The Federal Highway Administration (FHWA) identifies functional classification as a key item in transportation data. Streets and highways are grouped into classes according to the service they provide. The California Road System uses this system in determining Federal funding to maintain the roads.
How Do We Use Functional Classification?
The 1991 Intermodal Surface Transportation Efficiency Act (ISTEA) required the reclassification of the entire public road system from Federal-Aid Systems to the National Highway System (NHS). ISTEA retained the Interstate System as a subsystem of the NHS, but abolished the Federal Aid primary, secondary, and urban designations. It aligned Federal Aid eligibility with functional classifications. In addition to Federal Aid allocation, we use functional classification in planning highway systems, determining jurisdictional responsibility, and developing fiscal planning.
For Census 2000, the Census Bureau classifies "urban area" as all territory, population, and housing units located within an urbanized areas (UA) or an urbanized cluster (UC). The Census Bureau classifies a "rural" all territory, population, and housing units located outside of urbanized areas and urban clusters. It delineates UA and UC boundaries to encompass densely settled territory. Roadways such as, Principal Arterials, Minor Arterials, Collectors or Local can be classified in either category of urban or rural depending on their service they provide.
Principal arterials emphasize mobility with limited access. These include freeways, expressways and those arterials that are specifically designed to provide a high level of mobility with limited access to adjoining properties.
Minor arterials interconnect and augment the principle arterial system while providing a somewhat lower level of travel mobility due to less stringent access limitations.
Collectors provide a balanced function of land access and mobility within residential neighborhoods and commercial and industrial areas.
Local Roads and Streets
Local roads and streets have a primary function to provide direct access to abutting lands and connections to the higher order functional classifications.