The Washington State Department of Transportation (WSDOT) will soon begin construction on the long-anticipated SR 509/24th Avenue South to South 188th Street New Expressway project.
This project is the final, fully-funded stage (Stage 2) of the SR 509 Completion Project, and is part of a broader effort to improve traffic flow and safety in the region, creating a vital connection between Seattle’s south suburbs and the Port of Seattle, while also providing relief to local roadways.
The new expressway will link SR 509 with I-5 and include additional improvements such as better access for freight traffic, reduced congestion, and upgraded infrastructure to support future growth in the area. WSDOT hopes that the project will ease bottlenecks and improve travel times for commuters and commercial vehicles alike, enhancing economic and transportation efficiencies.
Online Open House
As part of the planning and community engagement process, WSDOT is inviting the public to participate in an online open house through Oct. 25, 2024. Residents, commuters, and businesses can access detailed project plans, timelines, and expected impacts by visiting the virtual platform at https://engage.wsdot.wa.gov/sr-509-expressway/. The platform also provides opportunities to submit feedback and ask questions directly to the project team.
The SR 509 extension is expected to play a critical role in regional transportation planning, offering a new north-south corridor that alleviates pressure on I-5 and improves access to Sea-Tac International Airport and other major destinations. WSDOT’s plans also emphasize the inclusion of safety enhancements, such as new pedestrian and cyclist pathways.
What’s included in the project?
The SR 509/24th Avenue South to South 188th Street New Expressway project includes:
- Over two new miles of expressway.
- An additional lane on southbound I-5 between SR 516 and South 272nd Street in Kent.
- Roundabouts at South 160th Street in Burien and South 188th Street in SeaTac.
- New noise walls.
- Restoring natural areas within the project corridor.
Project timeline
Early construction activities include vegetation clearing throughout the project area. Heavier construction work will begin in fall 2024. Check out the work zones in the following pages to learn what to expect in the areas you live, work and travel.
The SR 509 Completion Project is already under construction. Stage 1a opened to traffic in 2022, Stage 1b is expected to open to traffic in 2025, and Stage 2 is expected to be open to traffic in 2028.
WSDOT says that construction is slated to have significant completion by 2028.
WSDOT is starting construction on the State Route 509/24th Avenue South to South 188th Street New Expressway project in 2024. Access the online open house through October 25. https://t.co/QzZX3Psaue pic.twitter.com/8OBBZ5Tjfq
— City of Burien, WA (@Burien) September 24, 2024
