Contract summary
The SR 509 Stage 1b is the first major stage of the SR 509 Completion Project, located in King County in the cities of Des Moines, Kent and SeaTac. WSDOT plans to complete construction of the SR 509 Completion Project in two major stages by 2028.
When completed, the project will extend the existing four-lane SR 509 freeway from the SR 509/South 188th Street interchange in SeaTac, connecting to I-5 with a new interchange in the vicinity of South 212th Street. The project also builds approximately four miles of improvements along I-5 from I-5/SR 509 interchange to the I-5/S. 272nd Street interchange.
Publication Date
Contract status
Awarded
Contract ID
9424
County
King County
Submittal due date and time
Estimated value
$300,000,000 - $330,000,000
Funding source
A federally funded contract with a 8% underutilized disadvantaged business enterprise condition of award goal for design and a 10% goal for construction
Contact