Modeling indicated that coordinating fixed signal timing plans along congested arterial corridors leading into Seattle, Washington, and incorporating arterial traffic flow data into the traveler information system would reduce vehicle delay by 7 percent and 1.8 percent, respectively.

A modeling effort investigated the potential impact of coordinating traffic signal control between several jurisdictions along congested arterial corridors leading into Seattle. 

FINDINGS

The results of the study indicated that coordinating the fixed signal timing plans along the corridor would result in a seven percent reduction in vehicle delay, with no adverse impacts to cross-streets. The model indicated that this level of benefit could be maintained across varying levels of demand and weather conditions.

The model was also used to estimate the potential impacts of incorporating information on arterial traffic flow into an Advanced Traveler Information System use to provide freeway traveler information. The system design would allow motorists to make more informed decisions about whether to divert from a congested freeway to an adjacent arterial. Researchers estimated the system would reduce vehicle delay by 1.8 percent.

The Seattle metropolitan area had a considerably high level of ITS implementation prior to the MMDI projects, therefore the experiences of localities implementing these systems under differing conditions may vary significantly from those reported in Seattle.