Download or read book Evaluation of Signalized Intersection Safety Using Centracs System written by Xinkai Wu and published by . This book was released on 2017 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book In service Evaluation of a Detection control System for High speed Signalized Intersections written by Karl Zimmerman and published by . This book was released on 2005 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: Traffic engineers are often faced with operational and safety challenges at rural, high-speed signalized intersections. Vehicle-actuated control, combined with multiple advance detectors, is often used to improve operations and safety. However, this type of detection and control has not always resulted in a significant number of crashes. Crashes sometimes continue to occur at high-speed intersections, and delays to traffic movements can be unnecessarily long. An innovative detection-control system was developed for the Texas Department of Transportation to minimize both delay and crash frequency at rural intersections. This system was subsequently implemented at several intersections in Texas and its safety and operational benefits were evaluated. This report documents the findings and conclusions reached as a result of a three-year implementation project. The Detection-Control System was installed at each of eight intersections in Texas during the three-year period. Five of the intersections were suitable for a before-after study of safety and operational data. An evaluation of the before-after data indicated that the Detection-Control System was able to reduce delay by 14 percent, stop frequency by 9 percent, red-light violations by 58 percent, heavy-vehicle red-light violations by 80 percent, and severe crash frequency by 39 percent.
Download or read book A Signalized Intersection for Experimentation and Evaluation of Traffic Signal and Detection System Technology written by Kelvin R. Santiago-Chaparro and published by . This book was released on 2012 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
Download or read book Evaluation of Detection and Signing Systems for High Speed Signalized Intersections written by Prahlad D. Pant and published by . This book was released on 1996 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of two dynamic signs that begin to flash a few seconds before the onset of the yellow interval and a static sign that flashes all the time were examined at tangent and curved approaches to rural, high speed signalized intersections. The dynamic signs included (a) a PTSWF (prepare to stop when flashing) sign, and (b) a FSSA (flashing symbolic signal ahead) sign with green, yellow, and red circles. The static sign was a CFSSA (continuously flashing symbolic signal ahead) sign with the three circles. The effects of these signs on vehicular speeds at different segments of the intersection approach including the dilemma zone were analyzed as were the vehicle conflict rates and the responses from the drivers' surveys.
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.
Download or read book Evaluation of the Effectiveness of Traffic Responsive Systems on Intersection Congestion and Traffic Safety written by Rashad M. Hanbali and published by . This book was released on 1997 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
Download or read book Signalized Intersections written by Lee August Rodegerdts and published by . This book was released on 2004 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: This guide provides a single, comprehensive document with methods for evaluating the safety and operations of signalized intersections and tools to remedy deficiencies. The treatments in this guide range from low-cost measures such as improvements to signal timing and signage, to high-cost measures such as intersection reconstruction or grade separation. Topics covered include fundamental principles of user needs, geometric design, and traffic design and operation; safety and operational analysis techniques; and a wide variety of treatments to address existing or projected problems, including individual movements and approaches, pedestrian and bicycle treatments, and corridor techniques. It also covers alternative intersection forms that improve intersection performance through the use of indirect left turns and other treatments. Each treatment includes a discussion of safety, operational performance, multimodal issues, and physical and economic factors that the practitioner should consider. Although the guide focuses primarily on high-volume signalized intersections, many treatments are applicable for lower volume intersections as well. The information contained in this guide is based on the latest research available on treatments and best practices in use by jurisdictions across the United States. Additional resources and references are highlighted for the student, practitioner, researcher, or decisionmaker who wishes to learn more about a particular subject.
Download or read book Evaluation of Safety Strategies at Signalized Intersections written by Raghavan Srinivasan and published by Transportation Research Board. This book was released on 2011 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt: TRB’s National Cooperative Highway Research Program (NCHRP) Report 705: Evaluation of Safety Strategies at Signalized Intersections explores crash modification factors (CMFs) for safety strategies at signalized intersections. CMFs are a tool for quickly estimating the impact of safety improvements.
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
Download or read book Intersection Decision Support written by and published by . This book was released on 2006 with total page 418 pages. Available in PDF, EPUB and Kindle. Book excerpt: This project entailed the design, development, testing, and evaluation of intersection decision support (IDS) systems to address straight crossing path (SCP) intersection crashes. This type of intersection crash is responsible for more than 100,000 crashes and thousands of fatalities each year. In developing these IDS systems for both signalized and stop-controlled intersections, a top-down systems approach was used that determined the necessary system functions and evaluated the capability of different technologies to perform those functions. Human factors tests were also conducted that evaluated the effectiveness of warning algorithms and infrastructure-based driver-infrastructure interfaces in eliciting a stopping response from drivers about to be involved in an SCP intersection crash. Results indicated that further technological development is needed for the sensing and intersection state IDS functions. Furthermore, infrastructure-based warning interfaces tested were greatly outperformed by previously-tested in-vehicle warnings. Thus, future research on IDS systems should focus on their infrastructure-cooperative configuration, where the system supports an in-vehicle warning.
Download or read book Safety Evaluation of Corner Clearance at Signalized Intersections written by U. S. Department Of Transportation and published by Createspace Independent Publishing Platform. This book was released on 2018-07-18 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: Safety evaluation of corner clearance at signalized intersections /
Download or read book NCHRP Report 705 written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development and Evaluation of a Detection control System for Rural Intersections written by James A. Bonneson and published by . This book was released on 2001 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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:
Download or read book Safety Evaluation of Corner Clearance at Signalized Intersections written by Thanh Le and published by . This book was released on 2018 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study evaluates corner clearance at signalized intersections under the Development of Crash Modification Factors program for the Evaluation of Low-Cost Safety Improvements Pooled Fund Study. Geometric, traffic, and crash data were obtained for signalized intersections with various corner clearances from the State of California and the City of Charlotte, North Carolina. A cross-sectional analysis was conducted to estimate the effects of corner clearance while controlling for other differences among study sites. The estimated CMFs indicated that more limited clearance (i.e., driveway(s) within 50 ft of the signalized intersection) on receiving corners was associated with increases for all crash types, based on the data included in this analysis. These increases were statistically significant at the 90-percent level or greater for total, fatal and injury, rear-end, sideswipe, right-angle, and nighttime crashes. Only the results for turning crashes were not statistically significant at the 90-percent level. For limited corner clearance on the approach corners, the results indicated statistically significant reductions in total, fatal and injury, and rear-end crashes. The results also indicated reductions in sideswipe and nighttime crashes, and increases in right-angle and turning crashes, but none of these results were statistically significant at the 90-percent level.
