SR 99

The timeline for crews to complete temporary emergency repairs of the northbound State Route 99 First Avenue South bridge has been extended to 11:59 p.m. on Friday, March 13.

Washington State Department of Transportation bridge maintenance crews have been working to modify existing grated panels and install steel plates over the cracked grates to restore safe vehicle access across all lanes since the full closure began on Monday morning, March 9.

UPDATE: The series of westbound SR 18 lane, ramp and directional closures has been postponed and will be rescheduled at a later date. The scheduled work on the SR 99 First Avenue Bridge has also been canceled. The information has been removed in the news release below.

SEATTLE – It’s about time for people who use the State Route 99 tunnel under downtown Seattle to get a grip.

Beginning Monday night, Aug. 18, contractor crews working for the Washington State Department of Transportation will texturize lanes in the tunnels to improve traction for vehicles.

The quick-moving project requires up to five nightly closures in each the northbound and southbound tunnels. Work is expected to wrap up before Labor Day weekend.

Update: Oct. 10, 2024 - I-5 lane closures in Seattle will now include northbound lanes between mid-Boeing Field and the West Seattle Bridge. The updated information is reflected in the release below.

Update: Oct. 9, 2024 - The hours for the I-405 overnight lane reductions and ramp closures have changed. Note the lane closures will occur 8 p.m. Friday, Oct. 11 to 8 a.m. Saturday, Oct. 12. Ramps will be closed from 11 p.m. Friday to 8 a.m. Saturday. This updated information is reflected in the release below.

SEATTLE – Both directions of the State Route 99 tunnel in Seattle will close the first two weekends in October for its first six-year inspection. The tunnel opened to travelers in February 2019 to replace the Alaskan Way Viaduct and provide safety and mobility improvements along Seattle's central waterfront. 

Closure details

From 10 p.m. Friday, Oct. 4, until 6 a.m. Saturday, Oct. 5, and from 10 p.m. Friday, Oct. 11, until 6 a.m. Sunday, Oct. 13, both directions of the SR 99 tunnel will close.