Drivers in Burien, Des Moines, SeaTac, and Kent should prepare for multiple nighttime lane and ramp closures on Interstate 5, State Route 516, and SR 509 from Monday, Aug. 18 through Friday morning, Aug. 22.
The closures support work on the SR 509 Completion Project, including roadway sign installation, paving, and striping. Work hours vary by location, with most closures between 8 p.m. and 6 a.m. Detours will be posted where ramps are closed.
Key impacts include:
I-5: Up to three southbound lanes closed nightly between S. 200th St./Military Rd. S. and S. 272nd St. Aug. 18–20; up to four lanes closed later in the week in both directions between SR 509 and S. 200th St.
SR 516: Nightly lane closures in both directions between SR 99 and Military Rd. S., plus ramp closures to northbound and southbound I-5.
SR 509: Overnight closures of the 24th Ave. S. on-ramp to southbound SR 509 Aug. 18–19 and Aug. 20–22.
The SR 509 Completion Project will ultimately add three miles of new tolled highway between I-5 and S. 188th St. near Sea-Tac Airport. Portions have already opened, with final completion expected in 2029.
More details, maps, photos, and a 3D video tour are available on WSDOT’s SR 509 project page.
Photos of construction work are available on the project’s Flickr page. A 3D video tour is also available on WSDOT’s YouTube page.
Specific Closure Times:
I-5 lane closure information
Monday, Aug. 18 through the morning of Wednesday, Aug. 20
- 11:30 p.m. to 6 a.m. – Up to three lanes of southbound I-5 will close nightly between South 200th Street/Military Road South (Exit 151) and South 272nd Street (Exit 147).
Monday, Aug. 18 through the morning of Friday, Aug. 22
- 11:59 p.m. to 3:30 a.m. – Up to four lanes of northbound I-5 will close nightly between SR 509 (Exit 150) and South 200th Street/Military Road South (Exit 151).
Wednesday, Aug. 20 through the morning of Friday, Aug. 22
- 11:59 p.m. to 5 a.m. – Up to four lanes of southbound I-5 will close nightly between South 200th Street/Military Road South (Exit 151) and South 272nd Street (Exit 147).
I-5 ramp closure information
Monday, Aug. 18 through the morning of Tuesday, Aug. 19
- 9:30 p.m. to 3:30 a.m. – The northbound I-5 exit to SR 516 will close overnight. A signed detour will be in place.
- 11:30 p.m. to 4 a.m. – The southbound I-5 exit to SR 516 will close overnight. A signed detour will be in place.
Wednesday, Aug. 20 through the morning of Friday, Aug. 22
- 11:30 p.m. to 4 a.m. – The southbound I-5 exit to SR 516 will close nightly. A signed detour will be in place.
SR 516 lane closure information
Monday, Aug. 18 through the morning of Tuesday, Aug. 19
- 8 p.m. to 5 a.m. – One lane of eastbound SR 516 will close overnight between Military Road South and SR 99. A signed detour will be in place.
- 10:30 p.m. to 4 a.m. – Westbound SR 516 will close overnight between Military Road South and SR 99. A signed detour will be in place.
SR 516 ramp closure information
Monday, Aug. 18 through the morning of Tuesday, Aug. 19
- 11:59 p.m. to 2:30 a.m. – The eastbound SR 516 ramp to northbound I-5 will close overnight. A signed detour will be in place.
Tuesday, Aug. 19 through the morning of Friday, Aug. 22
- 11 p.m. to 3:30 a.m. – The westbound SR 516 ramp to northbound I-5 will close nightly. A signed detour will be in place.
SR 509 ramp closure information
Monday, Aug. 18 through the morning of Tuesday, Aug. 19
- 10:30 p.m. to 4 a.m. – The 24th Avenue South on-ramp to southbound SR 509 will close overnight. A signed detour will be in place.
Wednesday, Aug. 20 through the morning of Friday, Aug. 22
- 10:30 p.m. to 4 a.m. – The 24th Avenue South on-ramp to southbound SR 509 will close nightly. A signed detour will be in place.
