Two things have long been known about land-use regulations. One is that elements of them—in the form of large lot requirements and other aspects of “exclusionary zoning”—have led to racial and economic segregation. The other is that restrictive land use and building codes in cities limit housing construction (and therefore housing supply), leading to increased costs, worse affordability problems, and deepened inequality in urban centers.
What hasn’t been fully understood—until now—is how restrictive land-use regulations in cities and urban centers shape segregation across entire metropolitan areas. A new study by Michael C. Lens and Paavo Monkkonen from UCLA’s Luskin School of Public Health, published in the Journal of the American Planning Association, takes on the precise nature of the connection between land-use restrictions and the economic segregation of metros. The study uses new and better measures for both segregation and land-use restrictions to examine this relationship in 95 large metropolitan areas in 2000 and 2010.
To measure land-use regulation, the study uses the Wharton Residential Land-Use Regulation Index (developed by the real-estate economist Joseph Gyourko and his collaborators), which is based on 11 categories of land-use regulation. To get at economic segregation, the study uses advanced measures from the sociologists Sean Reardon of Stanford, David O’ Sullivan of Berkeley, and Kendra Bischoff of Cornell, which assess not just income segregation overall, but how segregated the poor and the wealthy are across metro areas. The study employs detailed statistical models that control for factors that influence segregation, such as population size, race, poverty, affluence, inequality, and the number of jurisdictions.