Implement a communication structure across jurisdictions that facilitates the flow of traffic data and allows agencies to coordinate traffic signal timing.
Phoenix and Seattle’s experiences with coordinating traffic signal timing across jurisdictional boundaries.
Made Public Date


United States


United States

Cross-Jurisdictional Signal Coordination in Phoenix and Seattle


In 1996, the U.S. Department of Transportation established the Metropolitan Model Deployment Initiative (MMDI). The purpose of this effort was to create model deployments that represent integrated transportation management systems. The objectives of the initiative included determining the effects of increased deployment on traffic characteristics and operations and documenting the benefits that enabled the specific sites to be selected. This case study looks at cross-jurisdictional traffic signal coordination in the Phoenix and Seattle metropolitan regions and is one of a series of studies documenting the level of ITS integration in several major metropolitan areas. In Phoenix, the study focused on signal timing changes that were implemented along the Scottsdale/Rural Road Corridor, a major north/south arterial corridor in Arizona that connects Scottsdale and Tempe. In Seattle, the study focused on a simulation of proposed signal timing changes along two major arterials (SR 99 and SR 522) in North Seattle. Lessons learned included that cross-jurisdictional coordination of signal timing requires a coordinated communications structure. It can provide a seamless commute from one jurisdiction to the next.

Lessons Learned

Develop a cross-jurisdictional communications infrastructure that allows jurisdictions to share real-time traffic operations information and update signal plans. The idea of a multi-jurisdictional system allows regional goals to be initiated and achieved.

Signal coordination requires careful planning for maximum efficiency. In the Scottsdale/Tempe area, the boundary for coordination previously existed at a jurisdictional separation. Moving this coordination boundary to a more functional boundary (Loop 202) has provided a seamless commute from one jurisdiction to the next. A functional boundary is an area at which traffic signal coordination is less of an issue. For the Phoenix area, regional traffic signal coordination has been achieved through careful planning and increased coordination efforts.

Local participants predict that careful coordination and cooperation will have a long-range impact on traffic operations in the East Valley, and that maintaining and updating coordination and communication efforts will provide increased benefits in the future. Ideas such as this can provide municipalities with the framework needed to deploy similar Smart Corridor systems.

Benefits similar to those witnessed in Phoenix (reductions in traveler delays, decrease in crash risk) were observed in a traffic signal modeling effort in Seattle.

Cross-Jurisdictional Signal Coordination in Phoenix and Seattle

Cross-Jurisdictional Signal Coordination in Phoenix and Seattle
Publication Sort Date
Carter, Mark, Hesham Rakha

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