SR 18 Over Tiger Mountain Set for Full Weekend Closure

SR 18 Over Tiger Mountain Set for Full Weekend Closure

Beginning Friday evening, State Route 18 will be completely shut down in both directions between I-90 and Issaquah-Hobart Road. The closure is part of a coordinated effort by the Washington State Department of Transportation (WSDOT) to perform essential maintenance and advance a major widening project that will eventually transform this stretch into a four-lane highway.

What Travelers Need to Know:

• Timeline: The highway will close at 9 p.m. on Friday and is scheduled to remain inaccessible until 5 a.m. the following Monday.
• Access Restricted: No through-traffic will be allowed over the Tiger Mountain summit. Local access will be maintained only for residents and businesses south of I-90 up to Southeast 104th Street.+1
• Recommended Detours: Drivers should prepare for significant delays and use alternate routes such as I-405, SR 169, or SR 900.
• Freight Warning: Large trucks and semi-trailers are strongly advised to stick to I-405 and I-90. City streets in Issaquah and the Issaquah-Hobart Road are not equipped to handle heavy freight traffic.
• Scope of Work: Maintenance crews will focus on repairing guardrails, clearing drainage, and trimming overhanging vegetation. Simultaneously, construction teams will work on shifting lanes and removing temporary barriers as part of the ongoing I-90/SR 18 interchange improvement project.

By bundling these tasks into a single weekend, officials hope to avoid a series of smaller, more frequent disruptions. Commuters are encouraged to check real-time traffic apps and WSDOT’s online portal for the latest updates before heading out.