Here We Go (Again) SR 18 to Close for Five Days at I-90 Starting May 29

State Route 18 will close around the clock for more than five days starting at 9 p. m. on May 29 to facilitate the construction of a diverging diamond interchange at Interstate 90. The Washington State Department of Transportation (WSDOT) aims to complete this section of the I-90/SR 18 Interchange Improvements project by summer. This closure avoids disruption during the Memorial Day weekend and reduces the need for multiple night closures in the future.

During this period, crews will install drainage systems, pave new roadways, and construct concrete islands. While eastbound and westbound I-90 traffic remains unaffected, travelers should prepare for delays and follow detour signs. Freight traffic must avoid unsuitable routes in Issaquah, opting instead for designated detours. Upon reopening on June 4, most construction on the southern end of the interchange will be complete, with additional work continuing on the northern end. This project also involves widening over two miles of SR 18 to enhance traffic flow and safety.