Friday, August 11, 2023

Stay out of traffic on I-405 during the weekend of Aug. 19-20: Know before you go!

By Victoria Miller

If your travels take you between Renton and Bellevue, heads up!

During the weekend of Aug. 19-20, Interstate 405 will have a FULL WEEKEND CLOSURE to replace a culvert that runs under the highway. Prepare for delays, use alternate routes, or consider delaying your trip if possible.

Give me the details!

From 10 p.m. Friday, Aug. 18 until 5 a.m. Monday, Aug. 21, both directions of I-405 will be fully closed between Sunset Boulevard in Renton (Exit 5) and Coal Creek Parkway in Bellevue (Exit 10). This closure is for I-405, Renton to Bellevue Widening and Express Toll Lanes work that includes building a box culvert to replace a fish barrier, making it easier for fish to swim and improve the fish habitat upstream. Signed detours will be in place for this full closure on I-405.

Several ramps will also be closed during this weekend closure:

  • Sunset Boulevard Northeast on-ramp to northbound I-405
  • All ramps at North 30th Street to I-405
  • All ramps at Northeast 44th Street to I-405
  • All ramps at 112th Avenue Southeast/Lake Washington Boulevard Southeast (Exit 9) to I-405
  • Coal Creek Parkway Southeast on-ramp to southbound I-405

Whether driving on northbound or southbound I-405, you will need to take a different route during these full lane and ramp closures.

Northbound drivers will exit at State Route 900/Sunset Boulevard Northeast in Renton and rejoin I-405 at Coal Creek Parkway in Bellevue. Another option is to follow additional detour signs to rejoin northbound I-405 at Southeast Eighth Street near downtown Bellevue.

Southbound drivers will exit at Coal Creek Parkway and get back on I-405 at North Southport Drive in Renton. They can also exit at Southeast Eighth Street or Lake Washington Boulevard Southeast (Exit 9) and follow additional signs to detour to North Southport Drive.

During this full weekend closure, travelers should expect:

  • Delays and congestion: Plan for slower travel times on I-405 and longer waits along the detour routes.
  • Reduced speed limits in work zones: Anytime you’re in or approaching these construction work zones, please give our crews room, slow down, be patient, and stay alert.
  • Potential noise: Construction work can also make loud noises ad cause vibrations.

Why is this happening?

As we have talked about earlier this year, summer 2023 is a busy season for construction projects across our state. This closure is happening now because we need warm, dry weather for some of the tasks and state laws related to fish passages determine the timeframe for when those tasks can be done.

Stay informed!

The best way to stay up to date is to follow us @WSDOT_Traffic on Twitter and check our real-time Traffic Map to see how things look. Travelers can also sign up for our I-405/Renton to Bellevue project interest list by emailing us at, subscribe to the weekly Eastside of Lake Washington Transportation newsletter, and download the WSDOT app.

Travelers with questions about this closure and the project can call the 24-hour I-405/Renton to Bellevue construction hotline at 425-818-0161, or email us at


concerned I405 detour said...

I hope wsdot is putting "local access only" signs on the detour route to keep traffic off of the residential streets

Fishgrabr said...

Considering the necessity of the detour your hoop is a bit to much to expect.

Debbie said...

Are they really blasting at 1230 am???? Our dog is going crazy and we keep hearing the light booms.

Ben Edelman said...

Sometimes closures end early, when work goes faster than planned. We've even seen that for other closures on the east side within the last year.

If this closure ends early, how can drivers find out? I know from experience that signs -- even electronic signs -- can give outdated information.

(Asking because I'll have a journey late late Sunday night, for which the affected section of 405 would massively shorten my journey time, if it's open.)

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