Signalized Intersections

Author: Daiheng Ni

Publisher: Springer Nature

ISBN: 9783030385491

Category: Technology & Engineering

Page: 335

View: 234

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.
Light Rail Vehicle Collisions with Vehicles at Signalized Intersections

Author: Kelley Klaver Pecheux

Publisher: Transportation Research Board

ISBN: 9780309098212

Category: Electric railroad accidents

Page: 50

View: 918

This report presents the mitigation methods tested and used by transit agencies to reduce collisions between light rail vehicles (LRVs) and motor vehicles where light rail transit (LRT) runs through or adjacent to highway intersections controlled by conventional traffic signals. A particular focus is placed on collisions occurring between LRVs and vehicles making left-hand turns at these intersections. This report offers success stories and specific actions to achieve positive results, as well as examples of unsuccessful actions. The issues addressed include a range of LRT operations and environments such as median-running, side-running, contra-flow, and mixed-use LRT alignments; urban and suburban setting; and a variety of U.S. geographic regions.
Guidelines for Timing Yellow and All-red Intervals at Signalized Intersections

Author: Hugh W. McGee

Publisher: Transportation Research Board

ISBN: 9780309258593

Category: Traffic safety

Page: 93

View: 913

TRB National Cooperative Highway Research Program (NCHRP) Report 731: Guidelines for Timing Yellow and All-Red Intervals at Signalized Intersections offers guidance for yellow change and all-red clearance intervals at signalized intersections. The guidelines provide a framework that can be easily applied by state and local transportation agencies.
Signalized Intersections

Author: Lee August Rodegerdts


ISBN: NWU:35556032763005

Category: Roads

Page: 376

View: 877

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.
Evaluation of High-speed Isolated Signalized Intersections in California

Author: Simon Washington


ISBN: NWU:35556020274585

Category: Electronic traffic controls

Page: 162

View: 123

High-speed isolated signalized intersections (HSISI's) are generally encountered after long uninterrupted and uncongested flow conditions, thereby catching some motorists by surprise. For this reason alone, approaches to HSISI's need to have safe and effective warning, control, and intersection geometric treatments. This research identified characteristics at California HSISI's that relate to accident rates. A data base consisting of approximately 100 intersection and approach variables was established and used to investigate advance warning, signal timing and phasing, channelization, signal equipment configurations, shoulder widths and types, median widths and types, and approach speeds.
Impacts on Safety of Left-turn Treatment at High Speed Signalized Intersections

Author: T. H. Maze


ISBN: NWU:35556022386510

Category: Left-turn lanes

Page: 94

View: 659

Left-turning traffic is a major source of conflicts at intersections. Though an average of only 10% to 15% of all approach traffic turns left, these vehicles are involved in approximately 45% of all accidents. This report presents the results of research conducted to develop models which estimate approach accident rates at high speed signalized intersections. The objective of the research was to quantify the relationship between traffic and intersection characteristics, and accident potential of different left turn treatments. Geometric, turning movement counts, and traffic signal phasing data were collected at 100 intersections in Iowa using a questionnaire sent to municipalities. Not all questionnaires resulted in complete data and ultimately complete data were derived for 63 intersections providing a database of 248 approaches. Accident data for the same approaches were obtained from the Iowa Department of Transportation Accident Location and Analysis System (ALAS). Regression models were developed for two different dependent variables: 1) the ratio of the number of left turn accidents per approach to million left turning vehicles per approach, and 2) the ratio of accidents per approach to million traffic movements per approach. A number of regression models were developed for both dependent variables. One model using each dependent variable was developed for intersections with low, medium, and high left turning traffic volumes. As expected, the research indicates that protected left turn phasing has a lower accident potential than protected/permitted or permitted phasing. Left turn lanes and multiple lane approaches are beneficial for reducing accident rates, while raised medians increase the likelihood of accidents. Signals that are part of a signal system tend to have lower accident rates than isolated signals. The resulting regression models may be used to determine the likely impact of various left turn treatments on intersection accident rates. When designing an intersection approach, a traffic engineer may use the models to estimate the accident rate reduction as a result of improved lane configurations and left turn treatments. The safety benefits may then be compared to any costs associated with operational effects to the intersection (i.e., increased delay) to determine the benefits and costs of making intersection safety improvements.