Highway System Plan

The Washington State Highway System Plan (HSP) is the state highway component of the Washington State Multimodal Transportation Plan (SMTP). The SMTP is the state's overall transportation plan that will include an analysis of facilities the state owns and those in which the state has an interest. The HSP serves as the basis for the six-year highway program and the two-year biennial budget request to the State Legislature. WSDOT is dedicated to delivering an HSP that implements the Legislature's goals. This is accomplished through the coordination and integration of specific components from many statewide modal and program plans. The HSP is also aligned to the Washington Transportation Plan (WTP), which outlines the policies adopted by the Washington State Transportation Commission.

WSDOT will communicate regularly and frequently at all levels within the department and with external partners throughout the HSP development process. Our goal is to create a long-range plan that provides decision-makers with the most cost-effective strategies. This is accomplished through a continual system-wide performance measuring and monitoring program, where WSDOT collects and analyzes data to determine current and future performance of the highway system. Assets that don't meet established performance threshold criteria are identified as needs. WSDOT develops cost-effective strategies, based on analysis of performance outcomes and best management practices (both national and international), to provide high benefit solutions for identified needs. WSDOT aims first to maintain, preserve, and improve the operating efficiency of the existing highway system before adding to the system.

Statewide Plan Documents

Highway System Plan Chapters



    • I-90 Corridor (Eastern Region) (pdf 3.4 mb)
    • I-5 US12 to SR121 Interchange (Olympic Region) (pdf 6 mb)
      Also includes Martin Way Interchange to Nisqually Interchange Vicinities)
    • I-182 from I-82 to US395 (South Central Region) (pdf 3.9 mb)
      Also includes I-82: SR823 to US97, and I-90: Cabin Creek to Cle Elum/SR 970)
    • I-5 from Columbia River to SR 500 (Southwest Region) (pdf 4 mb)
      Also includes: I-5: SR 500 to Dike St., Toutle Rest Area to Exit 88A, and I-205: Columbia River to SR 500 to I-5)
    • I-5 Nisqually to Tacoma (Urban Planning) (pdf 22 mb)
      Also includes: I-5 to I-405 and King/Snohomish County Line to US 2 to Snohomish/Skagit County Line, and I-90: I-5 to I-405 at Factoria, to Sunset Way in Issaquah, to Northwest Region Boundary, and I-405: I-5 at Tukwila to I-90, I-90 to I-5 in Lynnwood, and I-705: I-5 to Shuster Parkway Vicinity)
    • I-5 Northbound, Stillaguamish River-International Boundary(Northwest Region Mt. Baker Area) (pdf 7 mb)

    Please send your comments or questions about the plan to hsp@wsdot.wa.gov .