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Title: Quantifying the Benefits of Coordinated Traffic-Signal Systems
Contact: Michael D. Fontaine
Associate Director for Safety, Operations, and Traffic Engineering
Project No.: 92459
Target Date: 09/17/2010

Traffic engineers generally assume that coordinated traffic signals perform better, in terms of travel time, delay, and stops, than those that operate independently. However, very little quantitative information is available regarding the benefits of coordination.  In addition, in some cases, coordination has been reported to result in a deterioration of signal performance, particularly in situations where frequent phase skips occur on side streets.  Phase skips trigger an earlier return to green on the coordinated phases and a resulting disruption in progression. This project will quantify the operational benefits of coordinated traffic signals as compared to isolated signals by conducting before-and-after studies at two sites in Virginia. This project will also provide recommendations to improve the operations of coordinated traffic signals as they are identified through these case studies.

     B. Brian Park
     Catherine C. McGhee