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FHWA Home / Safety / Intersection / Advanced Dilemma-Zone Detection System

Advanced Dilemma-Zone Detection System

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May 2009
FHWA-SA-09-008




Purpose

The Advanced Dilemma-Zone Detection system enhances safety at signalized intersections by modifying traffic control signal timing to reduce the number of drivers that may have difficulty deciding whether to stop or proceed during a yellow phase. This may reduce rear-end crashes associated with unsafe stopping and angle crashes due to illegally continuing into the intersection during the red phase.

Alternative Names

Detection-Control System (D-CS), Intelligent Detection-Control System.

This summary is one in a series describing Innovative Intersection Safety Treatments. The summaries identify new technologies and techniques to improve intersection safety developed since NCHRP Report 500, Volumes 5 and 12, were published in 2003 and 2004, respectively. These treatments show promise for improving safety but comprehensive effectiveness evaluations are not yet available.

Operation

Figure 1: Advanced Dilemma-Zone Detection system components as applied in TxDOT Detection-Control System study referenced in this fact sheet. Click on image for detailed description.
Figure 2: Advanced Dilemma-Zone Detection design as applied in TxDOT Detection-Control System study referenced in this fact sheet. Click on image for detailed description.

Potential Benefits

The Advanced Dilemma-Zone Detection system has several benefits relative to traditional multiple detector systems, which have upstream detection for vehicles in the dilemma zone but do not take the speed or size of individual vehicles into account. These benefits include:

Agency Experience

FHWA is conducting on-going effectiveness evaluations of the TxDOT study described above, and more complete results are expected in the spring of 2010.

Implementation Considerations

Manual on Uniform Traffic Control Devices (MUTCD) Specifications

Costs

Learn More

Jim Bonneson, Senior Research Engineer
Texas Transportation Institute
979.845.1713
j-bonneson@tamu.edu

Henry Wickes, Project Director
Traffic Operations Division, TxDOT
512.506.5125
hwickes@dot.state.tx.us

Ed Rice, Intersection Safety Team Leader
FHWA Office of Safety
202.366.9064
ed.rice@dot.gov

As part of the TxDOT study, the Advanced Dilemma-Zone Detection system was implemented at eight different intersections in Texas. Similar systems may have been installed in other locations. Zimmerman, K. and J. Bonneson. "In-Service Evaluation of a Detection-Control System for High-Speed Signalized Intersections," FHWA/TX-05/5-4022-01-1, Federal Highway Administration, 2005. Available at http://tti.tamu.edu/documents/5-4022-01-1.pdf.

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Page last modified on September 4, 2014.
Safe Roads for a Safer Future - Investment in roadway safety saves lives
Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000