Clear, accessible definitions for common urban planning terms.
What Is Sprawl?
Sprawl is one of the most common terms used to describe built environments in the United States and the world. It can be applied to urban, suburban, and exurban settings, and it's almost never a compliment.
The term "sprawl" describes the result of unrestricted and rapid expansion of development into the periphery of metropolitan areas. In the United States, sprawl is most often characterized by single-family residential housing, the separation of residential neighborhoods from retail and commercial land uses, and the increased reliance on the private automobile for transportation. In some other countries, sprawl has less of a suburban connotation than in the United States. In Mexico City and New Delhi, for example, sprawl describes expansive mixed-use density, usually home to low-income, marginalized communities.
The word sprawl is highly politicized and is almost always used with a negative connotation, as evidenced by the origin of the term: "sprawl" was first used in an article in The Times in 1955 as a negative comment to describe the outskirts of London.
A lack of scientific consensus about how to define sprawl compounds the lack of consensus created by the controversial nature of the term. Some researchers measure sprawl by calculating the average number of residential units per acre in a given area. Others calculate it relative to the spread of population without a well-defined center (i.e., decentralization) or the separation of land uses, for example.
Sprawl is frequently characterized as the result of a lack of planning, but the history of development in the United States is far more complex than this reductive description allows. Much of the development that would be classified as sprawl is highly planned, in fact, to respond to demand in the market for homeownership. Sprawl is usually organized into subdivisions of master planned communities, with homes grouped onto one part of the development, separate from retail areas. The retail areas, in turn, are usually defined by their large scale—big box stores, strip malls, and office buildings surrounded by large parking lots. Because of the standardization of design and planning of these communities, sprawl is frequently attacked on aesthetic grounds and faulted for lacking the same kind of cultural dynamism that can be found in more urban areas.
Critics also argue that sprawling suburban developments follow the path of least resistance as a result of the slow growth planning that has controlled the development of U.S. urban areas since the middle of the 20th century. Thus, these critics argue, even the largest cities in the United States have spent several decades embodying the characteristics of suburban sprawl by limiting the development of density, forcing sprawling development to provide space for the growth of the country's population. According to this argument, sprawling development patterns result from distortions of the free market created by development resistance in core urban areas.
Proponents of the suburban way of life suggest those criticisms are exaggerated or elitist, pointing to the preponderance of sprawl as evidence of the economic and cultural preferences of the vast majority of the U.S. population. What Americans want, according to these arguments, are homes with more space in the interior of the home, spacious yards on the exterior of the property, distance from the noise and bustle of more urban locations, and enough proximity to still reach the jobs and services of the city by car.
Despite the cultural debate about the value of suburban development patterns, sprawl has left an indelible mark on the American landscape as well as unequivocally negative effects—the latter due to automobile dependence and the loss of agricultural lands, wildlife habitat, and natural open spaces as a consequence of constant expansion. The cycles of suburban expansion and urban contraction have also cemented legacies of racist and classist discrimination in the U.S. built environment.
While suburban and urban settings might seem at first glance to share little in common, sprawling developments have had tremendous consequences for central cities and urban neighborhoods over the decades. Throughout the past century of U.S. development history, sprawl has also provided the location for examples of the country's tendency for discrimination and marginalization of low-income Americans, as well as Black, Indigenous, and People of Color.
During the period of economic prosperity in the United States following the end of World War II, many Americans had gained enough new financial security to purchase single-family homes and private automobiles. At the same time, continued road-building projects like the development of the Interstate Highway System, made it possible to build homes on land that was previously located too far from the jobs and economic activity of cities.
When the inhabitants of a city spread out into surrounding suburban and exurban areas, less densely packed city centers can have trouble generating the funds to maintain services and infrastructure. The "white flight" of the second half of the 20th century—the departure of affluent white populations for suburban communities—led to the decline of many cities around the country and also further entrenched patterns of segregation.
Sprawling development also came with negative outcomes for the newly developed areas on the fringes of metropolitan regions. Sprawl can also be described as "greenfield development"—buildings and infrastructure on land previously in a more natural state or productive for agriculture. In addition to transforming the natural qualities of the land, automobiles and commercial uses create air pollution and greenhouse gas emissions while large expanses of pavement send pollutants directly into watersheds and out into the ocean.
With the negative consequences of sprawl more widely documented and accepted, several political and planning responses have been crafted as a check on the outward development pressure that has defined the country's response to population growth for many decades. One of the most direct approaches is the implementation of "urban growth boundaries," which set geographic limitations on the extent of development. The state of Oregon has established a statewide urban growth boundary. Other locations with urban growth boundaries include Ventura County in California and the city of Toronto in Ontario, Canada.
Planning reform movements like "Smart Growth" and the Congress for the New Urbanism have also proposed policy responses to sprawl, advocating for changes to planning policies that allow more density around transit resources, for example, or more walkable environments with a mix of residential, retail, and other commercial uses. These kinds of advocacy efforts have attempted to short-circuit the market pressure driving sprawl by allowing both urban and existing suburban areas to absorb more population growth, also reducing automobile dependence for work, errands, and entertainment.
Another approach for controlling the spread of sprawl is achieved by pricing the uses of resources These kinds of market-based fees can include emission fees, congestion charges, toll roads, and property tax reforms. These fees can serve as a disincentive for environmentally destructive behavior while also generating revenue that can fund the adaptation and mitigation of the problems associated with sprawl.
Other responses to traditional sprawl include the development of ecovillages, which plan and design new subdivisions to balance the need for habitation with the environmental effects of development. Planners living in rural or exurban locations can also use zoning practices known as "conservation districts" or "conservation developments" to control the amount of development density and infrastructure development that occurs in more sparsely populated areas.