The other day, I had a meeting with Sam Staley and we both lamented the paucity of good empirical evidence about how land use regulations actually affect the built environment. For the ubiquitous minimum parking requirements, the only thing I’ve seen up until now was this study about the effects for LA County’s population of 10 million. But searching on Google Scholar, I found a 2011 article called Minimum parking requirements and housing affordability in New York City in the journal Housing Policy Debate which also addresses the issue:
[…] In this article, we explore the theoretical objections to minimum parking requirements and the limited empirical literature. We then use lot-level data and GIS to analyze parking requirements in New York City to determine to what extent they are already effectively sensitive to transit proximity. Finally, we examine developer response to parking requirements by comparing the number of spaces that are actually built to the number required by applicable zoning law. Our results indicate that the per-unit parking requirement in New York is, on average, lower in areas near rail transit stations, but the required number of spaces per square foot of lot area is higher, on average, in transit accessible areas. We also find that by and large, developers tend to build only the bare minimum of parking required by zoning, suggesting that the minimum parking requirements are binding for developers, as argued by critics, and that developers do not simply build parking out of perceived marked [sic?] need. Our results raise the possibility that even in cities with complex and tailored parking requirements, there is room to tie the requirements more closely to contextual factors. Further, such changes are likely to result in fewer parking spaces from residential developers.
In the comments of the post with the aforementioned study about parking minimums in LA County, Randal O’Toole, the Antiplanner, said that LA is the densest urban area in the country and so these results are not generalizable elsewhere. If that sounds surprising to you, it’s because he’s using a very primitive measure called “average density” that is in fact a poor proxy for determining whether a place is auto- or transit-oriented. Your intuitions about Los Angeles are right – it’s probably not at all out of the ordinary when it comes to auto-orientedness in American cities.
But the New York study will be interesting when I can get my hands on it because of Staten Island. If parking minimums in Staten Island are largely binding constraints on developers, then I think it’s fair to say that they are probably binding for much of Westchester, Long Island, and North Jersey. With these two studies, I think we’ve come very close to proving that a very large amount of people in and around America’s cities are forced by parking minimums to sprawl and become more auto-oriented than they otherwise would choose in a free market.