Authors: Michael Manville, Alex Beata, Donald Shoup
Date: June 3, 2013
Project: Turning Housing into Driving: Parking Requirements and Density in Los Angeles and New York
This article examines the idea that residential minimum parking requirements are associated with lower housing and population densities, and higher vehicle densities (residential vehicles per square mile). Cities frequently use minimum parking requirements to manage traffic, but parking requirements accommodate vehicles, suggesting they should lead to more driving and congestion rather than less. If parking requirements reduce congestion, they likely do so not by reducing the number of vehicles in an area, but by reducing the density of housing and people. We support this idea by comparing the Los Angeles and New York urbanized areas. We show that differences in housing, vehicle and population density across and within these urbanized areas are closely correlated with differences in the share of housing units that include parking, and that the share of housing units that include parking is in turn correlated with the stringency of parking requirements. Compared to Los Angeles, New York shifts less of the cost of driving into its housing market. We further show that within New York City, a ten percent increase in minimum parking requirements is associated with a 5 percent increase in vehicles per square mile, a four percent increase in vehicles per person, and an 6 percent reduction in both population and housing density. These relationships remain even after controlling for street layout and proximity to the subway.
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