Signalized Intersections
Technical Assistance & Tools
NCHRP Report 500: Volume 12: A Guide for Reducing Collisions at Signalized Intersections [HTML, PDF 1.62 MB]
A Review of the Signalized Intersections: Informational Guide, FHWA-HRT-04-092, 2004.
Because traffic signals play an important role in improving safety at intersections, the FHWA produced Signalized Intersections: Informational Guide, which provides methods for evaluating the safety and operations of signalized intersections and tools to remedy deficiencies. The guide includes examples of novel treatments and current best practices by jurisdictions across the United States. These treatments include low-cost measures such as improvements to signal timing and signs, and high-cost measures such as intersection reconstruction or grade separation.FHWA / AASHTO Scan Signalized Intersection Safety, May 10, 2002 through May 26, 2002. [HTML, PPT 14.5 MB]
The international scan visited the United Kingdom, Germany, the Netherlands, and Sweden. The goals and objectives were to (1) identify promising and readily implementable intersection-safety solutions and/or programs for deployment in the United States; (2) identify and overcome implementation barriers and special needs and (3) gather specific examples and documentation.Effectiveness of All-Red Clearance Interval on Intersection Crashes
Minnesota Department of Transportation, May 2004. [PDF 1.91 MB]
Crashes at signalized intersections account for approximately 20% of all crashes both nationally and within the State of Minnesota. Past research suggests that the use of all-red clearance interval at signalized intersections may reduce intersection crashes, particularly those related to signal violations. Other research suggests that this reduction may only be temporary. This research evaluates the safety effect of all-red clearance intervals at low-speed urban 4-way intersections in the City of Minneapolis. While results indicate short-term reductions in crash rates approximately one year after the implementation, long-term reductions are not observed.Traffic Detector Handbook, Volume I, FHWA-HRT-06-008 [PDF 9.6 MB]
Traffic Detector Handbook, Volume II, FHWA-HRT-06-139 [PDF 10 MB]
Research
Active Projects
Best TxDOT Practices for Signal Timing and Detection Design at Intersections
Start date: 2006/9/1: End date: 2008/8/31
Source Organization: Texas Department of TransportationCausal Factors for Intersection Crashes in Northern Virginia
Start date: 2006/2/1: End date: 2008/12/31
Index Terms: Intersections, Crash injury research, Motor vehicles, Databases, Accident data, Research projects, Northern Virginia,
Source Organization: Virginia Transportation Research CouncilEvaluation of Safety Strategies at Signalized Intersections
Start date: 2006/11/1: End date: 2009/10/31
Source Organization: National Cooperative Highway Research ProgramHigh-Speed Expressway Intersections Study of Crash Risk Factors
This proposal is to extend the recently completed Empirical Bayes analysis of expressway intersections by evaluating a number of factors to identify those that are associated with successful or unsuccessful signalization projects. This will be done by accomplishing the following: (1) Evaluate the signalization including timing, signal warrants, and auxiliary flashers (2) Evaluate the character of the intersections in terms of access density (on the side road), type and amount of adjacent development, and physical characteristics (orientation, grade, median width, elevation differences between lane groups, and curves).
Start date: 2005/11/1
Source Organization: Iowa State University, Ames
Date Added: 03/02/2006Investigate Low-Cost Safety Measures at Signalized Intersections.
Study objective will be to investigate the use of low-cost countermeasures to reduce crashes at signalized intersections.
Start date: 2005/9/1
Source Organization: Kentucky Transportation CenterPlacement of Detection Loops on High-Speed Approaches to Traffic Signals.
The primary objective of this project is to determine the best distance to place detectors on the approaches to high-speed signalized intersections through a comprehensive research program of modeling and field testing alternative configurations. This project will also include an itemized list of recommended practices and benefit cost-tradeoffs.
Start date: 2006/7/1
End date: 2008/6/30
Source Organization: North Carolina Department of Transportation
Date Added: 08/23/2006Safety and Operational Evaluations of Signalized Intersection Design and Control Treatments
Research objectives are to: (1) develop a tool to assess the safety, operations, and access (utility and disutility) of inserting new interchanges in urban areas; and (2) provide technical support to road jurisdictions in applying novel intersection designs, and conduct further safety and operational evaluations of novel intersections.
Start date: 2005/12/13
End date: 2008/1/1
Source Organization: Federal Highway Administration
Resources
- Improving Signalized Intersections. Public Roads Magazine. January/February 2005.
Training
Safety Analysis-Signalized Intersections
Institute of Transportation Engineers. The course is a guided tutorial that assists transportation professionals in analyzing crash data and identifying appropriate countermeasures to reduce the frequency of crashes and the fatalities, personal injury and property damage involved. Key concepts are explained using an interactive format and reinforced through a case study. Upon completion you’ll be able to:- Identify locations for crash studies;
- Determine data requirements;
- Construct and interpret a collision diagram;
- Group crash data and isolate crash types;
- Identify possible causes; and
- Recommend viable safety countermeasures.
Traffic Control Devices-Traffic Signal Needs Determination, Institute of Transportation Engineers. This course is part of the traffic control devices series and has been developed as a guided tutorial to assist staff engineers and technicians in using the methodology outlined in the Manual on Uniform Traffic Control Devices (MUTCD) 2000 for Traffic Control Signal Needs Study. The key concepts underpinning the process of determining signal needs are explained and case studies are used to illustrate the dependent variables. A PDF summary of the course is available for future reference. Upon completion you’ll be able to:
- Identify steps in a traffic signal needs determination;
- Collect and analyze traffic data;
- Determine if warrant conditions are met;
- Identify the appropriate report requirements;
- Assemble an engineering study report;
- Identify the advantages and disadvantages of installing a traffic signal; and
- Identify alternative improvements.
Professional Development Module: Engineering Intersections to Reduce Red-Light Running
Red-light running is a complex problem with few simple answers. This one-hour training program emphasizes engineering countermeasures to red-light running. Potential countermeasures discussed in this module address signal visibility and conspicuity, signal timing, increasing the likelihood that drivers will stop and reducing or eliminating the need for stopping. ITE, 2004. CD-ROM. ISBN: 0-935403-85-X.Traffic Signal Design and Operation Training Course, FHWA-NHI-133028
Signalized Intersection Guidebook Workshop, FHWA-NHI-380078
