The District Department of Transportation and the District of Columbia Office of Planning recently led a research effort to understand how parking utilization in multi-family residential buildings is related to neighborhood and building characteristics. Prior research has shown that overbuilding of residential parking leads to increased automobile ownership, vehicle miles traveled, and congestion. Parking availability can affect travel mode choices and decrease the use of transportation alternatives. In addition, zoning regulations requiring parking supplies that exceed demand can increase housing costs and inhibit the development of mixed-use, mixed-income, pedestrian-friendly neighborhoods. The primary research goal is to develop an empirical model for parking utilization in Washington, D.C. and to apply the model to an interactive, web-based tool, named ParkRight DC, to support and guide parking supply decisions. A transparent, data driven process for parking supply decisions may help relieve problems associated with over- or under-supply of parking.

This paper outlines the data collection, model development process, functionality of the resulting tool, and findings on key relationships and policy implications. The model and associated tool relies on local information reflecting residential development and auto ownership patterns drawn from a survey of multi-family residential parking use at 115 buildings covering approximately 20,000 dwelling units in the District.  The resulting model achieved an R-square of 0.835, which is a very strong model given the complexity of the relationship being researched.