Full ITS deployment in the Seattle area projected to reduce recurrent congestion delays by 3.2 percent and incident related delays by 50 percent.

The projected results of full ITS deployment in a large metropolitan area.

May 2005
Seattle,Washington,United States

Summary Information

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 SystemsCentral Control Signal Coordination
Emergency Vehicle Signal Preemption
Transit Vehicle Signal Priority
Freeway Management SystemsCentral Control Ramping Metering
Transit ManagementFixed-Route Automated Scheduling and Automatic Vehicle Location
Fixed-Route Security Systems
Electronic Transit Fare Payment
Incident Management SystemsIncident Detection, Verification, Response, and Management
Emergency Management SystemsEmergency Vehicle Control Service
Emergency Vehicle AVL
Traveler InformationPhone- and Web-Based Traveler Information System
Kiosk-Based Traveler Information
Highway Advisory Radio
Dynamic Message Signs
Crash Prevention and SafetyRailroad Crossing Monitoring Systems
Commercial Vehicle OperationsWeigh-in-Motion and Safety Information Exchange
Combination Screening and Clearance
Supporting DeploymentTraffic Management Center
Transit Management Center
Emergency Management
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.
Deployment of ITS also resulted in significant reduction of incident-related delay.
  • 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.

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Benefits and Costs of Full Operations and ITS Deployment: A 2003 Simulation for Seattle

Published By: United States Department of Transportation Federal Highway Administration ITS Joint Program Office

Source Date: May 2005

EDL Number: 13977

Other Reference Number: Report No. FHWA-JPO-04-033


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Goal Areas


Typical Deployment Locations

Metropolitan Areas


coordinated signals, signal coordination, centralized signal control, signal synchronization, traffic signals, advanced signal control, signal timing optimization, coordinated signal control, advanced signal controller, traffic signal retiming, retiming, ramp meters, delay reduction, traffic incident management, recurring delay, incident-related delay

Benefit ID: 2015-01029