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Field Testing And Implementation Of Dilemma Zone Protection And Signal Coordination At Closely Spaced High Speed Intersections
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Book Synopsis Field Testing and Implementation of Dilemma Zone Protection and Signal Coordination at Closely-spaced High-speed Intersections by :
Download or read book Field Testing and Implementation of Dilemma Zone Protection and Signal Coordination at Closely-spaced High-speed Intersections written by and published by . This book was released on 2005 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: Historically, high speed signalized intersections have reported many crashes and have always posed a challenge to traffic engineers for enhancing safety at these intersections. The area close to the intersection, called the dilemma zone, poses a high accident potential for the driver in stopping safely during the yellow interval or in proceeding through the intersection before the beginning of red. The driver is in a potentially hazardous situation whereby, if he tries to cross the intersection at the onset of red interval, he may end up in an angle accident with the cross street traffic or if he accelerates through yellow, he may end up in a rear-end collision. The uncertain situation in a dilemma zone can potentially lead to rear-end or right angle collisions.
Book Synopsis Dilemma Zone Protection and Signal Coordination at Closely-spaced High-speed Intersections by : Prahlad D. Pant
Download or read book Dilemma Zone Protection and Signal Coordination at Closely-spaced High-speed Intersections written by Prahlad D. Pant and published by . This book was released on 2001 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: A feasibility study of dilemma zone problems, performed by collecting and analyzing traffic flow data at a high-speed signalized intersection, showed that the maximum green extension or cutback needed to get a vehicle out of the dilemma zone is generally no more than 2 seconds. If we scan all vehicles on a link just a few seconds before the beginning of a yellow interval, we may be able to extend or cut back the green interval so that the vehicles can avoid the dilemma zone. For each vehicle approaching an intersection on the link that is about to turn yellow, there is a time interval such that (a) the vehicle will be in the dilemma zone without green extension (or cutback) or (b) it will be in the dilemma zone when there are T seconds of extension (or cutback). So the task is to find the smallest nonnegative integer T that is not in any of these time intervals and extend (or cut back) the current interval by T seconds. This T can always be found and assuming there are no other restrictions, dilemma zones can be avoided and the extension (or cutback) is done at most once for each green interval. The simulation study, performed by modifying the source codes of NETSIM, showed that the signal timing generated by a bandwidth maximization program (PASSER-II) resulted in a lower number of vehicles in the dilemma zone than that generated by a delay minimization program (TRANSYT-7F). Additionally, the signal timing generated by the combination of the two programs, that is, by minimizing delay within the constraint of bandwidth maximization, resulted in an even lower number of vehicles in the dilemma zone than those generated by each program alone. The technique developed in this study can be implemented if the speeds and positions of all vehicles on the roadway can be recorded at small time intervals (e.g., 1 sec). Recommendations are made for implementing and testing the developed technique.
Book Synopsis Dilemma Zone Protection and Signal Coordination at Closely-spaced High-speed Intersections by : Prahlad D. Pant
Download or read book Dilemma Zone Protection and Signal Coordination at Closely-spaced High-speed Intersections written by Prahlad D. Pant and published by . This book was released on 2006 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt: A feasibility study of dilemma zone problems, performed by collecting and analyzing traffic flow data at a high-speed signalized intersection, showed that the maximum green extension or cutback needed to get a vehicle out of the dilemma zone is generally no more than two seconds. Scanning all vehicles on a link just seconds before the beginning of a yellow interval may extend or cut back the green interval so that vehicles can avoid the dilemma zone. For each vehicle approaching an intersection on a link about to turn yellow there is a time interval that (a) the vehicle will be in dilemma zone without green extension (or cutback) or (b) it will be in dilemma zone when there is T seconds of extension (or cutback). The task becomes to find the smallest nonnegative integer T that is not in any of these time intervals and extend or cutback the current interval by T seconds. This T can always be found and assuming there are no other restrictions, dilemma zones can be avoided and the extension or cutback is done at most once for each green interval. The simulation study, performed by modifying the source codes of NETSIM, showed that the signal timing generated by a bandwidth maximization program (PASSER II) resulted in a lower number of vehicles in dilemma zone than that generated by a delay minimization program (TRANSYT-7F). Additionally, the signal timing generated by the combination of the two programs, that is, by minimizing delay within the constraint of bandwidth maximization, resulted in even lower number of vehicles in dilemma zone than those generated by each program alone. The technique developed in this study can be implemented if the speeds and positions of all vehicles in the roadway can be recorded at small time intervals (e.g., 1 sec.). Recommendations are made for implementing and testing the developed technique.
Book Synopsis Human Factors Guidelines for Road Systems by : John L. Campbell
Download or read book Human Factors Guidelines for Road Systems written by John L. Campbell and published by Transportation Research Board. This book was released on 2012 with total page 319 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This report completes and updates the first edition of NCHRP Report 600: Human Factors Guidelines for Road Systems (HFG), which was published previously in three collections. The HFG contains guidelines that provide human factors principles and findings for consideration by, and is a resource document for, highway designers, traffic engineers, and other safety practitioners."--Foreword.
Book Synopsis Dilemma Zone Protection on High-speed Arterials by : Bhaven Naik
Download or read book Dilemma Zone Protection on High-speed Arterials written by Bhaven Naik and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Driver behavior within the dilemma zone can be a major safety concern at high-speed signalized intersections, especially for heavy trucks. The Nebraska Department of ROADS (NDOR) has developed an implemented an Actuated Advance Warning (AAW) dilemma zone protection system. The AAW system has been documented as being effective at improving traffic safety at isolated signalized intersections. However, the system is yet to be used at signalized intersections operating in the coordinated mode. This study tested the feasibility of deploying the system on arterials where the signals are closely spaced and operate in a coordinated mode. A microsimulation approach -- integration of traffic microsimulation and surrogate safety performance measures -- was developed to assess the potential benefits (safety and operation) in-lieu of observed traffic and crash data. The analysis of conflicts indicated that, on average, there were 30%, 7%, and 30% reductions in the number of rear-end, lane change, and crossing conflicts respectively when the AAW system was used. In terms of the relative productivity of the system, the number of vehicles that were processed during a specified analysis period revealed that there were generally more vehicles processed when the AAW system was not in place. Also, the overall link travel times were slightly higher when the system was in place" (page viii).
Book Synopsis Placement of Detection Loops on High Speed Approaches to Traffic Signals by :
Download or read book Placement of Detection Loops on High Speed Approaches to Traffic Signals written by and published by . This book was released on 2010 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report contains the results of the NC Department of Transportation research project Placement of Detection Loops on High Speed Approaches to Traffic Signals (HWY 2007-13). The goal of this project was to determine the best places to locate detectors on the approaches to high-speed signalized intersections and the best signal control strategy to employ in conjunction with those sensor placement ideas to minimize dilemma zone occurrences.
Download or read book Report written by and published by . This book was released on 1964 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis A Novel Approach to Dilemma Zone Problem for High Speed Signalized Intersections by : Venkata Suresh Raavi
Download or read book A Novel Approach to Dilemma Zone Problem for High Speed Signalized Intersections written by Venkata Suresh Raavi and published by . This book was released on 2010 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Safety and efficiency are both major concern at high-speed intersections. It has been a major challenge for traffic engineers over the years to increase efficiency without sacrificing delay. An IntelliDrive signal control system was developed in the University of Akron's transportation lab based on the concept of IntelliDrive technology that can improve safety significantly while retaining efficiency. The new intelligent signal control system can address the dynamic dilemma zone problem, thus providing maximum safety at intersections. Every vehicle in the system is addressed to its own dilemma boundary rather than addressing dilemma zone for the whole intersection approach. By obtaining advance speed information, vehicle classification, vehicle location from the stop line, for every vehicle for every second in the system in real time, unneeded extensions can be avoided. Thus the intersection not only operates more safely, but also more efficiently because of the proposed algorithm logic that utilizes IntelliDrive technology. IntelliDrive test bed was created in VISSIM simulation platform and tested for operational efficiency when safety criteria are met. This thesis also discusses the characteristics of the Peak Flow Factor (PFF) which is the ratio between peak hourly volume and peak flow rate within the hour. Despite the fact that the Highway Capacity Manual (HCM) requires use of this ratio in evaluating the Levels of Service (LOS) of roadway facilities, a very limited amount of prior research has been made on its variability. Subsequently, the HCM established a time interval of 15 minutes for obtaining the peak flow rate without much explanation on why this time interval was chosen. In order to investigate the PFF's effectiveness for representing the variation of flow within peak hour, this research focuses on PFF analysis and time series models of the PFF at various time intervals for signalized isolated intersections. Results showed that the PFF decreased when time interval decreased and that significant differences in the stability were apparent when each time interval were compared. In addition, the developed time series models showed the the[sic] PFF can be forecasted with relative accuracy and simulation models within this study demonstrated the test results from data are dependable."--Abstract.
Book Synopsis Guidelines for Detector Placement on High-speed Approaches to Signalized Intersections by :
Download or read book Guidelines for Detector Placement on High-speed Approaches to Signalized Intersections written by and published by . This book was released on 1997 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary objective of this research was to validate the new TxDOT procedures for loop detector placement on high-speed approaches to signalized intersections. The study approach involved conducting a field study at selected sites to compare the proposed new loop configuration to the existing configuration. The data analysis included investigating approach speeds to the intersection, driver actions in response to a yellow indication, and vehicle location at the onset of yellow. The Results from the field study revealed that the new loop configuration is as good as, and in some cases better than the old loop configuration. Because the new loop configuration can detect vehicles further upstream from the intersection (at the beginning of the dilemma zone), it results in fewer vehicles being caught in the dilemma zone at the onset of yellow. Also, because the new loop configuration typically resulted in more vehicles running the yellow light instead of stopping, fewer rear-end accidents may result. In addition, the new loop configuration resulted in fewer vehicles running the red light, also a major cause of accidents.
Book Synopsis Evaluation of Advance Warning Signals on High Speed Signalized Intersections by : Peter T. Martin
Download or read book Evaluation of Advance Warning Signals on High Speed Signalized Intersections written by Peter T. Martin and published by . This book was released on 2003 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Development of a Second Generation Detection-control System for Safer Operation of High Speed Signalized Intersections by : Karl H. Zimmerman
Download or read book Development of a Second Generation Detection-control System for Safer Operation of High Speed Signalized Intersections written by Karl H. Zimmerman and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This Innovations Deserving Exploratory Analysis project improved and evaluated a detection-control system (D-CS) for enhanced traffic safety at high speed signalized intersections. A literature review was conducted to identify potential enhancements to the D-CS control algorithm required to create the "second generation" D-CS algorithm. The needed enhancements included dilemma zone protection based on vehicle size, real-time dilemma zone changes, coordination, and real-time measures of effectiveness reporting. After selecting the most feasible enhancements, the control algorithm was modified and tested in the laboratory. Based on laboratory test results and refinements, a "second generation" D-CS control algorithm was developed capable of providing dilemma zone protection specific to vehicle type using a modified system to prevent max out during "Stage 2" operation.
Book Synopsis Evaluation of Detection and Signing Systems for High Speed Signalized Intersections by : Prahlad D. Pant
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.
Book Synopsis In-service Evaluation of a Detection-control System for High-speed Signalized Intersections by : Karl Zimmerman
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.
Book Synopsis Signalized Intersections by : Daiheng Ni
Download or read book Signalized Intersections written by Daiheng Ni and published by . This book was released on 2020 with total page 345 pages. Available in PDF, EPUB and Kindle. Book excerpt: This textbook introduces the basics principles of intersection signalization including need studies, signal phasing, sequencing, timing, as well as more advanced topics such as detectors, controllers, actuated control schemes, and signal coordination. The book covers a variety of topics critical to the set up and operation of intersections controlled by traffic signals. Professor Ni imparts a basic understanding of how intersections work, what justifies intersection signalization, how to properly design phasing and timing plans for intersections, what is needed to run traffic-responsive signals, the workings of traffic controller cabinets, and how to set up signal coordination at multiple intersections--competencies essential to transportation professionals in charge of traffic operation at federal, state, and local levels. Aimed at students in transportation engineering programs with a focus on intersection signalization, the book is also ideal for researchers of traffic dynamics and municipal civil and transportation engineers.
Book Synopsis Traffic Signal Timing Manual by : U.s. Department of Transportation
Download or read book Traffic Signal Timing Manual written by U.s. Department of Transportation and published by CreateSpace. This book was released on 2015-02-20 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report serves as a comprehensive guide to traffic signal timing and documents the tasks completed in association with its development. The focus of this document is on traffic signal control principles, practices, and procedures. It describes the relationship between traffic signal timing and transportation policy and addresses maintenance and operations of traffic signals. It represents a synthesis of traffic signal timing concepts and their application and focuses on the use of detection, related timing parameters, and resulting effects to users at the intersection. It discusses advanced topics briefly to raise awareness related to their use and application. The purpose of the Signal Timing Manual is to provide direction and guidance to managers, supervisors, and practitioners based on sound practice to proactively and comprehensively improve signal timing. The outcome of properly training staff and proactively operating and maintaining traffic signals is signal timing that reduces congestion and fuel consumption ultimately improving our quality of life and the air we breathe. This manual provides an easy-to-use concise, practical and modular guide on signal timing. The elements of signal timing from policy and funding considerations to timing plan development, assessment, and maintenance are covered in the manual. The manual is the culmination of research into practices across North America and serves as a reference for a range of practitioners, from those involved in the day to day management, operation and maintenance of traffic signals to those that plan, design, operate and maintain these systems.
Book Synopsis Evaluation of Dilemma Zone Advance Warning Signals at High Speed Signalized Intersections by : Vikram Chakravarthy Kalyani
Download or read book Evaluation of Dilemma Zone Advance Warning Signals at High Speed Signalized Intersections written by Vikram Chakravarthy Kalyani and published by . This book was released on 2006 with total page 134 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.
