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

urban area An urban area, built-up area or urban agglomeration is a human settlement with a high population density and infrastructure of built environment. Urban areas are created through urbanization and are categorized by urban morphology as cities ...

s of housing, commercial development, and roads over large expanses of land, with little concern for

urban planning Urban planning, also known as town planning, city planning, regional planning, or rural planning, is a technical and political process that is focused on the development and design of land use and the built environment, including air, water, ...

. In addition to describing a special form of

urbanization Urbanization (or urbanisation) refers to the population shift from rural to urban areas, the corresponding decrease in the proportion of people living in rural areas, and the ways in which societies adapt to this change. It is predominantly t ...

, the term also relates to the social and environmental consequences associated with this development. Medieval suburbs suffered from the loss of protection of city walls, before the advent of

industrial warfare Industrial warfare is a period in the history of warfare ranging roughly from the early 19th century and the start of the Industrial Revolution to the beginning of the Atomic Age, which saw the rise of nation-states, capable of creating and eq ...

. Modern disadvantages and costs include increased travel time, transport costs, pollution, and destruction of the countryside. The cost of building urban infrastructure for new developments is hardly ever recouped through property taxes, amounting to a subsidy for the developers and new residents at the expense of existing property taxpayers. In Continental Europe, the term ''

peri-urbanisation Peri-urbanisation relates to the processes of scattered and dispersive urban growth that create hybrid landscapes of fragmented and mixed urban and rural characteristics. Origin The expression originates from the French word ' ("peri-urban" m ...

'' 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 residential density, using the average number of residential units per acre in a given area. Others associate it with

decentralization Decentralization or decentralisation is the process by which the activities of an organization, particularly those regarding planning and decision making, are distributed or delegated away from a central, authoritative location or group. Conce ...

(spread of population without a well-defined centre), discontinuity (

leapfrog Leapfrog is a children's game in which players vault over each other's stooped backs. History Games of this sort have been called by this name since at least the late sixteenth century.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 Segregation may refer to: Separation of people * Geographical segregation, rates of two or more populations which are not homogenous throughout a defined space * School segregation * Housing segregation * Racial segregation, separation of humans ...

, 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.

Definition

The term "urban sprawl" was often used in the letters between Lewis Mumford and Frederic J. Osborn, firstly by Osborn in his 1941 letter to Mumford and later by Mumford, generally condemning the waste of agricultural land and landscape due to suburban expansions. The term was used in an article in ''

The Times ''The Times'' is a British daily national newspaper based in London. It began in 1785 under the title ''The Daily Universal Register'', adopting its current name on 1 January 1788. ''The Times'' and its sister paper '' The Sunday Times'' (f ...

'' in 1955 as a negative comment on the state of

London London is the capital and List of urban areas in the United Kingdom, largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary dow ...

's outskirts. Definitions of sprawl vary; researchers in the field acknowledge that the term lacks precision. p. 475. Batty et al. defined sprawl as "uncoordinated growth: the expansion of community without concern for its consequences, in short, unplanned, incremental urban growth which is often regarded unsustainable." Bhatta et al. wrote in 2010 that despite a dispute over the precise definition of sprawl, there is a "general consensus that urban sprawl is characterized by nunplanned and uneven pattern of growth, driven by a multitude of processes and leading to inefficient resource utilization." Reid Ewing has shown that sprawl has typically been characterized as

urban development Urban means "related to a city". In that sense, the term may refer to: * Urban area, geographical area distinct from rural areas * Urban culture, the culture of towns and cities Urban may also refer to: General * Urban (name), a list of peop ...

s exhibiting at least one of the following characteristics: low-density or single-use development, strip development, scattered development, and/or

leapfrog Leapfrog is a children's game in which players vault over each other's stooped backs. History Games of this sort have been called by this name since at least the late sixteenth century.accessibility" and "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 Per se may refer to: * '' per se'', a Latin phrase meaning "by itself" or "in itself". * Illegal ''per se'', the legal usage in criminal and antitrust law * Negligence ''per se'', legal use in tort law * Per Se (restaurant), a New York City restaur ...

, constitute sprawl depending on the form it takes, although Gordon & Richardson have argued that the term is sometimes used synonymously with

suburbanization Suburbanization is a population shift from central urban areas into suburbs, resulting in the formation of (sub)urban sprawl. As a consequence of the movement of households and businesses out of the city centers, low-density, peripheral urba ...

in a pejorative way.

Examples and counterexamples

According to the National Resources Inventory (NRI), about of land in the United States was developed between 1982 and 2017. Presently, the NRI classifies approximately 100,000 more square kilometres (40,000 square miles) (an area approximately the size of

Kentucky Kentucky ( , ), officially the Commonwealth of Kentucky, is a state in the Southeastern region of the United States and one of the states of the Upper South. It borders Illinois, Indiana, and Ohio to the north; West Virginia and Virginia ...

) as developed than the Census Bureau classifies as urban. The difference in the NRI classification is that it includes rural development, which by definition cannot be considered to be "urban" sprawl. Currently, according to the 2000 Census, approximately 2.6 percent of the U.S. land area is urban. Approximately 0.8 percent of the nation's land is in the 37 urbanized areas with more than 1,000,000 population. In 2002, these 37 urbanized areas supported around 40% of the total American population. Nonetheless, some

s like

Detroit Detroit ( , ; , ) is the largest city in the U.S. state of Michigan. It is also the largest U.S. city on the United States–Canada border, and the seat of government of Wayne County. The City of Detroit had a population of 639,111 at t ...

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, the Netherlands Amsterdam ( , , , lit. ''The Dam on the River Amstel'') is the Capital of the Netherlands, capital and Municipalities of the Netherlands, most populous city of the Netherlands, with The Hague being the seat of government. It has a population ...

; Brussels, Belgium;

Copenhagen, Denmark Copenhagen ( or .; da, København ) is the capital and most populous city of Denmark, with a proper population of around 815.000 in the last quarter of 2022; and some 1.370,000 in the urban area; and the wider Copenhagen metropolitan ar ...

;

Frankfurt Frankfurt, officially Frankfurt am Main (; Hessian: , " Frank ford on the Main"), is the most populous city in the German state of Hesse. Its 791,000 inhabitants as of 2022 make it the fifth-most populous city in Germany. Located on it ...

Hamburg (male), (female) en, Hamburger(s), Hamburgian(s) , timezone1 = Central (CET) , utc_offset1 = +1 , timezone1_DST = Central (CEST) , utc_offset1_DST = +2 , postal ...

and

Munich Munich ( ; german: München ; bar, Minga ) is the capital and most populous city of the German state of Bavaria. With a population of 1,558,395 inhabitants as of 31 July 2020, it is the third-largest city in Germany, after Berlin and Ha ...

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...

; and Zurich, Switzerland, albeit without the dismantling of infrastructure that occurred in the United States. Despite popular notions of being a sprawling city, 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 Greater Mexico City refers to the conurbation around Mexico City, officially called Metropolitan Area of the Valley of Mexico ( es, Zona metropolitana del Valle de México). It encompasses Mexico City itself and 60 adjacent municipalities of the S ...

, Delhi National Capital Region and

Beijing } Beijing ( ; ; ), alternatively romanized as Peking ( ), is the capital of the People's Republic of China. It is the center of power and development of the country. Beijing is the world's most populous national capital city, with over 21 ...

, are often regarded as sprawling despite being relatively dense and mixed use.

History

Many theories speculate as to the reason for the creation of urban sprawl. The theory of "flight from blight" explains that aspects of living in urban areas, such as high taxes, crime rates, poor infrastructure and school qualities lead to many people moving out of urban areas and into surrounding suburban cities. According to

The Limits to Growth ''The Limits to Growth'' (''LTG'') is a 1972 report that discussed the possibility of exponential economic and population growth with finite supply of resources, studied by computer simulation. The study used the World3 computer model to simula ...

, reasons why wealthier people move to suburbs include noise, pollution, crime, drug addiction, poverty, labor strikes, and breakdown of social services. 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 cities.

Characteristics

Despite the lack of a clear agreed upon description of what defines sprawl most definitions often associate the following characteristics with sprawl. BosWash-Night-Labeled

Single-use development

This refers to a situation where commercial, residential, institutional and industrial areas are separated from one another. Consequently, large tracts of land are devoted to a single use and are segregated from one another by open space, infrastructure, or other barriers. As a result, the places where people live, work, shop, and recreate are far from one another, usually to the extent that walking, transit use and bicycling are impractical, so all these activities generally require a car. The degree to which different

land use Land use involves the management and modification of natural environment or wilderness into built environment such as settlements and semi-natural habitats such as arable fields, pastures, and managed woods. Land use by humans has a long ...

s are mixed together is often used as an indicator of sprawl in studies of the subject. According to this criterion, China's

can be classified as "high-density sprawl", a seemingly self-contradictory term coined by

New Urbanist New Urbanism is an urban design movement which promotes environmentally friendly habits by creating walkable neighbourhoods containing a wide range of housing and job types. It arose in the United States in the early 1980s, and has gradually inf ...

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 and spatial mismatch

Traffic jam Marginal Pinheiros 6122 SAO 07 2009

Job sprawl is another land use symptom of urban sprawl and car-dependent communities. It is defined as low-density, geographically spread-out patterns of employment, where the majority of jobs in a given metropolitan area are located outside of the main city's central business district (CBD), and increasingly in the suburban periphery. It is often the result of urban disinvestment, the geographic freedom of employment location allowed by predominantly car-dependent commuting patterns of many American suburbs, and many companies' desire to locate in low-density areas that are often more affordable and offer potential for expansion.

Spatial mismatch Spatial mismatch is the mismatch between where low-income households reside and suitable job opportunities. In its original formulation (see below) and in subsequent research, it has mostly been understood as a phenomenon affecting African-American ...

is related to job sprawl and economic

environmental justice Environmental justice is a social movement to address the unfair exposure of poor and marginalized communities to harms from hazardous waste, resource extraction, and other land uses.Schlosberg, David. (2007) ''Defining Environmental Justic ...

. Spatial mismatch is defined as the situation where poor urban, predominantly minority citizens are left without easy access to entry-level jobs, as a result of increasing job sprawl and limited transportation options to facilitate a

reverse commute A reverse commute is a round trip, regularly taken, from an urban area to a suburban one in the morning, and returning in the evening. It is almost universally applied to trips to work in the suburbs from homes in the city. This is in opposition to ...

to the suburbs. 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 The Brookings Institution, often stylized as simply Brookings, is an American research group founded in 1916. Located on Think Tank Row in Washington, D.C., the organization conducts research and education in the social sciences, primarily in e ...

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.

Low-density

Sprawl often refers to low-

density Density (volumetric mass density or specific mass) is the substance's mass per unit of volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' can also be used. Mathematical ...

development Development or developing may refer to: Arts *Development hell, when a project is stuck in development *Filmmaking, development phase, including finance and budgeting *Development (music), the process thematic material is reshaped * Photograph ...

. There is no precise definition of "low density," but it might commonly mean

Single-family home A stand-alone house (also called a single-detached dwelling, detached residence or detached house) is a free-standing residential building. It is sometimes referred to as a single-family home, as opposed to a multi-family residential dwelli ...

s on large lots. Such buildings usually have fewer stories and are spaced farther apart, separated by

lawn A lawn is an area of soil-covered land planted with grasses and other durable plants such as clover which are maintained at a short height with a lawnmower (or sometimes grazing animals) and used for aesthetic and recreational purposes. ...

landscaping Landscaping refers to any activity that modifies the visible features of an area of land, including the following: # Living elements, such as flora or fauna; or what is commonly called gardening, the art and craft of growing plants with a goal ...

, roads or parking lots. In the United States 2–4 houses per acre (5–10 per hectare) might be considered low-density while in the UK 8–12 per acre (or 20–30 per hectare) would still be considered low-density. Because more automobiles are used in the USA, much more land is designated for parking. The impact of low density development in many communities is that developed or "urbanized" land is increasing at a faster rate than the population is growing. Overall density is often lowered by "

leapfrog Leapfrog is a children's game in which players vault over each other's stooped backs. History Games of this sort have been called by this name since at least the late sixteenth century.green belt A green belt is a policy and land-use zone designation used in land-use planning to retain areas of largely undeveloped, wild, or agricultural land surrounding or neighboring urban areas. Similar concepts are greenways or green wedges, which ...

s, 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. 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 Local government is a generic term for the lowest tiers of public administration within a particular sovereign state. This particular usage of the word government refers specifically to a level of administration that is both geographically-l ...

built all the streets in a given location, the town could expand without interruption and with a coherent circulation system, because it had condemnation power. 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.

Conversion of agricultural land to urban use

Land for sprawl is often taken from fertile

agricultural land Agricultural land is typically land ''devoted to'' agriculture, the systematic and controlled use of other forms of lifeparticularly the rearing of livestock and production of cropsto produce food for humans. It is generally synonymous with ...

s, which are often located immediately surrounding cities; the extent of modern sprawl has consumed a large amount of the most productive agricultural land, as well as forest, desert and other wilderness areas. In the United States the seller may avoid tax on profit by using a

tax break Tax break also known as tax preferences, tax concession, and tax relief, are a method of reduction to the tax liability of taxpayers. Government usually applies them to stimulate the economy and increase the solvency of the population. By this fi ...

exempting

like-kind exchange A like-kind exchange under United States tax law, also known as a 1031 exchange, is a transaction or series of transactions that allows for the disposal of an asset and the acquisition of another replacement asset without generating a current tax ...

s from

capital gains tax A capital gains tax (CGT) is the tax on profits realized on the sale of a non-inventory asset. The most common capital gains are realized from the sale of stocks, bonds, precious metals, real estate, and property. Not all countries impose a c ...

; proceeds from the sale are used to purchase agricultural land elsewhere and the transaction is treated as a "swap" or trade of like assets and no tax is due. Thus urban sprawl is subsidized by the tax code. In China, land has been converted from rural to urban use in advance of demand, leading to vacant rural land intended for future development, and eventual urban sprawl.

Housing subdivisions

Housing subdivision Subdivisions are the act of dividing land into pieces that are easier to sell or otherwise develop, usually via a plat. The former single piece as a whole is then known as a subdivision. Subdivisions may be simple, involving only a single sell ...

s are large tracts of land consisting entirely of newly built residences.

architectural firm

Duany Plater-Zyberk & Company DPZ CoDesign (DPZ) (formerly Duany Plater-Zyberk & Co. and DPZ Partners) is an architecture and town planning firm based in Miami, Florida, founded in 1980 by the husband-and-wife team of Andrés Duany and Elizabeth Plater-Zyberk. The firm is one o ...

state that housing subdivisions "are sometimes called villages, towns, and neighbourhoods by their developers, which is misleading since those terms denote places that are not exclusively residential." They are also referred to as developments. Subdivisions often incorporate curved roads and cul-de-sacs. 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.

Lawn

After the

Second World War World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposi ...

, residential

s became commonplace in suburbs, notably, but not exclusively in North America. The development of country clubs and golf courses in the early 20th century further promoted lawn culture in the United States. Lawns now take up a significant amount of land in suburban developments, contributing to sprawl.

Commercial developments

In areas of sprawl, commercial use is generally segregated from other uses. In the U.S. and Canada, these often take the form of

strip malls A strip mall, strip center or strip plaza is a type of shopping center common in North America where the stores are arranged in a row, with a sidewalk in front. Strip malls are typically developed as a unit and have large parking lots in front. ...

, which refer to collections of buildings sharing a common parking lot, usually built on a high-capacity roadway with commercial functions (i.e., a "strip"). Similar developments in the UK are called Retail Parks. Strip malls consisting mostly of

big box store A big-box store (also hyperstore, supercenter, superstore, or megastore) is a physically large retail establishment, usually part of a chain of stores. The term sometimes also refers, by extension, to the company that operates the store. The te ...

s or category killers are sometimes called "power centers" (U.S.). These developments tend to be low-density; the buildings are single-story and there is ample space for parking and access for delivery vehicles. This character is reflected in the spacious landscaping of the parking lots and walkways and clear signage of the retail establishments. Some strip malls are undergoing a transformation into

Lifestyle centers A lifestyle center (American English), or lifestyle centre (English in the Commonwealth of Nations, Commonwealth English), is a shopping center or mixed-used commercial development that combines the traditional retail functions of a shopping mal ...

; entailing investments in common areas and facilities (plazas, cafes) and shifting tenancy from daily goods to recreational shopping. Wal-Mart Supercenter, Luray, Virginia

Another prominent form of retail development in areas characterized by sprawl is the

shopping mall A shopping mall (or simply mall) is a North American term for a large indoor shopping center, usually anchored by department stores. The term "mall" originally meant a pedestrian promenade with shops along it (that is, the term was used to refe ...

. 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

department store A department store is a retail establishment offering a wide range of consumer goods in different areas of the store, each area ("department") specializing in a product category. In modern major cities, the department store made a dramatic app ...

s (Gruen and Smith 1960). 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 shopping centres of nearby cities since the shopping malls act as a surrogate for the city centre (Crawford 1992). Some downtowns have responded to this challenge by building shopping centres of their own (Frieden and Sagelyn 1989). 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 Eric Matthew Schlosser (born August 17, 1959) is an American journalist and author known for his investigative journalism, such as in his books ''Fast Food Nation'' (2001), '' Reefer Madness'' (2003), and '' Command and Control: Nuclear Weapons, ...

, in his book ''

Fast Food Nation ''Fast Food Nation: The Dark Side of the All-American Meal'' is a 2001 book by Eric Schlosser. First serialized by ''Rolling Stone'' in 1999, the book has drawn comparisons to Upton Sinclair's 1906 muckraking novel '' The Jungle''. The book ...

'', 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.

Effect

Urban sprawl is associated with a number of negative environmental outcomes. One of the major environmental problems associated with sprawl is

land loss Land loss is the term typically used to refer to the conversion of coastal land to open water by natural processes and human activities. The term ''land loss'' includes coastal erosion. It is a much broader term than coastal erosion because land l ...

habitat loss Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...

and subsequent reduction in

biodiversity Biodiversity or biological diversity is the variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic (''genetic variability''), species (''species diversity''), and ecosystem (''ecosystem diversity'') l ...

. A review by Czech and colleagues finds that urbanization endangers more species and is more geographically ubiquitous in the mainland United States than any other human activity. Urban sprawl is disruptive to native flora & fauna and introduces

invasive plants An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species adv ...

into their environments. Although the effects can be mitigated through careful maintenance of native vegetation, the process of ecological succession and public education, sprawl represents one of the primary threats to biodiversity. Regions with high birth rates and immigration are therefore faced with environmental problems due to unplanned urban growth and emerging megacities such as Kolkata. Other problems include: * flooding, which results from increased

impervious surface Impervious surfaces are mainly artificial structures—such as pavements (roads, sidewalks, driveways and parking lots, as well as industrial areas such as airports, ports and logistics and distribution centres, all of which use considerable p ...

s for

road A road is a linear way for the conveyance of traffic that mostly has an improved surface for use by vehicles (motorized and non-motorized) and pedestrians. Unlike streets, the main function of roads is transportation. There are many types of ...

s and parking (''see''

urban runoff Urban runoff is surface runoff of rainwater, landscape irrigation, and car washing created by urbanization. Impervious surfaces (roads, parking lots and sidewalks) are constructed during land development. During rain , storms and other precip ...

) * increased temperatures from heat islands, which leads to a significantly increased risk of mortality in elderly populations. At the same time, the urban cores of these and nearly all other major cities in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

Western Europe Western Europe is the western region of Europe. The region's countries and territories vary depending on context. The concept of "the West" appeared in Europe in juxtaposition to "the East" and originally applied to the ancient Mediterranean ...

, and Japan that did not annex new territory experienced the related phenomena of falling household size and, particularly in the U.S., "

white flight White flight or white exodus is the sudden or gradual large-scale migration of white people from areas becoming more racially or ethnoculturally diverse. Starting in the 1950s and 1960s, the terms became popular in the United States. They refer ...

", 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 Impervious surfaces are mainly artificial structures—such as pavements (roads, sidewalks, driveways and parking lots, as well as industrial areas such as airports, ports and logistics and distribution centres, all of which use considerable pa ...

(

concrete Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most wid ...

and

asphalt Asphalt, also known as bitumen (, ), is a sticky, black, highly viscous liquid or semi-solid form of petroleum. It may be found in natural deposits or may be a refined product, and is classed as a pitch. Before the 20th century, the term ...

) in the suburbs, rainfall is less effectively absorbed into the

groundwater Groundwater is the water present beneath Earth's surface in rock and soil pore spaces and in the fractures of rock formations. About 30 percent of all readily available freshwater in the world is groundwater. A unit of rock or an unconsolidated ...

aquifer An aquifer is an underground layer of water-bearing, permeable rock, rock fractures, or unconsolidated materials ( gravel, sand, or silt). Groundwater from aquifers can be extracted using a water well. Aquifers vary greatly in their characteris ...

s. This threatens both the quality and quantity of water supplies. Sprawl increases

water pollution Water pollution (or aquatic pollution) is the contamination of water bodies, usually as a result of human activities, so that it negatively affects its uses. Water bodies include lakes, rivers, oceans, aquifers, reservoirs and groundwater. ...

as rain water picks up

gasoline Gasoline (; ) or petrol (; ) (see ) is a transparent, petroleum-derived flammable liquid that is used primarily as a fuel in most spark-ignited internal combustion engines (also known as petrol engines). It consists mostly of organi ...

, motor oil, heavy metals, and other pollutants in

runoff Runoff, run-off or RUNOFF may refer to: * RUNOFF, the first computer text-formatting program * Runoff or run-off, another name for bleed, printing that lies beyond the edges to which a printed sheet is trimmed * Runoff or run-off, a stock marke ...

from parking lots and roads. Chicagoland air

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.

Health

Sprawl leads to increased driving, which in turn leads to vehicle emissions that contribute to

air pollution Air pollution is the contamination of air due to the presence of substances in the atmosphere that are harmful to the health of humans and other living beings, or cause damage to the climate or to materials. There are many different typ ...

and its attendant negative impacts on human

health Health, according to the World Health Organization, is "a state of complete physical, mental and social well-being and not merely the absence of disease and infirmity".World Health Organization. (2006)''Constitution of the World Health Organiza ...

. In addition, the reduced physical activity implied by increased automobile use has negative health consequences. Sprawl significantly predicts chronic medical conditions and health-related quality of life, but not mental health disorders. The American Journal of Public Health and the American Journal of Health Promotion, have both stated that there is a significant connection between sprawl,

obesity Obesity is a medical condition, sometimes considered a disease, in which excess body fat has accumulated to such an extent that it may negatively affect health. People are classified as obese when their body mass index (BMI)—a person's ...

, and hypertension.McKee, Bradford.
As Suburbs Grow, So Do Waistlines
", ''

The New York Times ''The New York Times'' (''the Times'', ''NYT'', or the Gray Lady) is a daily newspaper based in New York City with a worldwide readership reported in 2020 to comprise a declining 840,000 paid print subscribers, and a growing 6 million paid d ...

'', September 4, 2003. Retrieved on February 7, 2008. Loud vehicles can cause stress, prevent sleep, and minimize social interactions in public for people living in cities (especially homeless people). 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.

Safety

A heavy reliance on automobiles increases traffic throughout the city as well as automobile crashes, pedestrian injuries, and air pollution. Motor vehicle crashes are the leading cause of death for Americans between the ages of five and twenty-four and is the leading accident-related cause for all age groups. Residents of more sprawling areas are generally at greater risk of dying in a car crash due to increased exposure to driving. Evidence indicates that pedestrians in sprawling areas are at higher risk than those in denser areas, although the relationship is less clear than for drivers and passengers in vehicles. 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.

Economy

Living in larger, more spread out spaces generally makes public services more expensive. Since car usage becomes endemic and public transport often becomes significantly more expensive, city planners are forced to build highway and parking infrastructure, which in turn decreases taxable land and revenue, and decreases the desirability of the area adjacent to such structures. Providing services such as

water Water (chemical formula ) is an Inorganic compound, inorganic, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living ...

, sewers, road maintenance, and

electricity Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as describ ...

is also more expensive per household in less dense areas, given that sprawl increases lengths of power lines, roads, and pipes, necessitating higher maintenance costs. 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 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). Petrol use urban density

Social

Urban sprawl may be partly responsible for the decline in social capital in the United States. Compact neighborhoods can foster casual social interactions among neighbors, while sprawl creates barriers. Sprawl tends to replace public spaces with private spaces such as fenced-in backyards. Critics of sprawl maintain that sprawl erodes

quality of life Quality of life (QOL) is defined by the World Health Organization as "an individual's perception of their position in life in the context of the culture and value systems in which they live and in relation to their goals, expectations, standards ...

. 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 James Howard Kunstler (born October 19, 1948) is an American author, social critic, public speaker, and blogger. He is best known for his books ''The Geography of Nowhere'' (1994), a history of American suburbia and urban development, ''The Long ...

has argued that poor

aesthetics Aesthetics, or esthetics, is a branch of philosophy that deals with the nature of beauty and taste, as well as the philosophy of art (its own area of philosophy that comes out of aesthetics). It examines aesthetic values, often expressed t ...

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 Residential segregation in the United States is the physical separation of two or more groups into different neighborhoods—a form of segregation that "sorts population groups into various neighborhood contexts and shapes the living environment a ...

. 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.

Debate

According to Nancy Chin, a large number of effects of sprawl have been discussed in the academic literature in some detail; however, the most contentious issues can be reduced "to an older set of arguments, between those advocating a planning approach and those advocating the efficiency of the market." Those who criticize sprawl tend to argue that sprawl creates more problems than it solves and should be more heavily regulated, while proponents argue that markets are producing the economically most efficient settlements possible in most situations, even if problems may exist. However, some market-oriented commentators believe that the current patterns of sprawl are in fact the result of distortions of the free market. Chin cautions that there is a lack of "reliable empirical evidence to support the arguments made either for or against sprawl." She mentions that the lack of a common definition, the need for more quantitative measures "a broader view both in time and space, and greater comparison with alternative urban forms" would be necessary to draw firmer conclusions and conduct more fruitful debates. Arguments opposing urban sprawl include concrete effects such as health and environmental issues as well as abstract consequences including neighborhood vitality.

American American(s) may refer to: * American, something of, from, or related to the United States of America, commonly known as the "United States" or "America" ** Americans, citizens and nationals of the United States of America ** American ancestry, pe ...

public policy Public policy is an institutionalized proposal or a decided set of elements like laws, regulations, guidelines, and actions to solve or address relevant and real-world problems, guided by a conception and often implemented by programs. Public p ...

analyst

Randal O'Toole Randal O'Toole (born 1952) is an American public policy analyst. The majority of O'Toole's work has focused on public lands, land-use regulation, and transportation, particularly light rail. He frequently criticized proposals for passenger rail ...

of the

Cato Institute The Cato Institute is an American libertarian think tank headquartered in Washington, D.C. It was founded in 1977 by Ed Crane, Murray Rothbard, and Charles Koch, chairman of the board and chief executive officer of Koch Industries.Koch Ind ...

, a libertarian

think tank A think tank, or policy institute, is a research institute that performs research and advocacy concerning topics such as social policy, political strategy, economics, military, technology, and culture. Most think tanks are non-governmenta ...

, has argued that sprawl, thanks to the automobile, gave rise to affordable suburban neighborhoods for

middle class The middle class refers to a class of people in the middle of a social hierarchy, often defined by occupation, income, education, or social status. The term has historically been associated with modernity, capitalism and political debate. Com ...

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.

Groups that oppose sprawl

The

American Institute of Architects The American Institute of Architects (AIA) is a professional organization for architects in the United States. Headquartered in Washington, D.C., the AIA offers education, government advocacy, community redevelopment, and public outreach to su ...

, American Planning Association, and

Smart Growth America Smart Growth America (SGA) is a US non-profit 501(c)(3) organization headquartered in Washington, D.C. SGA's mission is to ensure that urban development policies foster safe, equitable, and sustainable community growth. SGA is a coalition of ...

recommend against sprawl and instead endorses

smart Smart or SMART may refer to: Arts and entertainment * ''Smart'' (Hey! Say! JUMP album), 2014 * Smart (Hotels.com), former mascot of Hotels.com * ''Smart'' (Sleeper album), 1995 debut album by Sleeper * '' SMart'', a children's television se ...

, mixed-use development, including buildings in close proximity to one another that cut down on automobile use, save energy, and promote walkable, healthy, well-designed neighborhoods. The Sierra Club, the San Francisco Bay Area's

Greenbelt Alliance Greenbelt Alliance is a San Francisco Bay Area nonprofit organization founded to help the region handle a climate change. The organization's mission is to protect precious open spaces while focusing equitable, climate-smart growth within existing ...

1000 Friends of Oregon 1000 Friends of Oregon is a private, non-profit 501(c)(3) organization that advocates for land-use planning. It was incorporated on October 11, 1974, following the creation of Oregon's statewide land-use system in 1973 by then-governor Tom McCal ...

and counterpart organizations nationwide, and other environmental organizations oppose sprawl and support investment in existing communities.

NumbersUSA NumbersUSA is an anti-immigrationExplaining 'Chain Migration'

, a national organization advocating

immigration reduction Opposition to immigration, also known as anti-immigration, has become a significant political ideology in many countries. In the modern sense, immigration refers to the entry of people from one state or territory into another state or territory ...

, also opposes urban sprawl, and its executive director,

Roy Beck Roy Howard Beck is an American author, as well as the founder and president of the anti-immigration advocacy organization NumbersUSA. He is former Washington, DC bureau chief of Booth Newspapers and an environment-beat newspaper reporter, formerly ...

, specializes in the study of this issue.

Consumer preference

One of the primary debates around suburban sprawl is the extent to which sprawl is the result of consumer preference. Some, such as Peter Gordon, a professor of planning and economics at the University of Southern California's School of

Urban Planning Urban planning, also known as town planning, city planning, regional planning, or rural planning, is a technical and political process that is focused on the development and design of land use and the built environment, including air, water, ...

and Development, argue that most households have shown a clear preference for low-density living and that this is a fact that should not be ignored by planners. Gordon and his frequent collaborator, Harry Richardson have argued that 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

Los Angeles - Echangeur autoroute 110 105

Whether urban sprawl increases the problems of automobile dependency or not, policies of

smart growth Smart growth is an urban planning and transportation theory that concentrates growth in compact walkable urban centers to avoid sprawl. It also advocates compact, transit-oriented, walkable, bicycle-friendly land use, including neighborhood sc ...

have been fiercely contested issues over several decades. An influential study in 1989 by Peter Newman and Jeff Kenworthy compared 32 cities across North America, Australia, Europe and Asia. The study has been criticised for its methodology, but the main finding, that denser cities, particularly in Asia, have lower car use than sprawling cities, particularly in North America, has been largely accepted, although the relationship is clearer at the extremes across continents than it is within countries where conditions are more similar. 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. US36WBCO47

Those not opposed to low density development argue that traffic intensities tend to be less, traffic speeds faster and, as a result, ambient

is lower. (Se
demographia's
report.) 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 Wendell Cox is an American urban policy analyst and proponent of the use of the private car over rail projects. He is the principal and sole owner of Wendell Cox Consultancy/Demographia, based in the St. Louis metropolitan region and editor of thre ...

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.

Transportation inequality

Critics of urban sprawl say that the United States' improper treatment of minority groups' access to transportation is a major downside to the continuation of urban sprawl. In many urban centers, such as Los Angeles and San Francisco, transportation in minority areas is lacking. As found by Kate Baldridge of Golden Gate University Law, areas with high minority populations typically see less than adequate transportation options, leading to overcrowded and unsafe transportation routes that do not provide a comprehensive means of transportation. This disparity is made more evident because minority residents are more reliant on public transportation. According to Baldridge, this means that minority groups cannot move from urban areas, while people with higher incomes and thus better access to transportation can move out of urban areas and into surrounding suburbs.

Paradox of intensification

Reviewing the evidence on urban intensification,

and their effects on travel behaviour Melia et al. (2011) found support for the arguments of both supporters and opponents of

measures to counteract urban sprawl. Planning policies that increase population densities in urban areas do tend to reduce car use, but the effect is a weak one, so doubling the population density of a particular area will not halve the frequency or distance of car use. These findings led them to propose the paradox of intensification, which states:

Risk of increased housing prices

There is also some concern that anti-sprawl policies will increase housing prices. Some research suggests Oregon has had the largest housing affordability loss in the nation, but other research shows that Portland's price increases are comparable to other Western cities. In Australia, it is claimed by some that housing affordability has hit "crisis levels" due to "urban consolidation" policies implemented by state governments. In Sydney, the ratio of the price of a house relative to income is 9:1. The issue has at times been debated between the major political parties.

Proposed alternatives

Many critics concede that sprawl produces some negative externalities; however there is some dispute about the most effective way to reduce these negative effects. Gordon & Richardson for example argue that the costs of building new public transit is disproportionate to the actual environmental or economic benefits, that land use restrictions will increase the cost of housing and restrict economic opportunity, that infill possibilities are too limited to make a major difference to the structure of American cities, and that the government would need to coerce most people to live in a way that they do not want to in order to substantially change the impact of sprawl. They argue that the property market should be deregulated to allow different people to live as they wish, while providing a framework of market based fees (such as emission fees,

congestion charging Congestion pricing or congestion charges is a system of surcharging users of public goods that are subject to congestion through excess demand, such as through higher peak charges for use of bus services, electricity, metros, railways, tele ...

road pricing Road pricing (also road user charges) are direct charges levied for the use of roads, including road tolls, distance or time-based fees, congestion charges and charges designed to discourage the use of certain classes of vehicle, fuel sour ...

) to mitigate many of the problems associated with sprawl such as congestion and increased pollution.

Alternative development styles

Early attempts at combatting urban sprawl

The Metropolitan Green Belt among the green belts of England

Starting in the early 20th century, environmentalist opposition to urban sprawl began to coalesce, with roots in the

garden city movement The garden city movement was a 20th century urban planning movement promoting satellite communities surrounding the central city and separated with greenbelts. These Garden Cities would contain proportionate areas of residences, industry, and ...

, as well as pressure from campaign groups such as the

Campaign to Protect Rural England CPRE, The Countryside Charity, formerly known by names such as the ''Council for the Preservation of Rural England'' and the ''Council for the Protection of Rural England'', is a charity in England with over 40,000 members and supporters. Forme ...

(CPRE). Under

Herbert Morrison Herbert Stanley Morrison, Baron Morrison of Lambeth, (3 January 1888 – 6 March 1965) was a British politician who held a variety of senior positions in the UK Cabinet as member of the Labour Party. During the inter-war period, he was Minis ...

's 1934 leadership of the

London County Council London County Council (LCC) was the principal local government body for the County of London throughout its existence from 1889 to 1965, and the first London-wide general municipal authority to be directly elected. It covered the area today kno ...

, the first formal proposal was made by the Greater London

Regional Planning Regional planning deals with the efficient placement of land-use activities, infrastructure, and settlement growth across a larger area of land than an individual city or town. Regional planning is related to urban planning as it relates land ...

Committee "to provide a reserve supply of public open spaces and of recreational areas and to establish a

green belt A green belt is a policy and land-use zone designation used in land-use planning to retain areas of largely undeveloped, wild, or agricultural land surrounding or neighboring urban areas. Similar concepts are greenways or green wedges, which ...

or girdle of open space". It was again included in an advisory Greater London Plan prepared by

Patrick Abercrombie Sir Leslie Patrick Abercrombie (; 6 June 1879 – 23 March 1957) was an English regional and town planner. Abercrombie was an academic during most of his career, and prepared one city plan and several regional studies prior to the Second Worl ...

in 1944. The Town and Country Planning Act of 1947 expressly incorporated green belts into all further national

s. 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 A development plan sets out a local authority's policies and proposals for land use in their area. The term is usually used in the United Kingdom. A Local Plan is one type of development plan. The development plan guides and shapes day-to-day dec ...

. 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 An urban growth boundary, or UGB, is a regional boundary, set in an attempt to control urban sprawl by, in its simplest form, mandating that the area inside the boundary be used for urban development and the area outside be preserved in its natural ...

in the U.S. was in Fayette County, Kentucky, in 1958.

Maryland

Maryland underwent many "Smart Growth" initiatives, starting in 1997 with the Smart Growth Areas Act. This act allocated funding towards areas that either were already undergoing growth, or areas that had plans of growth. Maryland also implemented the 1997 Rural Legacy Act, which distributed grants to private land owners and allowed them to purchase development rights. Brownfields Voluntary Cleanup and Revitalization Incentive Programs also incentivized the usage of previously contaminated properties by allowing property owners to avoid liability for the property. The state also offered incentives, such as tax breaks and loans for repairs to contaminated areas. Another program created by the state of Maryland was the Job Creation Tax Credit Program, which encouraged businesses to relocate into select areas, reducing the intensity of urban sprawl in some areas. The Live Near Your Work Program also incentivized employees to purchase homes in areas closer to their work. This led to a reduced commute time, and more of an emphasis on homeownership rather than renting.

Contemporary anti-sprawl initiatives

The term 'smart growth' has been particularly used in North America. The terms '

compact city The compact city or city of short distances is an urban planning and urban design concept, which promotes relatively high residential density with mixed land uses. It is based on an efficient public transport system and has an urban layout which ...

' and 'urban intensification' are often used to describe similar concepts in Europe, and particularly in the UK, where it has influenced government policy and planning practice in recent years. The state of

Oregon Oregon () is a state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington, while the Snake River delineates much of its eastern boundary with Idaho. T ...

enacted a law in 1973 limiting the area urban areas could occupy, through urban growth boundaries. As a result,

Portland Portland most commonly refers to: * Portland, Oregon, the largest city in the state of Oregon, in the Pacific Northwest region of the United States * Portland, Maine, the largest city in the state of Maine, in the New England region of the northeas ...

, the state's largest urban area, has become a leader in

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 An urban area, built-up area or urban agglomeration is a human settlement with a high population density and infrastructure of built environment. Urban areas are created through urbanization and are categorized by urban morphology as cities ...

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 Agricultural land is typically land ''devoted to'' agriculture, the systematic and controlled use of other forms of lifeparticularly the rearing of livestock and production of cropsto produce food for humans. It is generally synonymous with bo ...

around the metro area. Much of

San Francisco Bay Area The San Francisco Bay Area, often referred to as simply the Bay Area, is a populous region surrounding the San Francisco, San Pablo, and Suisun Bay estuaries in Northern California. The Bay Area is defined by the Association of Bay Area Go ...

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

, a non-profit land conservation and urban planning organization. In other areas, the design principles of

New Urbanism New Urbanism is an urban design movement which promotes environmentally friendly habits by creating walkable neighbourhoods containing a wide range of housing and job types. It arose in the United States in the early 1980s, and has gradually i ...

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 Los Angeles ( ; es, Los Ángeles, link=no , ), often referred to by its initials L.A., is the List of municipalities in California, largest city in the U.S. state, state of California and the List of United States cities by population, sec ...

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 Public transport (also known as public transportation, public transit, mass transit, or simply transit) is a system of transport for passengers by group travel systems available for use by the general public unlike private transport, typic ...

. 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: # People living the closest to these business districts on average have more money to spend locally because they spend less on their cars. # Because such people rely more on bicycling, walking, and transit than on driving, they tend to focus more of their commerce on locally-owned neighborhood businesses that are convenient for them to reach.

Walkability Walkability is a term for planning concepts best understood by the mixed-use of amenities in high-density neighborhoods where people can access said amenities by foot. It is based on the idea that urban spaces should be more than just transport ...

is a measure of how friendly an area is to

walking Walking (also known as ambulation) is one of the main gaits of terrestrial locomotion among legged animals. Walking is typically slower than running and other gaits. Walking is defined by an ' inverted pendulum' gait in which the body vaults ...

. Walkability has many health, environmental, and economic benefits. However, evaluating walkability is challenging because it requires the consideration of many subjective factors. Factors influencing walkability include the presence or absence and quality of footpaths, sidewalks, 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 Urban design is an approach to the design of buildings and the spaces between them that focuses on specific design processes and outcomes. In addition to designing and shaping the physical features of towns, cities, and regional spaces, urban d ...

. 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 cities. 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.

Notes and references

External links

{{DEFAULTSORT:Urban Sprawl Urbanization Human geography Decentralization Urban studies and planning terminology Environmental terminology Environmental design Sustainable urban planning