Overnight lane closures on I-5 in the SeaTac, Des Moines and Kent area continue Monday, Dec. 2 through the morning of Tuesday, Dec. 3, according to the Washington State Department of Transportation (WSDOT). The closures will allow contractor crews to install guardrails. Crews will also close ramps on SR 509 from Monday, Dec. 2 through Friday, Dec. 6. Local road closures in SeaTac and Burien continue Monday, Dec. 2 through Friday, Dec. 6. This work is part of the SR 509 Completion Project.

I-5 lane closure information 

Monday, Dec. 2 through the morning of Tuesday, Dec. 3

SR 509 ramp closure information 

Monday, Dec. 2 through the morning of Thursday, Dec. 5
    • 9 p.m. to 5 a.m. – The southbound SR 509 on-ramp from South 160th Street will close nightly. A signed detour will be in place.
Wednesday, Dec. 4 through the morning of Friday, Dec. 6
    • 10 p.m. to 5 a.m. – The northbound SR 509 off-ramp to South 160th Street will close nightly. A signed detour will be in place.

Local road closure information 

Monday, Dec. 2 through Wednesday, Dec. 4
    • 7 a.m. to 3 p.m. – One lane of 34th Avenue in SeaTac will close daily. Flaggers will alternate traffic.
Monday, Dec. 2 through Friday, Dec. 6
    • 7 a.m. to 3 p.m. – One lane of South 208th Street in SeaTac will close daily. Flaggers will alternate traffic.
Tuesday, Dec. 3 through Friday, Dec. 6
    • 7 a.m. to 3 p.m. – One lane of South 216th Street in SeaTac will close daily. Flaggers will alternate traffic.
An interactive project map that allows people to explore the new SR 509 Expressway, the SR 516 interchange and other elements of the completion project is also available online.

SR 509 Completion Project information 

The SR 509 Completion Project builds 3 miles of new tolled highway between I-5 and South 188th Street near the south end of Seattle-Tacoma International Airport. The new highway will be completed in stages. The portion currently under construction between I-5 and 24th Avenue is scheduled to open in 2025. The final stage will build the remaining 2 miles of the expressway between 24th Avenue South and South 188th Street. The entire project is planned for completion in 2028.

Puget Sound Gateway Program overview 

The SR 509 Completion Project is part of WSDOT’s Puget Sound Gateway Program, which also includes the SR 167 Completion Project in Pierce County. Combined, the two completion projects finish critical missing links in Washington’s highway and freight network.

Know before you go 

Before heading out the door, travelers can find the latest information on the WSDOT app, the real-time travel map, or by subscribing to WSDOT’s email and text alerts.