow speed for the higher speed limit condition.

  5. Kinetic Monte Carlo simulations of one-dimensional and two-dimensional traffic flows: comparison of two look-ahead rules.

    PubMed

    Sun, Yi; Timofeyev, Ilya

    2014-05-01

    We employ an efficient list-based kinetic Monte Carlo (KMC) method to study traffic flow models on one-dimensional (1D) and two-dimensional (2D) lattices based on the exclusion principle and Arrhenius microscopic dynamics. This model implements stochastic rules for cars' movements based on the configuration of the traffic ahead of each car. In particular, we compare two different look-ahead rules: one is based on the distance from the car under consideration to the car in front of it, and the other one is based on the density of cars ahead. The 1D numerical results of these two rules suggest different coarse-grained macroscopic limits in the form of integro-differential Burgers equations. The 2D results of both rules exhibit a sharp phase transition from freely flowing to fully jammed, as a function of the initial density of cars. However, the look-ahead rule based on the density of the traffic produces more realistic results. The KMC simulations reported in this paper are compared with those from other well-known traffic flow models and the corresponding empirical results from real traffic.

  6. Kinetic Monte Carlo simulations of one-dimensional and two-dimensional traffic flows: Comparison of two look-ahead rules

    NASA Astrophysics Data System (ADS)

    Sun, Yi; Timofeyev, Ilya

    2014-05-01

    We employ an efficient list-based kinetic Monte Carlo (KMC) method to study traffic flow models on one-dimensional (1D) and two-dimensional (2D) lattices based on the exclusion principle and Arrhenius microscopic dynamics. This model implements stochastic rules for cars' movements based on the configuration of the traffic ahead of each car. In particular, we compare two different look-ahead rules: one is based on the distance from the car under consideration to the car in front of it, and the other one is based on the density of cars ahead. The 1D numerical results of these two rules suggest different coarse-grained macroscopic limits in the form of integro-differential Burgers equations. The 2D results of both rules exhibit a sharp phase transition from freely flowing to fully jammed, as a function of the initial density of cars. However, the look-ahead rule based on the density of the traffic produces more realistic results. The KMC simulations reported in this paper are compared with those from other well-known traffic flow models and the corresponding empirical results from real traffic.

  7. Arizona Traffic Safety Education, K-8. Grade 4.

    ERIC Educational Resources Information Center

    Mesa Public Schools, AZ.

    One in a series designed to assist Arizona elementary and junior high school teachers in developing children's traffic skills, this curriculum guide for grade 4 deals with the how and why of traffic safety. Based on the introduction to highway safety rules and laws that students have mastered in grades K through 3, the program for grades 4 through…

  8. Arizona Traffic Safety Education, K-8. Grade 5.

    ERIC Educational Resources Information Center

    Mesa Public Schools, AZ.

    One in a series designed to assist Arizona elementary and junior high school teachers in developing children's traffic skills, this curriculum guide for grade 5 deals with the how and why of traffic safety. Based on the introduction to highway safety rules and laws that students have mastered in grades K through 3, the program for grades 4 through…

  9. Arizona Traffic Safety Education, K-8. Grade 6.

    ERIC Educational Resources Information Center

    Mesa Public Schools, AZ.

    One in a series designed to assist Arizona elementary and junior high school teachers in developing children's traffic skills, this curriculum guide for grade 6 deals with the how and why of traffic safety. Based on the introduction to highway safety rules and laws that students have learned in grades K through 3, the program for grades 4 through…

  10. Police Traffic Services Supervisor Instructor Training Institute. Final Report.

    ERIC Educational Resources Information Center

    Cleven, Arlene M.

    The purpose of the study was to expose key individuals to the National Highway Traffic Safety Administration (NHTSA) developed curriculum materials for police traffic services supervisors and to teach them how to teach. The objective was accomplished through the conduct of five 30-hour instructor training institutes conducted in various areas of…

  11. 75 FR 19670 - Marine Highway Projects

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-15

    ... No: 2010-8619] DEPARTMENT OF TRANSPORTATION Maritime Administration Marine Highway Projects ACTION: Solicitation of applications for Marine highway projects. SUMMARY: The Department of Transportation is soliciting applications for Marine Highway Projects as specified in the America's Marine Highway Program...

  12. 23 CFR Appendix B to Subpart B of... - Required Contract Provisions, Appalachian Development Highway System and Local Access Roads...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS..., sex, or national origin. The contractor will take affirmative action to ensure that applicants are..., sex, or national origin. Such action shall include, but not be limited to the following:...

  13. Depuration of highway runoff water into grass-covered embankments.

    PubMed

    Boivin, P; Saadé, M; Pfeiffer, H R; Hammecker, C; Degoumois, Y

    2008-06-01

    The management of polluted road runoff water is an important issue in environmental protection. A strategy could be to perform local depuration by infiltration into the soils of the embankment, but knowledge for designing such systems is lacking. This study aims at discussing the relevant soil properties, by estimating the long-term depuration of road runoff water infiltrating into the sandy soil embankment of the A9 highway in Wallis, Switzerland. This was done by estimating the heavy metals (HM) mass balance of two sites 23 and 12 years old, respectively. The accumulated HM were estimated by soil and GB analyses. The HM input was estimated by average water quality and traffic. The results were discussed using two-dimensional simulation of infiltration and a 14 months in situ monitoring of the runoff from the pavement to the embankment and at the bottom of the embankment. The soil properties were appropriate for both small particle adsorption and filtration. A good match between input and stored pollutant charges was found, and the HM profiles accorded well with infiltration simulation and monitoring results, which showed that 80-100% of the runoff water infiltrated into the embankment. Replacement of the cracked concrete gutters by an infiltration channel made of similar soil is recommended. These results oppose the Swiss guidelines for road-polluted water infiltration, as much more clayey soils are recommended. These later soils are difficult to find in Switzerland, and may allow for preferential flow through macro pores, in contrast to the studied site.

  14. The Carrot Highway [Videotape].

    ERIC Educational Resources Information Center

    Wyss, Ron

    "The Carrot Highway" is a 40-minute award-winning videotape that takes viewers on a whirlwind tour around the world to tell the story of the carrot. This videotape reveals the carrot in all its glory by cleverly integrating live-action, music, animation, videotape footage, and games. Viewers travel with a troupe of animated carrot characters to…

  15. The Information Highway.

    ERIC Educational Resources Information Center

    Gore, Al

    1994-01-01

    The new information marketplace is based on a network of wide, two-way highways comprised of private owners and developers, makers of information appliances (televisions, telephones, computers, and combinations of all three), information providers (local broadcasters, digital libraries, information service providers, and entrepreneurs), and…

  16. The Information Highway.

    ERIC Educational Resources Information Center

    Gore, Al

    1994-01-01

    The new information marketplace is based on a network of wide, two-way highways comprised of private owners and developers, makers of information appliances (televisions, telephones, computers, and combinations of all three), information providers (local broadcasters, digital libraries, information service providers, and entrepreneurs), and…

  17. The Carrot Highway [Videotape].

    ERIC Educational Resources Information Center

    Wyss, Ron

    "The Carrot Highway" is a 40-minute award-winning videotape that takes viewers on a whirlwind tour around the world to tell the story of the carrot. This videotape reveals the carrot in all its glory by cleverly integrating live-action, music, animation, videotape footage, and games. Viewers travel with a troupe of animated carrot characters to…

  18. The development of an ecological approach to manage the pollution risk from highway runoff.

    PubMed

    Crabtree, B; Dempsey, P; Johnson, I; Whitehead, M

    2009-01-01

    In the UK, the Highways Agency is responsible for operating, maintaining and improving the strategic road network in England. One focus of the Highways Agency's ongoing research into the nature and impact of highway runoff is aimed at ensuring that the Highways Agency will meet the requirements of the EU Water Framework Directive. A research programme, undertaken in partnership with the Environment Agency, is in progress to develop a better understanding of pollutants in highway runoff and their ecological impact. The paper presents the outcome of a study to: (1) monitor pollutants in highway runoff under different climate and traffic conditions; (2) develop standards to assess potential ecological risks from soluble pollutants in highway runoff; and (3) develop a model to predict pollutant concentrations in highway runoff. The model has been embedded in a design tool incorporating risk assessment procedures and receiving water standards for soluble and insoluble pollutants--the latter has been developed elsewhere in another project within the research programme. The design tool will be used to support improved guidance on where, and to what level, treatment of runoff is required for highway designers to manage the risk of ecological impact from highway runoff.

  19. Simulation of the enhanced traffic alert and collision avoidance system (TCAS 2)

    NASA Technical Reports Server (NTRS)

    Rojas, R. G.; Burnside, W. D.; Law, P.; Grandchamp, B.

    1985-01-01

    The OSU aircraft code is used to analyze and simulate the TCAS 2 circular array which is mounted on the fuselage of a Boeing 737 aircraft. It is shown that the sum and difference patterns radiated by the circular array are distorted by the various structures of the aircraft, i.e., wings, tail, etc. Furthermore, monopulse curves are calculated and plotted for several beam positions and THETA angles. As expected, the worst cases of distortion occur when the beams are pointed toward the tail of the aircraft.

  20. Reducing prospective memory error and costs in simulated air traffic control: External aids, extending practice, and removing perceived memory requirements.

    PubMed

    Loft, Shayne; Chapman, Melissa; Smith, Rebekah E

    2016-09-01

    In air traffic control (ATC), forgetting to perform deferred actions-prospective memory (PM) errors-can have severe consequences. PM demands can also interfere with ongoing tasks (costs). We examined the extent to which PM errors and costs were reduced in simulated ATC by providing extended practice, or by providing external aids combined with extended practice, or by providing external aids combined with instructions that removed perceived memory requirements. Participants accepted/handed-off aircraft and detected conflicts. For the PM task, participants were required to substitute alternative actions for routine actions when accepting aircraft. In Experiment 1, when no aids were provided, PM errors and costs were not reduced by practice. When aids were provided, costs observed early in practice were eliminated with practice, but residual PM errors remained. Experiment 2 provided more limited practice with aids, but instructions that did not frame the PM task as a "memory" task led to high PM accuracy without costs. Attention-allocation policies that participants set based on expected PM demands were modified as individuals were increasingly exposed to reliable aids, or were given instructions that removed perceived memory requirements. These findings have implications for the design of aids for individuals who monitor multi-item dynamic displays. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  1. Piloted simulation of an air-ground profile negotiation process in a time-based Air Traffic Control environment

    NASA Technical Reports Server (NTRS)

    Williams, David H.; Green, Steven M.

    1993-01-01

    Historically, development of airborne flight management systems (FMS) and ground-based air traffic control (ATC) systems has tended to focus on different objectives with little consideration for operational integration. A joint program, between NASA's Ames Research Center (Ames) and Langley Research Center (Langley), is underway to investigate the issues of, and develop systems for, the integration of ATC and airborne automation systems. A simulation study was conducted to evaluate a profile negotiation process (PNP) between the Center/TRACON Automation System (CTAS) and an aircraft equipped with a four-dimensional flight management system (4D FMS). Prototype procedures were developed to support the functional implementation of this process. The PNP was designed to provide an arrival trajectory solution which satisfies the separation requirements of ATC while remaining as close as possible to the aircraft's preferred trajectory. Results from the experiment indicate the potential for successful incorporation of aircraft-preferred arrival trajectories in the CTAS automation environment. Fuel savings on the order of 2 percent to 8 percent, compared to fuel required for the baseline CTAS arrival speed strategy, were achieved in the test scenarios. The data link procedures and clearances developed for this experiment, while providing the necessary functionality, were found to be operationally unacceptable to the pilots. In particular, additional pilot control and understanding of the proposed aircraft-preferred trajectory, and a simplified clearance procedure were cited as necessary for operational implementation of the concept.

  2. Effect of working memory load on electrophysiological markers of visuospatial orienting in a spatial cueing task simulating a traffic situation.

    PubMed

    Vossen, Alexandra Y; Ross, Veerle; Jongen, Ellen M M; Ruiter, Robert A C; Smulders, Fren T Y

    2016-02-01

    Visuospatial attentional orienting has typically been studied in abstract tasks with low ecological validity. However, real-life tasks such as driving require allocation of working memory (WM) resources to several subtasks over and above orienting in a complex sensory environment. The aims of this study were twofold: firstly, to establish whether electrophysiological signatures of attentional orienting commonly observed under simplified task conditions generalize to a more naturalistic task situation with realistic-looking stimuli, and, secondly, to assess how these signatures are affected by increased WM load under such conditions. Sixteen healthy participants performed a dual task consisting of a spatial cueing paradigm and a concurrent verbal memory task that simulated aspects of an actual traffic situation. Behaviorally, we observed a load-induced detriment of sensitivity to targets. In the EEG, we replicated orienting-related alpha lateralization, the lateralized ERPs ADAN, EDAN, and LDAP, and the P1-N1 attention effect. When WM load was high (i.e., WM resources were reduced), lateralization of oscillatory activity in the lower alpha band was delayed. In the ERPs, we found that ADAN was also delayed, while EDAN was absent. Later ERP correlates were unaffected by load. Our results show that the findings in highly controlled artificial tasks can be generalized to spatial orienting in ecologically more valid tasks, and further suggest that the initiation of spatial orienting is delayed when WM demands of an unrelated secondary task are high.

  3. Analysis and Simulation of Traffic Control for Resource Management in DVB-Based Broadband Satellite Access Networks

    NASA Astrophysics Data System (ADS)

    Impemba, Ernesto; Inzerilli, Tiziano

    2003-07-01

    Integration of satellite access networks with the Internet is seen as a strategic goal to achieve in order to provide ubiquitous broadband access to Internet services in Next Generation Networks (NGNs). One of the main interworking aspects which has been most studied is an efficient management of satellite resources, i.e. bandwidth and buffer space, in order to satisfy most demanding application requirements as to delay control and bandwidth assurance. In this context, resource management in DVB-S/DVB-RCS satellite technologies, emerging technologies for broadband satellite access and transport of IP applications, is a research issue largely investigated as a means to provide efficient bi-directional communications across satellites. This is in particular one of the principal goals of the SATIP6 project, sponsored within the 5th EU Research Programme Framework, i.e. IST. In this paper we present a possible approach to efficiently exploit bandwidth, the most critical resource in a broadband satellite access network, while pursuing satisfaction of delay and bandwidth requirements for applications with guaranteed QoS through a traffic control architecture to be implemented in ground terminals. Performance of this approach is assessed in terms of efficient exploitation of the uplink bandwidth and differentiation and minimization of queuing delays for most demanding applications over a time-varying capacity. Opnet simulations is used as analysis tool.

  4. The effect of different delineator post configurations on driver speed in night-time traffic: a driving simulator study.

    PubMed

    Nygårdhs, Sara; Lundkvist, Sven-Olof; Andersson, Jan; Dahlbäck, Nils

    2014-11-01

    The aim of the study was to investigate how different delineator post configurations affect driver speed in night-time traffic. In addition, the potential speed effect of introducing a secondary task was investigated. The study was carried out in a car simulator on a road stretch including straight road sections as well as curves with different radii. Fourteen drivers participated in the study and the results show that absence of delineator posts leads to reduced speed. However, provided that there are delineator posts continuously present along the road, the overall driver speed is basically the same, regardless of the spacing between the delineator posts. The results also imply that to reduce driver speed in curves with small radius, using more compact spacing of posts in these curves as compared to in curves with a larger radius, could be a potential strategy. Additionally, the speed reducing effect of a secondary task was only prevailing where the task was initiated. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Effect of gravitational force upon traffic flow with gradients

    NASA Astrophysics Data System (ADS)

    Komada, Kazuhito; Masukura, Shuichi; Nagatani, Takashi

    2009-07-01

    We study the effect of gravitational force upon traffic flow on a highway with sag, uphill, and downhill. We extend the optimal velocity model to take into account the gravitational force which acts on vehicles as an external force. We study the traffic states and jamming transitions induced by the slope of highway. We derive the fundamental diagrams (flow-density diagrams) for the traffic flow on the sag, the uphill, and downhill by using the extended optimal velocity model. We clarify where and when traffic jams occur on a highway with gradients. We show the relationship between densities before and after the jam. We derive the dependence of the fundamental diagram on the slope of gradients.

  6. Evaluation of a simulation-based surrogate safety metric.

    PubMed

    Wang, Chen; Stamatiadis, Nikiforos

    2014-10-01

    The development of surrogate safety measures is essential due to the problems of availability and quality of historical crash data. The Aggregate Conflict Propensity Metric (ACPM) is a surrogate metric recently proposed and it is based on conflict studies and traffic simulations. ACPM is expected to be capable of assessing the relative safety levels of traffic facilities and/or treatments in order to help traffic engineers to select appropriate treatments based on traffic safety estimates. This paper presents three experimental tests conducted to evaluate the reliability of ACPM. In each test, ACPM is compared to a traditional conflict indicator in terms of identifying and ranking safety of traffic conditions under various traffic volumes based on traffic simulations. ACPM shows its strength and reliability in all three tests, as it provides results highly consistent with the Highway Safety Manual. The experimental tests indicate that ACPM is a promising surrogate safety measure that can appropriately identify relative safety among traffic treatments and/or facilities and provide traffic engineers with useful information on potential safety impact. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Simulation study of traffic car accidents at a single lane roundabout

    NASA Astrophysics Data System (ADS)

    Echab, H.; Lakouari, N.; Ez-Zahraouy, H.; Benyoussef, A.

    2016-07-01

    In this paper, using the Nagel-Schreckenberg model, we numerically investigate the probability Pac of entering/circulating car accidents to occur at single-lane roundabout under the expanded open boundary. The roundabout consists of N on-ramps (respectively, off-ramps). The boundary is controlled by the injecting rates α1,α2 and the extracting rate β. The simulation results show that, depending on the injecting rates, the car accidents are more likely to happen when the capacity of the rotary is set to its maximum. Moreover, we found that the large values of rotary size L and the probability of preferential Pexit are reliable to improve safety and reduce accidents. However, the usage of indicator, the increase of β and/or N provokes an increase of car accident probability.

  8. Highway increases concentrations of toxic metals in giant panda habitat.

    PubMed

    Zheng, Ying-Juan; Chen, Yi-Ping; Maltby, Lorraine; Jin, Xue-Lin

    2016-11-01

    The Qinling panda subspecies (Ailuropoda melanoleuca qinlingensis) is highly endangered with fewer than 350 individuals inhabiting the Qinling Mountains. Previous studies have indicated that giant pandas are exposed to heavy metals, and a possible source is vehicle emission. The concentrations of Cu, Zn, Mn, Pb, Cr, Ni, Cd, Hg, and As in soil samples collected from sites along a major highway bisecting the panda's habitat were analyzed to investigate whether the highway was an important source of metal contamination. There were 11 sites along a 30-km stretch of the 108th National Highway, and at each site, soil samples were taken at four distances from the highway (0, 50, 100, and 300 m) and at three soil depths (0, 5, 10 cm). Concentrations of all metals except As exceeded background levels, and concentrations of Cu, Zn, Mn, Pb, and Cd decreased significantly with increasing distance from the highway. Geo-accumulation index indicated that topsoil next to the highway was moderately contaminated with Pb and Zn, whereas topsoil up to 300 m away from the highway was extremely contaminated with Cd. The potential ecological risk index demonstrated that this area was in a high degree of ecological hazards, which were also due to serious Cd contamination. And, the hazard quotient indicated that Cd, Pb, and Mn especially Cd could pose the health risk to giant pandas. Multivariate analyses demonstrated that the highway was the main source of Cd, Pb, and Zn and also put some influence on Mn. The study has confirmed that traffic does contaminate roadside soils and poses a potential threat to the health of pandas. This should not be ignored when the conservation and management of pandas is considered.

  9. Performance of vegetative controls for treating highway runoff

    SciTech Connect

    Barrett, M.E.; Walsh, P.M.; Malina, J.F. Jr.; Charbeneau, R.J.

    1998-11-01

    Vegetative storm water controls include grassed swales and vegetated filter strips. The effectiveness of these controls for removing pollutants found in runoff from highways and other urban areas has not been demonstrated to the satisfaction of regulatory agencies; therefore, these technologies have been limited to applications as pretreatment devices for other structural runoff controls. Many highways in Texas and other areas discharge storm water to grassy medians and shoulder areas, which act as both filter strips and grassed swales. The runoff flows overland down the sides of the median as in a filter strip and then parallel to the highway as in a grassed swale. This study investigated the capability of vegetated highway medians for treating storm water runoff in the Austin, Texas area. Two medians on major highways were monitored to document pollutant removal efficiencies. The medians were designed solely for storm water conveyance and differed in slope and vegetation type. In addition, the highways adjacent to the medians had different average daily traffic counts and contributing drainage areas. Removal efficiencies at the two sites were remarkably similar despite these differences and were comparable with those observed in structural controls such as sedimentation/filtration systems (i.e., greater than 85% removal of suspended solids). The majority of pollutant removal occurred on the sides of the median, indicating the effectiveness of vegetated filter strips. Consequently, the effect of the length of the median (measured parallel to the highway) on the amount of removal was minimal. These data indicate that medians with side slopes of less than 12% and a length of at least 8 m are effective in reducing storm water loads from highways.

  10. Pilots' use of a traffic alert and collision-avoidance system (TCAS 2) in simulated air carrier operations. Volume 1: Methodology, summary and conclusions

    NASA Technical Reports Server (NTRS)

    Chappell, Sheryl L.; Billings, Charles E.; Scott, Barry C.; Tuttell, Robert J.; Olsen, M. Christine; Kozon, Thomas E.

    1989-01-01

    Pilots' use of and responses to a traffic alert and collision-avoidance system (TCAS 2) in simulated air carrier line operations are described in Volume 1. TCAS 2 monitors the positions of nearby aircraft by means of transponder interrogation, and it commands a climb or descent when conflicting aircraft are projected to reach an unsafe closest point-of-approach within 20 to 25 seconds. A different level of information about the location of other air traffic was presented to each of three groups of flight crews during their execution of eight simulated air carrier flights. A fourth group of pilots flew the same segments without TCAS 2 equipment. Traffic conflicts were generated at intervals during the flights; many of the conflict aircraft were visible to the flight crews. The TCAS equipment successfully ameliorated the seriousness of all conflicts; three of four non-TCAS crews had hazardous encounters. Response times to TCAS maneuver commands did not differ as a function of the amount of information provided, nor did response accuracy. Differences in flight experience did not appear to contribute to the small performance differences observed. Pilots used the displays of conflicting traffic to maneuver to avoid unseen traffic before maneuver advisories were issued by the TCAS equipment. The results indicate: (1) that pilots utilize TCAS effectively within the response times allocated by the TCAS logic, and (2) that TCAS 2 is an effective collision avoidance device. Volume II contains the appendices referenced in Volume I, providing details of the experiment and the results, and the text of two reports written in support of the program.

  11. Pilots' use of a traffic alert and collision-avoidance system (TCAS 2) in simulated air carrier operations. Volume 2: Appendices

    NASA Technical Reports Server (NTRS)

    Chappell, Sheryl L.; Billings, Charles E.; Scott, Barry C.; Tuttell, Robert J.; Olsen, M. Christine; Kozon, Thomas E.

    1989-01-01

    Pilots' use of and responses to a traffic alert and collision-avoidance system (TCAS 2) in simulated air carrier line operations are discribed in Volume 1. TCAS 2 monitors the positions of nearby aircraft by means of transponder interrogation, and it commands a climb or descent which conflicting aircraft are projected to reach an unsafe closest point-of-approach within 20 to 25 seconds. A different level of information about the location of other air traffic was presented to each of three groups of flight crews during their execution of eight simulated air carrier flights. A fourth group of pilots flew the same segments without TCAS 2 equipment. Traffic conflicts were generated at intervals during the flights; many of the conflict aircraft were visible to the flight crews. The TCAS equipment successfully ameliorated the seriousness of all conflicts; three of four non-TCAS crews had hazardous encounters. Response times to TCAS maneuver commands did not differ as a function of the amount of information provided, nor did response accuracy. Differences in flight experience did not appear to contribute to the small performance differences observed. Pilots used the displays of conflicting traffic to maneuver to avoid unseen traffic before maneuver advisories were issued by the TCAS equipment. The results indicate: (1) that pilots utilize TCAS effectively within the response times allocated by the TCAS logic, and (2) that TCAS 2 is an effective collision avoidance device. Volume 2 contains the appendices referenced in Volume 1, providing details of the experiment and the results, and the text of two reports written in support of the program.

  12. Noise barrier for the Temuco ByPass Highway

    NASA Astrophysics Data System (ADS)

    Gerard, Christian; Campos, Aldo; Belfiore, Sergio

    2002-11-01

    Increases in traffic and the emergent Highway Concession Program created by the Public Works Ministry of the Chilean government, have led to the necessity of providing acoustic protection in inhabited areas in which the level of noise exceeds that allowed by the standard. Around the world, the installation of acoustic barriers has been one of the main measures of the controlling traffic noise. This is the case with the Temuco ByPass Highway, an extension of 21 km, located in a rural area typical of the environment and landscape of the South of Chile. A total of 6000 lineal meters of transparent acoustic barrier (Methacrylate) was installed. This barrier is the first one of its type to be installed in South America, and theoretical calculations and practical results are analyzed in this work. (To be presented in Spanish.)

  13. Potential impacts of highway median barriers on wildlife: state of the practice and gap analysis.

    PubMed

    Clevenger, Anthony P; Kociolek, Angela V

    2013-11-01

    Median barriers separate lanes of traffic moving in opposite directions on multilane highways. Such traffic safety devices can reduce head-on collisions but also have the potential to reduce landscape permeability by impeding wildlife movements across highways. Median barriers may also increase the risk of wildlife-vehicle collisions if an animal becomes trapped or confused amid barriers searching for a place to cross. A 2002 Transportation Research Board report highlighted the need to better understand the potential impacts of highway median barriers on wildlife. This lack of information can cause significant project delays and increase transportation project costs. This study represents the first attempt in North America to bring together information about highway median and roadside barriers and wildlife and provide preliminary guidelines to balance the needs of motorist safety and wildlife movements.

  14. Potential Impacts of Highway Median Barriers on Wildlife: State of the Practice and Gap Analysis

    NASA Astrophysics Data System (ADS)

    Clevenger, Anthony P.; Kociolek, Angela V.

    2013-11-01

    Median barriers separate lanes of traffic moving in opposite directions on multilane highways. Such traffic safety devices can reduce head-on collisions but also have the potential to reduce landscape permeability by impeding wildlife movements across highways. Median barriers may also increase the risk of wildlife-vehicle collisions if an animal becomes trapped or confused amid barriers searching for a place to cross. A 2002 Transportation Research Board report highlighted the need to better understand the potential impacts of highway median barriers on wildlife. This lack of information can cause significant project delays and increase transportation project costs. This study represents the first attempt in North America to bring together information about highway median and roadside barriers and wildlife and provide preliminary guidelines to balance the needs of motorist safety and wildlife movements.

  15. A superstatistical model of vehicular traffic flow

    NASA Astrophysics Data System (ADS)

    Kosun, Caglar; Ozdemir, Serhan

    2016-02-01

    In the analysis of vehicular traffic flow, a myriad of techniques have been implemented. In this study, superstatistics is used in modeling the traffic flow on a highway segment. Traffic variables such as vehicular speeds, volume, and headway were collected for three days. For the superstatistical approach, at least two distinct time scales must exist, so that a superposition of nonequilibrium systems assumption could hold. When the slow dynamics of the vehicle speeds exhibit a Gaussian distribution in between the fluctuations of the system at large, one speaks of a relaxation to a local equilibrium. These Gaussian distributions are found with corresponding standard deviations 1 /√{ β }. This translates into a series of fluctuating beta values, hence the statistics of statistics, superstatistics. The traffic flow model has generated an inverse temperature parameter (beta) distribution as well as the speed distribution. This beta distribution has shown that the fluctuations in beta are distributed with respect to a chi-square distribution. It must be mentioned that two distinct Tsallis q values are specified: one is time-dependent and the other is independent. A ramification of these q values is that the highway segment and the traffic flow generate separate characteristics. This highway segment in question is not only nonadditive in nature, but a nonequilibrium driven system, with frequent relaxations to a Gaussian.

  16. Impact of aviation highway-in-the-sky displays on pilot situation awareness.

    PubMed

    Williams, Kevin W

    2002-01-01

    Thirty-six pilots (31 men, 5 women) were tested in a flight simulator on their ability to intercept a pathway depicted on a highway-in-the-sky (HITS) display. While intercepting and flying the pathway, pilots were required to watch for traffic outside the cockpit. Additionally, pilots were tested on their awareness of speed, altitude, and heading during the flight. Results indicated that the presence of a flight guidance cue significantly improved flight path awareness while intercepting the pathway, but significant practice effects suggest that a guidance cue might be unnecessary if pilots are given proper training. The amount of time spent looking outside the cockpit while using the HITS display was significantly less than when using conventional aircraft instruments. Additionally, awareness of flight information present on the HITS display was poor. Actual or potential applications of this research include guidance for the development of perspective flight display standards and as a basis for flight training requirements.

  17. Alcohol and highway safety in a public health perspective.

    PubMed Central

    Dickman, F B

    1988-01-01

    The Public Health Service and the National Highway Traffic Safety Administration share the responsibility for problems related to injury prevention and control regarding the alcohol-impaired operation of motor vehicles. NHTSA activities have evolved over several decades within a general framework which emphasizes community-based systems. The National Highway Traffic Safety Administration is promoting program activities that stress community-level involvement in problems of alcohol and highway use. The public health approach to the mortality and morbidity resulting from alcohol use and motor vehicle operation entails examining and promoting those activities that address human factors. Techniques for Effective Alcohol Management (TEAM) is a cooperative effort representing sports, entertainment, insurance, vehicle manufacturer, and other organizations and agencies building community coalitions. The Centers for Disease Control is establishing research and collaborating centers to stimulate studies and exchange information on injury-related research. Alcohol countermeasures programs include training for law enforcement and legal officials, technology development efforts, and changes in laws applied to use of alcohol and other drugs. Outreach and networking activities have encouraged the initiation and coordination of community level groups active in promoting highway safety with regard to the use of alcohol. Statistical method changes are being discussed for surveillance of motor vehicle-related injuries for Health Objectives for the Nation for the Year 2000. NHTSA data systems being discussed are thought to be more timely and more sensitive to crash activity than methods now in use.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3141961

  18. Avionic Pictorial Tunnel-/Pathway-/Highway-In-The-Sky Workshops

    NASA Technical Reports Server (NTRS)

    Parrish, Russell V. (Compiler)

    2003-01-01

    In 1994-96, Langley Research Center held a series of interactive workshops investigating highway-in-the-sky concepts, which enable precise flight path control. These workshops brought together government and industry display designers and pilots to discuss and fly various concepts in an iterative manner. The primary emphasis of the first workshops was the utility and usability of pathways and the pros and cons of various features available. The final workshops were focused on the specific applications to the eXternal Visibility System (XVS) of the NASA High-speed Research Program, which was concerned with replacement of the forward windows in a High-speed Civil Transport with electronic displays and high resolution video cameras to enable a "No-Droop" configuration. The primary concerns in the XVS application were the prevention of display clutter and obscuration of hazards, as the camera image was the primary means of traffic separation in clear visibility conditions. These concerns were not so prominent in the first workshops, which assumed a Synthetic Vision System application in which hazard locations are known and obscuration is handled easily. The resulting consensus concept has been used since in simulation and flight test activities of many Government programs. and other concepts have been influenced by the workshop discussions.

  19. Scale-model study of the effectiveness of highway noise barriers.

    PubMed

    Busch, Todd; Hodgson, Murray; Wakefield, Clair

    2003-10-01

    A scale-model facility was developed to test the insertion loss (IL) of highway noise barriers. Three model materials were utilized to simulate packed-earth berms and ground (expanded polystyrene), vertical walls (dense polystyrene), and roadways (varnished particleboard). Thirty-eight noise-barrier configurations were tested and used to compare how IL varied with changes to the barrier profile for walls, berms, and combinations of walls and berms for receivers at a representative, highway-adjacent location. The atmospheric conditions were assumed to be homogeneous and nonrefracting. Changes of barrier surface impedance were also assessed. A highway line source was simulated by positioning both an air-jet point source and a receiver microphone at a series of equally spaced points, in order to form an array of source-receiver measurement pairs making differing angles of propagation to the noise-barrier crest line. The IL measurement results are presented in unweighted third-octave bands. In addition, total A-weighted insertion losses (ILA) were obtained by applying an A-weighted, traffic-noise spectrum. When a berm was modeled with surface impedance closely matching that of packed earth, it was found that walls outperformed berms by 1 to 2 dBA. When the surface impedance of a berm was modeled to be acoustically soft, the ILA increased sufficiently to favor berms by about 2 dBA. The result for an acoustically soft berm does not support the long-standing practice of assuming that earth berms outperform walls by 3 dBA, but is consistent with the performance predicted by newer prediction algorithms. When the slopes of berms were made shallower, the IL generally decreased for a berm alone, but generally increased in cases with a wall atop the berm.

  20. ICA-Derived EEG Correlates to Mental Fatigue, Effort, and Workload in a Realistically Simulated Air Traffic Control Task.

    PubMed

    Dasari, Deepika; Shou, Guofa; Ding, Lei

    2017-01-01

    Electroencephalograph (EEG) has been increasingly studied to identify distinct mental factors when persons perform cognitively demanding tasks. However, most of these studies examined EEG correlates at channel domain, which suffers the limitation that EEG signals are the mixture of multiple underlying neuronal sources due to the volume conduction effect. Moreover, few studies have been conducted in real-world tasks. To precisely probe EEG correlates with specific neural substrates to mental factors in real-world tasks, the present study examined EEG correlates to three mental factors, i.e., mental fatigue [also known as time-on-task (TOT) effect], workload and effort, in EEG component signals, which were obtained using an independent component analysis (ICA) on high-density EEG data. EEG data were recorded when subjects performed a realistically simulated air traffic control (ATC) task for 2 h. Five EEG independent component (IC) signals that were associated with specific neural substrates (i.e., the frontal, central medial, motor, parietal, occipital areas) were identified. Their spectral powers at their corresponding dominant bands, i.e., the theta power of the frontal IC and the alpha power of the other four ICs, were detected to be correlated to mental workload and effort levels, measured by behavioral metrics. Meanwhile, a linear regression analysis indicated that spectral powers at five ICs significantly increased with TOT. These findings indicated that different levels of mental factors can be sensitively reflected in EEG signals associated with various brain functions, including visual perception, cognitive processing, and motor outputs, in real-world tasks. These results can potentially aid in the development of efficient operational interfaces to ensure productivity and safety in ATC and beyond.

  1. Complexity of spatiotemporal traffic phenomena in flow of identical drivers: Explanation based on fundamental hypothesis of three-phase theory

    NASA Astrophysics Data System (ADS)

    Kerner, Boris S.

    2012-03-01

    Based on numerical simulations of a stochastic three-phase traffic flow model, we reveal the physics of the fundamental hypothesis of three-phase theory that, in contrast with a fundamental diagram of classical traffic flow theories, postulates the existence of a two-dimensional (2D) region of steady states of synchronized flow where a driver makes an arbitrary choice of a space gap (time headway) to the preceding vehicle. We find that macroscopic and microscopic spatiotemporal effects of the entire complexity of traffic congestion observed up to now in real measured traffic data can be explained by simulations of traffic flow consisting of identical drivers and vehicles, if a microscopic model used in these simulations incorporates the fundamental hypothesis of three-phase theory. It is shown that the driver's choice of space gaps within the 2D region of synchronized flow associated with the fundamental hypothesis of three-phase theory can qualitatively change types of congested patterns that can emerge at a highway bottleneck. In particular, if drivers choose long enough spaces gaps associated with the fundamental hypothesis, then general patterns, which consist of synchronized flow and wide moving jams, do not emerge independent of the flow rates and bottleneck characteristics: Even at a heavy bottleneck leading to a very low speed within congested patterns, only synchronized flow patterns occur in which no wide moving jams emerge spontaneously.

  2. Complexity of spatiotemporal traffic phenomena in flow of identical drivers: explanation based on fundamental hypothesis of three-phase theory.

    PubMed

    Kerner, Boris S

    2012-03-01

    Based on numerical simulations of a stochastic three-phase traffic flow model, we reveal the physics of the fundamental hypothesis of three-phase theory that, in contrast with a fundamental diagram of classical traffic flow theories, postulates the existence of a two-dimensional (2D) region of steady states of synchronized flow where a driver makes an arbitrary choice of a space gap (time headway) to the preceding vehicle. We find that macroscopic and microscopic spatiotemporal effects of the entire complexity of traffic congestion observed up to now in real measured traffic data can be explained by simulations of traffic flow consisting of identical drivers and vehicles, if a microscopic model used in these simulations incorporates the fundamental hypothesis of three-phase theory. It is shown that the driver's choice of space gaps within the 2D region of synchronized flow associated with the fundamental hypothesis of three-phase theory can qualitatively change types of congested patterns that can emerge at a highway bottleneck. In particular, if drivers choose long enough spaces gaps associated with the fundamental hypothesis, then general patterns, which consist of synchronized flow and wide moving jams, do not emerge independent of the flow rates and bottleneck characteristics: Even at a heavy bottleneck leading to a very low speed within congested patterns, only synchronized flow patterns occur in which no wide moving jams emerge spontaneously.

  3. Detecting highways of horizontal gene transfer.

    PubMed

    Bansal, Mukul S; Banay, Guy; Gogarten, J Peter; Shamir, Ron

    2011-09-01

    In a horizontal gene transfer (HGT) event, a gene is transferred between two species that do not have an ancestor-descendant relationship. Typically, no more than a few genes are horizontally transferred between any two species. However, several studies identified pairs of species between which many different genes were horizontally transferred. Such a pair is said to be linked by a highway of gene sharing. We present a method for inferring such highways. Our method is based on the fact that the evolutionary histories of horizontally transferred genes disagree with the corresponding species phylogeny. Specifically, given a set of gene trees and a trusted rooted species tree, each gene tree is first decomposed into its constituent quartet trees and the quartets that are inconsistent with the species tree are identified. Our method finds a pair of species such that a highway between them explains the largest (normalized) fraction of inconsistent quartets. For a problem on n species and m input quartet trees, we give an efficient O(m + n(2))-time algorithm for detecting highways, which is optimal with respect to the quartets input size. An application of our method to a dataset of 1128 genes from 11 cyanobacterial species, as well as to simulated datasets, illustrates the efficacy of our method.

  4. Assessing biological effects from highway-runoff constituents

    USGS Publications Warehouse

    Buckler, Denny R.; Granato, Gregory E.

    1999-01-01

    local ecosystem were reviewed to provide information on (1) the suitability of the existing data for a quantitative national synthesis, (2) the methods available to study the effects of highway runoff on local ecosystems, and (3) the potential for adverse effects on the roadside environment and receiving waters. Although many biological studies have been done, the use of different methods and a general lack of sufficient documentation precludes a quantitative national synthesis on the basis of the existing data. The Federal Highway Administration, the U.S. Environmental Protection Agency, the U.S. Geological Survey, the Intergovernmental Task Force on Monitoring Water Quality, and the National Resources Conservation Service all have developed and documented methods for assessing the effects of contaminants on ecosystems in receiving waters. These published methods can be used to formulate a set of protocols to provide consistent information from highway-runoff studies. Review of the literature indicates (qualitatively) that highway runoff (even from highways with high traffic volume) may not usually be acutely toxic. Tissue analysis and community assessments, however, indicate effects from highway- runoff sediments near discharge points (even from sites near highways with relatively low traffic volumes). At many sites, elevated concentrations of highway-runoff constituents were measured in tissues of species associated with aquatic sediments. Community assessments also indicate decreases in the diversity and productivity of aquatic ecosystems at some sites receiving highway runoff. These results are not definitive, however, and depend on many site-specific criteria that were not sufficiently documented in most of the studies reviewed.

  5. Ground-based time-guidance algorithm for control of airplanes in a time-metered air traffic control environment: A piloted simulation study

    NASA Technical Reports Server (NTRS)

    Knox, C. E.; Imbert, N.

    1986-01-01

    The rapidly increasing costs of flight operations and the requirement for increased fuel conservation have made it necessary to develop more efficient ways to operate airplanes and to control air traffic for arrivals and departures to the terminal area. One concept of controlling arrival traffic through time metering has been jointly studied and evaluated by NASA and ONERA/CERT in piloted simulation tests. From time errors attained at checkpoints, airspeed and heading commands issued by air traffic control were computed by a time-guidance algorithm for the pilot to follow that would cause the airplane to cross a metering fix at a preassigned time. These tests resulted in the simulated airplane crossing a metering fix with a mean time error of 1.0 sec and a standard deviation of 16.7 sec when the time-metering algorithm was used. With mismodeled winds representing the unknown in wind-aloft forecasts and modeling form, the mean time error attained when crossing the metering fix was increased and the standard deviation remained approximately the same. The subject pilots reported that the airspeed and heading commands computed in the guidance concept were easy to follow and did not increase their work load above normal levels.

  6. Blowing dust and highway safety in the southwestern US

    NASA Astrophysics Data System (ADS)

    Li, Junran; Lee, Jeff; Gill, Thomas

    2015-04-01

    Windblown dust poses a significant hazard to highway safety. In the southwestern US, dust related chain-reaction traffic accidents occurred every year, however, no known studies have specifically investigated this issue in this area. Remote sensing and field observations reveal that wind erosion in this region typically occurs in localized source areas, characterized as "hot spots", while most of the landscape does not erode. However, the spatial and temporal patterns of the hot spots and their relations to the occurrence of blowing dust to the highways are poorly understood. The lack of this critical information hinders highway managers to make informed and timely management decisions when wind events strike. Projected global changes, including changes in climate, land use, and land cover, will likely bring more frequent and extreme dust emissions to the southwestern US, including a majority of the Southern Plains, posing a serious threat to transportation safety in this region in the coming decades. Our preliminary investigation in west Texas indicated that a majority of the sources that contribute dust to the highways are located on sandy surface within a few kilometers of the highways and more than half of them are from cultivated cropland.

  7. Delivery performance of conventional aircraft by terminal-area, time-based air traffic control: A real-time simulation evaluation

    NASA Technical Reports Server (NTRS)

    Credeur, Leonard; Houck, Jacob A.; Capron, William R.; Lohr, Gary W.

    1990-01-01

    A description and results are presented of a study to measure the performance and reaction of airline flight crews, in a full workload DC-9 cockpit, flying in a real-time simulation of an air traffic control (ATC) concept called Traffic Intelligence for the Management of Efficient Runway-scheduling (TIMER). Experimental objectives were to verify earlier fast-time TIMER time-delivery precision results and obtain data for the validation or refinement of existing computer models of pilot/airborne performance. Experimental data indicated a runway threshold, interarrival-time-error standard deviation in the range of 10.4 to 14.1 seconds. Other real-time system performance parameters measured include approach speeds, response time to controller turn instructions, bank angles employed, and ATC controller message delivery-time errors.

  8. Accounting for anthropic energy flux of traffic in winter urban road surface temperature simulations with the TEB model

    NASA Astrophysics Data System (ADS)

    Khalifa, A.; Marchetti, M.; Bouilloud, L.; Martin, E.; Bues, M.; Chancibaut, K.

    2016-02-01

    Snowfall forecasts help winter maintenance of road networks, ensure better coordination between services, cost control, and a reduction in environmental impacts caused by an inappropriate use of de-icers. In order to determine the possible accumulation of snow on pavements, forecasting the road surface temperature (RST) is mandatory. Weather outstations are used along these networks to identify changes in pavement status, and to make forecasts by analyzing the data they provide. Physical numerical models provide such forecasts, and require an accurate description of the infrastructure along with meteorological parameters. The objective of this study was to build a reliable urban RST forecast with a detailed integration of traffic in the Town Energy Balance (TEB) numerical model for winter maintenance. The study first consisted in generating a physical and consistent description of traffic in the model with two approaches to evaluate traffic incidence on RST. Experiments were then conducted to measure the effect of traffic on RST increase with respect to non-circulated areas. These field data were then used for comparison with the forecast provided by this traffic-implemented TEB version.

  9. Temporary Losses of Highway Capacity and Impacts on Performance

    SciTech Connect

    Chin, S.M.

    2002-07-31

    Traffic congestion and its impacts significantly affect the nation's economic performance and the public's quality of life. In most urban areas, travel demand routinely exceeds highway capacity during peak periods. In addition, events such as crashes, vehicle breakdowns, work zones, adverse weather, and suboptimal signal timing cause temporary capacity losses, often worsening the conditions on already congested highway networks. The impacts of these temporary capacity losses include delay, reduced mobility, and reduced reliability of the highway system. They can also cause drivers to re-route or reschedule trips. Prior to this study, no nationwide estimates of temporary losses of highway capacity had been made by type of capacity-reducing event. Such information is vital to formulating sound public policies for the highway infrastructure and its operation. This study is an initial attempt to provide nationwide estimates of the capacity losses and delay caused by temporary capacity-reducing events. The objective of this study was to develop and implement methods for producing national-level estimates of the loss of capacity on the nation's highway facilities due to temporary phenomena as well as estimates of the impacts of such losses. The estimates produced by this study roughly indicate the magnitude of problems that are likely be addressed by the Congress during the next re-authorization of the Surface Transportation Programs. The scope of the study includes all urban and rural freeways and principal arterials in the nation's highway system for 1999. Specifically, this study attempts to quantify the extent of temporary capacity losses due to crashes, breakdowns, work zones, weather, and sub-optimal signal timing. These events can cause impacts such as capacity reduction, delays, trip rescheduling, rerouting, reduced mobility, and reduced reliability. This study focuses on the reduction of capacity and resulting delays caused by the temporary events mentioned

  10. 76 FR 6690 - Highway Systems; Technical Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-08

    ... Federal Highway Administration 23 CFR Part 470 RIN 2125-AF35 Highway Systems; Technical Correction... on the National Highway System and the Dwight D. Eisenhower System of Interstate and Defense Highways... agreement as future Interstate routes must be constructed to meet Interstate Highway System standards...

  11. 49 CFR 356.13 - Redesignated highways.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 5 2013-10-01 2013-10-01 false Redesignated highways. 356.13 Section 356.13... REGULATIONS § 356.13 Redesignated highways. Where a highway over which a regular route motor common carrier of... designation, the points between which the highway is redesignated, and each place where the highway is...

  12. 49 CFR 356.13 - Redesignated highways.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 5 2012-10-01 2012-10-01 false Redesignated highways. 356.13 Section 356.13... REGULATIONS § 356.13 Redesignated highways. Where a highway over which a regular route motor common carrier of... designation, the points between which the highway is redesignated, and each place where the highway is...

  13. 49 CFR 356.13 - Redesignated highways.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 5 2011-10-01 2011-10-01 false Redesignated highways. 356.13 Section 356.13... REGULATIONS § 356.13 Redesignated highways. Where a highway over which a regular route motor common carrier of... designation, the points between which the highway is redesignated, and each place where the highway is...

  14. 49 CFR 356.13 - Redesignated highways.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 5 2014-10-01 2014-10-01 false Redesignated highways. 356.13 Section 356.13... REGULATIONS § 356.13 Redesignated highways. Where a highway over which a regular route motor common carrier of... designation, the points between which the highway is redesignated, and each place where the highway is...

  15. 49 CFR 356.13 - Redesignated highways.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 5 2010-10-01 2010-10-01 false Redesignated highways. 356.13 Section 356.13... REGULATIONS § 356.13 Redesignated highways. Where a highway over which a regular route motor common carrier of... designation, the points between which the highway is redesignated, and each place where the highway is...

  16. High-resolution simulation of link-level vehicle emissions and concentrations for air pollutants in a traffic-populated eastern Asian city

    NASA Astrophysics Data System (ADS)

    Zhang, Shaojun; Wu, Ye; Huang, Ruikun; Wang, Jiandong; Yan, Han; Zheng, Yali; Hao, Jiming

    2016-08-01

    Vehicle emissions containing air pollutants created substantial environmental impacts on air quality for many traffic-populated cities in eastern Asia. A high-resolution emission inventory is a useful tool compared with traditional tools (e.g. registration data-based approach) to accurately evaluate real-world traffic dynamics and their environmental burden. In this study, Macau, one of the most populated cities in the world, is selected to demonstrate a high-resolution simulation of vehicular emissions and their contribution to air pollutant concentrations by coupling multimodels. First, traffic volumes by vehicle category on 47 typical roads were investigated during weekdays in 2010 and further applied in a networking demand simulation with the TransCAD model to establish hourly profiles of link-level vehicle counts. Local vehicle driving speed and vehicle age distribution data were also collected in Macau. Second, based on a localized vehicle emission model (e.g. the emission factor model for the Beijing vehicle fleet - Macau, EMBEV-Macau), this study established a link-based vehicle emission inventory in Macau with high resolution meshed in a temporal and spatial framework. Furthermore, we employed the AERMOD (AMS/EPA Regulatory Model) model to map concentrations of CO and primary PM2.5 contributed by local vehicle emissions during weekdays in November 2010. This study has discerned the strong impact of traffic flow dynamics on the temporal and spatial patterns of vehicle emissions, such as a geographic discrepancy of spatial allocation up to 26 % between THC and PM2.5 emissions owing to spatially heterogeneous vehicle-use intensity between motorcycles and diesel fleets. We also identified that the estimated CO2 emissions from gasoline vehicles agreed well with the statistical fuel consumption in Macau. Therefore, this paper provides a case study and a solid framework for developing high-resolution environment assessment tools for other vehicle-populated cities

  17. Response of benthic macroinvertebrate communities to highway construction in an Appalachian watershed

    USGS Publications Warehouse

    Hedrick, Lara B.; Welsh, S.A.; Anderson, James T.; Lin, L.-S.; Chen, Y.; Wei, X.

    2010-01-01

    Highway construction in mountainous areas can result in sedimentation of streams, negatively impacting stream habitat, water quality, and biotic communities. We assessed the impacts of construction of a segment of Corridor H, a four-lane highway, in the Lost River watershed, West Virginia, by monitoring benthic macroinvertebrate communities and water quality, before, during, and after highway construction and prior to highway use at upstream and downstream sites from 1997 through 2007. Data analysis of temporal impacts of highway construction followed a Before-After-Control-Impact (BACI) study design. Highway construction impacts included an increase in stream sedimentation during the construction phase. This was indicated by an increase in turbidity and total suspended solids. Benthic macroinvertebrate metrics indicated a community more tolerant during and after construction than in the period before construction. The percent of Chironomidae and the Hilsenhoff Biotic Index (HBI) increased, while percent of Ephemeroptera, Plecoptera, and Trichoptera (EPT) decreased. Our 10-year study addressed short-term impacts of highway construction and found that impacts were relatively minimal. A recovery of the number of EPT taxa collected after construction indicated that the benthic macroinvertebrate community may be recovering from impacts of highway construction. However, this study only addressed a period of 3 years before, 3 years during, and 4 years post construction. Inferences cannot be made concerning the long-term impacts of the highway, highway traffic, runoff, and other factors associated with highway use. Continual monitoring of the watershed is necessary to determine if the highway has a continual impact on stream habitat, water quality, and biotic integrity. ?? 2010 Springer Science+Business Media B.V.

  18. Highways of hope

    SciTech Connect

    2007-08-15

    It is hoped that through public-private partnerships between Alpha Natural Resources and Pioneer Group and Virginia Department of Transportation, and between one of these coal companies and Buchanan County, Virginia, Industrial Development Authority a four-lane 'highway of hope' between Lovers Gap and Poplar Gap will be paved and a ridge top connector route will eventually be completed to Bull Gap where it will intersect with the Coalfields Expressway and US 460. The town of Grundy is also looking into strip mining coal from beneath the small mountaintop airport at Lovers Gap and turning it into a regional airport. The article discusses these plans. 4 photos.

  19. Highways for National Defense

    DTIC Science & Technology

    2007-11-02

    system needs reports (RCS MTMC -74). • 2–4, page 7 Section II ACCESS ROAD NEEDS, page 8 General. • 2–5, page 8 Impact on highway construction or improvement...9 Access road needs report (RCS MTMC -75). • 2–10, page 9 ii AR 55–80/OPNAVINST 11210.1B/AFR 75–88/MCO 11210.2C/DLAR 4500.19 • 15 December 1982...and funding. • 2–17, page 12 Chapter 3 MANEUVER-AREA ROADS, page 12 Maneuver-area road condition report (RCS MTMC -76). • 3–1, page 12 Who will prepare

  20. Solar powered highway sign

    NASA Astrophysics Data System (ADS)

    Hayden, R. L.; Hutter, W.

    1980-09-01

    A roadside sign was equipped with lights powered by photovoltaic solar panels to improve nighttime visibility and evaluate equipment performance and needs. The photovoltaic panels were found to be reliable and effective for powering flashing lights on a highway warning sign. Cost of the panels is high so their use should be limited to locations where commercial electrical power is not available. Solar electric systems should be carefully designed to minimize costs and produce a reliable system. Sufficient prediction for the solar panels should be provided in areas where theft or vandalism might be a problem.

  1. Traffic Games: Modeling Freeway Traffic with Game Theory

    PubMed Central

    Cortés-Berrueco, Luis E.; Gershenson, Carlos; Stephens, Christopher R.

    2016-01-01

    We apply game theory to a vehicular traffic model to study the effect of driver strategies on traffic flow. The resulting model inherits the realistic dynamics achieved by a two-lane traffic model and aims to incorporate phenomena caused by driver-driver interactions. To achieve this goal, a game-theoretic description of driver interaction was developed. This game-theoretic formalization allows one to model different lane-changing behaviors and to keep track of mobility performance. We simulate the evolution of cooperation, traffic flow, and mobility performance for different modeled behaviors. The analysis of these results indicates a mobility optimization process achieved by drivers’ interactions. PMID:27855176

  2. Traffic Games: Modeling Freeway Traffic with Game Theory.

    PubMed

    Cortés-Berrueco, Luis E; Gershenson, Carlos; Stephens, Christopher R

    2016-01-01

    We apply game theory to a vehicular traffic model to study the effect of driver strategies on traffic flow. The resulting model inherits the realistic dynamics achieved by a two-lane traffic model and aims to incorporate phenomena caused by driver-driver interactions. To achieve this goal, a game-theoretic description of driver interaction was developed. This game-theoretic formalization allows one to model different lane-changing behaviors and to keep track of mobility performance. We simulate the evolution of cooperation, traffic flow, and mobility performance for different modeled behaviors. The analysis of these results indicates a mobility optimization process achieved by drivers' interactions.

  3. Precursor systems analyses of automated highway systems. An hypothesized evolution of an automated highway system. Resource materials. Final report, September 1993-November 1994

    SciTech Connect

    Ward, J.

    1996-01-01

    This document describes and broadly analyzes an evolutionary deployment scenario for an Automated Highway System in which vehicles equipped for automated operation are deployed in mixed traffic with unequipped, manually operated vehicles. A gradual evolution of incremental change, both in scope and capability of the automated features in the vehicle fleet is assumed.

  4. Long-path measurements of pollutants and micrometeorology over Highway 401 in Toronto

    NASA Astrophysics Data System (ADS)

    Staebler, R. M.; You, Y.; Mittermeier, R. L.; Moussa, S.; Liggio, J.; Su, Y.

    2015-12-01

    Highway traffic emissions are an important source of air pollution, especially in urban areas. Traffic-related pollution has been linked to a number of adverse health effects, such as respiratory problems, cancer, heart failure, and a general increase in mortality. Determining the pollutants involved and quantifying their emission rates is paramount in developing high resolution air quality models to predict future developments with some confidence. Highway 401, as it passes through Toronto, is the world's busiest highway with a typical traffic volume of over 450,000 vehicles per day. In July 2015, three weeks of measurements were conducted over the 401 with an open-path FTIR (Fourier Transform infra-red) spectrometer in parallel with a scintillometer, integrating a variety of gas concentrations as well as turbulence parameters over a 310m path length. Relationships between traffic volume, micrometeorological conditions and the build-up and venting of pollutants on the highway are analyzed and quantified, demonstrating the role of stratification and turbulence in the accumulation and dispersal of traffic emissions. The feasibility of deriving emission rates by combining the micrometeorological data from the scintillometer with the gas concentrations from the FTIR using an inverse dispersion approach is investigated. The suitability of this novel approach for long-term monitoring of emissions is discussed. The findings will be compared with output from a high-resolution air quality model (GEM-MACH) to aid future improvements in the sub-grid parameterization of pollutant dispersion.

  5. 38. LANDSCAPE HIGHWAY VIEW, OREGON STATE HIGHWAY 199. JOSPHINE COUNTY, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    38. LANDSCAPE HIGHWAY VIEW, OREGON STATE HIGHWAY 199. JOSPHINE COUNTY, OREGON. REEVES CREEK (WHERE ROAD WIDENS) 4 MILES NE OF CAVE JUNCTION. LOOKING S. - Redwood National & State Parks Roads, California coast from Crescent City to Trinidad, Crescent City, Del Norte County, CA

  6. Traffic Flow Wide-Area Surveillance system

    SciTech Connect

    Allgood, G.O.; Ferrell, R.K.; Kercel, S.W.; Abston, R.A.

    1994-09-01

    Traffic management can be thought of as a stochastic queuing process where the serving time at one of its control points is dynamically linked to the global traffic pattern, which is, in turn, dynamically linked to the control point. For this closed-loop system to be effective, the traffic management system must sense and interpret a large spatial projection of data originating from multiple sensor suites. This concept is the basis for the development of a Traffic Flow Wide-Area Surveillance (TFWAS) system. This paper presents the results of a study by Oak Ridge National Laboratory to define the operational specifications and characteristics, to determine the constraints, and to examine the state of technology of a TFWAS system in terms of traffic management and control. In doing so, the functions and attributes of a TFWAS system are mapped into an operational structure consistent with the Intelligent Vehicle Highway System (IVHS) concept and the existing highway infrastructure. This mapping includes identifying candidate sensor suites and establishing criteria, requirements, and performance measures by which these systems can be graded in their ability and practicality to meet the operational requirements of a TFWAS system. In light of this, issues such as system integration, applicable technologies, impact on traffic management and control, and public acceptance are addressed.

  7. Quality of stormwater runoff discharged from Massachusetts highways, 2005-07

    USGS Publications Warehouse

    Smith, Kirk P.; Granato, Gregory E.

    2010-01-01

    The U.S. Geological Survey (USGS), in cooperation with U.S. Department of Transportation Federal Highway Administration and the Massachusetts Department of Transportation, conducted a field study from September 2005 through September 2007 to characterize the quality of highway runoff for a wide range of constituents. The highways studied had annual average daily traffic (AADT) volumes from about 3,000 to more than 190,000 vehicles per day. Highway-monitoring stations were installed at 12 locations in Massachusetts on 8 highways. The 12 monitoring stations were subdivided into 4 primary, 4 secondary, and 4 test stations. Each site contained a 100-percent impervious drainage area that included two or more catch basins sharing a common outflow pipe. Paired primary and secondary stations were located within a few miles of each other on a limited-access section of the same highway. Most of the data were collected at the primary and secondary stations, which were located on four principal highways (Route 119, Route 2, Interstate 495, and Interstate 95). The secondary stations were operated simultaneously with the primary stations for at least a year. Data from the four test stations (Route 8, Interstate 195, Interstate 190, and Interstate 93) were used to determine the transferability of the data collected from the principal highways to other highways characterized by different construction techniques, land use, and geography. Automatic-monitoring techniques were used to collect composite samples of highway runoff and make continuous measurements of several physical characteristics. Flowweighted samples of highway runoff were collected automatically during approximately 140 rain and mixed rain, sleet, and snowstorms. These samples were analyzed for physical characteristics and concentrations of 6 dissolved major ions, total nutrients, 8 total-recoverable metals, suspended sediment, and 85 semivolatile organic compounds (SVOCs), which include priority polyaromatic

  8. Road traffic injuries in Colombia.

    PubMed

    Rodríguez, Deysi Yasmin; Fernández, Francisco José; Acero Velásquez, Hugo

    2003-01-01

    Road traffic injuries are a leading public health problem in Colombia. Pedestrians are the most vulnerable road users, especially in the main urban centers of Bogotá, Medellin and Cali. Data analyzed in this report include official statistics from the National Police and the National Institute of Legal Medicine and Forensic Sciences for 1996-2000, and results of a study conducted at the National University of Colombia in 2000. Methods from the Highway Capacity Manual were used for determining physical and technical variables, and a Geographical Information System tool was used for the location and spatial analysis of the road traffic crashes. Pedestrians accounted for close to 32% of injuries and 40% of the deaths from road traffic crashes. The problem of road traffic crashes existed predominately in urban areas. In the main urban centers, pedestrians constituted nearly 68% of road traffic crash victims. The high level of risky road use behaviors demonstrated by pedestrians and drivers, and inadequate infrastructure for safe mobility of pedestrians in some sections of the road network were the main contributing factors. Major improvements were achieved in Bogotá following enhancements to the municipal transport system and other policies introduced since 1995. In conclusion, policies and programs for improving road safety, in particular pedestrian safety, and strengthening urban planning are top priority.

  9. 75 FR 18014 - Federal Highway Administration

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-08

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF TRANSPORTATION Federal Highway Administration AGENCY: Federal Highway Administration (FHWA), DOT. ACTION: Notice of...: Federal Highway Administration, Kentucky Division: Mr. Greg Rawlings, Transportation Specialist, 330 West...

  10. Algorithm and data support of traffic congestion forecasting in the controlled transport

    NASA Astrophysics Data System (ADS)

    Dmitriev, S. V.

    2015-06-01

    The topicality of problem of the traffic congestion forecasting in the logistic systems of product movement highways is considered. The concepts: the controlled territory, the highway occupancy by vehicles, the parking and the controlled territory are introduced. Technical realizabilityof organizing the necessary flow of information on the state of the transport system for its regulation has been marked. Sequence of practical implementation of the solution is given. An algorithm for predicting traffic congestion in the controlled transport system is suggested.

  11. UAS in the NAS Air Traffic Controller Acceptability Study-1: The Effects of Horizontal Miss Distances on Simulated UAS and Manned Aircraft Encounters

    NASA Technical Reports Server (NTRS)

    Ghatas, Rania W.; Comstock, James R., Jr.; Consiglio, Maria C.; Chamberlain, James P.; Hoffler, Keith D.

    2015-01-01

    This study examined air traffic controller acceptability ratings based on the effects of differing horizontal miss distances (HMDs) for encounters between UAS and manned aircraft. In a simulation of the Dallas/Fort Worth (DFW) East-side airspace, the CAS-1 experiment at NASA Langley Research Center enlisted fourteen recently retired DFW air traffic controllers to rate well-clear volumes based on differing HMDs that ranged from 0.5 NM to 3.0 NM. The controllers were tasked with rating these HMDs from "too small" to "too excessive" on a defined, 1-5, scale and whether these distances caused any disruptions to the controller and/or to the surrounding traffic flow. Results of the study indicated a clear favoring towards a particular HMD range. Controller workload was also measured. Data from this experiment and subsequent experiments will play a crucial role in the FAA's establishment of rules, regulations, and procedures to safely and efficiently integrate UAS into the NAS.

  12. Physics of Traffic

    NASA Astrophysics Data System (ADS)

    Schreckenberg, Michael

    2002-03-01

    In the past decade the investigation of the complex behaviour of traffic dynamics became an active field of (interdisciplinary) research. On the one hand this is due to a fastly growing availability of 'experimental' data from measurements with various kinds of sensors, on the other hand due to an enormous improvement of the modelling techniques from statistical physics. This has led to the identification of several new phases of traffic flow and the characterization of the corresponding phase transitions between them. Nowadays many of the occurring dynamical phenomena are understood quite well although a complete understanding, especially of the interrelation between the models on the different scales (micro-, meso-, macroscopic), is still missing. Whereas earlier attempts tried to describe traffic flow in a hydrodynamical formulation the current microscopic models are able to take into not only the physically correct motion of single cars but also certain aspects of the driver's behaviour. It turns out that the simple car following theories cannot explain the complex structures found, e.g., in synchronized traffic, a new state found only recently. Here a more detailed analysis is necessary which goes far beyond the pure modelling of the motion of the cars in analogy to granular media (grains of sand, pills, corn, etc.). The detailed knowledge of traffic dynamics not of purely scientific interest but also absolutely necessary for practical applications. With the help of online data from measurements of flows and speeds it is possible to construct a complete picture of the actual traffic state with real time simulations. As a very efficient model ansatz cellular automata have been shown to be a reasonable compromise between simulation speed and descripiton accuracy. Beyond the reproduction of the actual state a reliable traffic forecast should be possible although the driver's reaction on the forecast still remains unclear.

  13. Simulation of Water-Surface Elevations and Velocity Distributions at the U.S. Highway 13 Bridge over the Tar River at Greenville, North Carolina, Using One- and Two-Dimensional Steady-State Hydraulic Models

    USGS Publications Warehouse

    Wagner, Chad R.

    2007-01-01

    The use of one-dimensional hydraulic models currently is the standard method for estimating velocity fields through a bridge opening for scour computations and habitat assessment. Flood-flow contraction through bridge openings, however, is hydrodynamically two dimensional and often three dimensional. Although there is awareness of the utility of two-dimensional models to predict the complex hydraulic conditions at bridge structures, little guidance is available to indicate whether a one- or two-dimensional model will accurately estimate the hydraulic conditions at a bridge site. The U.S. Geological Survey, in cooperation with the North Carolina Department of Transportation, initiated a study in 2004 to compare one- and two-dimensional model results with field measurements at complex riverine and tidal bridges in North Carolina to evaluate the ability of each model to represent field conditions. The field data consisted of discharge and depth-averaged velocity profiles measured with an acoustic Doppler current profiler and surveyed water-surface profiles for two high-flow conditions. For the initial study site (U.S. Highway 13 over the Tar River at Greenville, North Carolina), the water-surface elevations and velocity distributions simulated by the one- and two-dimensional models showed appreciable disparity in the highly sinuous reach upstream from the U.S. Highway 13 bridge. Based on the available data from U.S. Geological Survey streamgaging stations and acoustic Doppler current profiler velocity data, the two-dimensional model more accurately simulated the water-surface elevations and the velocity distributions in the study reach, and contracted-flow magnitudes and direction through the bridge opening. To further compare the results of the one- and two-dimensional models, estimated hydraulic parameters (flow depths, velocities, attack angles, blocked flow width) for measured high-flow conditions were used to predict scour depths at the U.S. Highway 13 bridge by

  14. Surface Traffic Management Research

    NASA Technical Reports Server (NTRS)

    Jung, Yoo Chul

    2012-01-01

    This presentation discusses an overview of the surface traffic management research conducted by NASA Ames. The concept and human-in-the-loop simulation of the Spot and Runway Departure Advisor (SARDA), an integrated decision support tool for the tower controllers and airline ramp operators, is also discussed.

  15. The Classroom Traffic Jam

    ERIC Educational Resources Information Center

    Edwards, Arthur W.

    1977-01-01

    The importance of energy conservation is developed in this simulation. Children draw an automobile and then are asked to drive it through the classroom roadways. When a traffic jam results, students offer ways to eliminate it. The importance of mass transportation and car pools is stressed by the teacher. (MA)

  16. Determining the drivers' acceptance of EFTCD in highway work zones.

    PubMed

    Bai, Yong; Li, Yingfeng

    2011-05-01

    Traffic safety is a major concern in the temporary one-lane, two-way highway work zones due to the increasing of construction and maintenance operations. To prevent rear-end crashes and to mitigate the severity of these crashes caused by the inattentive driving, the utilization of the Emergency Flasher Traffic Control Device (EFTCD) was under consideration by government agencies, in addition to existing temporary traffic control devices installed in the one-lane, two-way highway work zones. The EFTCD was a newly proposed traffic warning device implemented through the use of vehicles' hazard warning flashers. The primary objective of the research project was to investigate the drivers' acceptance of the proposed EFTCD by measuring the mean speed changes of vehicles with and without EFTCD and by evaluating the drivers' opinions of the EFTCD using the survey method. Field experimental results revealed that the EFTCD effectively reduced the mean vehicle speeds in the upstream of two work zones. A slow speed is more likely to reduce the severity of a crash in work zones. In addition, survey results indicated that 60% of the drivers thought the EFTCD signified a need for speed reduction and 82% of drivers recommended the implementation of the EFTCD in one-lane, two-way work zones. These results provide the necessary scientific justifications for the government agencies to decide if the EFTCD should be implemented in the one-lane, two-way highway work zones to prevent rear-end crashes and to mitigate the severity of these crashes.

  17. Assessing the risk of secondary crashes on highways.

    PubMed

    Yang, Hong; Ozbay, Kaan; Xie, Kun

    2014-06-01

    The occurrence of "secondary crashes" is one of the critical yet understudied highway safety issues. Induced by the primary crashes, the occurrence of secondary crashes does not only increase traffic delays but also the risk of inducing additional incidents. Many highway agencies are highly interested in the implementation of safety countermeasures to reduce this type of crashes. However, due to the limited understanding of the key contributing factors, they face a great challenge for determining the most appropriate countermeasures. To bridge this gap, this study makes important contributions to the existing literature of secondary incidents by developing a novel methodology to assess the risk of having secondary crashes on highways. The proposed methodology consists of two major components, namely: (a) accurate identification of secondary crashes and (b) statistically robust assessment of causal effects of contributing factors. The first component is concerned with the development of an improved identification approach for secondary accidents that relies on the rich traffic information obtained from traffic sensors. The second component of the proposed methodology is aimed at understanding the key mechanisms that are hypothesized to cause secondary crashes through the use of a modified logistic regression model that can efficiently deal with relatively rare events such as secondary incidents. The feasibility and improved performance of using the proposed methodology are tested using real-world crash and traffic flow data. The risk of inducing secondary crashes after the occurrence of individual primary crashes under different circumstances is studied by employing the estimated regression model. Marginal effect of each factor on the risk of secondary crashes is also quantified and important contributing factors are highlighted and discussed. Massive sensor data can be used to support the identification of secondary crashes. The occurrence mechanism of these

  18. Highway accident severities and the mixed logit model: an exploratory empirical analysis.

    PubMed

    Milton, John C; Shankar, Venky N; Mannering, Fred L

    2008-01-01

    Many transportation agencies use accident frequencies, and statistical models of accidents frequencies, as a basis for prioritizing highway safety improvements. However, the use of accident severities in safety programming has been often been limited to the locational assessment of accident fatalities, with little or no emphasis being placed on the full severity distribution of accidents (property damage only, possible injury, injury)-which is needed to fully assess the benefits of competing safety-improvement projects. In this paper we demonstrate a modeling approach that can be used to better understand the injury-severity distributions of accidents on highway segments, and the effect that traffic, highway and weather characteristics have on these distributions. The approach we use allows for the possibility that estimated model parameters can vary randomly across roadway segments to account for unobserved effects potentially relating to roadway characteristics, environmental factors, and driver behavior. Using highway-injury data from Washington State, a mixed (random parameters) logit model is estimated. Estimation findings indicate that volume-related variables such as average daily traffic per lane, average daily truck traffic, truck percentage, interchanges per mile and weather effects such as snowfall are best modeled as random-parameters-while roadway characteristics such as the number of horizontal curves, number of grade breaks per mile and pavement friction are best modeled as fixed parameters. Our results show that the mixed logit model has considerable promise as a methodological tool in highway safety programming.

  19. Highway Traffic Accident Investigation and Reporting: Course Guide.

    ERIC Educational Resources Information Center

    Daugherty, Ronald D.; And Others

    This course guide for administrators and curriculum planners is intended for use with lesson plans for the instructor and a student study guide, available as VT 019 457 and VT 019 456, respectively. As part of a curriculum package developed by The Center for Vocational and Technical Education after a nationwide survey, this document contains…

  20. Highway Traffic Accident Investigation and Reporting: Student Study Guide.

    ERIC Educational Resources Information Center

    Daugherty, Ronald D.; And Others

    This study guide for students in a basic training program for accident investigation is intended for use with lesson plans for the instructor and a manual for administrators and planners, available as VT 019 457 and VT 019 455, respectively. As part of a curriculum package developed by the Center for Vocational and Technical Education after a…