Lydia Lo and Yonah Freemark have an interesting new paperon zoning in Louisville on the Urban Institute website. They point out that of the land zoned for single-family housing, 59 percent is zoned R4, requiring 9000-square-foot lots, which means no more than five houses per acre.
From a transportation standpoint, this is not ideal. Even the most cursory Google search reveals that a neighborhood should have at least eight or ten units per acre to support minimal bus service. This is because if only a few people live near a bus stop, only a few people will ride the bus. So Louisville’s zoning generally prohibits density high enough for decent bus service.
Similarly, from a housing supply standpoint, such zoning is not ideal either. Obviously, a development with 5 houses per acre contributes less to regional housing supply than one with 10 houses per acre.
Much ink has been spilled over the evils of zoning places for nothing but single-family housing. But perhaps the density of housing is just as important as its form.