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 will affect South King County from July 14 to July 20, 2025, as part of ongoing maintenance efforts. The closures will enable crews to complete essential tasks, such as striping and replacing bridge expansion joints on I-5, and performing paving and electrical work on SR 516 and SR 509. Specific nightly closure schedules include significant lane reductions on I-5, with detours established for affected exits. The SR 509 Completion Project, which adds three miles of tolled highway, aims to improve connectivity between I-5 and South 188th Street near Seattle-Tacoma International Airport. The newly opened section of the highway between I-5 and 24th Avenue South is part of a phased approach, with completion projected by 2029.

This infrastructure enhancement is crucial for local traffic and freight movement in the region. Motorists should heed the posted detour signs and plan alternative routes during the closures. The project is part of WSDOT’s broader Puget Sound Gateway Program, which addresses critical gaps in the state's transportation network.