Bay Area UrbanSim is the Metropolitan Transportation Commission’s (MTC’s) regional land use model. The model is used to analyze how planning policies affect the location choices of households, businesses, and real estate developers over the long term (i.e, 20 to 30 years). Typical analyses include: assessing changes in development patterns due to proposed changes in policies such as zoning or urban limit lines; assessing the spatial and economic results of housing subsidies or fees; and assessing shifts in development patterns due to transportation investments. The system simultaneously examines the impacts of both land use and transportation policies and investments in an integrated and consistent manner.
A simple parking policy such as reduction or elimination of minimum parking requirements per unit is examined in Bay Area UrbanSim by lowering the costs associated with building a typical residential project, but placing a value on parking spaces as an independent unit feature. Future year simulations would then be used to assess the degree to which this policy increases housing affordability and shifts development to infill locations. This analysis assumes that households would accept housing bundled with less parking and a lower overall housing cost. As information is gathered, the UrbanSim database could also provide insight into alternative parking locations (e.g., street parking) that a household might shift to if it allowed lower housing costs. A major limitations to successful analysis with Bay Area UrbanSim stem from the difficulty in simulating user demand for less parking or no parking as well as the value of a parking space for different market segments.