The Federal Highway Administration initiated a study to explore the benefits and costs of fully deploying operational strategies and integrating ITS in the large metropolitan area of Seattle. The strategies included in Seattle's Full Operations and ITS Deployment Scenario were identified by consulting with local agencies to identify the overall ITS program planned through the next 25 years. The benefits are contingent on complete deployment of the full operations and ITS deployment scenario. The selected strategies are listed in the following table.
|Arterial Traffic Management Systems||Central Control Signal Coordination|
|Emergency Vehicle Signal Preemption|
|Transit Vehicle Signal Priority|
|Freeway Management Systems||Central Control Ramping Metering|
|Transit Management||Fixed-Route Automated Scheduling and Automatic Vehicle Location|
|Fixed-Route Security Systems|
|Electronic Transit Fare Payment|
|Incident Management Systems||Incident Detection, Verification, Response, and Management|
|Emergency Management Systems||Emergency Vehicle Control Service|
|Emergency Vehicle AVL|
|Traveler Information||Phone- and Web-Based Traveler Information System|
|Kiosk-Based Traveler Information|
|Highway Advisory Radio|
|Dynamic Message Signs|
|Crash Prevention and Safety||Railroad Crossing Monitoring Systems|
|Commercial Vehicle Operations||Weigh-in-Motion and Safety Information Exchange|
|Combination Screening and Clearance|
|Supporting Deployment||Traffic Management Center|
|Transit Management Center|
|Information Service Provider Center|
|Closed Circuit TV and Loop Detectors|
The ITS deployment was shown to improve system speeds and reduce delay, particularly during congested, delay-prone commute hours.
- Overall reduction in delay caused by recurring congestion was projected to be 3.2 percent, amounting to approximately 10,700 vehicle hours of delay per day, or nearly 2.7 million hours per year.
- Reductions are greatest on primary roadways with the greatest concentration of ITS and operations deployments during the commute periods.
- This reduction, estimated only for freeways, amounted to an average of nearly 55,100 hours saved per day, a decrease of more than 50 percent of the total freeway incident-related delay.
- Reduction in incident-related delay was most significant during congested commute periods. More than 63 percent of the total incident-related delay reduction was observed in the afternoon commute period, amounting to an average savings of nearly two minutes per freeway trip during this time.
- An additional 36 percent of the total reduction in incident related delay was observed during the morning commute hours, with the remaining 1 percent in reduction observed throughout the remainder of the day.
Federal Highway Administration
ITS Joint Program Office