The SR 410/Traffic Avenue Interchange is significant to the growing South Sound region; it is a freight route, provides access to a regional commuter rail station, access to the free for emergency services, and acts as the entrance to downtown Sumner. The existing overpass allowed only a single-lane in each direction and was a major bottleneck for traffic.
The existing two-lane structure was upgraded to accommodate south-bound traffic and a new, adjacent structure provides two lanes for northbound traffic and a new, wide non-motorized pathway for pedestrians and bicyclists. The parallel structure is a 134-foot single span providing additional clearance for a future lane addition on the SR 410 mainline. Intersections at either end of the interchange where traffic merges with SR 410 were reconstructed, left-turn lanes were lengthened, and new traffic signals installed to control traffic flow and reduce blockages. Parametrix led the design efforts for the interchange improvements.