This study furthers the efforts of the U.S. Department of Housing and Urban Development's Regulatory Barriers to Affordable Housing study series, which started with the 1991 report of the President's Commission on Regulatory Barriers to Affordable Housing (also known as the Kemp Commission), "Not in my Backyard: Removing Barriers to Affordable Housing," and the 2005 update "Why Not in Our Community: Removing Barriers to Affordable Housing." As part of the Department's effort to document these regulatory barriers and identify effective approaches to overcoming them, it commissioned this Planning Advisory Service Report from the American Planning Association's Research Department, by Professor Gerrit Knaap of the University of Maryland.
HUD initially focused on this issue - limiting multifamily housing through exclusionary zoning - because it is one of the most common and most pervasive barriers to affordable housing in America. The Kemp Commission identified exclusionary zoning practices as a key regulatory barrier in 1991. What had been lacking, however, was systematic, reliable empirical evidence to document these concerns.