Urban sprawl (also known as suburban sprawl or urban encroachment) is defined as "the spreading of urban developments (such as houses and shopping centers) on undeveloped land near a city". Urban sprawl has been described as the unrestricted growth in many of housing, commercial development, and roads over large expanses of land, with little concern for very dense urban planning. Sometimes the urban areas described as the most "sprawling" are the most densely populated.
In Europe, the term peri-urbanisation is often used to denote similar dynamics and phenomena, but the term urban sprawl is currently being used by the European Environment Agency. There is widespread disagreement about what constitutes sprawl and how to quantify it. For example, some commentators measure sprawl by Urban density, using the average residential units per acre in a given area. Others associate it with decentralization (spread of population without a well-defined centre), discontinuity (leapfrogging development, as defined below), segregation of uses, and so forth.
The term urban sprawl is highly politicized and almost always has negative connotations. It is criticized for causing environmental degradation, intensifying segregation, and undermining the vitality of existing urban areas, and is attacked on aesthetic grounds. The pejorative meaning of the term means that few openly support urban sprawl as such. The term has become a rallying cry for managing urban growth.
Reid Ewing has shown that sprawl has typically been characterized as urban developments exhibiting at least one of the following characteristics: low-density or single-use development, strip development, scattered development, and/or Leapfrogging development (areas of development interspersed with vacant land). He argued that a better way to identify sprawl was to use indicators rather than characteristics because this was a more flexible and less arbitrary method. He proposed using "accessibility" and "lack of functional open space" as indicators. Ewing's approach has been criticized for assuming that sprawl is defined by negative characteristics.
What constitutes sprawl may be considered a matter of degree and will always be somewhat subjective under many definitions of the term. Ewing has also argued that suburban development does not, per se, constitute sprawl depending on the form it takes, although Gordon & Richardson have argued that the term is sometimes used synonymously with suburbanization in a pejorative way.
Nonetheless, some like Detroit have expanded geographically even while losing population. But it was not just urbanized areas in the U.S. that lost population and sprawled substantially. According to data in "Cities and Automobile Dependence" by Kenworthy and Laube (1999), urbanized area population losses occurred while there was an expansion of sprawl between 1970 and 1990 in Amsterdam, Netherlands; Brussels, Belgium; Copenhagen, Denmark; Frankfurt, Hamburg and Munich, Germany; and Zürich, Switzerland, albeit without the dismantling of infrastructure that occurred in the United States.
Despite its sprawl, Metropolitan Los Angeles is the densest major urban area (over 1,000,000 population) in the US, being denser than the New York urban area and the San Francisco urban area. Most of metropolitan Los Angeles is built at more uniform low to moderate density, leading to a much higher overall density for the entire region. This is in contrast to New York, San Francisco or Chicago which have compact, high-density cores surrounded by areas of very low-density suburban periphery, such as eastern Suffolk County in the New York metro area and Marin County in the San Francisco Bay Area.
Some cases of sprawl challenge the definition of the term and what conditions are necessary for urban growth to be considered sprawl. Metropolitan regions such as Greater Mexico City, Delhi National Capital Region Beijing, and the Greater Tokyo Area are often regarded as sprawling despite being relatively dense and mixed use.
Others suggest that Urban Sprawl is a natural product of population increases, higher wages, and therefore better access to housing. Improvement in transportation also means that individuals are able to live further from large cities and industrial hubs, thus increasing demand for better housing further from the noise of cities. This leads to the creation of sprawling residential land development surrounding densely packed urban areas.
According to this criterion, China's urbanization can be classified as "high-density sprawl", a seemingly self-contradictory term coined by New Urbanism Peter Calthorpe. He explains that despite the high-rise buildings, China's superblocks (huge residential blocks) are largely single-use and surrounded by giant arterial roads, which detach different functions of a city and create an environment unfriendly to pedestrians.
Job sprawl has been documented and measured in various ways. It has been shown to be a growing trend in America's metropolitan areas. The Brookings Institution has published multiple articles on the topic. In 2005, author Michael Stoll defined job sprawl simply as jobs located more than radius from the CBD, and measured the concept based on year 2000 U.S. Census data. Other ways of measuring the concept with more detailed rings around the CBD include a 2001 article by Edward Glaeser and Elizabeth Kneebone's 2009 article, which show that sprawling urban peripheries are gaining employment while areas closer to the CBD are losing jobs. These two authors used three geographic rings limited to a radius around the CBD: or less, 3 to , and 10 to . Kneebone's study showed the following nationwide breakdown for the largest metropolitan areas in 2006: 21.3% of jobs located in the inner ring, 33.6% of jobs in the 3–10 mile ring, and 45.1% in the 10–35 mile ring. This compares to the year 1998 – 23.3%, 34.2%, and 42.5% in those respective rings. The study shows CBD employment share shrinking, and job growth focused in the suburban and exurban outer metropolitan rings.
Overall density is often lowered by "Leapfrogging development". This term refers to the relationship, or lack of it, between subdivisions. Such developments are typically separated by large , i.e. tracts of undeveloped land, resulting in an overall density far lower even than the low density indicated by localized per-acre measurements. This is a 20th and 21st century phenomenon generated by the current custom of requiring a developer to provide subdivision infrastructure as a condition of development.DeGrove, John and Robyne Turner (1991), "Local Government in Florida: Coping with Massive and Sustained Growth" in Huckshorn, R. (ed.) Government and Politics in Florida. University of Florida Press, Gainesville. Usually, the developer is required to set aside a certain percentage of the developed land for public use, including roads, parks and schools. In the past, when a local government built all the streets in a given location, the town could expand without interruption and with a coherent circulation system, because it had eminent domain. Private developers generally do not have such power (although they can sometimes find local governments willing to help), and often choose to develop on the tracts that happen to be for sale at the time they want to build, rather than pay extra or wait for a more appropriate location.
Some research argues that religious ideas about how humans should live (and die) promote low-density development and may contribute to urban sprawl.
Subdivisions often incorporate curved roads and . These subdivisions may offer only a few places to enter and exit the development, causing traffic to use high volume collector streets. All trips, no matter how short, must enter the collector road in a suburban system.
Another prominent form of retail development in areas characterized by sprawl is the shopping mall. Unlike the strip mall, this is usually composed of a single building surrounded by a parking lot that contains multiple shops, usually "anchored" by one or more .Gruen, Victor and Larry Smith (1960) Shopping towns USA: the planning of shopping centers, Van Nostrand Reinhold Company, New York. The function and size is also distinct from the strip mall. The focus is almost exclusively on recreational shopping rather than daily goods. Shopping malls also tend to serve a wider (regional) public and require higher-order infrastructure such as highway access and can have floorspaces in excess of . Shopping malls are often detrimental to downtown of nearby cities since the shopping malls act as a surrogate for the city centre.Crawford, Margaret (1992) "The World in a Shopping Mall" in Sorkin, Michael (ed.), Variations on a Theme Park, The new American city and the end of public space, Hill and Wang, New York, pp. 3–30. Some downtowns have responded to this challenge by building shopping centres of their own.Frieden, Bernard J. and Sagalyn, Lynne B. (1989) Downtown Inc.: How America Rebuilds Cities, MIT Press, Cambridge, MA.
Fast food chains are often built early in areas with low property values where the population is expected to boom and where large traffic is predicted, and set a precedent for future development. Eric Schlosser, in his book Fast Food Nation, argues that fast food chains accelerate suburban sprawl and help set its tone with their expansive parking lots, flashy signs, and plastic architecture (65). Duany Plater Zyberk & Company believe that this reinforces a destructive pattern of growth in an endless quest to move away from the sprawl that only results in creating more of it.
Regions with high birth rates and immigration are therefore faced with environmental problems due to unplanned urban growth and emerging megacities such as Kolkata, Shenzhen, and Chongqing. Unregulated urban sprawl in these areas contributes to severe pollution, resource depletion, and ecosystem degradation. For instance, Kolkata's expansion has led to extensive deforestation and wetland destruction, endangering biodiversity and increasing flood risks. Additionally, Chongqing, as one of China’s fastest-growing urban centers. struggles with severe air pollution due to its reliance on coal-powered industries, with particulate matter (Particulates) levels often exceeding World Health Organization safety limits. The rapid expansion of urban infrastructure in such megacities increases greenhouse gas emissions, with transportation and construction sectors contributing significantly to climate change. Moreover, poor urban planning leads to inadequate sanitation and waste management systems, with cities like Kolkata generating over 5,000 metric tons of waste daily, much of which remains untreated and contributes to water contamination.
Other problems include:
During the mid-to-late 20th century, many major cities in the United States, Western Europe, and Japan experienced population decline due to shrinking household sizes and suburbanization, leading to significant environmental impacts. The expansion of suburban areas resulted in increased land consumption, habitat fragmentation, and higher carbon emissions from car-dependent development. In the U.S., suburbanization was accelerated by policies favoring highway construction and single-family housing, contributing to urban sprawl and loss of arable land. While recent urban revitalization has slowed these trends, challenges such as rising energy demands, heat island effects, and pressure on water resources persist. At the same time, the urban cores of these and nearly all other major cities in the United States, Western Europe, and Japan that did not annex new territory experienced the related phenomena of falling household size and, particularly in the U.S. ( see white flight) sustaining population losses. This trend has slowed somewhat in recent years, as more people have regained an interest in urban living.
Due to the larger area consumed by sprawling suburbs compared to urban neighborhoods, more farmland and wildlife habitats are displaced per resident. As forest cover is cleared and covered with impervious surfaces (concrete and Asphalt concrete) in the suburbs, rainfall is less effectively absorbed into the groundwater . This threatens both the quality and quantity of water supplies. Sprawl increases water pollution as rain water picks up gasoline, motor oil, heavy metals, and other pollutants in surface runoff from parking lots and roads.
Gordon & Richardson have argued that the conversion of agricultural land to urban use is not a problem due to the increasing efficiency of agricultural production; they argue that aggregate agricultural production is still more than sufficient to meet global food needs despite the expansion of urban land use.
In the years following World War II, when vehicle ownership was becoming widespread, public health officials recommended the health benefits of suburbs due to soot and industrial fumes in the city center. However, air in modern suburbs is not necessarily cleaner than air in urban neighborhoods. In fact, the most polluted air is on crowded highways, where people in suburbs tend to spend more time. On average, suburban residents generate more per capita pollution and carbon emissions than their urban counterparts because of their increased driving, as well as larger homes.
Sprawl also reduces the chance that people will take the bicycle for their commute which would be better for their health. Bicycles are a common mode of transportation for those living in urban centers due to many factors. One major factor many people consider relates to how, when one rides a bike to, say, their workplace, they are exercising as they do so. This multi-tasking is better for one's health than automatic transport.
A 2023 meta-analysis found that individuals living in sprawling areas had a 20% higher risk of obesity and a 15% higher risk of developing hypertension compared to residents of compact urban environments. Reduced walkability and longer commuting times were identified as key contributing factors.
Research covered in the Journal of Economic Issues and State and Local Government Review shows a link between sprawl and emergency medical services response and fire department response delays.
Residents of low-density areas spend a higher proportion of their income on transportation than residents of high density areas. The unplanned nature of outward urban development is commonly linked to increased dependency on cars. In 2003, a British newspaper calculated that urban sprawl would cause an economic loss of £3,905 per year, per person through cars alone, based on data from the RAC plc estimating that the average cost of operating a car in the UK at that time was £5,000 a year, while train travel (assuming a citizen commutes every day of the year, with a ticket cost of 3 pounds) would be only £1,095. Additionally, increased density increases the supply of housing in desirable areas, and thus, it also decreases housing prices in those areas (by the logic of supply and demand).
A 2022 Building & Cities report found that urban sprawl in Lagos, has significantly increased housing costs and displaced low-income populations into poorly connected suburban areas, deepening economic inequality and limiting access to employment opportunities and essential services. Similar patterns have been observed in other rapidly urbanizing regions, where the uncontrolled outward growth of cities disproportionately affects vulnerable populations.
Critics of sprawl maintain that sprawl erodes quality of life. Duany and Plater-Zyberk believe that in traditional neighborhoods the nearness of the workplace to retail and restaurant space that provides cafes and convenience stores with daytime customers is an essential component to the successful balance of urban life. Furthermore, they state that the closeness of the workplace to homes also gives people the option of walking or riding a bicycle to work or school and that without this kind of interaction between the different components of life the urban pattern quickly falls apart. James Howard Kunstler has argued that poor aesthetics in suburban environments make them "places not worth caring about", and that they lack a sense of history and identity.
Urban sprawl has class and racial implications in many parts of the world; the relative homogeneity of many sprawl developments may reinforce class and racial divides through residential segregation.
Numerous studies link increased population density with increased aggression. Some people believe that increased population density encourages crime and anti-social behavior. It is argued that human beings, while social animals, need significant amounts of social space or they become agitated and aggressive. However, the relationship between higher densities and increased social pathology has been largely discredited.
Human-wildlife interactions
As cities expand into previously undisturbed ecosystems, the potential for zoonotic disease transmission increases due to closer interactions between humans and wildlife. For example, urban sprawl has been linked to outbreaks of diseases such as Ebola, Zika fever, and even Hantavirus, as humans come into contact with wildlife.
As rural-to-urban migration increases, informal settlements—often located on the periphery of cities—tend to be crowded, lack adequate resources (e.g., sanitation, healthcare), and suffer from poor infrastructure. These factors create additional opportunities for zoonotic diseases to thrive and spread among humans.
Increased vector-borne disease risk
Urban sprawl also leads to the loss of natural habitats and habitat fragmentation, which increases contact between wildlife (including those that carry pathogens) and human populations due to the disruption of their ecosystems. This expansion also creates favorable conditions for the spread of vector-borne diseases.
As cities grow, they often develop environments with stagnant water, increased humidity, and higher temperatures—ideal conditions for breeding disease-carrying mosquitoes. These conditions help facilitate the survival of mosquitoes, particularly Aedes species, which have been linked to the transmission of Zika fever, Malaria, and Chikungunya.
Environmental changes and disease emergence
Changes in land use are a major driver of emerging infectious diseases, as they influence species distribution, abundance, movement, and interactions—all of which affect the transmission of zoonotic diseases.WHO. (n.d.). Biodiversity & Infectious Diseases . Questions & Answers. Retrieved from https://www.who.int/docs/default-source/climate-change/qa-infectiousdiseases-who.pdf?sfvrsn=3a624917_3 For example, deforestation reduces the habitat of certain wildlife species, causing them to move closer to human settlements and ultimately increasing the likelihood of disease spillover.
One Health and urban sprawl
The One Health framework emphasizes the interconnectedness of human, animal, and environmental health. Addressing the risks of zoonotic diseases in the context of urban sprawl requires an integrated approach that considers the health of all three domains. Effective public health strategies must involve urban planning that takes into account the potential for zoonotic disease transmission, as well as monitoring and controlling animal populations, improving sanitation, and promoting vaccination and disease prevention.
Arguments opposing urban sprawl include concrete effects such as health and environmental issues as well as abstract consequences including neighborhood vitality. United States public policy analyst Randal O'Toole of the Cato Institute, a libertarian think tank, has argued that sprawl, thanks to the automobile, gave rise to affordable suburban neighborhoods for middle class and lower class individuals, including non-whites. He notes that efforts to combat sprawl often result in subsidizing development in wealthier and whiter neighborhoods while condemning and demolishing poorer minority neighborhoods.
Within cities, studies from across many countries (mainly in the developed world) have shown that denser urban areas with greater mixture of land use and better public transport tend to have lower car use than less dense suburban and ex-urban residential areas. This usually holds true even after controlling for socio-economic factors such as differences in household composition and income. This does not necessarily imply that suburban sprawl causes high car use, however. One confounding factor, which has been the subject of many studies, is residential self-selection: people who prefer to drive tend to move towards low density suburbs, whereas people who prefer to walk, cycle or use transit tend to move towards higher density urban areas, better served by public transport. Some studies have found that, when self-selection is controlled for, the built environment has no significant effect on travel behavior. More recent studies using more sophisticated methodologies have generally refuted these findings: density, land use and public transport accessibility can influence travel behavior, although social and economic factors, particularly household income, usually exert a stronger influence.
Those not opposed to low density development argue that traffic intensities tend to be less, traffic speeds faster and, as a result, ambient air pollution is lower. Kansas City, Missouri is often cited as an example of ideal low-density development, with congestion below the mean and home prices below comparable Midwestern cities. Wendell Cox and Randal O'Toole are leading figures supporting lower density development.
Longitudinal (time-lapse) studies of commute times in major metropolitan areas in the United States have shown that commute times decreased for the period 1969 to 1995 even though the geographic size of the city increased. Other studies suggest, however, that possible personal benefits from commute time savings have been at the expense of environmental costs in the form of longer average commute distances, rising vehicles-miles-traveled (VMT) per worker, and despite road expansions, worsening traffic congestion.
These findings led them to propose the paradox of intensification, which states:
In Australia, it is claimed by some that housing affordability has hit "crisis levels" due to "urban consolidation" policies implemented by state governments." Seeking solutions to the housing affordability crisis ", University of South Australia, October 24, 2005. Retrieved on February 8, 2008. In Sydney, the ratio of the price of a house relative to income is 9:1.Saunders, Peter (2005). " After the House Price Boom: Is this the end of the Australian dream? ", Policy. Retrieved on February 8, 2008. The issue has at times been debated between the major political parties.Archer, Lincoln. " Kevin Rudd says John Howard is ignoring housing ", News Limited, November 5, 2007. Retrieved on February 8, 2008.
Several cities have adopted strategies to curb urban sprawl effectively. Portland, Oregon, established an Urban Growth Boundary (UGB) to contain development within a designated area, promoting higher-density, walkable neighborhoods and preserving surrounding farmland. Singapore has pioneered Transit-Oriented Development (TOD), concentrating housing, employment, and services around an extensive mass transit system to minimize automobile dependency and urban expansion. London’s longstanding Greenbelt policy restricts urban development beyond specific zones to protect green space and control metropolitan growth.
Under Herbert Morrison's 1934 leadership of the London County Council, the first formal proposal was made by the Greater London Regional Planning Committee "to provide a reserve supply of public open spaces and of recreational areas and to establish a green belt or girdle of open space". It was again included in an advisory Greater London Plan prepared by Patrick Abercrombie in 1944. The Town and Country Planning Act of 1947 expressly incorporated green belts into all further national urban developments.
New provisions for compensation in the 1947 Town and Country Planning Act allowed local authorities around the country to incorporate green belt proposals in their first development plans. The codification of Green Belt policy and its extension to areas other than London came with the historic Circular 42/55 inviting local planning authorities to consider the establishment of Green Belts. The first urban growth boundary in the U.S. was in Fayette County, Kentucky, in 1958.
The state of Oregon enacted a law in 1973 limiting the area urban areas could occupy, through urban growth boundaries. As a result, Portland, the state's largest urban area, has become a leader in smart growth policies that seek to make urban areas more compact (they are called urban consolidation policies). After the creation of this boundary, the population density of the urbanized area increased somewhat (from 1,135 in 1970 to 1,290 per km2 in 2000.) Although the growth boundary has not been tight enough to vastly increase density, the consensus is that the growth boundaries have protected great amounts of wild areas and farmland around the metro area.
Much of San Francisco Bay Area has also adopted urban growth boundaries; 25 of its cities and 5 of its counties have urban growth boundaries. Many of these were adopted with the support and advocacy of Greenbelt Alliance, a non-profit land conservation and urban planning organization.
In other areas, the design principles of New Urbanism have been employed to combat urban sprawl. The concept of circular flow land use management has been developed in Europe to reduce land take by urban sprawl through promoting inner-city and brownfield development.
Although cities such as Los Angeles are well known for sprawling suburbs, policies and public opinion are changing. Transit-oriented development, in which higher-density mixed-use areas are permitted or encouraged near transit stops, is encouraging more compact development in certain areas: particularly those with light and heavy rail transit systems.
Bicycles are the preferred means of travel in many countries: Also, bicycles are permitted in public transit. Businesses in areas of some towns in which bicycle use is high are thriving. Bicycles and transit contribute in two important ways toward the success of businesses:
Walkability is a measure of how friendly an area is to walking. Walkability has many health, environmental, and economic benefits. However, evaluating walkability is challenging because it requires the consideration of many subjectivity factors. Factors influencing walkability include the presence or absence and quality of , , or other pedestrian right-of-ways, traffic and road conditions, land use patterns, building accessibility, and safety, among others. Walkability is an important concept in sustainable urban design.
Land use policies are one potential avenue to reduce the effects of urban sprawl. These policies take the form of boundaries to urban growth, regional development rights, and development centralized in urban areas. Housing policies, such as inclusionary zoning, rental vouchers in suburban areas, and a focus on employer-assisted housing are another approach to combatting urban sprawl. Gasoline taxes and increased funding towards the construction of public transportation also help to reduce the necessity of commuting in and out of urban areas.
Examples and counterexamples
History
Characteristics
Single-use development
Job sprawl and spatial mismatch
Low-density
Conversion of agricultural land to urban use
Housing subdivisions
Lawn
Commercial developments
Effects
Environmental
Health
Safety
Economy
Social
Urban sprawl and emerging zoonotic diseases
Debate
Groups that oppose sprawl
Consumer preference
They argue that sprawl generates enough benefits for consumers that they continue to choose it as a form of development over alternative forms, as demonstrated by the continued focus on sprawl type developments by most developers. However, other academics such as Reid Ewing argue that while a large segment of people prefer suburban living that does not mean that sprawl itself is preferred by consumers, and that a large variety of suburban environments satisfy consumer demand, including areas that mitigate the worst effects of sprawl. Others, for example Kenneth T. Jackson have argued that since low-density housing is often (notably in the U.S.) subsidized in a variety of ways, consumers' professed preferences for this type of living may be over-stated.
Automobile dependency
Transportation inequality
Paradox of intensification
Risk of increased housing prices
Proposed alternatives
Alternative development styles
Early attempts at combatting urban sprawl
Maryland
Contemporary anti-sprawl initiatives
See also
Related topics
Related terminology
Notes and references
Further reading
Articles and reports
Video
External links
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