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Estimation Of Crossing Conflict At Signalized Intersection Using High Resolution Traffic Data
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Book Synopsis Estimation of Crossing Conflict at Signalized Intersection Using High-resolution Traffic Data by : Henry X. Liu
Download or read book Estimation of Crossing Conflict at Signalized Intersection Using High-resolution Traffic Data written by Henry X. Liu and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This project explores the possibility of using high-resolution traffic signal data to evaluate intersection safety. Traditional methods using historical crash data collected from infrequently and randomly occurring vehicle collisions can require several years to identify potentially risky situations. By contrast, the proposed method estimates potential traffic conflicts using high-resolution traffic signal data collected from the SMART-Signal system. The potential conflicts estimated in this research include both red-light running events, when stop-bar detectors are available, and crossing (i.e. right-angle) conflicts. Preliminary testing based on limited data showed that estimated conflict frequencies were better than AADT for predicting frequencies of angle crashes. With additional validation this could provide a low-cost and easy-to-use tool for traffic engineers to evaluate traffic safety performance at signalized intersections.
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.
Book Synopsis Using Detailed Signal and Detector Data to Investigate Intersection Crash Causation by : Gary Arnold Davis
Download or read book Using Detailed Signal and Detector Data to Investigate Intersection Crash Causation written by Gary Arnold Davis and published by . This book was released on 2013 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt: Traffic crashes may not always result in severe or fatal injuries, but they can still have nontrivial impacts on system performance, particularly during heavy traffic conditions. One way toward reducing the frequency of such incidents is to first identify the necessary circumstances that resulted in the collision. However, road crashes, particularly intersection related crashes, are complex phenomenon and often result from different combinations of causal factors. Recently, methods for recording high-resolution arterial traffic data have been developed, and it is important for traffic safety engineers to explore such high-resolution data to understand the causes of crashes. In this research one such integrated event based system, known as SMART SIGNAL, which collects and stores detailed loop detector and signal activity, was used to identify the events leading to a crash or a potential crash and illuminate the mechanisms by which traffic conditions and driver decisions interact to produce those events. Two specific event types, a signal violation crash and vehicle pedestrian crash, were evaluated. For the signal violation crash study, SMART SIGNAL data were used to identify the incident and the vehicles involved in the crash. It was then shown how high-resolution data could support a traditional reconstruction of this crash. For vehicle pedestrian interactions, detector and signal activity data were used to predict pedestrian crash risk in the absence of clearance interval at three signalized intersections. A simulation-based method was used to first estimate crash probabilities, and then a counterfactual approach to calculate the probability of the absence of the all-red phase as a necessary condition for the occurrence of the crash provided an alternate estimate of crash-reduction factors for the all-red phase.
Book Synopsis Traffic Conflict Characteristics by :
Download or read book Traffic Conflict Characteristics written by and published by . This book was released on 1967 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Traffic Conflict Techniques for Safety and Operations by : Martin R. Parker
Download or read book Traffic Conflict Techniques for Safety and Operations written by Martin R. Parker and published by . This book was released on 1989 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: Based on previous research and experiences, the procedures described in this guide provide a standard, cost effective method for using traffic conflicts to diagnose safety and operational problems at intersections. The guide contains definitions with illustrations and examples of conflict types, step by step procedures for conducting a conflict study, methods for analyzing and interpreting the data, and guidelines for using conflict data to select countermeasures. Because the reliability of conflict data is dependent upon the ability of the observers to record conflicts accurately, a section of the guide is devoted to training data collectors. Also available, as a training aid and reference source, is an observer's manual.
Book Synopsis Data-Driven Approaches for Robust Signal Plans in Urban Transportation Networks by : Zahra Amini
Download or read book Data-Driven Approaches for Robust Signal Plans in Urban Transportation Networks written by Zahra Amini and published by . This book was released on 2018 with total page 67 pages. Available in PDF, EPUB and Kindle. Book excerpt: In urban transportation networks with signalized intersections a robust pre-timed signal plan is a practical alternative to adaptive control strategies, since it has less complexity and an easier implementation process. Recent advances in technology are making data collection at traffic signals economical and data-driven approaches are likely to benefit from the large traffic data. Data-driven approaches are necessary for designing robust timing plans that can satisfy rapid traffic volume fluctuation and demand growth. This dissertation introduces four data-driven approaches for studying and improving traffic conditions at signalized intersections. Firstly, I discuss the development and testing of two algorithms for checking the quality of traffic data and for estimating performance measures at intersections. The first of these algorithms estimates the systematic error of the detector data at signalized intersections by using flow conservation. According to the ground truth data from a real-world network, the algorithm can reduce the error in the data up to 25%. The second algorithm helps in estimating intersection performance measures in real-time by measuring the number of the vehicles in each approach using high resolution(HR) data. An offset optimization algorithm was developed to adjust signal offsets so as to improve the delay in the system. The performance of three real-world networks using the offsets obtained by the algorithm and those obtained from the widely used Synchro optimization tool, are compared using the VISSIM microscopic simulation model. Simulation results show up to a 30% reduction in the average number of stops and total delay that vehicles experience along the major routes when using the proposed algorithms’ optimized offsets. The fourth algorithm estimates the appropriate switching time between designed timing plans during the day based on the traffic profile of the intersection by using the K-means clustering method. In conclusion, these four algorithms extract useful information from HR data about traffic at signalized intersections. Moreover, the algorithms assist in designing robust timing plans for satisfying demand fluctuations at signalized intersection. Lastly, simulation results from real-world networks illustrate the significant improvements that the proposed data-driven approaches can make in the control systems at urban transportation networks.
Book Synopsis Intersection Safety Evaluation Using High Resolution Traffic Signal Data by : Natanael. D. Vall
Download or read book Intersection Safety Evaluation Using High Resolution Traffic Signal Data written by Natanael. D. Vall and published by . This book was released on 2013 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Analysis of Queue Characteristics at Signalized Intersections Near Highway-railroad Grade Crossing by : Amna Chaudhry
Download or read book Analysis of Queue Characteristics at Signalized Intersections Near Highway-railroad Grade Crossing written by Amna Chaudhry and published by . This book was released on 2015 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt: Analysis of traffic queues at signalized intersections which are in close proximity to highway-railroad grade crossings is of primary importance for determining if the normal signal operation needs to be preempted for railroad operations by providing a special signal mode for safe clearance of the queued vehicles from the tracks before the train arrival, and prohibiting any conflicting traffic movements towards the crossing. Such queuing analysis becomes even more critical where direct observations of traffic queues are not possible or where the assessment is needed for a future location. Inadequate estimation of queues from signalized intersections to the nearby railroad grade crossing can lead to severe safety issues. Underestimation of queue lengths may lead to an unsafe design while significantly overestimated queues may cause unnecessary traffic delays consequently leading to violations of the active traffic control devices at the crossing. In order to determine an adequate approach for reasonable estimation of queue lengths at signalized intersections near highway-railroad grade crossings, this dissertation first evaluated and compared different currently used microscopic simulation-based methods (i.e. Sim-Traffic and VISSIM) for their adequacy in estimating the queue lengths. After that several comparisons are made between the queue estimation from the simulation-based and other deterministic analytical methods including Highway Capacity Software, Synchro, and Railroad Assessment Tool. The comparisons drawn between each method helped identifying the differences and specific limitations of each method in including the impact of various important factors on the resulting queue estimation. The recommendations are provided on the basis of model capability to adequately count the impact of various significant traffic factors on queue estimation and considering minimizing the risk of underestimated queues. Based on the analysis findings, a microscopic simulation based procedure is developed using Sim-Traffic for estimating the 95th percentile queue lengths on various existing signalized intersection configurations near highway-rail grade crossings to help evaluate the need for signal preemption. In addition, recommendations are developed, if preemption is necessary, for determining queue clearance distance and minimum track clearance time. The recommended procedure is developed considering minimizing the risk of underestimated queues or unsafe design at such locations, and simplify the design and decision-making process.
Book Synopsis Evaluation of Urban Intersections Using Traffic Conflicts Measures by : Mike E. Clayton
Download or read book Evaluation of Urban Intersections Using Traffic Conflicts Measures written by Mike E. Clayton and published by . This book was released on 1977 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Safety Evaluation of Right Turns Followed by U-turns at Signalized Intersections (6 Or More Lane Arterials) as an Alternative to Direct Left Turns by : Lu, Jian John Lu
Download or read book Safety Evaluation of Right Turns Followed by U-turns at Signalized Intersections (6 Or More Lane Arterials) as an Alternative to Direct Left Turns written by Lu, Jian John Lu and published by . This book was released on 2005 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Estimation of Delay and Queue Length at Non-signalized Intersections by : Mario R. Duran
Download or read book Estimation of Delay and Queue Length at Non-signalized Intersections written by Mario R. Duran and published by . This book was released on 1986 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Traffic Conflict Techniques for Safety and Operations by : Martin R. Parker
Download or read book Traffic Conflict Techniques for Safety and Operations written by Martin R. Parker and published by . This book was released on 1989 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: This manual provides basic background information and step-by-step procedures for conducting traffic conflict surveys at signalized and unsignalized intersections. The manual was prepared as a training aid and reference source for persons who are assigned the responsibility of conducting traffic conflict observations at intersections. Based on previous research and experiences, the survey techniques described in this manual provide a standard, cost-effective method for accurately observing and recording traffic conflicts. The manual contains definitions with illustrations and examples of conflict types, and instructions for conducting the field activities, including time schedules, forms, and other details. The results of traffic conflict observations are used to diagnose safety and operational problems and to evaluate the effectiveness of treatments. Observer training techniques, as well as procedures for analyzing and interpreting the results of conflict surveys, are presented in the engineer's guide.
Book Synopsis Traffic Conflict Characteristics by : Stuart R. Perkins
Download or read book Traffic Conflict Characteristics written by Stuart R. Perkins and published by . This book was released on 1967 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis On-line Calculation of Signal [i.e. Signalized] Intersection Performance by : Sandeep M. Pandya
Download or read book On-line Calculation of Signal [i.e. Signalized] Intersection Performance written by Sandeep M. Pandya and published by . This book was released on 1987 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Operation, Analysis, and Design of Signalized Intersections by : Michael Kyte
Download or read book Operation, Analysis, and Design of Signalized Intersections written by Michael Kyte and published by Createspace Independent Publishing Platform. This book was released on 2014-07-04 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Before they begin their university studies, most students have experience with traffic signals, as drivers, pedestrians and bicycle riders. One of the tasks of the introductory course in transportation engineering is to portray the traffic signal control system in a way that connects with these experiences. The challenge is to reveal the system in a simple enough way to allow the student "in the door," but to include enough complexity so that this process of learning about signalized intersections is both challenging and rewarding. We have approached the process of developing this module with the following guidelines: * Focusing on the automobile user and pretimed signal operation allows the student to learn about fundamental principles of a signalized intersection, while laying the foundation for future courses that address other users (pedestrians, bicycle riders, public transit operators) and more advanced traffic control schemes such as actuated control, coordinated signal systems, and adaptive control. * Queuing models are presented as a way of learning about the fundamentals of traffic flow at a signalized intersection. A graphical approach is taken so that students can see how flow profile diagrams, cumulative vehicle diagrams, and queue accumulation polygons are powerful representations of the operation and performance of a signalized intersection. * Only those equations that students can apply with some degree of understanding are presented. For example, the uniform delay equation is developed and used as a means of representing intersection performance. However, the second and third terms of the Highway Capacity Manual delay equation are not included, as students will have no basis for understanding the foundation of these terms. * Learning objectives are clearly stated at the beginning of each section so that the student knows what is to come. At the end of each section, the learning objectives are reiterated along with a set of concepts that students should understand once they complete the work in the section. * Over 70 figures are included in the module. We believe that graphically illustrating basic concepts is an important way for students to learn, particularly for queuing model concepts and the development of the change and clearance timing intervals. * Over 50 computational problems and two field exercises are provided to give students the chance to test their understanding of the material. The sequence in which concepts are presented in this module, and the way in which more complex ideas build on the more fundamental ones, was based on our study of student learning in the introductory course. The development of each concept leads to an element in the culminating activity: the design and evaluation of a signal timing plan in section 9. For example, to complete step 1 of the design process, the student must learn about the sequencing and control of movements, presented in section 3 of this module. But to determine split times, step 6 of the design process, four concepts must be learned including flow (section 2), sequencing and control of movements (section 3), sufficiency of capacity (section 6), and cycle length and splits (section 8). Depending on the pace desired by the instructor, this material can be covered in 9 to 12 class periods.
Book Synopsis Re-evaluation of Traffic Control at Non-signalized Intersections by : Everett C. Carter
Download or read book Re-evaluation of Traffic Control at Non-signalized Intersections written by Everett C. Carter and published by . This book was released on 1986 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Roundabouts by : Lee August Rodegerdts
Download or read book Roundabouts written by Lee August Rodegerdts and published by Transportation Research Board. This book was released on 2010 with total page 407 pages. Available in PDF, EPUB and Kindle. Book excerpt: TRB's National Cooperative Highway Research Program (NCHRP) Report 672: Roundabouts: An Informational Guide - Second Edition explores the planning, design, construction, maintenance, and operation of roundabouts. The report also addresses issues that may be useful in helping to explain the trade-offs associated with roundabouts. This report updates the U.S. Federal Highway Administration's Roundabouts: An Informational Guide, based on experience gained in the United States since that guide was published in 2000.
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