The projects initial phase constructs six-lanes from SR 509’s current end point at South 188th Street to I-5. The project includes a freeway-to-freeway HOV connection at the I-5/SR 509 interchange and new lanes on I-5 to South 272nd Street. This new connection is expected to draw more than 1,000 vehicles per hour and thousands of trucks per day that currently travel through a major I-5 choke point. In order to afford the extension to I-5, construction of the South Airport Access Interchange would wait until the Port of Seattle is ready to construct the South Access Roadway and the proposed 28th Avenue South arterial connection would be delayed to a later phase.

Benefits:

• Provides HOV lanes and connections to I-5 supporting multimodal transportation options, with a direct connection to future LRT stations at South 200th Street.
• Completing the SR 509 missing link will improve use and efficiency of the existing SR 509 segment to the north.
• This new freeway connection will improve the movement of freight among the Port of Seattle, the Duwamish industrial area and the Kent Valley industrial complex. The new connection is estimated to save freight carriers more than $60 million annually by creating shorter trips.
• An SR 509 connection with I-5 provides a viable travel option to I-5, reducing congestion on Southcenter Hill and improving the people- carrying capacity of the north/south corridors.

Updated: Sept. 22, 2003