BURIEN – Roundabout construction at the South 160th Street and SR 509 interchange will bring the final weekend-long closure from Saturday, Aug. 23 at 6 a.m. through Monday, Aug. 25 at 5 a.m.
What’s Closing
- South 160th Street in both directions between Fifth Place South and Ambaum Cut Off South.
- On-ramps from South 160th Street to northbound and southbound SR 509.
- Northbound SR 509 off-ramp to South 160th Street.
The southbound SR 509 off-ramp to westbound South 160th Street will remain open.
Detours
- Drivers on South 160th Street: use South 156th or South 168th streets.
- Pedestrians and cyclists: detour on the south side of South 160th Street.
- SR 509 ramp closures: signed detours will direct drivers to First Avenue South, Des Moines Memorial Drive South, South 188th Street, and South 148th Street.
- Local access to homes, businesses, and Fifth Place South will stay open.
Why It’s Happening
Crews will finish paving work around two new roundabouts at the interchange as part of the SR 509 Completion Project.
Project Background
The SR 509 Completion Project is adding 3 miles of new tolled highway between I-5 and South 188th Street, near Sea-Tac Airport. Portions opened earlier this summer, with full completion expected by 2029.
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