Urban Sprawl

Urban sprawl refers to the expansion of poorly planned, low-density, auto-dependent development, which spreads out over large amounts of land, putting long distances between homes, stores, and work and creating a high segregation between residential and commercial uses with harmful impacts on the people living in these areas and the ecosystems and wildlife that have been displaced. Although some would argue that urban sprawl has its benefits, such as creating local economic growth, urban sprawl has many negative consequences for residents and the environment, such as higher water and air pollution, increased traffic fatalities and jams, loss of agricultural capacity, increased car dependency, higher taxes, increased runoff into rivers and lakes, harmful effects on human health, including higher rates of obesity, high blood pressure, hypertension and chronic diseases, increased flooding, decrease in social capital and loss of natural habitats, wildlife and open space. In its path, urban sprawl consumes immeasurable acres of forests, farmland, woodlands and wetlands and in its wake, leaves vacant storefronts, boarded up houses, closed businesses, abandoned and usually contaminated industrial sites, and traffic congestion, which can stretch miles from urban centers and is creating a hidden debt of unfunded infrastructure and services, urban decay, social dysfunction, and environmental degradation. Learn more.

Explore Smart Growth America: Measuring Sprawl and Its Impact: "In this first-of-its-kind study, the product of three years of research, the authors define, measure and evaluate metropolitan sprawl and its impacts and create an impact based on four factors: residential density, neighborhood mix of uses, strength of activity centers and downtowns, and accessibility of the street network."

According to the report, “Federal involvement in real estate: A call for examination,” by the nonprofit Smart Growth America, each year the federal government spends about $450 billion in subsidies to create an incentive for suburban sprawl and redistribute income from the poor to the rich. Learn more.

Effects of Urban Sprawl

Increased Air Pollution - Urban sprawl increases car and truck traffic by creating longer and more frequent commutes, which leads to a major increase in air pollution and ground-level smog. Vehicles are the number one cause of air pollution in many urban areas with serious implications for public, wildlife and ecosystem health. According to the Union of Concerned Scientists, "Poor air quality increases respiratory ailments like asthma and bronchitis, heightens the risk of life-threatening conditions like cancer, and burdens our health care system with substantial medical costs." As Americans spend the equivalent of 55 eight-hour workdays behind the wheel every year and urban areas continue to sprawl, more time is spent in cars and more traffic congestion occurs over a larger area, which contributes to the growing emissions of greenhouse gases and the continued degradation of air quality in urban areas. Cars, trucks and buses are the biggest source of cancer-causing air pollution, spewing more than 12 billion pounds of toxic chemicals each year, or almost 50 pounds per person. Discover the Effects of Cars, Trucks and Air Pollution

Increased Water Pollution - Urban sprawl increases water pollution as rain water picks up gasoline, lawn chemicals, heavy metals, paints spills, motor oil, pet wastes, construction site erosion and other pollutants in runoff from lawns, driveways, roads and parking lots, which can eventually travel in large, concentrated amounts, polluting nearby water sources, such as a stream, river or lake. Furthermore, air pollution eventually falls out to become water pollution, such as nitrogen and other chemical contaminants, which harm both the air and the water. For example, in the Chesapeake Bay, up to one-third of the nitrogen that pollutes the Bay and its rivers comes from the air. Runoff pollution affects about 40% of the surveyed rivers, lakes, and estuaries in the U.S. and is now the nation's leading threat to water quality. Each year more than 100,000 acres of wetlands, which are nature's water filters, capable of removing up to 90% of the pollutants in water, are destroyed, in large part to urban sprawl. Consequently, wetland destruction by sprawling new developments leads directly to polluted water. Learn More About Water Pollution

Increased Water Consumption - Urban sprawl can create water distribution issues and lead to water over-consumption as more water is consumed for lawn watering and other landscape activities, which can strain and deplete local water supply systems. According to the EPA, "An American family of four can use 400 gallons of water per day, and about 30 percent of that is devoted to outdoor uses. More than half of that outdoor water is used for watering lawns and gardens. Nationwide, landscape irrigation is estimated to account for almost one-third of all residential water use, totaling more than 7 billion gallons per day. Other residential outdoor uses include washing automobiles, maintaining swimming pools, and cleaning sidewalks and driveways." Discover 'Urban Sprawl: Impacts on Urban Water Use'

Degraded Human Health - Poor community design, such as poorly planned, low-density, auto-dependent development, makes it more difficult for people to get physical activity and maintain a healthy weight. There is a clear correlation between urban sprawl and the epidemic levels of obesity and increase of chronic diseases associated with physical inactivity. A Smart Growth America study compared the county sprawl index to the health characteristics of more than 200,000 individuals living in the 448 counties and found that people living in counties marked by sprawling development are likely to walk and bike less, weigh more, drive more, have a higher body mass index (BMI) and suffer more from hypertension (i.e. high blood pressure) than people who live in less sprawling counties. The odds of having hypertension, or high blood pressure, are six percent higher for every 50- point increase in the degree of sprawl and physical inactivity and being overweight are factors in over 200,000 premature deaths each year. The increase of air pollutants from urban sprawl, such as nitrogen oxide, hydrocarbons, ozone and particulate matter, increases respiratory ailments like asthma and bronchitis and heightens the risk of life-threatening conditions like cancer. Furthermore, sprawling dark roadways and rooftops expands the heat island effect by effectively absorbing more heat from the sun and reradiating it as thermal infrared radiation, which increases day and night time temperatures and compromises human health and comfort. Higher air pollution levels and warmer days and nights contribute to general discomfort, respiratory difficulties, non-fatal heat strokes, heat cramps and exhaustion and heat related mortality. The National Oceanic and Atmospheric Administration reports that heat is usually more deadly in the U.S. and typically kills more people each year than hurricanes, tornadoes, floods and lightning put together. Learn more.

Wasted Tax Money and Crowded Schools - Instead of improving existing communities, U.S. tax money subsidizes new sprawling developments and communities, costing counties and cities millions of dollars for new schools, water and sewer lines and increased fire and police protection, which forces higher taxes on existing residents. As homes and businesses spread out farther apart, the costs of providing community services increase, forcing local governments to provide for widely spaced services and residents of these communities to subsidize them with higher taxes at the local, state and federal level. Moreover, according to the Sierra Club, "Sprawl creates crowded schools in the suburbs and empty, crumbling schools in center cities. New development puts more children in suburban schools, but does not pay for the new schools that inevitably must be built. According to Florida's Department of Education, 17,738 temporary or trailer classrooms are currently in use in that state, and a report by the Conference Board claims that 20 percent of school kids in California learn in temporary classrooms." Learn more.

Loss in Open Space, Parks, Farmland and Wildlife Habitats - Urban sprawl threatens productive farmland, transforms parks and open spaces into highways and strip malls and destroys more than one million acres of parks, farms and open space each year. As sprawling neighborhoods and highways engulf open space, the natural habitats of wildlife are disappearing beneath the concrete, which is threatening important ecosystems in the U.S. and around the world, such as the Chesapeake Bay, the Everglades and the San Fransisco Bay, and is among the biggest threats to endangered plants as well. In its path, sprawl consumes thousands of acres of forests and farmland, woodlands and wetlands. Each year an area about one kilometer wide and stretching from San Francisco to New York is lost to development in the United States. threatening the continuity of high national crop output with such high rates of development. For example, between 1950 and 2002, the number of acres of farmland in Wisconsin dropped by 32.6%, from 23.6 million acres down to 15.9 million, due to land use and urban sprawl, which has reduced the number of Wisconsin farms from 178,000 down to 77,000, from 1910 to 2002 . According to National Geographic, "Sprawl is claiming farmland at the rate of 1.2 million acres (10.5 million hectares) a year. Throw in forest and other undeveloped land and, for net annual loss of open space, you're waving good-bye to more than two million acres (10.8 million hectares)." The American Farmland Trust reports that an astounding 70% of prime or unique farmland is now in the path of rapid development and a study in the journal PLoS ONE finds that 1.4 million hectares of open space was lost to urban sprawl in the United States from 1990 - 2000. According to the Clean Water Action Council, "We're chewing up farms at an alarming rate across the U.S., to create new highways, fringe industrial parks and sprawled housing developments. This loss reduces our ability to grow food, fiber and timber. In many areas, urban development pressure and increased property taxes are forcing farmers out of business. They often sell their farms for housing developments, to provide financial security for their retirement. Wild forests, meadows, and wetlands are also disappearing, replaced by pavement, buildings and sterile urban landscaping. The remaining habitat is smaller, degraded and more fragmented, making survival of certain wildlife species very difficult as they try to reach breeding ponds, hibernation sites, feeding locations, or to establish viable nesting areas." Discover the Advantages of Open Space

American Journal of Health Promotion: Relationship Between Urban Sprawl and Physical Activity, Obesity, and Morbidity Smart Growth America: Measuring the Health Effects of Sprawl - A National Analysis of Physical Activity, Obesity and Chronic Disease

"The consequences of watershed degradation from development have been felt across the country. In the Puget Sound region of Washington state, for example, major floods that were 25-year events now occur annually; "the sponge is full," according to King County analyst Tom Kiney. Similarly, in Akron, Ohio, runoff from residential areas has been estimated at up to 10 times that of pre-development conditions, and runoff from commercial development has been estimated at 18 times that before development. In several Maryland, Pennsylvania, and Virginia watersheds that drain into the Chesapeake Bay, pollution from development has been found to exceed -- in some cases dramatically -- pollution from industry and agriculture. Even in counties that have enacted stormwater-management regulations, the pace of development is causing pollutant loads to increase." ~ NRDC: Paving Paradise - Sprawl and the Environment

Sprawl 101 - How Sprawl Hurts Us All

Increased Traffic Congestion and Traffic-Related Fatalities - As urban areas spread out, trip times are lengthened, residents are forced to virtually drive everywhere, spending more time in their cars and trucks, and traffic congestion occurs over a larger area. According to the Sierra Club, "The average American driver spends 443 hours per year - the equivalent of 55 eight-hour workdays - behind the wheel. Residents of sprawling communities drive three to four times as much as those living in compact, well-planned areas. Adding new lanes and building new roads just makes the problem worse - studies show that increasing road capacity only leads to more traffic and more sprawl." The heavy reliance on automobiles not only increases traffic congestion and air pollution, but also automobile crashes and pedestrian injuries. 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 sprawling communities are at greater risk of dying in a car crash. According to National Geographic, "Sprawl keeps a person in the driver's seat. The suburban family, on average, makes ten car trips a day (keeping in mind that most families have two vehicles). A commuter living an hour's drive from work annually spends the equivalent of 12 workweeks, or 500 hours, in a car. Traffic delays rack up more than 72 billion dollars in wasted fuel and productivity." Discover Transportation Choices that Avoid Traffic Congestion

Increases Risk and Damage from Floods - Sprawling developments drain and destroy wetlands, which absorb flood waters, and can be built in floodplains, which leads to a higher susceptibility to flood waters. According to the Sierra Club, "In the last eight years, floods in the United States killed more than 850 people and caused more than $89 billion in property damage. Much of this flooding occurred in places where weak zoning laws allowed developers to drain wetlands and build in floodplains."