King County Council Update: Upcoming closure of SR 18 near the I-90 interchange

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King County Councilmember Reagan Dunn

Your Weekly Update on What's Happening at the King County Council  

Dear Friends and Neighbors,

I have heard concerns from many of you that the Washington State Department of Transportation (WSDOT) has announced a five-day, round-the-clock closure of SR 18 near the I-90 interchange. From 9 p.m. Thursday, May 15, to 5 a.m. Wednesday, May 21, only emergency vehicles, school buses and transit buses will be allowed beneath the I-90 bridges. Drivers can detour using eastbound and westbound I-90 and looping around at exit 22 (Preston-Fall City) or exit 27 (Southeast North Bend Way). 

I know that extended closures are a hurdle for all who rely on the highway, including myself. This is why in 2023, I sent a letter to WSDOT requesting they convene an interagency task force to give cities and other impacted groups input on a traffic management plan so that everyone can plan and adapt to delays and congestion. This letter was also signed by the mayors of Maple Valley, Issaquah, Snoqualmie, Covington, Black Diamond, and Kent; multiple Chambers of Commerce; the Snoqualmie Tribe; and the Puget Sound Regional Fire Authority. As a result, the SR 18 Task Force began meeting regularly and many stakeholders have been able to offer feedback and solutions to help alleviate the stress felt by nearby communities.

The good news is that when SR 18 reopens on May 21, most of the construction on the southern end of the new interchange will be complete. The next project phase will involve construction under the I-90 bridges and on the northern end of the project before traffic can be shifted into the final diverging diamond configuration later this summer. In addition to building the new interchange, WSDOT will be adding two lanes on SR 18 between the interchange and Deep Creek later this year.

Though continued construction and traffic delays can be painful, I am optimistic that WSDOT’s work will ultimately make driving this route easier through increased capacity and improved traffic flow. You can read more about WSDOT’s ongoing work at the I-90 – SR 18 Interchange Improvements webpage.

All my best,

Dunn-signature

Reagan Dunn
King County Councilmember
District 9