Scenario planning is a term that describes a wide range of approaches. No two scenario planning endeavors are exactly alike. Scenarios represent alternative future conditions that could materialize in response to drivers such as shifts in external forces (for example new technology, environmental patterns or global trade patterns) or the consequences of deliberate policy choices played out over time (such as land use policies or infrastructure investments); visioning is one form of scenario planning that emphasizes desired end states and outcomes rather than external forces and uncertainty.
Scenario planning enables a wide array of people, including stakeholder or the public, to identify a range of potential consequences (e.g. impacts on the environment or public health) associated with alternative decisions, and to consider how those consequences could affect their ability to achieve goals or to experience desired community outcomes.
By examining the impacts of alternative decisions on their ability to achieve visions and goals, planners can identify robust strategies or policy options that best “hold up” across the spectrum of possible future conditions.
Through this approach transportation professionals and citizens work together to analyze and shape the long-term future of their communities. Scenario planning allows planners and community members to understand how different policies, plans, and programs will affect a community or region. This tool can be used in the transportation planning process to assess long-term risks, financing, system management and operations, and corridor planning. Traditional scenario planning efforts assess scenarios by using measures such as vehicle miles traveled, shifts in modal split, impacts on open spaces, or contributions to air pollution.
Scenario planning is an optional process described in the transportation planning regulations. In support of scenario planning, FHWA has:
Planners may use scenario planning in a number of different ways:
The technique also supports integrated planning and statewide, regional, or corridor planning, as well as visioning activities not associated with long-range planning. Scenario planning practitioners have typically focused on the relationships between transportation, land use, and population growth or declining growth, using scenarios to build consensus around preferred transportation investments or growth patterns.
Practitioners typically create a baseline scenario, which assumes that present plans for transportation investment are carried out and that recent development patterns remain the same. Alternative scenarios might also be created to examine how changes in baseline assumptions, trends, or investments might affect the region or study area.