ALERT: Opening Day of Boating Season daytime closures in Montlake on May 2

Major changes are coming to your SR 520 commute. Read more about upcoming traffic shifts on our blog.

SR 520/I-5 Express Lanes Connection Project

Despite the clouds, Seattle is looking pretty spectacular in this overhead view of the SR 520/I-5 interchange with Lake Union and downtown in the background. Crews recently wrapped improvements at the interchange, including a flyover ramp that will eventually connect SR 520 to the I-5 Express Lanes when the Portage Bay Bridge and Roanoke Lid Project is complete.

Completed in 2025, the SR 520/I-5 Express Lanes Connection Project created a dedicated reversible transit and carpool connection between SR 520 and the I-5 Express Lanes, along with a reversible transit/carpool ramp at the I-5/Mercer Street interchange.

I-5 Express Lanes Connection Project Webpage

SR 520/I-5 Express Lanes Connection Project

Construction photos

Sign up for email updates