Land use choices strongly affect public health. More or less direct effects on air and water pollution are well recognized, but other less direct but important impacts have only recently begun to reach public attention. "Urban sprawl" may be defined as development of low-population-density settlements around high-density cities, either by emigration from the core cities or by influx of new residents from elsewhere.
Sprawl results from thousands of personal decisions and from policies and subsidies that are outcomes of the electoral process. Special interests such as the highway and automobile lobbies spend vast sums to exert pressure; developers often state sincerely that they will build whatever the market demands. The fact that sprawl is in part subsidized by government policies—for example, building roads and sewers and supporting low gas prices partly at the expense of non-users, in effect providing greater subsidies for suburban than for low-income core-city housing—further emphasizing that the "choice" of living in sprawl development is not a simple free-market or quality of life option. In addition, in choosing sprawl over core city redevelopment, we are in effect incurring public health burdens.
RELATIVELY DIRECT EFFECTS OF SPRAWL ON PUBLIC HEALTH
Air Pollution. Life in sprawl developments demands up to three times as much driving as in high-density urban areas. Since high levels of the monitored pollutants can trigger loss of federal highway funds, affected metropolitan regions such as Atlanta are changing their development policies. Light rail and other forms of mass transit can reduce auto pollution in suitable situations but, in the absence of special planning, may not decrease sprawl.
Water Pollution. In 1998 the Environmental Protection Administration (EPA) reported that 35 percent of the nation's rivers and 45 percent of its lakes were polluted and not clean enough for swimming or fishing. Although some of the pollutants were from agricultural and industrial sources and landfills, many resulted indirectly from sprawl. For instance, increased bacteria come from overextended and overloaded sewer systems, overflows of "combined sewers," and leaking home septic systems. Road "runoff" of automobile oils and battery metals and road salt also contribute to water pollution and may affect public health.
Other Impacts of Increased Auto Usage. With increased mileage, higher speeds, and fewer sidewalks, pedestrian accidents have increased, especially among children and elderly, comprising some 13 percent of traffic accident fatalities in 1997 and 1998. Remarkably, 59 percent of pedestrian deaths occurred where there was no access to crosswalks, that is, in typical sprawl roadways. A related factor was the higher speeds prevalent in suburban (vs. urban) roads, since speed and fatality are highly correlated. If states were willing to spend highway funds on pedestrian safety, there are many shortterm measures (e.g., "traffic calming," more crosswalks) that could be taken, but at some point, slowing of traffic will encounter public resistance. Another impact in typical sprawl development is the loss of easy access of the elderly to medical care, social services, and shopping once they stop driving; since mass transit is not generally available. This problem is bound to become more severe as the elderly begin to comprise some 20 to 25 percent of our population by 2050.
INDIRECT EFFECTS OF SPRAWL ON PUBLIC HEALTH
A few examples illustrate that there are also some indirect impacts of urban sprawl on public health.
Duplication of Medical Infrastructure. As hospitals expand to meet the needs of the more affluent and growing population, they often cannot afford to maintain medical centers both in a population-depleted or relatively poor inner city and in the suburbs.
Quality of Life and Health. The stress of commuting and congestion decreases time and
There are strong and often compelling social reasons or perceptions why many Americans prefer low-density suburban to urban living, beyond the known or hidden subsidies that promote this population shift. However, to the greatest extent possible, the public health impacts need to be consciously factored into the public costs of sprawl so that provisions are made to minimize these costs to those (especially inner-city residents) who are negatively affected and to offer everyone more balanced choices of places to live and work. The so-called "Smart Growth" movement offers a variety of land use choices that minimize the negative public health impacts discussed here.
Jacobs, J. (1993). The Death and Life of Great American Cities. New York: Vintage Books.
Surface Transportation Policy Project (2000). Mean Streets 2000: Pedestrian, Health, and Federal Transportation Spending. Washington, DC: Author.
U.S. Congress, Office of Technology Assessment (1995). The Technological Reshaping of Metropolitan America (OTAH ETIH 643). Washington, DC: U.S. Government Printing Office.