Lane and ramp closures on I-5, SR 516 and SR 509 in South King County continue this week

Lane and ramp closures on I-5, SR 516, and SR 509 in South King County will continue through the morning of August 8, 2025, according to the Washington State Department of Transportation (WSDOT). The closures will facilitate roadway sign installations on I-5, electrical work on SR 516, and paving on SR 509. Specific closure times include nightly lane reductions on I-5 from August 4 to August 8, with detours in place for affected exits. The SR 509 Completion Project aims to build a new tolled highway that connects I-5 to South 188th Street, enhancing access to Seattle-Tacoma International Airport. The project opened a segment between I-5 and 24th Avenue South in June and a tunnel under I-5 at the SR 516 interchange in July.

This construction addresses critical gaps in Washington's highway network and is part of the larger Puget Sound Gateway Program. The entire SR 509 Completion Project is set for completion by 2029. Improved access and infrastructure are expected to benefit regional traffic flow significantly.