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Using Micro Simulated Traffic Conflicts As A Surrogate Safety Assessment Technique For Evaluating Safety Performance Of Transit Design Alternatives At Signalized Intersections
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Book Synopsis Using Micro-simulated Traffic Conflicts as a Surrogate Safety Assessment Technique for Evaluating Safety Performance of Transit Design Alternatives at Signalized Intersections by : Lu Li
Download or read book Using Micro-simulated Traffic Conflicts as a Surrogate Safety Assessment Technique for Evaluating Safety Performance of Transit Design Alternatives at Signalized Intersections written by Lu Li and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
Download or read book Safe Mobility written by Dominique Lord and published by Emerald Group Publishing. This book was released on 2018-04-18 with total page 511 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book increases the level of knowledge on road safety contexts, issues and challenges; shares what can currently be done to address the variety of issues; and points to what needs to be done to make further gains in road safety.
Book Synopsis HUTSIM: Urban Traffic Simulation and Control Model: Principles and Applications by : Iisakki Kosonen
Download or read book HUTSIM: Urban Traffic Simulation and Control Model: Principles and Applications written by Iisakki Kosonen and published by . This book was released on 1999 with total page 249 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tiivistelmä. - Sammandrag.
Book Synopsis Next Generation Safety Performance Monitoring at Signalized Intersections Using Connected Vehicle Technology by : Liteng Zha
Download or read book Next Generation Safety Performance Monitoring at Signalized Intersections Using Connected Vehicle Technology written by Liteng Zha and published by . This book was released on 2014 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: Crash-based safety evaluation is often hampered by randomness, lack of timeliness, and rarity of crash occurrences. Surrogate safety data are commonly used as an alternative to crash data; however, its current practice is still resource intensive and prone to human errors. The advent of connected vehicle technology allows vehicles to communicate with each other as well as infrastructure wirelessly. Through this platform, vehicle movements and signal status at the facilities can be automatically and continually monitored in real time. This study explores the viability of long-term safety performance evaluation at signalized intersection using connected vehicle technology. The development focuses on vehicle-to-infrastructure (V2I) communications which require one road-side equipment (RSE) and some level of on-board equipment to be successful. To accomplish the objective, the researchers defined useful safety measures and developed specific algorithms to derive them in real time from the V2I communication data sets. The safety measures were categorized into single-OBE measures and dual-OBE measure based on the number of the equipped vehicle needed to be monitored. We used vehicles trapped in dilemma zone as the single-OBE measure. The dual-OBE measures included rear-end and crossing conflicts. Different simulation scenarios were designed in VISSIM to test the effectiveness of the proposed framework, effect of market penetration rate as well as required observation period for effective implementation. The evaluation results indicated that the application can effectively detect changes in safety performance at full market penetration. It can detect a shift of crash pattern from rear-end crashes to right-angle crashes due to the shorted inter green interval at low traffic volume as well as the mitigation of this pattern during the medium-to-high traffic volume. The selected measures can also identify the increasing risk of rear-end and right-angle crashes after removing advance detectors at the major approaches. Sensitivity analysis from the 60 simulation hours' data showed that more than 40% and 60% penetration rate is likely to be required for a reliable detection in the low volume level and medium-to-high volume level, respectively. Increase of traffic volume activated the corresponding phases more frequently and may result in fewer safety measures being collected. Although losing the power of detection, single-OBE measure was demonstrated to be more reliable at lower penetration rate. Under low OBE market penetrations, observation period can be extended to compensate for small sample size. However, the required observation periods vary with the types of safety indicators being collected and the levels of OBE saturation. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/152565
Book Synopsis Use of Traffic Conflicts to Estimate Vehicle-pedestrian Safety at Signalized Intersections by : Hiba Nassereddine
Download or read book Use of Traffic Conflicts to Estimate Vehicle-pedestrian Safety at Signalized Intersections written by Hiba Nassereddine and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding how vehicle drivers and pedestrians interact is key to identifying countermeasures that improve the safety of the interactions. As a result, techniques that can be used to evaluate the effectiveness of traffic control device-based safety countermeasures without the need to wait for the availability of crash data are needed. Using video data, the interactions between right-turning vehicles and conflicting pedestrians were documented for sites with a permissive circular green indication or a flashing yellow arrow (FYA) permissive right turn indication and quantified using vehicle and pedestrian position timestamps. Multiple non-probabilistic linear regression models were created to describe the relationship between the position of the pedestrian within the crosswalk and the time for a right turning vehicle maneuver to be completed. Given the nature of the models output, a Pedestrian Respect Indicator (PRI) is introduced as an indicator of the safety of vehicle-pedestrian interactions. The higher the PRI, the more "respect" towards pedestrians. Surrogate safety measures (SSMs) have allowed to step away from traditional approach and analyze safety performance without relying on crash records. In recent years, the use of surrogate measures to estimate crash probabilities with extreme value theory (EVT) models has been an alternative approach to its use as aggregate crash frequency predictors. Univariate and bivariate extreme value theory models were developed using the block maxima (BM) approach and the peak over threshold (POT) approach. In addition, Bayesian hierarchical models were developed for each approach. Using the resulting estimates, the number of crashes was estimated for each model. The estimated crashes from the Bayesian hierarchical models were closer to the observed number of crashes than those from other models. Time to complete a turn produced better fit models indicating that the time to complete a turn is a good representation of traffic interactions. Obtaining SSMs from video data requires complex processing and large video data sizes. A software-based framework to estimate SSMs, such as PET and time-to-collision (TTC) values between right-turn-on-red (RTOR) and through vehicles was proposed and it demonstrated the feasibility of using vehicle trajectories obtained from existing radar-based vehicle detection systems to calculate such measures.
Download or read book Utilities and Roadside Safety written by and published by Transportation Research Board. This book was released on 2004 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Development of a Safety Evaluation Procedure for Identifying High-risk Signalized Intersections in the Virginia Department of Transportation's Northern Virginia District by : Young-Jun Kweon
Download or read book Development of a Safety Evaluation Procedure for Identifying High-risk Signalized Intersections in the Virginia Department of Transportation's Northern Virginia District written by Young-Jun Kweon and published by . This book was released on 2007 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research was undertaken to develop an evaluation procedure to identify high-risk four-legged signalized intersections in VDOT's Northern Virginia district by traffic movements and times of day. By using the developed procedure, traffic engineers are expected to be able to identify signalized intersections where the traffic crash occurrences under different traffic conditions for different times of day are more frequent than would normally be expected. Using generalized linear models such as negative binomial models, one safety performance function was estimated for each of nine crash population reference groups formed by three traffic crash patterns (crash patterns 1, 4, and 6) and four times of day (A.M. peak, mid day, P.M. peak, and evening off peak). Crash pattern 1 is a same-direction crash (rear-end, sideswipe or angle crash) that occurs after exiting the intersection; crash pattern 4 is a right-angle crash between two adjacent straight-through vehicle movements in the intersection; and crash pattern 6 is an angle or head-on or opposite sideswipe crash between a straight-through vehicle movement and an opposing left-turn vehicle movement in the intersection. The procedure developed in this study is based on the empirical Bayes (EB) method. Additional data do not need to be collected in order to use the EB procedure because all the data required for applying the EB procedure should be obtainable from VDOT's crash database and from Synchro input data that are already available to traffic engineers for traffic signal phase plans. Thus, the EB procedure is cost-effective and readily applicable. For easy application of the EB procedure, an EB spreadsheet was developed using Microsoft Excel, and a users' guide was prepared. These are available from the author upon request.
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 0 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.
Author :European Conference of Ministers of Transport Publisher :OECD Publishing ISBN 13 :9282103781 Total Pages :286 pages Book Rating :4.2/5 (821 download)
Book Synopsis Speed Management by : European Conference of Ministers of Transport
Download or read book Speed Management written by European Conference of Ministers of Transport and published by OECD Publishing. This book was released on 2006-10-13 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt: Speeding is the number one road safety problem in a large number of OECD/ECMT countries. It is responsible for around one third of the current, unacceptably high levels of road fatalities. Speeding has an impact not only on accidents but also on the ...
Book Synopsis Safety Data, Analysis, and Evaluation by :
Download or read book Safety Data, Analysis, and Evaluation written by and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "TRB?s Transportation Research Record: Journal of the Transportation Research Board, No. 2514, explores 19 papers related to safety data, analysis, and evaluation in the transportation sector, including: Exploring Driver Error at Intersections: Key Contributors and Solutions; Level of Service of Safety Revisited; Longitudinal Analysis of Rural Interstate Fatalities in Relation to Speed Limit Policies; Predicting Crashes on Expressway Ramps with Real-Time Traffic and Weather Data; Multilevel Logistic Regression Modeling for Crash Mapping in Metropolitan Areas; Simulated Traffic Conflicts: Do They Accurately Represent Field-Measured Conflicts?; Assessing Safety Improvements to Pedestrian Crossings Using Automated Conflict Analysis; Understanding Factors Affecting Frequency of Traffic Conflicts Between Electric Bicycles and Motorized Vehicles at Signalized Intersections; Comparative Analysis of Injury Severity Resulting from Pedestrian?Motor Vehicle and Bicycle?Motor Vehicle Crashes on Roadways in Alabama; Validation of Crash Modification Factors Derived from Cross-Sectional Studies with Regression Models; Fault Determination for Crashes in Vermont: Implications of Distance from Home; Crash Patterns at Signalized Intersections; Analyses of Multiyear Statewide Secondary Crash Data and Automatic Crash Report Reviewing; Assessment of Pedestrian Risk at Crossings with Kinematic?Probabilistic Model; Predicting Driver Injury Severity in Single-Vehicle and Two-Vehicle Crashes with Boosted Regression Trees; Effects of Geodemographic Profiles of Drivers on Their Injury Severity from Traffic Crashes Using Multilevel Mixed-Effects Ordered Logit Model; Copula-Based Joint Model of Injury Severity and Vehicle Damage in Two-Vehicle Crashes; Identifying Optimal High-Risk Driver Segments for Safety Messaging: Geodemographic Modeling Approach; Evaluation of Signalized-Intersection Crash Screening Methods Based on Distance from Intersection."--Publisher's description.
Book Synopsis Proceedings of AICCE'19 by : Fadzli Mohamed Nazri
Download or read book Proceedings of AICCE'19 written by Fadzli Mohamed Nazri and published by Springer Nature. This book was released on 2019-11-28 with total page 1635 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book gathers the latest research, innovations, and applications in the field of civil engineering, as presented by leading national and international academics, researchers, engineers, and postgraduate students at the AWAM International Conference on Civil Engineering 2019 (AICCE’19), held in Penang, Malaysia on August 21-22, 2019. The book covers highly diverse topics in the main fields of civil engineering, including structural and earthquake engineering, environmental engineering, geotechnical engineering, highway and transportation engineering, water resources engineering, and geomatic and construction management. In line with the conference theme, “Transforming the Nation for a Sustainable Tomorrow”, which relates to the United Nations’ 17 Global Goals for Sustainable Development, it highlights important elements in the planning and development stages to establish design standards beneficial to the environment and its surroundings. The contributions introduce numerous exciting ideas that spur novel research directions and foster multidisciplinary collaborations between various specialists in the field of civil engineering.
Book Synopsis Fundamentals of Traffic Simulation by : Jaume Barceló
Download or read book Fundamentals of Traffic Simulation written by Jaume Barceló and published by Springer Science & Business Media. This book was released on 2011-01-06 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: The increasing power of computer technologies, the evolution of software en- neering and the advent of the intelligent transport systems has prompted traf c simulation to become one of the most used approaches for traf c analysis in s- port of the design and evaluation of traf c systems. The ability of traf c simulation to emulate the time variability of traf c phenomena makes it a unique tool for capturing the complexity of traf c systems. In recent years, traf c simulation – and namely microscopic traf c simulation – has moved from the academic to the professional world. A wide variety of traf- c simulation software is currently available on the market and it is utilized by thousands of users, consultants, researchers and public agencies. Microscopic traf c simulation based on the emulation of traf c ows from the dynamics of individual vehicles is becoming one the most attractive approaches. However, traf c simulation still lacks a uni ed treatment. Dozens of papers on theory and applications are published in scienti c journals every year. A search of simulation-related papers and workshops through the proceedings of the last annual TRB meetings would support this assertion, as would a review of the minutes from speci cally dedicated meetings such as the International Symposiums on Traf c Simulation (Yokohama, 2002; Lausanne, 2006; Brisbane, 2008) or the International Workshops on Traf c Modeling and Simulation (Tucson, 2001; Barcelona, 2003; Sedona, 2005; Graz 2008). Yet, the only comprehensive treatment of the subject to be found so far is in the user’s manuals of various software products.
Book Synopsis Alternative Types of Roundabouts by : Tomaž Tollazzi
Download or read book Alternative Types of Roundabouts written by Tomaž Tollazzi and published by Springer. This book was released on 2014-11-07 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a history of roundabouts, an introduction to their design, calculations of their capacity and traffic-safety features. It describes the key features of standard roundabouts and their limitations. Alternative types of roundabouts are a fairly recent development and have only been implemented in a few countries to date. The book illustrates a broad variety of these recent alternative types of roundabouts, as well as proposed types still in the development phase, explaining for each the specific needs it meets, its advantages and drawbacks. In closing, the book offers an outlook on the role of roundabouts in future street traffic.
Book Synopsis Transportation Decision Making by : Kumares C. Sinha
Download or read book Transportation Decision Making written by Kumares C. Sinha and published by John Wiley & Sons. This book was released on 2011-09-09 with total page 576 pages. Available in PDF, EPUB and Kindle. Book excerpt: This pioneering text provides a holistic approach to decisionmaking in transportation project development and programming, whichcan help transportation professionals to optimize their investmentchoices. The authors present a proven set of methodologies forevaluating transportation projects that ensures that all costs andimpacts are taken into consideration. The text's logical organization gets readers started with asolid foundation in basic principles and then progressively buildson that foundation. Topics covered include: Developing performance measures for evaluation, estimatingtravel demand, and costing transportation projects Performing an economic efficiency evaluation that accounts forsuch factors as travel time, safety, and vehicle operatingcosts Evaluating a project's impact on economic development and landuse as well as its impact on society and culture Assessing a project's environmental impact, including airquality, noise, ecology, water resources, and aesthetics Evaluating alternative projects on the basis of multipleperformance criteria Programming transportation investments so that resources can beoptimally allocated to meet facility-specific and system-widegoals Each chapter begins with basic definitions and concepts followedby a methodology for impact assessment. Relevant legislation isdiscussed and available software for performing evaluations ispresented. At the end of each chapter, readers are providedresources for detailed investigation of particular topics. Theseinclude Internet sites and publications of international anddomestic agencies and research institutions. The authors alsoprovide a companion Web site that offers updates, data foranalysis, and case histories of project evaluation and decisionmaking. Given that billions of dollars are spent each year ontransportation systems in the United States alone, and that thereis a need for thorough and rational evaluation and decision makingfor cost-effective system preservation and improvement, this textshould be on the desks of all transportation planners, engineers,and educators. With exercises in every chapter, this text is anideal coursebook for the subject of transportation systems analysisand evaluation.
Book Synopsis Safety Performance of Median U-turn Intersections by : Jonathan James Kay
Download or read book Safety Performance of Median U-turn Intersections written by Jonathan James Kay and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of alternative intersection designs can provide both safety and operational benefits for road users at potentially lower costs when implemented in the appropriate setting. The Federal Highway Administration has previously recognized a subset of alternative intersections designs broadly referred to as "reduced left-turn conflict intersections" as a proven safety countermeasure that have been shown to decrease the risk of potentially severe crash types by reducing conflict points through the use of indirect left-turn movements. Median U-turn intersections (also referred to as "Michigan lefts" or "boulevard turnarounds") are one such alterative design that accommodates indirect left-turn movements via directional U-turn crossovers located within the median along one or both of the intersecting roadways. Michigan has long been a pioneer in the implementation of median U-turns along urban and suburban divided boulevards, with initial installations dating back several decades. Additionally, various indirect left-turn configurations have been implemented along rural highways and frontage roads for urban freeways.While prior work has consistently demonstrated that median U-turn intersection designs represent an effective countermeasure that can improve operational performance and reduce the frequency of severe crash types when implemented in the appropriate context, much of the extant research is outdated and several important areas of investigation remain unexplored. This includes defining the appropriate crash influence area, the impacts of pre-conversion characteristics, impacts to pedestrian and bicycle collisions, and evaluating crashes pre/post conversion (e.g., longitudinal panel data) compared to a purely cross-sectional evaluation. To address these and other knowledge gaps, research was performed to quantify the safety performance characteristics and develop analytical tools related to the utilization of median U-turn intersections. Historical traffic crash data were collected for signalized and unsignalized intersections in Michigan where left-turns are accommodated by a median U-turn design. To allow for comparison of the performance between the median U-turn and traditional designs, data were also collected for a sample of reference intersections (divided and undivided) where conventional direct left-turn movements were maintained. A novel approach was developed to define the safety performance influence area of a median U-turn intersection, which subsequently improved the method of identifying and collecting target crash data. Utilizing the traffic crash data, a series of analyses were performed to identify the differences between conventional and median U-turn intersections, and to also identify the differences in safety performance between various median U-turn design characteristics. The analyses compared crash rates, types, severity distributions, and severe injury collision patterns, and included development of series of safety performance functions and crash modification factors. The results were then generalized into a series of recommendations for roadway agencies considering future implementation of median U-turn intersections, including specific design recommendations intended to improve safety performance for all road users.Ultimately, it was concluded that median U-turn designs represent an effective safety countermeasure to target the reduction of severe crash types for both unsignalized and signalized intersections. While there are some potential tradeoffs with respect to non-injury crash frequencies for specific pre-conversion configurations, the use of these indirect left-turn intersection designs is consistent with the Safe System approach adopted by the United States Department of Transportation within the National Roadway Safety Strategy. Unsignalized median U-turn intersections offer superior fatal and injury crash performance compared to conventional unsignalized intersections. The removal of the crossing conflict points at unsignalized median U-turn designs (which include a closed median at the intersection) essentially eliminates the pattern of severe head on left-turn and angle collisions occurring within conventional intersections. However, it is important to recognize that non-injury crashes were shown to increase when converting a conventional unsignalized intersection to a median U-turn at locations with an existing median on the major roadway.Signalized median U-turn intersections offer superior safety performance for both injury and non-injury crashes compared to conventional signalized intersections along undivided roadways. However, the comparison of median U-turns locations to conventional divided signalized intersections was limited by a lack of reference sites with comparable traffic volumes. Annual average frequencies of severe pedestrian and bicycle crashes were similar between the signalized median U-turn and conventional undivided sites. Finally, several design features of signalized median U-turn intersections were identified as having a significant impact on safety performance, including the distance to crossovers from the main intersection, the length of weaving areas, the number of signalized crossovers, and the number of storage lanes.
Book Synopsis Calculation of Roundabouts by : Raffaele Mauro
Download or read book Calculation of Roundabouts written by Raffaele Mauro and published by Springer Science & Business Media. This book was released on 2010-03-10 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: Roundabouts have become one of the most significant traffic control measures because they are generally statistically safer and more efficient than traditional at grade intersections. This book is dedicated to the evaluation of the operating conditions of roundabouts. In five parts, it thoroughly illustrates the calculation of the capacity, including reliability, and waiting phenomena parameters, such as the times spent in the system and queue lengths. Fully worked examples are included throughout the chapters, with detailed explanations.
