Smart growth

From Wikipedia, the free encyclopedia

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 schools, complete streets, and mixed-use development with a range of housing choices. The term "smart growth" is particularly used in North America. In Europe and particularly the UK, the terms "compact city", "urban densification" or "urban intensification" have often been used to describe similar concepts, which have influenced government planning policies in the UK, the Netherlands and several other European countries. 

Smart growth values long-range, regional considerations of sustainability over a short-term focus. Its sustainable development goals are to achieve a unique sense of community and place; expand the range of transportation, employment, and housing choices; equitably distribute the costs and benefits of development; preserve and enhance natural and cultural resources; and promote public health.

Basic concept

Smart Growth is a theory of land development that accepts that growth and development will continue to occur, and so seeks to direct that growth in an intentional, comprehensive way. Its proponents include urban planners, architects, developers, community activists, and historic preservationists. The term "Smart Growth" is an attempt to reframe the conversation from "growth" versus "no growth" (or NIMBY) to good/smart growth versus bad/dumb growth. Proponents seek to distinguish Smart Growth from urban sprawl which they claim causes most of the problems that fuel opposition to urban growth, such as traffic congestion and environmental degradation. Smart growth principles are directed at developing sustainable communities that provide a greater range of transportation and housing choices and prioritize infill and redevelopment in existing communities rather than development of "greenfield" farmland or natural lands. Some of the fundamental aims for the benefits of residents and the communities are increasing family income and wealth, providing safe walking routes to schools, fostering livable, safe and healthy places, stimulating economic activity (both locally and regionally), and developing, preserving and investing in built and natural resources. Smart growth "principles" describe the elements of community that are envisioned and smart growth "regulations" describe the various approaches to implementation, that is, how federal, state, and municipal governments choose to fulfill smart growth principles. Some of these regulatory approaches such as Urban Growth Boundaries predate the use of the term Smart Growth. One of the earliest efforts to establish smart growth forward as an explicit regulatory framework were put forth by the American Planning Association. In 1997, the APA introduced a project called Growing Smart and published "Growing Smart Legislative Guidebook: Model Statutes for Planning and the Management of Change." The U.S. Environmental Protection Agency defines smart growth as “development that serves the economy, the community, and the environment. It changes the terms of the development debate away from the traditional growth/no growth question to how and where should new development be accommodated” 

Smart growth is related to, or may be used in combination with the following concepts:

• New Urbanism
• Growth management
• New Community Design
• Sustainable Development
• Resource Stewardship
• Land Preservation
• Preventing urban sprawl
• Creating sense of place
• Development Best Practices
• Preservation Development
• Sustainable transport
• Triple Bottom Line (TBL) Accounting - People, Planet, Profit
• The Three Pillars - Human, Natural, and Created Capital

The smart growth approach to development is multifaceted and can encompass a variety of techniques. For example, in the state of Massachusetts smart growth is enacted by a combination of techniques including increasing housing density along transit nodes, conserving farm land, and mixing residential and commercial use areas. Perhaps the most descriptive term to characterize this concept is Traditional Neighborhood Development, which recognizes that smart growth and related concepts are not necessarily new, but are a response to car culture and sprawl. Many favor the term New Urbanism, which invokes a new, but traditional way of looking at urban planning. 

There are a range of best practices associated with smart growth, these include: supporting existing communities, redeveloping underutilized sites, enhancing economic competitiveness, providing more transportation choices, developing livability measures and tools, promoting equitable and affordable housing, providing a vision for sustainable growth, enhancing integrated planning and investment, aligning, coordinating, and leveraging government policies, redefining housing affordability and making the development process transparent.

Related, but somewhat different, are the overarching goals of smart growth, and they include: making the community more competitive for new businesses, providing alternative places to shop, work, and play, creating a better "Sense of Place," providing jobs for residents, increasing property values, improving quality of life, expanding the tax base, preserving open space, controlling growth, and improving safety.

Basic principles

There are 10 accepted principles that define smart growth:

1. Create a range of employment opportunities.
2. Mix land uses
3. Take advantage of compact building design.
4. Create walkable neighborhoods and a range of housing opportunities and choices
5. Foster distinctive, attractive communities with a strong sense of place
6. Preserve open space, farmland, natural beauty, and critical environmental areas
7. Strengthen and direct development towards existing communities
8. Provide in advance a variety of transportation choices, urban and social infrastructure based on population projections
9. Make development decisions sustainable, predictable, fair, and cost effective
10. Encourage community and stakeholder collaboration in development decisions

History

Transportation and community planners began to promote the idea of compact cities and communities and adopt many of the regulatory approaches associated with Smart Growth in the early 1970s. The cost and difficulty of acquiring land (particularly in historic and/or areas designated as conservancies) to build and widen highways caused some politicians to reconsider basing transportation planning on motor vehicles. 

The Congress for the New Urbanism, with architect Peter Calthorpe, promoted and popularized the idea of urban villages that relied on public transportation, bicycling, and walking instead of automobile use. Architect Andrés Duany promoted changing design codes to promote a sense of community, and to discourage driving. Colin Buchanan and Stephen Plowden helped to lead the debate in the United Kingdom. 

The Local Government Commission which presents the annual New Partners for Smart Growth conference adopted the original Ahwahnee Principles in 1991 which articulates many of the major principles now generally accepted as part of smart growth movement such as Transit oriented development, a focus on walking distance, greenbelts and wildlife corridors, and infill and redevelopment. The document was co-authored by several of the founders of the New Urbanist movement. The Local Government Commission has been co-sponsoring Smart Growth related conferences since 1997. The New Partners for Smart Growth Conference started under that name circa 2002.

Smart Growth America, an organization devoted to the promoting Smart Growth in the United States, was founded in 2002. This organization leads an evolving coalition of national and regional organizations most of which predated its founding such as 1000 Friends of Oregon founded in 1975 and the Congress for the New Urbanism founded in 1993. The EPA launched its smart growth program in 1995.

Rationale for smart growth

Smart growth is an alternative to urban sprawl, traffic congestion, disconnected neighborhoods, and urban decay. Its principles challenge old assumptions in urban planning, such as the value of detached houses and automobile use.

Environmental protection

Environmentalists promote smart growth by advocating urban-growth boundaries, or Green belts, as they have been termed in England since the 1930s.

Public health

Transit-oriented development can improve the quality of life and encourage a healthier, pedestrian-based lifestyle with less pollution. The United States Environmental Protection Agency suggests Smart growth to reduce air pollution, improve water quality, and reduce greenhouse gas emissions.

Reaction to existing subsidies

Smart Growth advocates claim that much of the urban sprawl of the 20th Century was due to government subsidies for infrastructure that redistribute the true costs of sprawl. Examples include subsidies for highway building, fossil fuels, and electricity.

Electrical subsidies

With electricity, there is a cost associated with extending and maintaining the service delivery system, as with water and sewage, but there also is a loss in the commodity being delivered. The farther from the generator, the more power is lost in distribution. According to the Department of Energy's (DOE) Energy Information Administration (EIA), 9 percent of energy is lost in transmission. Current average cost pricing, where customers pay the same price per unit of power regardless of the true cost of their service, subsidizes sprawl development. With electricity deregulation, some states now charge customers/developers fees for extending distribution to new locations rather than rolling such costs into utility rates.

New Jersey, for example, has implemented a plan that divides the state into five planning areas, some of which are designated for growth, while others are protected. The state is developing a series of incentives to coax local governments into changing zoning laws that will be compatible with the state plan. The New Jersey Board of Public Utilities recently proposed a revised rule that presents a tiered approach to utility financing. In areas not designated for growth, utilities and their ratepayers are forbidden to cover the costs of extending utility lines to new developments—and developers will be required to pay the full cost of public utility infrastructure. In designated growth areas that have local smart plans endorsed by the State Planning Commission, developers will be refunded the cost of extending utility lines to new developments at two times the rate of the revenue received by developers in smart growth areas that do not have approved plans.

Elements

Growth is "smart growth", to the extent that it includes the elements listed below.

Compact neighborhoods

Compact, livable urban neighborhoods attract more people and business. Creating such neighborhoods is a critical element of reducing urban sprawl and protecting the climate. Such a tactic includes adopting redevelopment strategies and zoning policies that channel housing and job growth into urban centers and neighborhood business districts, to create compact, walkable, and bike- and transit-friendly hubs. This sometimes requires local governmental bodies to implement code changes that allow increased height and density downtown and regulations that not only eliminate minimum parking requirements for new development but establish a maximum number of allowed spaces. Other topics fall under this concept:

• mixed-use development
• inclusion of affordable housing
• restrictions or limitations on suburban design forms (e.g., detached houses on individual lots, strip malls and surface parking lots)
• inclusion of parks and recreation areas

In sustainable architecture the recent movements of New Urbanism and New Classical Architecture promote a sustainable approach towards construction, that appreciates and develops smart growth, architectural tradition and classical design. This in contrast to modernist and globally uniform architecture, as well as leaning against solitary housing estates and suburban sprawl. Both trends started in the 1980s.

Transit-oriented development

Transit-oriented development (TOD) is a residential or commercial area designed to maximize access to public transport, and mixed-use/compact neighborhoods tend to use transit at all times of the day. Many cities striving to implement better TOD strategies seek to secure funding to create new public transportation infrastructure and improve existing services. Other measures might include regional cooperation to increase efficiency and expand services, and moving buses and trains more frequently through high-use areas. Other topics fall under this concept:

• Transportation Demand Management measures
• road pricing system (tolling)
• commercial parking taxes

Pedestrian- and bicycle-friendly design

Biking and walking instead of driving can reduce emissions, save money on fuel and maintenance, and foster a healthier population. Pedestrian- and bicycle-friendly improvements include bike lanes on main streets, an urban bike-trail system, bike parking, pedestrian crossings, and associated master plans. The most pedestrian- and bike-friendly variant of smart growth and New Urbanism is New Pedestrianism because motor vehicles are on a separate grid.

Others

• Preserving open space and critical habitat, reusing land, and protecting water supplies and air quality
• Transparent, predictable, fair and cost-effective rules for development
• Historic preservation
• Setting aside large areas where development is prohibited, nature is able to run its course, providing fresh air and clean water.
• Expansion around already existing areas allows public services to be located where people are living without taking away from the core city neighborhoods in large urban areas.
• Developing around preexisting areas decreases the socioeconomic segregation allowing society to function more equitably, generating a tax base for housing, educational and employment programs.

Policy tools

Zoning ordinances

The most widely used tool for achieving smart growth is modification of local zoning laws. Zoning laws are applicable to most cities and counties in the United States. Smart Growth advocates often seek to modify zoning ordinances to increase the density of development and redevelopment allowed in or near existing towns and neighborhoods and/or restrict new development in outlying or environmentally sensitive areas. Additional density incentives can be offered for development of brownfield and greyfield land or for providing amenities such as parks and open space. Zoning ordinances typically include minimum parking requirements. Reductions in or elimination of parking minimums or imposition of parking maximums can also reduce the amount of parking built with new development increasing land available for parks and other community amenities.

Urban growth boundaries

Related to zoning ordinances, an Urban Growth Boundary (UGB) is a tool that used in some U.S. cities to contain high density development to certain areas. The first urban growth boundary in the United States was established in 1958 in Kentucky. Subsequently, urban growth boundaries were established in Oregon in the 1970s and Florida in the 1980s. Some believe that UGBs contributed to the escalation of housing prices from 2000 to 2006, as they limited the supply of developable land. However, this is not completely substantiated because prices continued to rise even after municipalities expanded their growth boundaries.

Transfer of development rights

Transfer of development rights (TDR) systems are intended to allow property owners in areas deemed desirable for growth (such as infill and brownfield sites) to purchase the right to build at higher densities from owners of properties in areas deemed undesirable for growth such as environmental lands, farmlands or lands outside of an urban growth boundary. TDR programs have been implemented in over 200 U.S. communities.

Provision of social infrastructure

Systematic provision of infrastructure such as schools, libraries, sporting facilities and community facilities is an integral component of smart growth communities. This is commonly known as 'social infrastructure' or 'community infrastructure'. In Australia, for example, most new suburban developments are master planned, and key social infrastructure is planned at the outset.

Environmental impact assessments

One popular approach to assist in smart growth in democratic countries is for lawmakers to require prospective developers to prepare environmental impact assessments of their plans as a condition for state and/or local governments to give them permission to build their buildings. These reports often indicate how significant impacts generated by the development will be mitigated, the cost of which is usually paid by the developer. These assessments are frequently controversial. Conservationists, neighborhood advocacy groups and NIMBYs are often skeptical about such impact reports, even when they are prepared by independent agencies and subsequently approved by the decision makers rather than the promoters. Conversely, developers will sometimes strongly resist being required to implement the mitigation measures required by the local government as they may be quite costly. 

In communities practicing these smart growth policies, developers comply with local codes and requirements. Consequently, developer compliance builds communal trust because it demonstrates a genuine interest in the environmental quality of the community.

Communities implementing smart growth

The United States Environmental Protection Agency has recognized these cities for implementing smart growth principles:

• Arlington, Virginia
• Minneapolis and Saint Paul, Minnesota
• Davidson, North Carolina
• Denver, Colorado

The smart growth Network has recognized these U.S. cities for implementing smart growth principles:

• The Kentlands; Gaithersburg, Maryland (for live-work units)
• East Liberty; Pittsburgh, Pennsylvania (establishing downtown retail)
• Moore Square Museums Magnet Middle School; Raleigh, North Carolina (for being located downtown)
• Garfield Park; Chicago, Illinois(retaining transit options)
• Murphy Park; St. Louis, Missouri (bringing the features of suburban living to the city)
• Pine Barrens, Southern New Jersey (for transfer of development rights away from undeveloped land)
• Chesterfield Township, New Jersey (for township wide transfer of development rights away from forest and farmland and development of the several hundred acre New Urbanism community of Old York Village.

In July 2011, The Atlantic magazine called the BeltLine, a series of housing, trail, and transit projects along a 22-mile (35-km) long disused rail corridor surrounding the core of Atlanta, the United States' "most ambitious smart growth project".

In Savannah, Georgia (US) the historic Oglethorpe Plan has been shown to contain most of the elements of smart growth in its network of wards, each of which has a central civic square. The plan has demonstrated its resilience to changing conditions, and the city is using the plan as a model for growth in newer areas.

In Melbourne, Australia, almost all new outer-suburban developments are master planned, guided by the principles of smart growth.

Smart growth, urban sprawl and automobile dependency

Whether smart growth (or the 'Compact City') does or can reduce problems of automobile dependency associated with urban sprawl have been fiercely contested issues over several decades. A 2007 meta-study by Keith Barthomomew of the University of Utah found that reductions in driving associated with compact development scenarios averaged 8 percent ranging up to 31.7 percent with the variation being explained by degree of land use mixing and density. 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 behaviour. More recent studies using more sophisticated methodologies have generally refuted these findings: density, land use and public transport accessibility can influence travel behaviour, although social and economic factors, particularly household income, usually exert a stronger influence.

Paradox of intensification

Reviewing the evidence on urban intensification, smart growth and their effects on travel behaviour Melia et al. (2011) found support for the arguments of both supporters and opponents of smart growth. Planning policies which 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.

For example, Portland, Oregon a U.S. city which has pursued smart growth policies, substantially increased its population density between 1990 and 2000 when other US cities of a similar size were reducing in density. As predicted by the paradox, traffic volumes and congestion both increased more rapidly than in the other cities, despite a substantial increase in transit use.

These findings led them to propose the paradox of intensification, which states "Ceteris paribus, urban intensification which increases population density will reduce per capita car use, with benefits to the global environment, but will also increase concentrations of motor traffic, worsening the local environment in those locations where it occurs". 

At the citywide level it may be possible, through a range of positive measures to counteract the increases in traffic and congestion which would otherwise result from increasing population densities: Freiburg im Breisgau in Germany is one example of a city which has been more successful in this respect.

This study also reviewed evidence on the local effects of building at higher densities. At the level of the neighbourhood or individual development positive measures (e.g. improvements to public transport) will usually be insufficient to counteract the traffic effect of increasing population density. This leaves policy-makers with four choices: intensify and accept the local consequences, sprawl and accept the wider consequences, a compromise with some element of both, or intensify accompanied by more radical measures such as parking restrictions, closing roads to traffic and carfree zones. 

In contrast the City of Cambridge, Massachusetts reported that its Kendall Square Neighborhood saw a 40% increase in commercial space attended by a traffic decrease of 14%.

A report by CEOs for Cities report, "Driven Apart," showed that while denser cities in the United States may have more congested commutes they are also shorter on average in both time and distance. This is in contrast to cities where commuters face less congestion but drive longer distances resulting in commutes that take as long or longer.

Proponents

• Edward L. Glaeser
• Rollin Stanley

Criticism

Robert Bruegmann, professor of art history, architecture, and urban planning at the University of Illinois at Chicago and author of Sprawl: A Compact History, stated that historical attempts to combat urban sprawl have failed, and that the high population density of Los Angeles, currently the most dense urban area in the United States, "lies at the root of many of the woes experienced by L.A. today."

Wendell Cox is a vocal opponent of smart growth policies. He argued before the United States Senate Committee on Environment and Public Works that, "smart growth strategies tend to intensify the very problems they are purported to solve." Cox and Joshua Utt analyzed smart growth and sprawl, and argued that:

Our analysis indicates that the Current Urban Planning Assumptions are of virtually no value in predicting local government expenditures per capita. The lowest local government expenditures per capita are not in the higher density, slower growing, and older municipalities.
On the contrary, the actual data indicate that the lowest expenditures per capita tend to be in medium- and lower-density municipalities (though not the lowest density); medium- and faster-growing municipalities; and newer municipalities. This is after 50 years of unprecedented urban decentralization, which seems to be more than enough time to have developed the purported urban sprawl-related higher local government expenditures. It seems unlikely that the higher expenditures that did not develop due to sprawl in the last 50 years will evolve in the next 20 year, despite predictions to the contrary in The Costs of Sprawl 2000 research.
It seems much more likely that the differences in municipal expenditures per capita are the result of political, rather than economic factors, especially the influence of special interests.

The phrase "smart growth" implies that other growth and development theories are not "smart". There is debate about whether transit-proximate development constitutes smart growth when it is not transit-oriented. The National Motorists Association does not object to smart growth as a whole, but strongly objects to traffic calming, which is intended to reduce automobile accidents and fatalities, but may also reduce automobile usage and increase alternate forms of public transportation.

In 2002 the National Center for Public Policy Research, a self-described conservative think tank, published an economic study entitled "Smart Growth and Its Effects on Housing Markets: The New Segregation" which termed smart growth "restricted growth" and suggested that smart growth policies disfavor minorities and the poor by driving up housing prices.

Some libertarian groups, such as the Cato Institute, criticize smart growth on the grounds that it leads to greatly increased land values, and people with average incomes can no longer afford to buy detached houses.

A number of ecological economists claim that industrial civilization has already "overshot" the carrying capacity of the Earth, and "smart growth" is mostly an illusion. Instead, a steady state economy would be needed to bring human societies back into a necessary balance with the ability of the ecosystem to sustain humans (and other species).

A study released in November 2009 characterized the smart-growth policies in the U.S. state of Maryland as a failure, concluding that "[t]here is no evidence after ten years that [smart-growth laws] have had any effect on development patterns." Factors include a lack of incentives for builders to redevelop older neighborhoods and limits on the ability of state planners to force local jurisdictions to approve high-density developments in "smart-growth" areas. Buyers demand low-density development and because voters tend to oppose high density developments near them.

Beginning in 2010, groups generally associated with the Tea Party movement began to identify Smart Growth as an outgrowth of the United Nations Agenda 21 which they viewed as an attempt by international interests to force a "sustainable" lifestyle on the United States. However planning groups and even some smart growth opponents counter that Smart Growth concepts and groups predate the 1992 Agenda 21 conference. In addition the word "sustainable development" as used in the Agenda 21 report is often misread to mean real estate development when it typically refers to the much broader concept of human development in the United Nations and foreign aid context which addresses a broader slate of economic, health, poverty, and education issues.

Urban sprawl

From Wikipedia, the free encyclopedia

Measures for urban sprawl in Europe: upper left the Dispersion of the built-up area (DIS), upper right the Weighted urban proliferation (WUP)

 

View of suburban development in the Phoenix metropolitan area

 

Urban sprawl or suburban sprawl mainly refers to the unrestricted growth in many urban areas of housing, commercial development, and roads over large expanses of land, with little concern for urban planning. In addition to describing a particular form of urbanization, the term also relates to the social and environmental consequences associated with this development. In Continental Europe the term "peri-urbanisation" is often used to denote similar dynamics and phenomena, although 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 only with the average number of residential units per acre in a given area. But others associate it with decentralization (spread of population without a well-defined centre), discontinuity (leapfrog 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 attacked on aesthetic grounds. Due to the pejorative meaning of the term, few openly support urban sprawl as such. The term has become a rallying cry for managing urban growth.

Definition

The term "urban sprawl" was first used in an article in The Times in 1955 as a negative comment on the state of London's outskirts. Definitions of sprawl vary; researchers in the field acknowledge that the term lacks precision. 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 [an] unplanned and uneven pattern of growth, driven by multitude of processes and leading to inefficient resource utilization."

This picture shows the metropolitan areas of the Northeast Megalopolis of the United States demonstrating urban sprawl, including far-flung suburbs and exurbs illuminated at night.

 

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 leapfrog 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 "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.

Despite its world-famous reputation for urban sprawl and car culture, paradoxically, the Los Angeles metropolitan area is the densest in the United States.

 

Metropolitan Los Angeles for example, despite popular notions of being a sprawling city, is the densest metropolitan region in the US, being denser than the New York metropolitan area and the San Francisco Bay Area. Essentially, 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 cities such as New York, San Francisco or Chicago which have extremely compact, high-density cores but are surrounded by large areas of extremely low density.

The international cases of sprawl often draw into question the definition of the term and what conditions are necessary for urban growth to be considered sprawl. Metropolitan regions such Greater Mexico City, Delhi National Capital Region and Beijing, are often regarded as sprawling despite being relatively dense and mixed use.

Examples

According to the National Resources Inventory (NRI), about 8,900 square kilometres (2.2 million acres) of land in the United States was developed between 1992 and 2002. Presently, the NRI classifies approximately 100,000 more square kilometres (40,000 square miles) (an area approximately the size of Kentucky) 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 urban areas 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, the Netherlands; Brussels, Belgium; Copenhagen, Denmark; Frankfurt, Hamburg and Munich, Germany; and Zurich, Switzerland, albeit without the dismantling of infrastructure that occurred in the United States.

Characteristics

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

Traffic congestion in sprawling São Paulo, Brazil, which, according to Time magazine, has the world's worst traffic jams.

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 uses are mixed together is often used as an indicator of sprawl in studies of the subject.

Job sprawl and spatial mismatch

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 is related to job sprawl and economic environmental justice. 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 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 has published multiple articles on the topic. In 2005, author Michael Stoll defined job sprawl simply as jobs located more than 5-mile (8.0 km) 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 35-mile (56 km) radius around the CBD: 3 miles (4.8 km) or less, 3 to 10 miles (16 km), and 10 to 35 miles (56 km). 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 is often characterized as consisting of low-density development. The exact definition of "low density" is arguable, but a common example is that of single family homes on large lots. Buildings usually have fewer stories and are spaced farther apart, separated by lawns, landscaping, roads or parking lots. Specific measurements of what constitutes low-density is culturally relative; for example, in the United States 2–4 houses per acre might be considered low-density while in the UK 8–12 would still be considered low-density. Because more automobiles are used 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 development". This term refers to the relationship, or lack thereof, between subdivisions. Such developments are typically separated by large green belts, i.e. tracts of undeveloped land, resulting in an average 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 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.

Conversion of agricultural land to urban use

Land for sprawl is often taken from fertile agricultural lands, 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 exempting like-kind exchanges from capital gains tax; 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

Sprawl in Milton, Ontario. This photograph is an example of Canadian suburban development.

 

Housing subdivisions are large tracts of land consisting entirely of newly built residences. New Urbanist architectural firm Duany Plater-Zyberk & Company claim 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

Because the advent of sprawl meant more land for lower costs, home owners had more land at their disposal, and the development of the residential lawn after the Second World War became commonplace in suburbs, notably, but not exclusively in North America. The creation in the early 20th century of country clubs and golf courses completed the rise of lawn culture in the United States. Lawns now take up a significant amount of land in suburban developments, contributing in no small part 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, 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 stores 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; entailing investments in common areas and facilities (plazas, cafes) and shifting tenancy from daily goods to recreational shopping. 

Walmart Supercenter in Luray, Virginia.

 

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 department stores (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 a million square feet (ca. 100,000 m²). 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, 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.

Effects

Environmental

Urban sprawl is associated with a number of negative environmental outcomes. 

One of the major environmental problems associated with sprawl is land loss, habitat loss and subsequent reduction in biodiversity. 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 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 surfaces for roads and parking
• increased temperatures from heat islands, which leads to a significantly increased risk of mortality in elderly populations.

The urban sprawl of Melbourne.

 

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., "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) in the suburbs, rainfall is less effectively absorbed into the groundwater aquifers. 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 runoff from parking lots and roads. 

The Chicago metro area, nicknamed "Chicagoland".

 

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, and increased driving leads to vehicle emissions that contribute to air pollution and its attendant negative impacts on human health. 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, and hypertension.

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.

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.

Increased infrastructure/transportation costs

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, sewers, and electricity is also more expensive per household in less dense areas, given that sprawl increases lengths of power lines 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, which, assuming a citizen commutes every day of the year, with a ticket cost for a train at 3 pounds, every year a citizen would spend 1095 pounds on commuting to work, however; the RAC estimates that the average cost of operating a car in the UK is £5,000 a year, which means that urban sprawl would cause an economic loss of 3905 pounds per year, per person through cars alone. 

Major cities – per capita petrol use vs. population 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. 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.

Debate

Rural neighborhoods in Morrisville, North Carolina are rapidly developing into affluent, urbanized neighborhoods and subdivisions. The two images above are on opposite sides of the same street.

 

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 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.

Groups that oppose sprawl

The American Institute of Architects and the American Planning Association recommend against sprawl and instead endorses smart, 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, 1000 Friends of Oregon and counterpart organizations nationwide, and other environmental organizations oppose sprawl and support investment in existing communities. NumbersUSA, a national organization advocating immigration reduction, also opposes urban sprawl, and its executive director, Roy Beck, 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 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 "The principle of consumer sovereignty has played a powerful role in the increase in America’s wealth and in the welfare of its citizens. Producers (including developers) have responded rapidly to households’ demands. It is a giant step backward to interfere with this effective process unless the benefits of intervention substantially exceed its cost." 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.A.) subsidized in a variety of ways, consumers' professed preferences for this type of living may be over-stated.

Automobile dependency

A majority of Californians live, commute, and work in the vast and extensive web of Southern California freeways.

 

Whether urban sprawl does increase problems of automobile dependency and whether conversely, policies of smart growth can reduce them 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 behaviour. More recent studies using more sophisticated methodologies have generally refuted these findings: density, land use and public transport accessibility can influence travel behaviour, 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.

Paradox of intensification

Reviewing the evidence on urban intensification, smart growth and their effects on travel behaviour Melia et al. (2011) found support for the arguments of both supporters and opponents of smart growth 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: 

Ceteris paribus, urban intensification which increases population density will reduce per capita car use, with benefits to the global environment, but will also increase concentrations of motor traffic, worsening the local environment in those locations where it occurs.

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 or road pricing) 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 first proposed by the London County Council in 1935.

 

Starting in the early 20th century, environmentalist opposition to urban sprawl began to coalesce, with roots in the garden city movement, as well as pressure from campaign groups such as the Campaign to Protect Rural England (CPRE). 

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.

Contemporary anti-sprawl initiatives

The term 'smart growth' has been particularly used in North America. The terms 'compact city' or 'urban intensification' are often used to describe similar concepts in Europe and particularly the UK where it has influenced government policy and planning practice in recent years. 

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). While 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. 

Many parts of the San Francisco Bay Area have 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 District Regionalism and 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. 

While 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 where bicycle use is high are thriving. Bicycles and transit are contributing in two important ways toward the success of businesses:

• First, is that on average the people living the closest to these business districts have more money to spend locally because they don't spend as much on their cars.
• Second, because these 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 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 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.