Construction along State Route 18 near Tiger Mountain has slowed traffic through the area since it began. With temporary speed limit reductions on the way next week, travelers should plan now for a little additional time for their trips through the end of next year.
Beginning Monday, August 7, the Washington State Department of Transportation will temporarily reduce the speed limit in both directions of SR 18 between Interstate 90 and Tiger Mountain. The reductions are necessary to help protect highway construction crews on the I-90/SR 18 Interchange Improvements project and people traveling through the work zone.
Around-the-clock speed reductions
- A reduction to 30 mph will begin at the I-90 interchange and end at milepost 27.5, just south of Southeast 104th Street.
- A reduction to 45 mph will begin at milepost 27.5, just south of Southeast 104th Street, and end at milepost 23.8, just north of the Tiger Mountain summit.
Work zone details
- People traveling on SR 18 and Snoqualmie Parkway will see new speed limit signs.
- Drivers can expect the temporary speed limit reduction to last through late 2024.
- WSDOT will work with the Washington State Patrol to manage the enforcement of the new speed limit. Traffic fines double in work zones.
Why a speed reduction is needed
While contractor crews build the diverging diamond interchange and widen SR 18, traffic shifts will keep workers and travelers safe.
“In order to widen SR 18, we are building three new bridges and shifting lanes through the corridor,” said WSDOT Project Engineer James Harper. “Reducing the speed limit through our project area will help people navigate those traffic shifts through each stage of construction.”
People should expect traffic shifts and intermittent lane and ramp closures in the project area as crews work on bridge construction, drainage systems and utilities for the new interchange. WSDOT will announce closures in advance on the WSDOT app, travel center map and in project email updates.