CORPLAN: A SCENARIO PLANNING MODEL & TOOL
CorPlan is a scenario planning model that estimates land development potential using prototypical community elements as its building blocks. It uses ARCVIEW© geographic information system (GIS) software, and the associated databases can be linked to Excel spreadsheets. The development of CorPlan was funded by a Federal Highway Administration Transportation and Community and System Preservation grant for the Eastern Area Planning Initiative conducted by the Thomas Jefferson Planning District Commission for the Charlottesville, Virginia region. The tool has since been used to support planning work in a number of large and small communities throughout the United States.
CorPlan relies on prototypical community definitions (community elements) to estimate land development potential and how that potential translates into the location of households and jobs. Each community element represents the development and infrastructure characteristics of a 31-acre area – the area of a circle with a quarter mile diameter. The quarter mile scale encompasses the maximum comfortable walking distance to transit for typical Americans.
Each element reflects a unique existing or planned development pattern, such as urban downtowns, suburban retail areas, and village centers. The community elements are illustrated with a plan graphic and photos that convey their look and feel. Through workshops with community members and planners, enhanced community elements can be developed to represent characteristics of desired future development patterns (Figure 1). Each element is also associated with land use, infrastructure and socioeconomic data in order to estimate its development potential (Figure 2).
Estimating Future Land Use Potential
Users estimate land development potential in CorPlan by assigning one of the community elements to a subarea (Figure 3), such as collections of traffic zones or Census blocks that define boundaries for communities within the study area. CorPlan multiplies the land use, infrastructure and socioeconomic characteristics of the selected element by the total useable land in the subarea. Useable land includes both developed and vacant land suitable for development. The model sums the development potential for all subareas to estimate the total development potential for the study area.
Developing and Testing Scenarios
Users can quickly test alternative development scenarios by assigning community elements in different patterns, by adjusting the information in the community element inventories, and/or by creating new community elements to reflect community design characteristics that are not reflected in the existing inventory. For example, planners can try a scenario that assumes the continuation of a suburban retail pattern (shopping centers) along a major arterial corridor to determine how much land would be needed to extend to meet future retail employment forecasts at the existing scale and density. They can easily compare this to alternative scenarios that assume the creation of urban or enhanced suburban mixed use community centers along the corridor, which typically consume less land than the continuation of existing low-density patterns.
Connecting with Other Planning Tools
CorPlan makes a direct connection between land development patterns and socioeconomic characteristics. As alternative land use scenarios are tested the model automatically generates socioeconomic inputs for travel demand models. The unique travel parameters for each community element are incorporated into travel demand models so they can better reflect the influence of development patterns on travel characteristics.
CorPlan connects regional land development patterns with site-specific development guidelines. The regional land use map identifies community element boundaries, and each assigned element has very specific land use, building and infrastructure guidelines. Some localities have used the community elements as a resource to help guide the development of local design standards. CorPlan can also generate projected scal impacts of alternative scenarios, and a module to assess multi-modal accessibility is under development. Another future enhancement to CorPlan is connecting with environmental and community assessment tools. The detailed information available for each community element is well suited for these tools and enables users to quickly assess the impacts of alternative development patterns over large areas.