4 nights of lane restrictions on SR 18 over Tiger Mountain
Sep 9, 2026, 3:47 PM
A lane closed sign on the back of a construction truck. (Photo: AZ-BLT via Envato)
(Photo: AZ-BLT via Envato)
The Washington State Department of Transportation (WSDOT) is starting a four-night surveying project over Tiger Mountain Summit that will reduce a 6-mile stretch of eastbound SR 18 to a single lane overnight between Issaquah-Hobart Road and Deep Creek.
SR 18 lane restrictions start Thursday
The right lane of eastbound SR 18 will close nightly from 9 p.m. to 5 a.m. starting Thursday, Sept. 10, and ending Monday, Sept. 14. One eastbound lane will be open each night.
WSDOT will pause work on the night of Saturday, Sept. 12, and resume Sunday, Sept. 13, at 9 p.m.
Drivers should plan for delays and allow extra time traveling during the nightly lane reductions.
WSDOT reminds freight drivers that Issaquah-Hobart Road and Issaquah city streets are not suitable for semi-trucks and that drivers should not attempt to use them as a detour. Freight traffic, instead, should use westbound SR 169 to northbound I-405 to eastbound I-90, or other suitable alternate state routes.
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Additional closures planned
Similar single-lane, nightly closures in the westbound direction will occur for six nights beginning Tuesday, Sept. 15.
A full eastbound SR 18 closure will occur nightly from 9 p.m. to 5 a.m. for six nights beginning Wednesday, Sept. 23.
Nate Connors is a traffic reporter for KIRO Newsradio. Follow him on X. Read more of his stories here. Submit news tips here.
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