On-time performance of transit trips across the SR 520 bridge improved by 42 percent during peak periods after deployment of electronic tolling.
The Seattle/Lake Washington Corridor Urban Partnership Agreement projects evaluated tolling, technology, transit, and travel demand management strategies to reduce congestion.
Made Public Date

Seattle/Lake Washington Corridor Urban Partnership Agreement: National Evaluation Report

Summary Information

In 2006, the U.S. DOT initiated the UPA (Urban Partnership Agreement) program to demonstrate congestion reduction through strategies consisting of combinations of the 4Ts: Tolling, Transit, Telecommuting/TDM, and Technology. The Seattle/LWC UPA projects focused on reducing traffic congestion on SR 520 between I-405 and I-5, a heavily-traveled, east-west commuter route across Lake Washington. The lake separates Seattle from the eastern suburbs (including Bellevue and Redmond). These strategies included tolling all lanes of the SR 520 bridge, adding bus service in the SR 520 corridor, implementing active traffic management systems, and real-time traveler information signs on highways and at transit stops and stations. The suite of projects had a combined benefit-to-cost ratio of 1.76 due to travel time savings and reduced emissions.


From pre-deployment to post-deployment of electronic tolling on the SR 520 bridge, on-time performance of transit routes crossing the bridge improved from 47 percent to 67 percent in the morning peak (a 42 percent increase) and from 40 percent to 57 percent (a 42 percent increase) in the afternoon peak. In the westbound direction, on-time performance improved from 63 percent to 67 percent in the morning peak but dropped from 51 percent to 47 percent in the afternoon peak. Improvements were greatest in the eastbound direction where bus travel times were 0.9 and 1.7 minutes shorter. Speeds across the bridge increased by 14 to 18 mph.

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Deployment Locations