Integrating Observational And Microscopic Simulation Models For Traffic Safety Analysis

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Integrating Observational and Microscopic Simulation Models for Traffic Safety Analysis

Author : Usama Elrawy Shahdah
Publisher :
ISBN 13 :
Total Pages : 145 pages
Book Rating : 4.:/5 (18 download)

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Book Synopsis Integrating Observational and Microscopic Simulation Models for Traffic Safety Analysis by : Usama Elrawy Shahdah

Download or read book Integrating Observational and Microscopic Simulation Models for Traffic Safety Analysis written by Usama Elrawy Shahdah and published by . This book was released on 2014 with total page 145 pages. Available in PDF, EPUB and Kindle. Book excerpt: In safety analysis, two questions typically need to be addressed: 1) how to identify unsafe sites for priority intervention? and 2) how to determine the effectiveness of treatments introduced at these and other sites? Two types of approaches have been considered in the literature to provide answers for these questions: (1) observational models based on historical crash data and (2) observed or simulated higher risk vehicle interactions or traffic conflicts. Observational crash-based models are good at predicting higher severity crashes, but they tend to ignore higher risk vehicle interactions that compromise safety, that have not resulted in crashes (e.g. near misses). Proponents of microscopic simulation argue that ignoring these higher risk interactions can severely understate the safety problem at a given site and lead to a misallocation of scarce treatment funds. Another problem with observational crash prediction models is the need for sufficient crash data reported over an extended period of time to provide reliable estimates of “potential” lack of safety. This requirement can be a challenge for certain types of treatment and different sites or locations. Furthermore, observational approaches are not causal in nature, and as such, they fail to provide a sound “behavioural” rationale for “why” certain treatments affect safety. On the other hand, traffic conflicts occur more frequently than crashes and can provide a stronger experimental basis for estimating safety effects on a short-term basis. This is especially important given the rare random nature of crashes for certain traffic conditions. Additionally, they provide a more rational basis for lack of safety than is normally available from crash occurrence data. Basically, through the application of calibrated behavioural simulation, traffic conflicts can be linked to specific driver actions and responses at a given site, more so than conventional reported crashes. As such, they permit a causal underpinning for possible treatment effects and this is important to decision-makers because it underscores why certain treatments act to enhance safety, rather than simply providing an estimate of the treatment effect itself. Notwithstanding the usefulness of conflict-based measures, observed crashes remain the primary verifiable measure for representing failures in the transportation systems. Unfortunately traffic conflicts have not been formally linked to observed crashes, and hence their values as indicators for treatment effect have not been fully explored. This presents a challenge on how best to use both conflicts and observed crashes to better understand where safety is most problematic, where intervention is needed, and how best to resolve specific safety problems? In this thesis, the position is taken that a complete understanding of safety problems at a given site can only emerge from a more inclusive analysis of both observed crashes and traffic conflicts. This is explored by developing two integrated models: (1) An integrated priority ranking model is presented that combines estimates from observational crash prediction with an analysis of simulated traffic conflicts; (2) An integrated treatment model is presented that uses simulated traffic conflicts that are linked statistically to observed crashes to provide estimates of crash modification factor (CMF). The suitability of these integrated models has been evaluated using data for a sample of signalized intersections from Toronto for the period 1999-2006. In the absence of a benchmark (or true) priority ranking outcome, a number of evaluation criteria were considered, and the integrated ranking model was found to yield better results than both conventional observational crash-based models (including empirical Bayesian, potential for safety improvement methods) and conflict-based models (including conflict frequency and rate for different risk thresholds). For treatment effects, the results suggest that CMFs can be estimated reliably from conflicts derived from microsimulation, where the simulation platform has been sufficiently calibrated. The link between crashes and conflicts provides additional inferences concerning treatment effects, in those cases where treatments were not previously implemented (i.e., no after history). Since there is an absence of crash history, the treatment effect is based exclusively on simulated conflicts. Moreover, the integrated model has the added advantage of providing site-specific CMFs instead of applying a constant CMF across all sites considered for a potential treatment.

Integrating the Macroscopic and Microscopic Traffic Safety Analysis Using Hierarchical Models

Author : Qing Cai
Publisher :
ISBN 13 :
Total Pages : 183 pages
Book Rating : 4.:/5 (1 download)

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Book Synopsis Integrating the Macroscopic and Microscopic Traffic Safety Analysis Using Hierarchical Models by : Qing Cai

Download or read book Integrating the Macroscopic and Microscopic Traffic Safety Analysis Using Hierarchical Models written by Qing Cai and published by . This book was released on 2017 with total page 183 pages. Available in PDF, EPUB and Kindle. Book excerpt: Also, the integrated model provides more valuable insights about the crash occurrence at the two levels by revealing both macro- and micro-level factors. Subsequently, a novel hotspot identification method was suggested, which enables us to detect hotspots for both macro- and micro-levels with comprehensive information from the two levels. It is expected that the proposed integrated model and hotspot identification method can help practitioners implement more reasonable transportation safety plans and more effective engineering treatments to proactively enhance safety.

Assessing Safety Performance of Transportation Systems Using Microscopic Simulation

Author : Flávio José Craveiro Cunto
Publisher :
ISBN 13 : 9780494554920
Total Pages : 175 pages
Book Rating : 4.5/5 (549 download)

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Book Synopsis Assessing Safety Performance of Transportation Systems Using Microscopic Simulation by : Flávio José Craveiro Cunto

Download or read book Assessing Safety Performance of Transportation Systems Using Microscopic Simulation written by Flávio José Craveiro Cunto and published by . This book was released on 2008 with total page 175 pages. Available in PDF, EPUB and Kindle. Book excerpt: Transportation safety has been recognized as a public health issue worldwide, consequently, transportation researchers and practitioners have been attempting to provide adequate safety performance for the various transportation components and facilities to all road users given the usually scarce resources available. Safety engineers have been trying to make decisions affecting safety based on the knowledge extracted from different types of statistical models and/or observational before-after analysis. It is generally recognized that this type of factual knowledge is not easily obtained either statistically or empirically. Despite the intuitive link between road safety and observed crashes, a good understanding of the sequence of events prior to the crash can provide a more rational basis for the development of engineering countermeasures. The development of more comprehensive mechanistic models for safety assessment is heavily dependent on detailed vehicle tracking data that is not readily available. The potential of microscopic simulation in traffic safety and traffic conflict analysis has gained increasing interest mostly due to recent developments in human behaviour modelling and real-time vehicle data acquisition. In this thesis, we present a systematic investigation of the use of existing behavioural microscopic simulation models in short-term road safety studies.

Highway Safety Analytics and Modeling

Author : Dominique Lord
Publisher : Elsevier
ISBN 13 : 0128168196
Total Pages : 504 pages
Book Rating : 4.1/5 (281 download)

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Book Synopsis Highway Safety Analytics and Modeling by : Dominique Lord

Download or read book Highway Safety Analytics and Modeling written by Dominique Lord and published by Elsevier. This book was released on 2021-02-27 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt: Highway Safety Analytics and Modeling comprehensively covers the key elements needed to make effective transportation engineering and policy decisions based on highway safety data analysis in a single. reference. The book includes all aspects of the decision-making process, from collecting and assembling data to developing models and evaluating analysis results. It discusses the challenges of working with crash and naturalistic data, identifies problems and proposes well-researched methods to solve them. Finally, the book examines the nuances associated with safety data analysis and shows how to best use the information to develop countermeasures, policies, and programs to reduce the frequency and severity of traffic crashes. Complements the Highway Safety Manual by the American Association of State Highway and Transportation Officials Provides examples and case studies for most models and methods Includes learning aids such as online data, examples and solutions to problems

Non-Motorized Transport Integration into Urban Transport Planning in Africa

Author : Winnie V. Mitullah
Publisher : Taylor & Francis
ISBN 13 : 1317086988
Total Pages : 240 pages
Book Rating : 4.3/5 (17 download)

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Book Synopsis Non-Motorized Transport Integration into Urban Transport Planning in Africa by : Winnie V. Mitullah

Download or read book Non-Motorized Transport Integration into Urban Transport Planning in Africa written by Winnie V. Mitullah and published by Taylor & Francis. This book was released on 2017-07-14 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: What challenges do pedestrians and cyclists face in cities of the developing world? What opportunities do these cities have to provide for walking and cycling? Based on in-depth research conducted in Cape Town (South Africa), Dar es Salaam (Tanzania) and Nairobi (Kenya), this book explores these questions by presenting work on walking and cycling travel behaviour, the status of road safety in these cities, as well as an analysis of the infrastructure for walking and cycling, and the workings of the institutions responsible for planning for these modes. The book also presents case studies relating to particular opportunities and challenges, such as the development and evaluation of ‘walking bus’ interventions, and the opportunities micro-simulation of pedestrian interventions offers within a data-scarce environment. Non-motorized Transport Integration into Urban Transport Planning in Africa demonstrates that transport and urban planning remains situated in a logic of automobile-dependent transport planning and global city development. This logic of practice does not pay adequate attention to walking and cycling. It argues that a significant shift in both policy as well as political commitment is needed so as to prioritize walking and cycling as strategies for sustainable transport policy in urban Africa. This book will be a key text for practitioners and policy makers working in planning, transport policy and urban development in Africa, as well as students and scholars of African studies, development studies, urban geography, transport studies and sustainable development.

Simulation-based Evaluation of Traffic Safety Performance Using Surrogate Safety Measures

Author : Hong Yang
Publisher :
ISBN 13 :
Total Pages : 156 pages
Book Rating : 4.:/5 (785 download)

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Book Synopsis Simulation-based Evaluation of Traffic Safety Performance Using Surrogate Safety Measures by : Hong Yang

Download or read book Simulation-based Evaluation of Traffic Safety Performance Using Surrogate Safety Measures written by Hong Yang and published by . This book was released on 2012 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: Traffic safety evaluation is one of the most important processes in the analysis of transportation systems performance. The use of traditional crash-data-oriented methodologies to analyze traffic safety problems has been frequently questioned due to shortcomings such as unavailability and low quality of historical crash data. The advancement of traffic conflict techniques and micro-simulation tools motivated this dissertation to develop a simulation-based approach of combining micro-simulation models and traffic conflict technique to investigate the safety issues in traffic systems. The proposed simulation-based approach consists of two major components: the development of surrogate safety measures; and the integration of the developed surrogate safety measures with micro-simulation models. In this dissertation, a new surrogate safety measure is derived and applied in micro-simulation models to capture the conflict risk of the interactions among vehicles. The conceptual and computational logics of the proposed surrogate safety indicator are described in detail. A calibration procedure that focuses on safety evaluation using the simulation model with the new surrogate measure has been proposed. The proposed calibration approach has been developed based on the stochastic gradient approximation algorithms to find optimal parameters of the stochastic traffic simulation models. The calibration methodology has been implemented on a selected traffic simulation platform to test its performance. Simulated operational measurements and traffic conflict risk in terms of the surrogate safety measure are quantified and compared with observations derived from high resolution vehicle trajectory data. The calibrated traffic model has also been validated by using independent vehicle trajectory data saved as a hold-out sample. The results show that the fine-tuning of parameters using the proposed calibration approach can significantly improve the performance of the simulation model to describe actual traffic conflict risk as well as operational performance. The applicability of the proposed new surrogate measure and the simulation-based safety evaluation approach using this surrogate measure has been successfully demonstrated through several cases studies. The overall findings can inform road safety investigators as to how operations-oriented simulation models in conjunction with the surrogate safety measure can complement traffic safety evaluation in cases to which traditional approaches are not applicable.

Simulation of Traffic Crashes Using Cell Based Micro-simulation

Author : Victor Muchuruza
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (796 download)

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Book Synopsis Simulation of Traffic Crashes Using Cell Based Micro-simulation by : Victor Muchuruza

Download or read book Simulation of Traffic Crashes Using Cell Based Micro-simulation written by Victor Muchuruza and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: The deterioration of the safety of operation, coupled with the persistent increase in rearend crashes, is of great concern in finding accurate and realistic methods of modeling traffic flow and preventing traffic crashes. For some decades safety evaluation methods have relied on analysis of historical crash data. Since crashes are random and rare events and, in most cases, are independent events, it is difficult to find a sufficient number of crashes on a road section in a relatively short time period (e.g., a month or even a year). Thus, multi-year collection of crash data is used in safety analysis. Another safety evaluation method that has been practiced though in small scale is traffic conflict techniques (TCT). The advantage of using TCT in safety evaluations is the ability to test or study a safety strategy or improvement applied on the roadway facility in a relatively short period of time compared with traditional methods, which are dependent on crash data. However, use of TCT is not popular; perhaps because it needs extensive resources to collect, extract, and analyze conflict information. Moreover, like crash data analysis, use of TCT also makes concerned authorities reactive to the problem by responding to the crashes that have already occurred. Therefore, alternative proactive safety evaluation techniques that can improve the quality of traffic safety evaluation are needed at this time. One way of using proactive safety evaluation techniques and thus become more preventive than reactive towards dealing with the overall safety problem is to utilize the capability of traffic micro-simulation to assess safety on highways through examination of hazardous vehicle movements in the traffic stream. Using micro-simulation predictive methods, it may be possible to diagnose safety problems and apply appropriate remedial measures, rather than waiting until a crash occurs to remedy the problem. This means, a hazard can be early identified and possibly corrected before implementation of highway projects. In addition, the use of simulation tools to evaluate the safety of a traffic system can be advantageous because such tools provide extensive results for any study area within a relatively short time along with other traffic operational measures like level of service, delays, travel times, and capacities. Therefore, the objective of this dissertation was to analyze numerically the likelihood of the traffic crashes that might occur on the highway using cellular based micro-simulations. The modeling considered occurrence of rear-end crashes on high-speed highways with two lanes of traffic in each direction. Narrowing the safety evaluation to rear-end crashes, this study sought to analyze these crashes by providing simulation evidence of association between time-based traffic safety indicators and driver attributes with the likelihood of conflict or collision. To meet the study objectives, a stochastic cellular automata traffic model have been extended to use field-derived vehicle and driver characteristics. The vehicles' acceleration submodel in the simulation is categorized into different regimes depending on the prevailing traffic conditions. The vehicles' evolutions in the proposed micro-simulation model are based on kinematic equations to enhance the realism of their advancements. Behavioral variance in the model is introduced by taking in consideration both driver aggression and responsiveness to the traffic conditions. The model is calibrated using field data. Comparison of simulated spacings and speeds obtained from the simulation output with vehicle trajectories data obtained from the field return a Mean Absolute Percentage Error (MAPE) of less than 10% and a Theil's coefficient of inequality (U) of about 0.002. These statistics inferred that the proposed model worked well in replicating traffic on the field. In addition, correlation results showed that simulation results not only agree to the theoretical results but also to the detector data collected from the field. The driver behavior was found to contribute more in the likelihood of crashes which was determined by amount of great deceleration that driver apply to maintain safety during movement. The likelihood of vehicles to crash in the model was formulated from the Gamma distribution functions. Closer examination of the probability of a vehicle to crash in the model indicated that the likelihood of crashing is high when the traffic is flowing close to the maximum flow.

Modeling Multilevel Data in Traffic Safety

Author : Hoong Chor Chin
Publisher : Nova Science Publishers
ISBN 13 : 9781606922705
Total Pages : 0 pages
Book Rating : 4.9/5 (227 download)

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Book Synopsis Modeling Multilevel Data in Traffic Safety by : Hoong Chor Chin

Download or read book Modeling Multilevel Data in Traffic Safety written by Hoong Chor Chin and published by Nova Science Publishers. This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Background: In the study of traffic system safety, statistical models have been broadly applied to establish the relationships between the traffic crash occurrence and various risk factors. Most of the existing methods, such as the generalised linear regression models, assume that each observation (e.g. a crash or a vehicle involvement) in the estimation procedure corresponds to an individual situation. Hence, the residuals from the models exhibit independence. Problem: However, this "independence" assumption may often not hold true since multilevel data structures exist extensively because of the data collection and clustering process. Disregarding the possible within-group correlations may lead to production of models with unreliable parameter estimates and statistical inferences. Method: Following a literature review of crash prediction models, this book proposes a 5 T-level hierarchy, viz. (Geographic region level -- Traffic site level -- Traffic crash level -- Driver-vehicle unit level -- Vehicle-occupant level) Time level, to establish a general form of multilevel data structure in traffic safety analysis. To model properly the potential between-group heterogeneity due to the multilevel data structure, a framework of hierarchical models that explicitly specify multilevel structure and correctly yield parameter estimates is employed. Bayesian inference using Markov chain Monte Carlo algorithm is developed to calibrate the proposed hierarchical models. Two Bayesian measures, viz. the Deviance Information Criterion and Cross-Validation Predictive Densities, are adapted to establish the model suitability. Illustrations: The proposed method is illustrated using two case studies in Singapore: 1) a crash-frequency prediction model which takes into account Traffic site level and Time level; 2) a crash-severity prediction model which takes into account Traffic crash level and Driver-vehicle unit level. Conclusion: Comparing the predictive abilities of the proposed models against those of traditional methods, the study demonstrates the importance of accounting for the within-group correlations and illustrates the flexibilities and effectiveness of the Bayesian hierarchical approach in modelling multilevel structure of traffic safety data.

Analysis, Modeling and Simulation of Micro Scale Traffic Dynamics Under Different Driving Environments

Author : Hui Deng
Publisher :
ISBN 13 : 9781339542522
Total Pages : pages
Book Rating : 4.5/5 (425 download)

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Book Synopsis Analysis, Modeling and Simulation of Micro Scale Traffic Dynamics Under Different Driving Environments by : Hui Deng

Download or read book Analysis, Modeling and Simulation of Micro Scale Traffic Dynamics Under Different Driving Environments written by Hui Deng and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Individual driving behavior, such as anticipation, risk-taking and cooperative lane change, has significant impact on overall traffic flow characteristics and highway performance. It contributes to various traffic flow phenomena, including platooning, capacity drop and traffic oscillations. A good understanding of driving behavior under different driving environments, such as curved roads, lane-drops, merges and diverges, and platooning enabled by vehicle to vehicle communication, can help us design safer roads, and safer and more efficient autonomous or semi-autonomous driving vehicles. New car following models have been developed to capture the empirical observed anticipation and risk-taking driving behavior, and applied to investigate how anticipation and risk-taking may lead to different traffic flow phenomena and influence highway capacity and safety. Considering gap anticipation, full range traffic conditions can be reproduced, including free-flow, congestion and traffic jam under fixed and moving bottleneck, realistic flow capacities and fundamental diagrams with different levels of anticipation, as well as platoon driving when gap anticipation dependents on the gap. The effect of risk-taking on traffic safety is studied with a collision-possible car following model considering driver anticipation. Risk-taking leads to traffic oscillations and potential collision hazards when traffic is not stable. Longer length of view field can improve traffic safety, and large numbers of vehicle crashes happen when view field length is shorter than given threshold. Merge traffic dynamic has been studied by simulating of cooperative lane change, and drivers' merge location choice is studied to show its impact on traffic oscillations near merging junction. A simplified lane change cooperation strategy is developed and integrated with optimal speed car following logic to capture cooperative lane change behavior in merge junctions. This model can reproduce reasonable merge ratio, capacity drop, turn taking merging behavior and stop and go traffic at merge bottleneck. Lane change incentive and main lane traffic condition affect drivers' lane change behavior and leads to different merge location choice. Microscopic and macroscopic traffic simulation show merge location choice contributes to the formation of stop-and-go waves near merging junctions and the period of these waves are closely related to the distance between the two dominant merging locations. Theoretical and data analysis are used to reveal the correlation between drivers' anticipation, relaxation behavior and traffic hysteresis. Through an analysis of the trajectory data from NGSIM and a theoretical analysis of car-following models, it is revealed that traffic hysteresis is generated by an imbalance in driver relaxation and anticipation. By changing the strength of relaxation and anticipation, we are able to reproduce positive, negative and double hysteresis loops, as well as aggressive and timid driving behavior. It is further shown that the relative positions of acceleration and deceleration phase with respect to the equilibrium state is not unique and are determined by the comparative strength of relaxation and anticipation in different traffic conditions. This study suggests that traffic hysteresis can be suppressed by balancing driver relaxation and anticipation, and stop-and-go traffic can be smoothed by eliminating aggressive driving in congested traffic. A three-mode vehicle control law is proposed for ACC (Adaptive Cruise Control) and CACC (Cooperative Adaptive Cruise Control) and implemented in VENTOS (VEhicular NeTwork Open source Simulator). Traffic hysteresis and stability of studied both analytically and using VENTOS simulation. The ability of ACC/CACC to improve highway safety and eliminating traffic hysteresis is verified by traffic simulation under critical traffic conditions, including realistic stop-and-go traffic and worst case stopping. Through analytical approaches and simulation, we have demonstrated the stability and robustness of our proposed ACC/CACC control system against sensor measurement errors and lossy wireless communication links which is required to implement the CACC control logic. The benefit of wireless communication, even with some lossy links, is significant in ensuring stream stability and performance.

Vehicular Safety and Operations Assessment of Reserved Lanes Using Microscopic Simulation

Author : Chao Li
Publisher :
ISBN 13 :
Total Pages : 82 pages
Book Rating : 4.:/5 (113 download)

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Book Synopsis Vehicular Safety and Operations Assessment of Reserved Lanes Using Microscopic Simulation by : Chao Li

Download or read book Vehicular Safety and Operations Assessment of Reserved Lanes Using Microscopic Simulation written by Chao Li and published by . This book was released on 2017 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: Evaluation of roadway safety via the analysis of vehicular conflicts using microscopic simulation shows increasing preference among transportation professionals, mostly due to significant advances in computational technology that allows for better efficiency when compared with other traffic safety modeling approaches. In addition, since modeling vehicular interactions via simulation is intrinsic to the methodology, one may assess various impacts of safety treatments without disrupting vehicle movements and before proceeding with real-world implementations. VISSIM, a microscopic traffic simulation model, is used in this thesis to reproduce vehicular interactions of an urban High Occupancy Vehicle (HOV) arterial in Québec. The model is calibrated to reflect the observed real-world driving behavior. Vehicle conflicts are assessed using the Surrogate Safety Assessment Model (SSAM) developed by Federal Highway Administration (FHWA). The experimental results indicate that the existing study area has a significant safety problem, mostly due to high interactions between buses and passenger cars. Alternative geometric and control designs are evaluated to ameliorate traffic safety. It is shown that the proposed alternative solutions can be used to either efficiently eliminate many vehicular traffic conflicts, or to significantly reduce public transit delay while ameliorating traffic safety. It is expected that this methodology can be successfully applied to other similar reserved lanes facilities.

Towards Developing an Integrated Microscopic Traffic Simulation Model for Large Road Networks

Author : Frank Lehmann
Publisher :
ISBN 13 :
Total Pages : 274 pages
Book Rating : 4.:/5 (111 download)

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Book Synopsis Towards Developing an Integrated Microscopic Traffic Simulation Model for Large Road Networks by : Frank Lehmann

Download or read book Towards Developing an Integrated Microscopic Traffic Simulation Model for Large Road Networks written by Frank Lehmann and published by . This book was released on 2018 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt: Traffic jams have become one of the key topics in the 21st century and cause immense losses in productivity, increase CO2 emissions and affect driver stress, travel time predictability and increased wear and tear on vehicles. To test possible countermeasures, optimise existing infrastructure or develop new Intelligent Transport Systems (ITS), traffic has to be modelled. The inherent complexity which is a result of inter- and intra-driver heterogeneity, macroscopic feedback loops, local interactions, multi-modal transport and many more is tackled with simulations. By representing the (longitudinal) dynamics of individual vehicles (“microsimulation”), high model fidelity can be achieved. By aggregating the resulting trajectories, macroscopic phenomena emerge and can be incorporated to answer a wide range of traffic-related questions. Since human drivers vary in their perception of stimuli, preferences and reaction, randomness is inevitably and circumvents the construction of perfectly accurate models. Which microscopic features are needed and how they should be mathematically represented runs like a central thread through this thesis. First, it develops a systematic classification scheme to identify modelling strategies and evaluate advantages and shortcomings of (partly) discrete microsimulations. Because real-world trajectories are continuous in time and space, representing them discretely leads to artefacts which induces an upper precision boundary for all models operating on this level of discretisation. Such model-independent errors will be measured based on empirical, naturalistic and synthetically generated trajectories. It is also evaluated to which extent driver heterogeneity and randomness may be compensated with discrete components to simplify modelling and increase computational efficiency. Based on the gained insights, a new, integrated microscopic model is developed. The second major theme in this thesis are gridded, discrete road topologies (chequerboards, Manhattan layouts) populated with vehicles “hopping” from one location to the next. An extensive literature review summarise existing approaches and it is discussed how these standardised road networks and extremely simplified dynamics are well-suited as testbed for ITS. Based on identified research gaps a Timed Automata-based particle hopping model is developed. The two main tools to achieve the outlined objectives are literature reviews, data analysis and computer simulations. To construct the classification scheme, existing genealogies and typologies for traffic models and dynamical systems in other scientific disciplines were reviewed. Another approach was taken for conducting the literature review of chequerboard models: starting from the prototypical BML model, the citing sources are surveyed in reverse order, the behaviour of relevant models is synthesized and contradictions and gaps critically analysed. To quantify the model-independent error, datasets are sampled, quantised and discretised over a wide range of step sizes. Making use of naturalistic driving data, synthetically generated trajectories and high-quality experimental observations, the highest achievable errors for (partly) discrete microsimulations is measured. The dataset recorded under experimental conditions with a group of homogeneous drivers is reused to identify to quantify driver heterogeneity and find the maximum achievable correlations between car-following stimuli and reactions. In summary, this thesis shows that randomness and heterogeneity in human drivers is significant and exceeds the model-independent discretisation errors for a wide range of quantisation parameters. This justifies representing trajectory features discretely to increase computational efficiency and improve the modelling process. Based on this proposition two new formulations for simplistic and advanced microsimulations are developed. The former is able to reproduce all macroscopic free-flow to congestion phase transitions while the latter integrates lateral and longitudinal dynamics based on statistical microscopic properties. Both approaches fill gaps identified by a systematic literature review.

Potential of Integrating Microscopic and Mesoscopic Traffic Simulation Models

Author :
Publisher :
ISBN 13 :
Total Pages : 169 pages
Book Rating : 4.:/5 (392 download)

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Book Synopsis Potential of Integrating Microscopic and Mesoscopic Traffic Simulation Models by :

Download or read book Potential of Integrating Microscopic and Mesoscopic Traffic Simulation Models written by and published by . This book was released on 1997 with total page 169 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Enhanced Micro-simulation Models for Accurate Safety Assessment of Traffic Management ITS Solutions

Author : Wuping Xin
Publisher :
ISBN 13 :
Total Pages : 100 pages
Book Rating : 4.:/5 (413 download)

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Book Synopsis Enhanced Micro-simulation Models for Accurate Safety Assessment of Traffic Management ITS Solutions by : Wuping Xin

Download or read book Enhanced Micro-simulation Models for Accurate Safety Assessment of Traffic Management ITS Solutions written by Wuping Xin and published by . This book was released on 2008 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: Much research has been conducted in the development, implementation, and evaluation of innovative ITS technologies aiming to improve traffic operations and driving safety. Existing micro-simulation modeling only describes normative car-following behaviors devoid of weakness and risks associated with real-life everyday driving. This research aims to develop a new behavioral car-following model that is pertinent to the true nature of everyday human driving. Unlike traditional car-following models that deliberately prohibit vehicle collisions, this new model builds upon multi-disciplinary findings explicitly taking into account perceptual thresholds, judgment errors, anisotropy of reaction times and driver inattention, in order to replicate "less-than-perfect" driving behavior with all its weaknesses and risks. Most importantly, all parameters of this model have direct physical meaning; this ensures vehicle collisions are replicated as a result of behavioral patterns rather than simply being numerical artifacts of the model. Meanwhile, vehicle trajectories were extracted from real-life crashes collected from a freeway section of I-94WB. This is by far the first data collection efforts that aim to collect vehicle trajectories from real-life crashes to aid car-following modeling. These data were employed in this study to test, calibrate and validate the model. This new model is successful in replicating these vehicle trajectories as well as crashes.

An Evaluation of Traffic Simulation Models for Supporting ITS Development

Author : Sharon Adams Boxill
Publisher :
ISBN 13 :
Total Pages : 120 pages
Book Rating : 4.3/5 (555 download)

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Book Synopsis An Evaluation of Traffic Simulation Models for Supporting ITS Development by : Sharon Adams Boxill

Download or read book An Evaluation of Traffic Simulation Models for Supporting ITS Development written by Sharon Adams Boxill and published by . This book was released on 2000 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tools to evaluate networks under information supply are a vital necessity in light of the systems being implemented as part of the Intelligent Transportation Systems (ITS) deployment plan. One such tool is the traffic simulation model. This report presents an evaluation of the existing traffic simulation models to identify the models that can be potentially applied in ITS equipped networks. The traffic simulation models are categorized according to type (macroscopic, microscopic or mesoscopic), as well as functionality (highway, signal, integrated). The entire evaluation is conducted through two steps: initial screening and in-depth evaluation. The initial step generates a shorter but more specific list of traffic simulation models based on some pre-determined criteria. The in-depth evaluation identifies which model on the shorter list is suitable for a specific area of ITS applications. It is concluded from this research that presently CORSIM and INTEGRATION appear to have the highest probability of success in real-world applications. It is also found that by adding more calibration and validation in the U.S., the AIMSUN 2 and PARAMICS models will be brought to the forefront in the near term for use with ITS applications.

Surrogate Safety Measures from Traffic Simulation Models

Author : Douglas Gettman
Publisher :
ISBN 13 :
Total Pages : 118 pages
Book Rating : 4.:/5 (74 download)

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Book Synopsis Surrogate Safety Measures from Traffic Simulation Models by : Douglas Gettman

Download or read book Surrogate Safety Measures from Traffic Simulation Models written by Douglas Gettman and published by . This book was released on 2003 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This project investigates the potential for deriving surrogate measures of safety from existing microscopic traffic simulation models for intersections. The process of computing the measures in the simulation, extracting the required data, and summarizing the results is denoted as the Surrogate Safety Assessment Methodology. These surrogate measures could then be used to support traffic engineering alternatives evaluation with respect to safety for both signalized and unsignalized intersections. The report describes the five main activities of this project: (1) review of previous work in modeling of safety at traffic facilities (focusing on intersection safety modeling) using surrogate measures, (2) survey of the capabilities of existing traffic simulation models to support derivation of surrogate measures of safety, (3) identification of use cases and functional requirements for a surrogate safety assessment tool that interacts with traffic simulation model outputs, (4) specification of algorithms for calculating surrogate measures of safety appropriate for intersections, and (5) suggestions for validation activities to support the analysis potential for surrogate measures and compare surrogate measures from simulation models with field data and previous safety studies"--Technical report documentation page.

Microscopic Overtaking Model to Simulate Two-lane Highway Traffic Operation and Safety Performance

Author : Amir Hosein Ghods
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (126 download)

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Book Synopsis Microscopic Overtaking Model to Simulate Two-lane Highway Traffic Operation and Safety Performance by : Amir Hosein Ghods

Download or read book Microscopic Overtaking Model to Simulate Two-lane Highway Traffic Operation and Safety Performance written by Amir Hosein Ghods and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Rural two-lane highways make up a large portion of road networks around the world. The special geometric and traffic attributes of these highways pose special challenges to safety and traffic operation. In recent years, microscopic simulation models have gained increased acceptance as a reliable tool for investigating traffic operations and evaluating safety performance. Despite this trend, the development and application of these models to two-lane highway operations has not kept pace with those of freeways and urban networks, and this is due, in large part, to difficulties in modeling the overtaking process. This process has been rendered complex by the large number of inter-related decision factors that need to be considered by the overtaking driver in a bi-directional driving regime. In this research, a new overtaking gap-acceptance model is developed to simulate traffic operation and safety performance on two-lane highways. This model considers a wide spectrum of physical and behavioral variables that could affect overtaking. It does so by introducing a new safety-based gap-acceptance decision variable based on the overtaking driver's perception of time-to-collision (TTC) with an opposing vehicle. The decision to overtake was expressed as a function of the perceived TTC in comparison to an established driver risk threshold (critical TTC). The distribution of critical TTC among drivers are determined through a model calibration and validation procedure based on overtaking observational data obtained from a video-recording of a one-kilometer segment of a two-lane highway. Unlike previous models, the proposed gap-acceptance model makes use of only a few calibration parameters. The proposed overtaking models along with other components of a micro-simulation traffic model are implemented in a software framework that can simulate traffic and safety operation for two-lane highways. The overall simulation results demonstrate that the proposed simulation model can provide reliable measures of traffic and safety for two-lane highway operation. The overtaking model was found to yield both consistent and transferable results. The model is then applied successfully to provide more accurate estimates of traffic measures used in level-of-service analysis for two-lane highways and to compare these results to values reported in the two versions of the Highway Capacity Manual (HCM). In another application, this model is used to investigate the impact of truck mandated speed limiters on safety and traffic operation of two-lane highways and specifically their impact on overtaking. Finally, the potential implications of adaptive cruise control for overtaking and its resultant traffic and safety impacts are studied using the developed simulation model.

Integrated Model of Driving Behavior

Author : Tomer Toledo
Publisher : VDM Publishing
ISBN 13 : 9783836435567
Total Pages : 0 pages
Book Rating : 4.4/5 (355 download)

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Book Synopsis Integrated Model of Driving Behavior by : Tomer Toledo

Download or read book Integrated Model of Driving Behavior written by Tomer Toledo and published by VDM Publishing. This book was released on 2008 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Driving behavior models, which focus on acceleration, lane changing and gap acceptance decisions are essential to microscopic traffic simulation models and important to several other fields of transportation science and engineering. In this book, a framework for driving behavior modeling that integrates the various decisions driver make is developed, implemented and tested. This framework is based on the concepts of short-term goal and short-term plan, which captures inter-dependencies among the various decisions a driver makes as well as their planning and anticipation capabilities. Based on these concepts an integrated driving behavior model that captures both acceleration and lane changing behaviors is specified, estimated using detailed trajectory data and implemented and validated within a microscopic traffic simulation model. This book is addressed to modelers in transportation and traffic engineering and researchers and developers of traffic simulation models.