The US Census Bureau defines and delineates the geographic boundaries for urban(ized) areas based on residential population determined by each decennial Census. Census-defined urban(ized) areas are used to summarize and report data collected by the US Department of Transportation and other Federal agencies.
Urban Area boundaries
The definition of urban area includes urbanized areas, which have a population of 50,000 or more, and urban areas, which have a population of at least 5,000 and less than 50,000.
Every 10 years, following the release of decennial census data, the Wisconsin Department of Transportation (WisDOT) leads a process to adjust official boundaries for the state’s Metropolitan Planning Organizations (MPOs). The two types of boundaries are Urbanized Area (UZA) boundaries and Metropolitan Planning Area (MPA) boundaries.
Urbanized Area (UZA) boundaries
UZA boundaries are the official designation used by the Federal Highway Administration, the Federal Transit Administration and WisDOT to assign urban or rural funding for Surface Transportation Program (STP) projects. These boundaries are developed through a cooperative process that involves WisDOT, local government and MPO representatives. These boundaries are approved by WisDOT and an MPO Policy Board.
Metropolitan Planning Area (MPA) boundaries
MPA boundaries are the official jurisdiction of the MPOs. These boundaries define the extent of the expected growth for the metropolitan area during the next 20 years, and comprise the area within which the MPO will conduct transportation planning activities over the next 10 years—until the next decennial census. The MPA boundary must include the entire area within the Adjusted UZA boundary.
The MPA boundary is used by the federal government as the delineation between jurisdictions for the MPOs and WisDOT. Transportation projects that fall within the MPA boundaries are included in the respective MPOs’ Transportation Improvement Programs (TIPs); transportation projects that fall outside the Metropolitan Planning Area boundary are included in WisDOT's Statewide Transportation Improvement Program (STIP).
The federal government created MPOs and gave them many planning, programming and project selection responsibilities. Because of this elevated level of responsibility, the official designation of MPA boundaries every 10 years is an important activity, and requires the Governor—or his designee—to authorize those boundaries in conjunction with the MPOs. In Wisconsin, the Governor’s Office has designated this responsibility to the WisDOT Secretary.
Once signed by both parties, the signature block provided on the MPA boundary map printouts is the official authorization for the MPA boundary, and consequently, for transportation planning, programming, and project selection responsibilities for both the urbanized portion and non-urbanized portion of the MPA. As a result, the non-urbanized areas within the MPA boundaries are planned and programmed in each MPO’s Transportation Improvement Program (TIP) and Unified Planning Work Program (UPWP).