Construction crews working on the State Route 509 Completion Project will close lanes and ramps on northbound and southbound I-5 nightly beginning Monday, May 20 to install new highway signs, the Washington State Department of Transportation (WSDOT) announced.

The lane closures – which will continue through Thursday, May 23 – are necessary for the safety of crews who will install the new signage over the closed lanes.

Lane and ramp closure information 

Tuesday, May 21 through the morning of Thursday, May 23, 2024:

  • 9 p.m. to 4 a.m. – Up to two lanes of northbound I-5 will close nightly between South 272nd Street (Exit 147) and South 200th Street/Military Road South (Exit 151).
  • 11:59 p.m. to 5 a.m. – The westbound SR 516 ramp to northbound I-5 will close nightly. A signed detour will be in place.

Wednesday, May 22 through the morning of Thursday, May 23, 2024:

  • 11:30 p.m. to 5 a.m. – The SR 516 ramp to southbound I-5 will close. A signed detour will be in place. 

This work is weather-dependent and may be rescheduled in the event of rain.

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 Sea-Tac 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 by 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.