Parking regulations are a central part of American zoning. There is mounting evidence about the negative effects of parking requirements on the environment and housing affordability. Given this evidence, some cities have reduced or eliminated parking requirements in certain areas. Our research examines how real estate developers respond to municipal parking reforms. We answer two questions. First, how do parking requirements affect the amount of parking provided in new residential developments? Second, how do developers’ responses vary by building and neighborhood characteristics?

This research analyzes Seattle, Washington (USA), the site of 2012 policy reforms that reduced or eliminated parking requirements in most central and transit-oriented neighborhoods. Our dataset consists of 868 developments with 60,361 housing units approved between 2012 and 2017. We use descriptive statistics, build a counterfactual scenario, and specify ordinary least squares (OLS) regression models to identify relationships between parking requirements and actual parking provision.

We find that parking provision is closely, though not completely, tied to parking requirements. More than one-third of developments in the sample included the exact amount of required parking, including about two-thirds of developments subject to a minimum of one parking space per housing unit. About 70% of developments with no parking requirements did include some parking. Parking requirements were the most important predictor of the actual quantity of parking provision in the regression results using the full sample. There was more parking provision in less dense and mixed-use developments, and in neighborhoods with higher employment densities. Seattle developers built 40% less parking than would have been required prior to the reforms, resulting in 18,000 fewer parking spaces and saving an estimated $537 million.