Mainline northbound I-5 lane and ramp closures in Seattle set for Aug. 15-18

Northbound I-5 in Seattle will close from 11:59 p. m. on August 15 to 5 a. m. on August 18 for significant work on the Ship Canal Bridge.

Express lanes will operate only in the northbound direction during this closure, with no exits into downtown Seattle. Key on- and off-ramps, including Dearborn, Cherry, and Mercer streets, will be closed, limiting access to the city center. The Washington State Department of Transportation aims to complete drainage improvements and remove concrete barriers during this period. This project marks the first phase of a larger preservation effort for the Ship Canal Bridge, which includes future lane reductions planned for both northbound and southbound traffic. In 2026, northbound traffic will face four-month lane reductions, and in 2027, southbound traffic will be reduced for up to nine months.

The WSDOT mobile app will provide real-time travel updates to drivers. Community members can sign up for weekly email updates to stay informed about the project's progress.