Did Race Fence Off The American City? The Great Migration and the Evolution of Exclusionary Zoning
Abstract
I study how postwar Black migration caused American cities' suburbs to widely
restrict development with minimum lot sizes. When local governments use lot size regulations
to restrict the supply of dense housing, bunching is detectable across lot size distributions.
I develop an algorithm to measure bunching and produce a national panel for the regulation
spanning the 20th Century. Most suburbs adopted lot size controls from 1945--1970,
all the while Black Americans left the South for economic opportunity. I find the Great
Migration of Black Americans into non-Southern cities accelerated minimum lot size
adoption and caused up to half of baseline lot size restrictiveness. Migration of
poorer white Americans cause null or small negative effects. A sizable driver of
the Great Migration effect is local implementation of school desegregation before 1970.
The results support a theory where competition in policy planning still reinforced a
minority group's exclusion from local public goods.
As homes remain in place longer than their first owners, past lot size restrictiveness
can explain today's spatial disparities in racial sorting and economic mobility.