SR 18 Closed Between I-90 and Issaquah-Hobart Road, Oct. 16 20 for Highway Widening

The Washington State Department of Transportation will fully close SR 18 between I-90 and Issaquah-Hobart Road from October 16 to October 20 for highway widening. The closure will facilitate the paving of transitions, striping of lanes, and installation of barriers, setting the highway into its final configuration. When SR 18 reopens, it will have two lanes in each direction for over two miles south of I-90, which is expected to significantly improve traffic flow. This project is part of the I-90/SR 18 Interchange Improvements initiative, which includes a diverging diamond interchange that opened in July 2025. The new lanes will eliminate a congestion point just south of I-90, helping to reduce backups at the interchange.

Local access will be restricted, and freight traffic should avoid Issaquah-Hobart Road. Crews will work diligently to complete the project by 2026, when a final layer of asphalt will be applied. If heavy rain is predicted over the weekend, the closure may be postponed to ensure safety.