Urban sprawl, also known as suburban sprawl, is the spreading of a city and its suburbs over rural land at the fringe of an urban area. South San Jose (cropjpg||thumb|A suburban development in San Jose California.  Residents of sprawling neighborhoods tend to live in single-family homes and commute by automobile to work. Low population density is an indicator of sprawl. Population density (in agriculture standing stock and Standing crop) is a measurement of Population per unit area or unit volume Urban planners emphasize the qualitative aspects of sprawl such as the lack of transportation options and pedestrian friendly neighborhoods. Conservationists tend to focus on the actual amount of land that has been urbanized by sprawl. 
The term urban sprawl generally has negative connotations due to the health and environmental issues that sprawl creates.  Residents of sprawling neighborhoods tend to emit more pollution per person and suffer more traffic fatalities.  Sprawl is controversial, with supporters claiming that consumers prefer lower density neighborhoods and that sprawl does not necessarily increase traffic.  Sprawl is also linked with increased obesity since walking and bicycling are not viable commuting options. Obesity is a condition in which excess Body fat has accumulated to such an extent that health may be negatively affected  Sprawl negatively impacts land and water quantity and quality and may be linked to a decline in social capital. Social capital is a concept in business economics, Organizational behaviour, Political science, Public health, Sociology and natural 
Sprawl is characterized by several land use patterns which usually occur in unison:
This refers to a situation where commercial, residential, and industrial areas are separated from one another. Land use' is also often used to refer to the distinct land use types in Zoning. Within a urban area there is a tendency for land uses to Aggregate. Consequently, large tracts of land are devoted 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 is not practical, so all these activities generally require an automobile (though a bicycle may also be feasible). The bicycle, cycle, or bike is a pedal-driven, human-powered vehicle with two wheels attached to a frame, one behind 
Sprawl consumes much more land than traditional urban developments because new developments are of low density. The exact definition of "low density" is arguable, but a common example is that of single family homes, as opposed to apartments. Buildings usually have fewer stories and are spaced farther apart, separated by lawns, landscaping, roads or parking lots. A lawn is an area of recreational or amenity land planted with grass, and sometimes Clover and other plants which are maintained at a low even height Landscaping refers to any activity that modifies the visible features of an area of land including but not limited to living elements, such as A road is an identifiable route, way or path between two or more places. Parking lot (called a car park in Australia and the UK) is a cleared area that is more or less level and is intended for Parking vehicles Lot sizes are larger, and 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.
Another kind of low-density development is sometimes called leap-frog development. This term refers to the relationship, or lack thereof, between one subdivision and the next. Such developments are typically separated by large green belts, ie tracts of undeveloped land, resulting in an average density far lower even than the low density described in the previous paragraph. A green belt or greenbelt is a policy or land use designation used in Land use planning to retain areas of largely undeveloped wild or agricultural land This is a 20th and 21st century phenomenon generated by the current custom of requiring a developer to provide subdivision infrastructure as a condition of development (DeGrove and Turner, 1991).  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. Local governments are administrative offices that are smaller than a State. Eminent domain ( United States) compulsory purchase ( United Kingdom, New Zealand, Ireland) resumption/compulsory acquisition
Areas of urban sprawl are also characterized as highly dependent on automobiles for transportation, a condition known as automobile dependency. Transport or transportation is the movement of people and goods from one place to another Automobile dependency is a term coined by Professors Peter Newman and Jeff Kenworthy to capture the predicament of most cities in the United States Canada Australia and New Most activities, such as shopping, commuting to work, concerts, etc. Commuting is the process of Travelling between one's place of residence and regular place of work require the use of a car as a result of both the area's isolation from the city and the isolation the area's residential zones have from its industrial and commercial zones. Walking and other methods of transit are not practical; therefore, many of these areas have few or no sidewalks. Walking (also called ambulation) is the main form of Animal Locomotion on land, distinguished from Running and crawling In many suburban communities, even stores and activities that are close by are contrived to be much further, by separating uses with fences, walls, and drainage ditches.
Housing subdivisions are large tracts of land consisting entirely of newly-built residences. Calgary (ˈkælgəriː is the largest city in the Province of Alberta, Canada Alberta (ælˈbɝtə is one of Canada's prairie provinces. It became a province on September 1 1905 Country to "Dominion of Canada" or "Canadian Federation" or anything else please read the Talk Page Subdivision is the act of dividing land into pieces that are easier to sell or otherwise develop usually via a Plat. Duany and Plater-Zyberk claim that housing subdivisions “are sometimes called villages, towns, and neighborhoods by their developers, which is misleading since those terms denote places which are not exclusively residential. ”
Subdivisions often incorporate curved roads and culs-de-sac. "Dead End Street" redirects here For the song by The Kinks see Dead End Street (song. Such 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. (Duany Plater-Zyberk 5, 34)
Shopping centers are locations consisting of retail space. A shopping mall or shopping centre is a building or set of buildings that contain Retail units with interconnecting Walkways enabling visitors In the U. S. and Canada, suburban context these vary from strip malls which refer to collections of buildings sharing a common parking lot, usually built on a high-capacity roadway with commercial functions (i. A strip mall (also called a shopping plaza or mini-mall) is an open area Shopping center where the stores are arranged in a row with a Sidewalk e. , a "strip"). Similar developments in the UK are called Retail Parks. Strip malls/retail parks contain a wide variety of retail and non-retail functions that also cater to daily use (e. g. video rental, takeout food, laundry services, hairdresser). Strip malls consisting mostly of big box stores or category killers are sometimes called "power centers" (USA). Big-box store is a term that refers to a style of physically large Chain store, and by extension to the company behind the store Category killer is a term used in Marketing and Strategic management to describe a product, service, Brand, or company 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. A lifestyle center (or lifestyle centre) is a Shopping center or mixed-used commercial development that combines the traditional retail functions of a Shopping European countries such as France, Belgium and Germany have implemented size restrictions for superstores found in strip malls in an effort to limit sprawl (Davies 1995).
Another prominent form of retail development in areas characterized by "sprawl" is the shopping mall. A shopping mall or shopping centre is a building or set of buildings that contain Retail units with interconnecting Walkways enabling visitors Unlike the strip mall, this is usually comprised of a single building surrounded by a parking lot which contains multiple shops, usually "anchored" by one or more department stores (Gruen and Smith 1960). A department store is a Retail establishment which specializes in selling a wide range of products without a single predominant merchandise line. 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). Until recently, the largest shopping mall in the world was the West Edmonton Mall, while the largest in the United States is the Mall of America. West Edmonton Mall (WEM located in Edmonton, Alberta, Canada is the largest Shopping mall in North America and the fourth largest Mall of America (also MOA, MoA or the Megamall) is a super-regional shopping mall located in the Twin Cities suburb of Bloomington Now, several larger ones have been built and/or are planned in China. Shopping malls are often detrimental to downtown shopping centers of nearby cities since the shopping malls acts as a surrogate for the city center (Crawford 1992). A central business district ( CBD) is the commercial and often geographic heart of a city Some downtowns have responded to this challenge by building shopping centers of their own (Frieden and Sagelyn 1989; consider also Toronto Eaton Centre (1977), Ottawa's Rideau Centre, Boston's Shops at Prudential Center, and Providence's Providence Place). The Toronto Eaton Centre is a large Shopping mall and office complex in downtown Toronto, Ontario Canada, named after the now-defunct Eaton's Ottawa (ˈɒtəwə or sometimes /ˈɒtəwɑː/ is the Capital of Canada and the country's fourth largest municipality. Rideau Centre ( Centre Rideau in French) is a three-level Shopping centre on Rideau Street in downtown Ottawa, Ontario The Shops at Prudential Center is an urban Shopping mall located at the base of the Prudential Tower in Boston, Massachusetts. Providence Place, opened on August 20, 1999, is a modern urban Shopping mall in the central part of Providence Rhode Island, near the Rhode
In the 1970s the Ontario Government created the Ontario Downtown Renewal Programme (ODRP), which helped finance the building of several downtown malls across Ontario. See entry under Eaton Centre. Eaton's, which was once Canada 's largest Department store chain partnered with development companies throughout the 1970s and 1980s to develop downtown The program was created to reverse the tide of small business leaving downtowns for larger sites surrounding the city.
Fast food chains are common in suburban areas. Fast food is the term given to food that can be prepared and served very quickly They are often built early in areas with low property values where the population is about 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). Eric Schlosser (born August 17, 1959) is an award-winning American journalist and Author known for investigative or Muckraking Fast Food Nation The Dark Side of the All-American Meal (2001 is a book by Investigative journalist Eric Schlosser that examines the local and Duany Plater Zyberk & Company believe that this only reinforces a destructive pattern of growth in an endless quest to move away from the sprawl that only results in creating more of it (Duany Plater-Zyberk 26). Duany Plater-Zyberk & Company (DPZ is an architecture and town planning firm founded in 1980 by the husband-and-wife team of Andrés Duany and Elizabeth Plater-Zyberk
According to the National Resources Inventory (NRI), about 8,900 square kilometers (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 kilometers (40,000 square miles) (an area approximately the size of Kentucky) as developed than the Census Bureau classifies as urban. The Commonwealth of Kentucky ( is a state located in the East Central United States of America. The United States Census Bureau (officially Bureau of the Census as defined in Title) is the government agency that is responsible for the United States Census 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 US 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 have expanded geographically even while losing population. But it was not just US urbanized areas 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 Brussels, Belgium; Copenhagen, Denmark; Frankfurt, Germany; Hamburg, Germany; Munich, Germany and Zurich, Switzerland, albeit without the wholesale dismantling of public transit systems that occurred in the United States. Brussels (Bruxelles pronounced; Brussel pronounced) officially the Brussels Capital-Region, is Copenhagen (ˌkəʊpənˈheɪgən ˌkəʊpənˈhɑːgən ˈkəʊpənˌheɪgən ˈkəʊpənˌhɑːgən kʰøb̥ənˈhɑʊ̯ˀn kʰøb̥m̩ˈhɑʊ̯ˀn is the capital and largest city Hamburg (English, German: ˈhambʊɐk local pronunciation Low German / Low Saxon: Hamborg) is the second-largest city in Germany Munich (München; Minga is the capital city of Bavaria, Germany. Zürich (, Zürich German: Züri, Zurich, Zurigo; in English generally Zurich) is the largest city in Switzerland and capital of the
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 "white flight", sustaining population losses. Western Europe at its most general meaning means 'all the countries in the West of Europe ' For a topic outline on this subject see List of basic Japan topics. White flight is a term for the demographic trend in which working and Middle-class White people move away from Suburbs  This trend has slowed somewhat in recent years, as more people have regained an interest in urban living.
The term "Los Angelization" is also sometimes used for urban sprawl, though this may be misleading. Los Angeles was one of the world's first low density urbanized areas, as a result of wide automobile ownership. Automobile ownership is the sum of all the aspects associated with owning an Automobile. However, Los Angeles has become more dense over the past half-century, principally due to small lot zoning and a high demand for housing due to population growth. Los Angeles increased its density to 2240/km² (5,801 per square mile) in 1990. Land consumption per resident in 1990 was 0. 11 acre, which made Los Angeles the most densely populated urbanized area in America. 
The first urban growth boundary in the US was in Fayette County, Kentucky in 1958. Smart growth is an urban planning and transportation theory that concentrates growth in the center of a city to avoid Urban sprawl; and advocates compact Fayette County is a County located in the US state of Kentucky. Fifteen years later, the state of Oregon enacted a law in 1973 limiting the area urban areas could occupy, through urban growth boundaries. Oregon ( is a state in the Pacific Northwest region of the United States. 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). Portland is a city located in the Northwestern United States, near the Confluence of the Willamette and Columbia rivers Smart growth is an urban planning and transportation theory that concentrates growth in the center of a city to avoid Urban sprawl; and advocates compact 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) USA Urbanized Areas 1950-1990 USA Urbanized Areas 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 farm land 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. Greenbelt Alliance is a non-profit land conservation and urban planning organization that has worked in California's nine-county San Francisco Bay Area since 1958
In other areas, the design principles of District Regionalism and New Urbanism have been employed to combat urban sprawl. District Regionalism is an architectural term used to describe the organization of cities in city planning New Urbanism is an American Urban design movement that arose in the early 1980s
Arguments opposing urban sprawl run the gamut from the more concrete effects such as health and environmental issues to more abstract consequences involving neighorhood vitality.
Urban sprawl is associated with a number of negative environmental and public health outcomes. Public health is "the science and art of preventing disease prolonging life and promoting health through the organised efforts and informed choices of society organisations The primary cause of these negative outcomes is that sprawl leads to people having to depend on the automobile because it will be a greater distance to travel and people will not be able to walk or ride their bicycles to their destinations.
However, this is mitigated significantly with nearby development of shopping and recreation areas. Also, many people prefer to live close to their place of business which is increasingly centered less around urban areas. 
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. Public health is "the science and art of preventing disease prolonging life and promoting health through the organised efforts and informed choices of society organisations 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 pollution and carbon emissions than their urban counterparts because of their increased driving. Greenhouse gases are gaseous constituents of the atmosphere bothnatural and anthropogenic that absorb and emit radiation at specific wavelengths within the spectrum of thermal infrared 
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 at greater risk of dying in a car crash. 
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. Hypertension, also referred to as high blood pressure, HTN or HPN, is a medical condition in which the Blood pressure is chronically elevated  Presumably, living in a car centered culture forces inhabitants to drive everywhere, thus walking far less than their urban (and generally healthier) counterparts.
Urban sprawl may be partly responsible for the decline in social capital in the United States. Social capital is a concept in business economics, Organizational behaviour, Political science, Public health, Sociology and natural Compact neighborhoods can foster casual social interactions among neighbors, while low-density sprawl creates barriers to interaction. Sprawl tends to replace public spaces such as parks with private spaces such as fenced-in backyards. Residents of sprawling neighborhoods rarely walk for transportation, which reduces opportunities for face-to-face contact with neighbors. 
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 concrete in the suburbs, rainfall is less effectively absorbed into the ground water aquifers.  This threatens both the quality and quantity of water supplies. Sprawl increases water pollution as rain water picks up gasoline and oil runoff from parking lots and roads. Water pollution is the contamination of Water bodies such as Lakes Rivers Oceans and Groundwater caused by human activities Sprawl fragments the land which increases the risk of invasive species spreading into the remaining forest. Introduced species|Weed Invasive species is a phrase with several definitions
Living in a larger, more spread out space makes public services more expensive. Since car usage often becomes endemic and public transport often becomes significantly more expensive, city planners are forced to build large highway and parking infrastructure, which in turn decreases taxable land and revenue, and decreases the desirability of the area adjacent to such structures. * * * * * * * * * * * * * * * * * * * * * * Before adding any more images to this * * page please do carefully consider * * whether they would be mere decoration * * or actually improve Parking is the act of stopping a Vehicle and leaving it unoccupied for more than a brief time Infrastructure typically refers to the technical structures that support a society such as Roads Water supply, Wastewater, Power grids Providing services such as water, sewers, and electricity is also more expensive per household in less dense areas. 
Residents of low density areas spend a higher proportion of their income on transportation than residents of high density areas.  The RAC estimates that the average cost of operating a car in the UK is £5,000 a year. RAC plc (better known as just the RAC) is a breakdown company in the United Kingdom supplying products and services for motorists In Economics, average cost is equal to total cost divided by the number of goods produced (the output quantity Q  In comparison, a yearly underground ticket for a suburban commuter in London (where wages are higher than the national average) costs £1,000-1,500. The London Underground is a Metro system serving a large part of Greater London and neighbouring areas of Essex, Hertfordshire and Buckinghamshire
Quality of life has been argued to be eroded by lifestyles sprawl promotes. 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. A convenience store is a small store or shop. They are often located alongside busy roads or at gas/petrol stations. 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. (Duany Plater-Zyberk 6, 28). James Howard Kunstler has argued that the poor aesthetics of suburban environments make them "places not worth caring about", and that they lack a sense of history and identity. James Howard Kunstler (born 1948 is an American Author, Social critic, and Blogger who is perhaps best known for his book The Aesthetics or esthetics ( also spelled æsthetics) is commonly known as the study of sensory or sensori-emotional values sometimes called
Some blame suburbs for what they see as a homogeneity of society and culture, leading to sprawling suburban developments of people with similar race, background and socioeconomic status. White flight is a term for the demographic trend in which working and Middle-class White people move away from Suburbs Socioeconomic status (SES is a combined measure of an individual's or family’s economic and social position relative to others based on Income, Education, and  They claim that segregated and stratified development was institutionalized in the early 1950s and 1960s with the financial industries' then-legal process of redlining neighborhoods to prevent certain people from entering and residing in affluent districts. Redlining is the practice of denying or increasing the cost of services such as Banking, Insurance, access to jobs access to health care or even Supermarkets Sprawl may have a negative impact on public schools as finances have been pulled out of city cores and diverted to wealthier suburbs.  They argue that the residential and social segregation of whites from blacks in the United States creates a socialization process that limits whites' chances for developing meaningful relationships with blacks and other minorities, and that the segregation experienced by whites from blacks fosters segregated lifestyles and can lead to positive views about themselves and negative views about blacks. 
The American Institute of Architects recommends 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 American Institute of Architects (AIA is a professional organization for Architects in the United States. Smart growth is an urban planning and transportation theory that concentrates growth in the center of a city to avoid Urban sprawl; and advocates compact Mixed-use development is the practice of allowing more than one type of use in a building or set of buildings  The Sierra Club, the San Francisco Bay Area's Greenbelt Alliance, and other environmental organizations oppose sprawl and support investment in existing communities. Mission statement To explore enjoy and protect the wild places of the earth To practice and promote the responsible use of the earth's ecosystems and resources To educate and Greenbelt Alliance is a non-profit land conservation and urban planning organization that has worked in California's nine-county San Francisco Bay Area since 1958 
Peter Gordon, a professor of planning and economics at the University of Southern California's School of Urban Planning and Development, argues that many households in the United States, Canada, and Australia, especially middle and upper class families, have shown a preference for the suburban lifestyle. Is a concept in Sociology that refers to the group of people at the top of a Social hierarchy. Reasons cited include a preference towards lower-density development (for lower ambient noise and increased privacy), better schools, less crime, and a generally slower lifestyle than the urban one. Those in favor of a "free housing market" also argue that this sort of living situation is an issue of personal choice and economic means.  One suburban Detroit politician defends low-density development as the preferred lifestyle choice of his constituents, calling it ". . . the American Dream unfolding before your eyes. "  Recently however, a number of studies have suggested that many affluent "empty nesters" are heading back towards the inner city areas to "downsize" their housing and take advantage of the increased cultural offerings that such areas often have to offer.  In many other cities across the Western world, evidence of this trend can be found in geographic patterns of property values, where the highest prices are increasingly commanded in higher-density, inner-urban areas, reflecting their desirability as places to live for people with the finances to make a free choice.
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. Air pollution is the human introduction into the atmosphere of Chemicals Particulate matter, or Biological materials that cause harm or discomfort (See 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. Kansas City Missouri only Items for the metro area Kansas City Kansas or North Kansas City MO should go on their respective pages ' Real estate pricing deals with the valuation (finance and there are three main methods appraisals with comparable properties capitalization rate comparisons with similar Wendell Cox and Randal O'Toole are the leading figures supporting lower density development. Wendell Cox is an international public policy consultant He is the principal (and sole owner of Wendell Cox Consultancy (Demographia based in the St Randal O'Toole is an American Economist and Public policy analyst
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.  More recent data suggests that this trend has reversed, with the 2000 U. S. Census showing commute times increased over all previous periods. 
There is also some concern that Portland-style 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.  Another report suggests that zoning and other land use controls play the dominant role in making housing expensive. 
In Australia, it is claimed that 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 was being debated between the major political parties in the lead up to the Australian federal election. 
There are some sociologists such as Durkheim who suggest there is a link between population density and the number of rules that must be imposed. The theory goes that as people are moved closer together geographically their actions are more likely to noticeably impact others around them. This potential impact requires the creation of additional social or legal rules to prevent conflict. A simple example would be as houses become closer together the acceptable maximum volume of music decreases, as it becomes intrusive to other residents. 
There have been numerous studies that 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 a social animal, need significant amounts of social space or they become agitated and aggressive.