Zoning and the American Suburb

American suburbs are generally characterized by single-family neighborhoods featuring large lots, with few businesses or apartments. To understand the origins of this pattern of development, we construct the first panel dataset of suburban zoning maps and bylaws for a major American metropolitan area and ask how comprehensive land use regulation shaped the form of the suburbs of Chicago today. Our strategy identifies the impact of zoning using land that was undeveloped before such regulations were adopted. The typical post-zoning suburban neighborhood sets aside over 90 percent of land for single-family homes, but adopting the most diverse zoning we observe reduces the single-family share by about half, with most of this land redistributed to businesses and apartments in equal measure. Supply restrictions were also binding earlier than widely believed, and prewar minimum lot size regulations were associated with lots that were 20 percent larger than those that emerged from unregulated markets. Comprehensive land use regulation thus substantially increased the prevalence of single-family residential neighborhoods relative to the suburban form that would have prevailed without zoning, which would have featured more mixed uses and smaller lots.