By Adrian Bijan White

A new study by researchers at the UCLA Luskin School of Public Affairs shines a light on how zoning law changes in the largest U.S. metropolitan areas are increasing inequality and raising concerns about social mobility.

One of the most influential factors in shaping metropolitan areas, according to the study, is the government’s use of land regulations and zoning laws, which determine building densities and land uses. “The playing field,” according to the researchers, “is far from equal.”

It is well known that zoning laws and land regulation contribute to racial and economic segregation through “exclusionary zoning” policies, but the new study by Michael Lens and Paavo Monkkonen MPP ’05, assistant professors in Urban Planning, examines these processes in depth. Their research revealed four patterns in zoning restrictions.

Zoning policies in metropolitan areas isolate wealth

“We found that more stringent regulatory processes are related to the segregation of the affluent,” Lens said. “What we see is their ability to self segregate and to pass laws and regulations toward that end.” Lens added that policies allow for the concentration of wealth, rather than the concentration of poverty, within cities. The self-segregating ability of the wealthy derives from socioeconomic status and influence, which manifests itself in exclusionary zoning policy. Some classes, as a result, are excluded from certain neighborhoods and congregate in less desirable neighborhoods. Restrictions such as single-family zoning as opposed to higher density apartment complexes, raise housing prices and perpetuate cycles of exclusion.

Zoning laws across the entire metropolitan area are relevant

Within metropolitan areas, individual cities retain high levels of autonomy in terms of their zoning policies. As a result, cities often tailor their restrictions to appeal to higher-income residents. “If we had land use regulation at a regional scale, we could reduce the tendency of smaller, wealthy cities trying to zone for a certain kind of resident,” Monkkonen said. “However, this would require a change which would greatly reduce the city’s individual power.

“If you have a strict enough regulatory regime, you can’t build enough units in city neighborhoods which are experiencing accelerated changes in demographics,” Monkkonen added. “In terms of gentrification, you have an influx of higher income residents, which raises the value of said neighborhood. In terms of building development, if you can build enough units to keep up with rising demand, then lower-income households could stick around, which would result in an integrating process and not an exclusionary one.”

Bureaucratic construction processes and density restrictive policies hinder the development of surrounding cities in metropolitan areas and stagnate the supply of housing, making housing prices highly sensitive to shifting socioeconomic trends.

Localized zoning policies contribute to the segregation of neighborhoods

“Maximum density restrictions (single-family zoning) are the way in which cities restrict multi-family housing. People often assume that places with lower density rules have less poor people, which we can confirm.” Monkkonen asserts that local processes of density restriction contribute to the concentration of wealth. “If we can speed up housing construction processes and adapt zoning regulations to allow for the densification of neighborhoods, we could stabilize housing prices and render neighborhoods more inclusionary.”

Local policies within cities indirectly promote the exclusion of lower-income populations by restricting multi-family housing, according to the researchers. By maintaining lower levels of population density, the forces of supply and demand raise housing prices. Furthermore, different policies play out in different ways in terms of their effects on segregation. Areas that demonstrate very bureaucratic construction processes are highly segregated because of the inability to provide new housing. Segregation is also correlated with stronger local government restrictions, which often restrict population growth. On the other hand, segregation is not strongly associated with open-space requirements, supply restrictions or delayed approvals.

Centralized policies can mitigate segregation across metropolitan areas

There is some variation across states in the extent of local control over land use. “When you see checks on city regulations in metropolitan areas by the state, we witness lower levels of income segregation,” Lens said.

Centralized zoning policies reduce the effects of local government policies, which contribute to the segregation of neighborhoods, according to the study. By reducing the autonomy of individual cities, metropolitan areas as a whole can work towards higher levels of density, inclusionary housing policies and integration. “The government has regulatory tools to promote integration between middle- and lower-class communities; however, wealthy communities retain their ability to self segregate. Our research shows that local government regulations help them do so,” Lens said.

The political and economic influence of wealthy residents renders certain neighborhoods partially immune to the effects of inclusionary zoning regulations; however, authorities can target the integration of lower- and middle-class neighborhoods. “When you see checks on city regulations in metropolitan areas by the state, we witness lower levels of income segregation,” Monkkonen said. By dismantling bureaucratic construction processes and restrictions on density levels, which is often witnessed by state level regulations, cities can work toward stabilizing housing prices and integrating communities.

The study was published in the Journal of the American Planning Association (JAPA). It can be found at http://www.tandfonline.com/doi/full/10.1080/01944363.2015.1111163#abstract