Highway District No. 4 (HD4) is engaged with local, regional, and state transportation agencies to develop near- and long-term planning efforts to improve your transportation network, and provide for future transportation needs.

Caldwell Area Transportation Plan ("CATS Plan")

HD4 and the cities of Caldwell and Nampa have completed a 30-year transportation plan for the greater Caldwell area.  This plan is scheduled for adoption by the Caldwell city council in February 2024, and will be available following final approval by the city.

Canyon County Functional Classification Map

The Functional Classification Map adopted by Canyon County as part of its Comprehensive Plan describes the future intended function of both existing and proposed highways.  This map is located on the Canyon County Development Services website, and was adopted in 2012.

Community Planning Association of Southwest Idaho (COMPASS)

The Community Planning Association of Southwest Idaho (COMPASS) is an association of local governments working together to plan for the future of Ada and Canyon Counties. The agency conducts this work as the metropolitan planning organization (MPO) for the two-county area. The federal government requires the formation of an MPO when an urban area reaches 50,000 people. COMPASS has served as the MPO for northern Ada County (Boise area) since 1977 and for Canyon County (Nampa area) since early 2003. Northern Ada County became a “Transportation Management Area” when the population reached 200,000. This designation includes additional requirements for COMPASS to satisfy federal regulations, but also entitles the region to federal funds set aside for large urban areas.