what we do


Designing connections that balance regional mobility and local access

From rural highway off-ramps to complex freeway interchanges, Parametrix helps agencies plan and design interchanges that safely and efficiently move traffic from one road to another. We help agencies with freeway and local operational analysis for highway and local corridors, and have provided analysis for numerous interchange justification reports (IJR), interchange modification reports (IMR) interchange access modifications, and corridor studies. Our staff have developed great working relationships with FHWA and state DOT staff and can guide you through the approval process.

SR 410/Traffic Avenue Interchange
SR 410/Traffic Avenue Interchange
Sumner, Washington
Client: City of Sumner

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.

  • Gold Award – Social, Economic, and Sustainable Design, ACEC Washington



  • US 550, NM 313 to NM 528

    US 550, NM 313 to NM 528

  • SR 410/Traffic Avenue Interchange

    SR 410/Traffic Avenue Interchange

  • 116th Interchange at I-5

    I-5/116th Street NE Interchange

  • I-84 Karcher to Franklin | Parametrix

    I-84 Karcher to Franklin

  • I-5/Slater Road IJR | Parametrix

    I-5/Slater Road IJR

  • I-84 Meridian Road Interchange

    I-84 Meridian Road Interchange