Maps have been published illustrating the City Sector Model functional urban classifications for the 52 major metropolitan areas in the United States. The maps are available at Demographia City Sector Model Metropolitan Area Maps.
Functional Classifications of Metropolitan Areas
The City Sector Model allows a more representative functional analysis of urban core, suburban and exurban areas, by the use of smaller areas, rather than municipal boundaries.
The nearly 9,000 zip code tabulation areas of major metropolitan areas are categorized by functional characteristics, including urban form, density and travel behavior. There are four functional classifications, the urban core, earlier suburban areas, later suburban areas and exurban areas. The urban cores have higher densities, older housing and substantially greater reliance on transit, similar to the urban cores that preceded the great automobile oriented suburbanization that followed World War II. Exurban areas are beyond the built up urban areas. The suburban areas constitute the balance of the major metropolitan areas. Earlier suburbs include areas with a median house construction date before 1980. Later suburban areas have later median house construction dates.