How Urban Sprawl Works

Those opposed to urban sprawl advocate controlling the problem by building high-density urban areas -- in other words, accommodating more people per square mile in buildings that grow up, (such as high-rise apartments) rather than out (such as subdivisions with 200 or more homes). This would spare the outlying rural areas from what's often deemed unnecessary development.

Unfortunately, this type of planning doesn't take into account lifestyle preferences. Many people simply don't like the crowds, traffic and confined living quarters that typically characterize urban living. They eschew these problems for split-level homes on an acre of land in the suburbs. However, self-professed city-dwellers enjoy the vast cultural and entertainment opportunities available in many large urban areas, as well as shorter commute times that can be ventured on foot or via public transportation.

Most experts agree that sprawl is exacerbated by a couple of factors: population growth and poor land use. Population growth tends to make people feel more crowded in cities, causing them to head for the hills. Poor land use occurs when people increase the average amount of land they use (also called per capita sprawl), such as when they trade in a 1,400-square-foot apartment for a 3,000 square foot home on an acre or two of land.

Population growth is considered a major factor in sprawl, although some urban areas continue to grow outward despite a decline in population. Figures released by the Census Bureau in 2007 announced that both legal and illegal immigration stand to increase population in the United States by 105 million by the year 2060 if current rates continue. Add that to the normal birth rate, and the current U.S. population of 301 million could become 468 million, making the sprawl issue even more pressing [source: SignOnSanDiego]. After all, where will all these people go? In an interesting twist, the census figures revealed that 40 percent of immigrants are bypassing cities in favor of suburbs, where many jobs are now located [source: The New York Times].

As we've learned, sprawl is most prevalent in the United States, although it can be seen around the world. Typically, sprawl is happening around most of the big cities. What's influencing the trend? For one, the southeastern United States tends to be the sprawl capital of the country, thanks in large part to its availability of affordable housing. A survey conducted by USA Today found that four of the top five most sprawling cities are located in the Southeast (Atlanta; Nashville, Tenn.; Charlotte, N.C.; and Greensboro, N.C.). Austin, Texas, was the only non-southeastern city to crack the top five [source: USA Today].

Also playing a major role is the fact that the Southeast, unlike desert areas such as Las Vegas, has easier access to municipal water supplies, making it that much easier to set up shop in the suburbs. What's more, the Southeast doesn't have to contend with the geographical factors present in other parts of the country and world, such as mountains and desert. Geographical barriers limit the amount of sprawling one city can do.

Another contributing factor to sprawl is white flight, which occurs when people abandon cities in an effort to be surrounded by others of similar race and socioeconomic background. Cultural segregation has been particularly prominent in cities in the midwestern and northeastern United States, including Grand Rapids, Mich.; Indianapolis and Cincinnati [source: USA Today]. Critics see this phenomenon as a serious civil rights issue that pushes already financially strapped inner cities further down a vortex of crime and poverty.

Next, we'll learn more about the various pros and cons of urban sprawl.

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Many people believe that poor planning by municipalities and government institutions is what has led to uncontrolled sprawl in some areas. Other researchers believe sprawl to be the unavoidable result of car-based living, or people's increasing reliance on automobiles. What's for certain is that there is no solid consensus about whether sprawl is really a bad thing after all. Here are some of the reported downfalls and the perks of sprawl.

You name it, sprawl is alleged to have caused it (although it's nearly impossible to pinpoint all of­ the blame). One of the most obvious and talked-about consequences of sprawl is the loss of farmland at a rate of approximately 1.2 million acres (500,000 hectares) every year [source: National Geographic]. Environmental devastation, including the loss of tree cover and wildlife habitats as well as polluted drinking water, is commonly attributed to urban sprawl. Water pollution is caused by an increase in hard surfaces, such as pavement, that cannot absorb rainfall or runoff the way that soil can. This causes pollutants to be diverted into water sources, rather than be absorbed by the ground. Tree cover has been reduced by more than one-third over the past 25 years in Atlanta, Chesapeake Bay and Puget Sound alone [source: American Forests].

Increased automobile usage goes hand in hand with sprawl because people live farther away from work and because business districts in the suburbs aren't built in walking distance from homes. This has caused higher levels of smog and air pollution, resulting in more cases of asthma and other respiratory ailments. Furthermore, the United States, Europe and other parts of the world affected by urban sprawl have noted that increased amounts of driving beget greenhouse gas emissions that are believed to be linked to global climate changes [sources: Public Health Reports, EEA].

Longer commutes have resulted in high levels of automobile crashes, despite safer vehicles and safe driving campaigns. According to the National Highway Traffic Safety Administration (NHTSA), lower driver and passenger fatality rates are seen in dense cities as opposed to sprawl-friendly counterparts [source: Public Health Reports]. Pedestrian fatalities and injuries may also be related to sprawl because of pedestrian unfriendly walkways and increased traffic. Atlanta, considered by many experts to top the list of sprawl-offending cities, had an increase in pedestrian fatalities despite a national decline in the amount of these accidents. Car-based living is also credited in part with obesity.

Many experts believe that urban sprawl results in higher costs for the government agencies responsible for building streets, schools, utilities and other services required to support new residents in sprawling communities. Often, these costs result in higher taxes.

On the next page, we'll examine the pros of urban sprawl.

Although the pros of urban sprawl may be less numerous than the cons, it's hard to qualify which factors outweigh one another. And clearly the advantages of suburban living are pretty substantial, considering its popularity and the continuing influx of people migrating to the suburbs.

Thanks to less expensive land in outlying areas around cities, people are able to afford larger houses on larger lots. For growing families tired of shoving all their worldly possessions into tiny urban closets, this is a huge benefit. Also, it's no secret that homes closer to most urban areas are usually more expensive than homes farther out in the suburbs. Simply put, it's easier to own your share of the American Dream out in the suburbs.

In addition, better school systems are often available in the suburbs. According to the National Center for Policy Analysis (NCPA), in 1999, 73 percent of suburban New Jersey students scored "at or above" the basic reading level, whereas only 27 percent of urban students in New Jersey achieved the same goal [source: NCPA]. Of course, some of the more affluent residents can afford to send their children to private schools in urban areas, but many people do not have that luxury.

Crime rates tend to be lower in the suburbs than in urban areas, providing further incentive for families in particular to seek the white-picket fence safety of the outlying districts. In one study conducted by the U.S. Department of Justice, violent crime in cities in the period from 1993 to '98 was 37 percent higher than it was in the suburbs and 74 percent higher than in rural areas [source: Bureau of Justice Statistics].

The NCPA also asserts that the United States as a whole has plenty of land to grow on, since not even 5 percent of its total land has been developed. The organization states that urbanization is only responsible for one-fourth of the farmland lost since 1945 [source: NCPA].

On the next page, we'll discuss international sprawl and a couple of U.S. cities with interesting sprawl-related backgrounds.

Traditionally, Europe and much of the rest of the world haven't followed the "American model of suburbia" based on suburban living and reliance on vehicles for day-to-day activity [source: New Zealand Herald]. Rather, most of these populations have trended toward urban life and suburbs located immediately outside cities instead of the sprawling areas that Americans live in. However, the European Environment Agency (EEA) reports that times are changing. Although sprawl hasn't reached the proportions in Europe that it has in the United States, it's certainly on the rise. Since the 1950s, for example, European population has grown by 33 percent, while European cities have grown by 78 percent. Sprawl in Europe is becoming especially prevalent around areas featuring strong economic activity and high levels of population density, such as Paris, northern Italy, Belgium and the Netherlands [source: EEA].

One prime example of international sprawl is in Australia, which has quickly become one of the most urbanized countries in the world -- the majority of residents living in or around the Sydney coastline. Traffic, air pollution and rising costs of living are a few of the problems blamed on sprawl in the area. As such, planners are working overtime to figure out how to handle the expected population increase of 1.1 million by 2031. One of the current plans is to build more than 600,000 new homes directly to the south and west (to ease pain on the coastline), that will be in close proximity to train and bus stations and that will also have cycling and walking trails [source: China Daily].

One major city that many people probably assume to be the biggest offender is Los Angeles. In fact, L.A. has managed to curb sprawl despite an intense increase in population. The city has accomplished this largely through zoning requirements that kept housing lots small and close together [source: Sprawl City]. Not only has land consumption in the area not increased, it actually decreased by 8 percent while L.A.'s population density was on the rise between 1970 and 1990 [source: Sprawl City]. Given the popularity of the area, sprawl would have been far worse if L.A. planners hadn't planned ahead of time by encouraging high population density through strong live, work and play incentives for residents of the city proper.

Yet another city that flies in the face of sprawl-related reason is Detroit. The city experienced a 7 percent population decline between 1970 and 1990; however, the land area consumption increased by 28 percent. This is believed to be due to factors not related to population (like crime and cost of living) that pushed people toward outlying areas around the city. Despite this seeming exception to the population growth rule, Census Bureau data still shows that cities experience population growth sprawl at a much faster rate than large cities that experience decline [source: Sprawl City].

Next, we'll discuss how ordinary citizens can take action against sprawl.

While there is no one easy solution to urban sprawl, there are numerous ideas out there as to how it can be contained or planned more efficiently, at the very least. According to those opposed to sprawl, it's often fueled by poor planning by regional and local governments. A measure called smart growth advocates reducing sprawl by fixing up run-down urban communities, building new and better communities closer to cities, and preserving open space before it's developed.

The Sierra Club proposes a number of ideas to counter sprawl, including investing in environmentally friendly public transportation as well as providing other transportation options, like walking and cycling. The group also encourages local and regional planning committees to consider transportation needs, environmental concerns and land-use goals when planning for the future. One of the main concerns of families is affordable housing, which the Sierra Club insists must be provided in close proximity to jobs and public transit. Also, the group recommends that developers be charged for the costs of public services required by sprawl, such as water and sewer lines, new roads and public schools.

Many states have already adopted sprawl-related countermeasures. For example, Tennessee now requires all municipalities to identify urban growth boundaries [source: USA Today]. Other states are even using tax incentives to encourage wealthy rural landowners to donate land to conservationist organizations or to the state in which it's located. Experts agree that individuals need to take a vested interest on a large scale when it comes to curbing the negative effects associated with sprawl. For example, commuters should carpool or use public transit to reduce tailpipe emissions that contribute to air pollution.

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No matter how you fe­el about urban sprawl, it is an issue that warrants a closer examination by the powers-that-be. Are white picket fences an adequate trade-off for the displacement of wildlife? It's doubtful that anyone will ever agree. Hopefully, a realistic and attainable middle ground can be identified and reached in time.

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