SR 18

Wider SR 18 and new interchange expected to improve traffic flow

SNOQULAMIE – A pinch point that has kept the state’s second diverging diamond interchange from showing its full potential since opening last summer will soon be cleared, allowing State Route 18 traffic to flow.   

Contractor crews working for the Washington State Department of Transportation will expand more than 2 miles of SR 18 to two lanes in each direction from Interstate 90 to Deep Creek after a four-day closure of SR 18 over Tiger Mountain scheduled to begin Thursday night, Oct. 16.

Canceled: The closure of southbound I-405 between SR 900/East Sunset Boulevard and SR 167 is canceled due to equipment issues and will be rescheduled to another weekend. The release below has been updated to remove this closure. All other highway closures are going forward as planned.

UPDATE: The series of westbound SR 18 lane, ramp and directional closures has been postponed and will be rescheduled at a later date. The scheduled work on the SR 99 First Avenue Bridge has also been canceled. The information has been removed in the news release below.

Second extended closure near Snoqualmie begins Thursday, July 17

SNOQUALMIE – After several years of planning and design, and nearly 20 months of construction, it’s almost time for the state’s newest diamond to shine.

The Washington State Department of Transportation will open the second diverging diamond interchange in the state after an eight-day, round-the-clock closure of both directions of State Route 18 under the Interstate 90 overpasses scheduled to begin Thursday night, July 17. 

UPDATE: The five-day closure of State Route 18 at the Interstate 90 interchange has been rescheduled and will be from 9 p.m. Thursday, May 29, to 5 a.m. Wednesday, June 4. The dates have been updated in the release below. Release also updated to include High Point Way (exit 20) as part of the detour route.

Plan ahead for single lane, alternating weeknight traffic through end of March

TIGER MOUNTAIN – The Interstate 90/State Route 18 Interchange Improvements project is approaching a major milestone, as work begins Wednesday, Jan. 31, on the last of three bridges needed to widen a 2-mile section of SR 18 just south of I-90.