| The SR 509 Extension and Interstate 5 Improvement Project has been developed through many years of cooperative efforts between WSDOT, the Port of Seattle, King County, and the cities of Sea-Tac, Des Moines and Kent. The project proposes critical freight and mobility improvements for SR 509 including completion of the planned SR 509 corridor extension to I-5, improvements on I-5, and more direct access to Sea-Tac International Airport and the Kent Valley. |
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WSDOT received funding from the Transportation Research Board's Second Strategic Highway Research Program (SHRP 2) to test the Transportation for Communities—Advancing Projects through Partnerships (TCAPP) tool. TCAPP provides a systematic approach for reaching collaborative decisions about adding highway capacity that improves transportation while enhancing the environment, the economy, and the community.
Building on the SR 509 Extension Toll Feasibility Study completed in 2010, WSDOT and its partners will use the TCAPP decision making tool developed by the SHRP 2 program to move the project forward.
Why is WSDOT planning the phasing of the SR 509 extension?
Although the project is expected to provide benefits for passenger and freight movements, project funding has not materialized. Many attempts in the past, including the Regional Transportation Investment District, were made to fund the project, but were not successful. One of the key findings from the SR 509 Extension Toll Feasibility Study is that tolling would not only generate revenue, but would also help manage travel demand creating an opportunity to phase construction and reduce project costs. Another key finding from the toll feasibility study is that under the most favorable financial conditions, toll revenue could fund a significant portion of the construction cost of a scaled down, optimally phased project.
The End Result
Using TCAPP collaboration techniques, WSDOT will work with project partners to develop the following key recommendations for consideration by the state legislature:
- a preferred Phase 1 project for funding
- a preferred tolling strategy to help fund construction of the Phase 1 project
Contact Us
Shuming Yan
WSDOT Urban Planning Office
206-464-1276
urbanplanning@wsdot.wa.gov