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Functional Roadway Classifications

The functional classification system consists of four classes of roadways within the seven-county metropolitan area - principal arterials (which include Interstate freeways), minor arterials, collector streets and local streets.

The Metropolitan Highway System consists of 657 miles of principal arterials. The principal arterials are the most heavily used roads in the area, carrying 59% of the total vehicle miles traveled in the region. These roads are usually Interstate highways and other freeways or expressways. They are designed to carry longer trips at higher speeds with minimal land access. These roads are primarily owned and operated by MnDOT, although four are under the jurisdiction of counties.

More than 1,550 miles of “A” minor arterials supplement the principal arterial system and provide for mobility needs in the region. Planning for the approximately 11,600 miles of collectors and local streets, whose primary function is land access, is the responsibility of local units of government.

Functional classification involves determining what function each roadway should perform before determining street widths, speed limits, intersection control or other design features. Functional classification ensures that nontransportation factors, such as land use and development, are taken into account in planning and design of streets and highways.

A major purpose of functional classification is to determine which routes should be on the metropolitan highway system. Functional classification is also used to decide which roads to use for transit service. Once function is established, appropriate or desirable design and operational characteristics can be used as further guidelines for implementation.