News Flash


Posted on: September 24, 2018

I-90/SR 18 Interchange Improvement Construction Schedule on Track

City of Snoqualmie News Release

September 24, 2018

I-90/SR 18 Interchange Improvement Construction Schedule on Track

Snoqualmie, WA – As confirmed in a news release from Washington State Senator Mark Mullet, a newly designed interchange at I-90 and State Route 18 is on schedule for construction to begin in 2021 with anticipated completion in 2023.

The I-90/SR 18 interchange at exit 25 is one of the busiest in the state, used by people who live in the area, commuting from the east and west sides of Tiger Mountain; cross-state travelers, and freight haulers. Backups on both I-90 and SR18 are common and, at times, excessive.

A design consultant has been selected by the Washington State Department of Transportation (WSDOT) in December 2017. Design and preliminary work will run through 2020 and construction will occur from 2021 through 2023.

At this time a Diverging Diamond Interchange (DDI) is the leading concept, but WSDOT will conduct extensive community engagement, traffic and environmental analysis as an interchange design is developed and refined.  

“Currently, WSDOT is planning on reserving the area around the exit 25 weigh station for staging during construction. The City of Snoqualmie is actively encouraging WSDOT to use a portion of this area to allow for a temporary and designated on-ramp feeding directly off of Snoqualmie Parkway onto westbound I-90 during construction,” said Snoqualmie Mayor Matt Larson.

“While this may be a long shot, it would allow for a continual flow of traffic without a requirement for a stoplight for our morning commuters. WSDOT does not currently support this option.”
To comment on the possibility of having the dedicated on-ramp, please contact Mark Allison, the WSDOT Project Engineer assigned to this project, at 206-440-4578

Read more details about the project on the City of Snoqualmie website ( under “Smart Growth” or the WSDOT project page.


A video by Mayor Larson about the project is posted on the City of Snoqualmie YouTube page. Note that this video was filmed in May 2017. It states that construction may begin as early as 2019. That was accurate information at the time of filming 16 months ago. Now construction is anticipated to begin in 2021 with completion in 2023, fully four years ahead of original estimates.


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Joan Pliego, City of Snoqualmie 
425-888-8014 or 425-281-3317



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