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.
Canyon County Functional Classification Map
The Functional Classification Map adopted by HD4 describes the future intended function of both existing and proposed highways. The current map was developed by COMPASS in cooperation with all transportation agencies within the Treasure Valley.
COMPASS Regional Long Range Functional Classification Map July 2023
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.
