Tuesday, September 23, 2025

Southbound I-5, southbound I-405 and sections of SR 18 and I-90 in King County to close Sept. 26-29

by: Sidney Orr 

Make your weekend game plan now!

The University of Washington Huskies play the Ohio State Buckeyes on Saturday, Sept. 27. But starting Friday night, Sept. 26, our crews will also hit the field with big construction work across King County. Closures will last through Monday, Sept. 29. As crews tackle their work, drivers should make a game plan too.

Huddle up! Here’s the starting lineup:

I-5 southbound through Kent and Des Moines

Two maps showing local detours and regional routes through the southbound I-5 closure, SR 509 closure, and project area. Detailed route information in text below.
  • Southbound I-5 will close from SR 516/Kent Des Moines Road to South 272nd Street. The southbound SR 509 expressway will also close from 24th Avenue South to I-5.
  • Game time: 11:59 p.m. Friday, Sept. 26, to 4 a.m. Monday, Sept. 29.
  • Game plan: Crews will replace 60 worn-out concrete panels.
  • Local drivers can detour using SR 99 or Military Road South. For longer trips, southbound SR 167 will stay open.

I-405 southbound through Renton

A map showing the extent of the SB I-405 closure and detour route through the closure area. Detailed route information in text below.

  • Southbound I-405 will close from North Southport Drive/Sunset Boulevard Northeast to SR 167.
  • Game time: 11:59 p.m. Friday, Sept. 26, to 4 a.m. Monday, Sept. 29.
  • Game plan: Crews will put in new drainage, pave the road and shift lanes.
  • Drivers will follow a signed detour route on Sunset Boulevard Northeast.
  • Work may be rescheduled if rain is forecast.
  • This work is part of the I-405/Renton to Bellevue Widening and Express Toll Lanes project.

I-90 westbound through Issaquah

SR 18 westbound in Auburn

  • Westbound SR 18 reduced to one lane from 9 p.m. Friday, Sept. 26, to 1 a.m. Sunday, Sept. 28. The Auburn Way South on-ramp to westbound SR 18 will close at the same time.
  • Game time: All lanes will close from 2 a.m. Sunday, Sept. 28, to 5 a.m. Monday, Sept. 29. Westbound SR 18 traffic must exit to Auburn Way South but may use the on-ramp back onto the highway.
  • Game plan: Crews will replace bridge joints.
  • Westbound SR 18 traffic must exit to Auburn Way South during the full closure but may use the on-ramp back onto the highway.
  • Work may be rescheduled if rain is forecast.

Getting around

With all this work, here are the best ways to make sure you cross the goal line:

  • Avoid delay of game: If you can, leave earlier or later in the day to avoid heavy traffic on detour routes.
  • Call a timeout: Delay non-essential trips to help keep traffic moving – remember it’s a great weekend to watch football from your couch.
  • Always remember teamwork: Taking transit or carpooling will also reduce congestion on local and regional detours.

Know before you go

While this is our playbook, it's not the full game plan. Travelers are encouraged to check travel times on the Travel Center map, WSDOT mobile app and following the agency’s social media accounts.

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