Map showing detour through Tillicum for WSDOT overpass work

WSDOT: Union Avenue closed in Tillicum through May

March 20, 2020

FROM WSDOT: Travelers who use the Interstate 5 and Thorne Lane interchange headed to Camp Murray or Tillicum need to plan extra time into their trips.

At 8 a.m. Monday, March 16, construction crews working for the Washington State Department of Transportation building the new I-5/Thorne Lane interchange closed a one-block section of Union Avenue between Spruce Street and Thorne Lane.

The around-the-clock closure will be in place until the end of May. The closure will allow construction crews to raise the profile of Union Avenue over 23 feet so the street connects with the new Thorne Lane overpass.

During the closure, travelers will detour on Thorne Lane to Portland Avenue and to Berkeley Street.

Map showing detour through Tillicum for WSDOT overpass work

The I-5/Thorne Lane interchange will remain open during daytime hours, however crews will continue to close the off-and on-ramps during overnight hours.

Two-week closure of 146th Street Southwest

In addition to the Union Avenue closure, over the weekend construction crews closed 146th Street Southwest at Murray Road around-the-clock until March 28. This will allow new curbs and sidewalks to be built at the intersection of Murray Road and 146th Street Southwest. During the closure, drivers will detour using Spring Street Southwest and 150th Street Southwest.

WSDOT map showing road detours in Tillicum for new interchange

More information about construction at Thorne Lane is available via the WSDOT blog.

An updated construction schedule that lists overnight ramp closures for this project is available on Before heading out the door, travelers can find the latest road conditions on the WSDOT app and by following the WSDOT regional Twitter feed.