To relieve chronic traffic congestion and improve mobility along I-5 in the vicinity of Joint Base Lewis-McChord, Atkinson Construction is rebuilding the interchanges at Thorne Lane and Berkeley Street and adding lanes to I-5.

Atkinson Construction is widening 5.25 miles of Interstate 5 to add a fourth general-purpose lane in each direction. Atkinson’s team will replace the existing Thorne Lane and Berkeley Street interchanges and build grade-separated crossings over the adjacent Sound Transit railroad.

The team will also construct new auxiliary lanes along the interstate, reconstruct the Madigan Gate Access Control Point, raise the I-5 mainline grade to fill a sag at the Berkeley Interchange, and construct three intersection roundabouts.

The scope of work also includes a high-performance median barrier, retaining walls, sound walls, security walls, drainage, signing, illumination, and intelligent transportation systems.