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Congestion Reporting at WSDOT

Evaluating System Performance and Improving Mobility

WSDOT is recognized for its commitment to accurate and quality reporting on congestion. Since 1988, the department has been collecting, analyzing, and reporting on congestion to help the public and officials better understand how congestion is evolving and what mitigation strategies are effective for improving commutes. In 2007, the Legislature amended RCW 47.01.012 to create six transportation policy goals , including Mobility – Congestion Relief. WSDOT has adapted and expanded its congestion reporting to include mobility and congestion relief programs in all of its strategic and performance-based reporting, including the Gray Notebook

Annual Corridor Capacity Report (a.k.a. Congestion Report)

WSDOT's comprehensive annual multimodal analysis of state highway system performance

The Corridor Capacity Report informs the Legislature, stakeholders, education and research institutions, the media, communities and the public about the state of congestion and transportation capacity in Washington State. The detailed analysis in the report shows where and how much congestion occurs, and whether it has grown on state highways. The report focuses on the most traveled commute corridors around the state.

Starting in 2013, WSDOT introduced new performance measures and a new graphical display of information, all with an emphasis on multimodal and person-based metrics. The new measures include park and ride lot utilization, routinely congested highway segments, greenhouse gas emissions, transit ridership, and the costs of congestion for commuters. These measures complement the existing average and reliable travel times, hours of delay, vehicle miles traveled, Before and After results of projects and programs designed to mitigate congestion and help tell the multi-modal system capacity story. Finally, the report states how WSDOT is working towards the department’s three strategies for greater mobility and congestion relief – one of the state’s six key policy goals for transportation agencies .

Car in HOV Lane

Semi-Annual Travel Trends Report

Impacts of the economy on travel time trends

In 2008, WSDOT published its first semi-annual travel trends report as a result of the rapidly changing economy experienced nationally, as well as in Washington state. WSDOT has continued to produce these reports to provide an interim update on travel time trends in the central Puget Sound region as the Congestion Working Group manages to produce the comprehensive WSDOT Annual Congestion Report.

Ramp Meter on I-405

Semi-Annual Reports

Quarterly and Annual Updates on Mobility

Performance updates on programs that relieve congestion and provide commute options.

The Gray Notebook includes quarterly and annual updates on key mobility programs that help to mitigate congestion and provide alternate commute options: the Incident Response Program , Washington State Ferries  (WSF), and Amtrak Cascades . For WSF and Amtrak Cascades , these reports track key performance metrics such as ridership, on-time performance, and service reliability, and for the Incident Response program, the number of incidents cleared statewide and average clearance times. The annual Commute Options report tracks programs and trends like the percentage of Washington drivers who commute alone and alternative commute programs such as state-supported vanpools.

IR Truck in Action

Recent Mobility Updates


Moving Washington

WSDOT's program to fight congestion

WSDOT's Moving Washington program utilizes three balanced strategies to fight congestion: add capacity strategically, operate efficiently, and manage demand. As part of its regular congestion reporting, WSDOT shows how its programs and projects use these strategies to help fight congestion. Please visit the Moving Washington website for more information.

In addition, WSDOT uses its real-time data collection tools to help commuters plan their trips in ways that avoid or reduce additional congestion:

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