WSDOT Open House on extension of SR 509 will be Thursday, Dec. 17


The Washington State Department of Transportation (WSDOT) will be holding an Open House on the extension of SR 509 on Thursday, Dec. 17 at Highline College.

Project staff will be on hand to answer your questions and share project information.

WHEN: Thursday, December 17, 2015; 5 to 7 p.m.

WHERE: Highline College, Building 2, 2400 South 240th Street, Des Moines, WA 98198

Over the next few months, project staff will be re-engaging with stakeholders along the project alignment, undergoing a practical solutions process, and performing a re-evaluation of our previously completed environmental document.

Why is WSDOT extending SR 509?
Extending SR 509 will ease congestion on I-5, add a southern access point to Sea-Tac International Airport, and improve service between industrial districts by allowing general-purpose traffic, and up to 9,000 trucks daily, to bypass I-5, SR 99 and local streets.

The End Result
When finished, SR 509 will become a key component of the Seattle and south King County transportation network. When considered in conjunction with the planned Alaskan Way Viaduct improvements, the project provides a critical north-south corridor alternative to I-5 through Seattle and South King County.

Project Benefits

  • Reduced Congestion. Fewer vehicles and less traffic on I-5 in South King County by providing an alternate north-south route to I-5.
  • Advanced wetland mitigation. Environmental improvements completed in advance of the project improve water quality and wildlife habitats for the Des Moines Creek basin.
  • Intermodal freight mobility. Creating a direct route for freight and general traffic movements to and from the Puget Sound marine ports and the industrial areas of Seattle and South King County.
  • Airport Access. Provides for a new connection between I-5 and Sea-Tac Airport from the south.
  • Public value. By reducing travel times between Seattle and Tacoma by up to 12 minutes, the traveling public saves more than $100 million per year in travel time.
  • Intelligent transportation. In addition to adding revenue, creating a toll road will help manage travel demand in real time to improve system performance.

What is the project timeline?
Funding through the Connecting Washington Account will be distributed over a 16 year period. WSDOT anticipates construction will be complete in 2031.

Financial Information
This project received funding through the following sources:

  • 2005 Gas Tax -$30 million
  • 2003 Gas Tax – $35 million
  • Other funds – $21 million (from pre-existing state, federal and other partnerships)
  • Connecting Washington – $1.9 billion (shared between SR 509 and SR 167)

For more information, contact:

Emily Mannetti, Public Information
[email protected]

Omar Jepperson, P.E.
[email protected]

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