In the first such national study, health researchers found that people who live in counties marked by sprawl-style development tend to weigh more, are more likely to be obese and are more likely to suffer from high blood pressure. Full report, county-level statistics, health journal articles, links to related sites and media coverage of the report

Increasingly, public health officials are paying attention to the human health problems that appear to be associated with sprawling development. Learn about the problem, and potential solutions, below.

Sprawl and Health

Spread-out development was in part born out of a public health movement to separate where people lived from the factories then common in cities. ‘Garden cities’ of suburban housing developments were also seen as an antidote to overcrowded cities where disease spread too easily. Now, both of these threats have virtually disappeared, and we are coping with a new set of health problems that are aggravated by spread-out, auto-oriented development.

Physical Inactivity

Only about one-quarter of Americans get the recommended amount of exercise. This lack of inactivity has contributed to the obesity epidemic and is a factor in more than 200,000 deaths a year. Yet we build our communities in ways that discourage, rather than encourage, everyday physical activity. As a recent headline in USA Today put it: “City, suburban designs could be bad for your health.”

People who live in spread out, sprawling areas are less likely to have easy opportunities to get physical activity in the course of a day. They may live in housing subdivisions that are isolated from stores, schools, or other destinations that they or their children may want to reach on foot.

Neighborhood streets may not connect to each other, but only to busy high-speed arterial roads that are unpleasant or even unsafe for walking or biking. Transit service may be infrequent or too far away. And the many places they need to visit in a day may be many miles apart, but with convenient parking just steps from the front door. That means the most obvious and practical way to get everything done is via automobile.

Medical research shows that walking and similar moderate physical activity is important to maintaining weight and bestows many other health benefits, including lowering the risk of diabetes, stroke, and heart attack. Studies show that people in sprawling places walk less. Low-income communities and people of color, who are less likely to have access to walking paths, parks, and playgrounds, are also more likely to suffer from of obesity. Public health advocates have launched a major initiative to create “active living communities” – places where people can integrate physical activity into their daily lives as they bicycle to work, walk to shops, and climb stairs at the office. To find out more, visit the Active Living Network and Active Living by Design.

Air and Water Pollution

People in sprawling metro areas must cope with the dispersed pollutants associated with increased automobile use. Road transportation is a major contributor to the formation of ozone, which aggravates asthma. Nine million children have asthma. Smog, created in large part by auto emissions, has been shown to be a factor in causing asthma among children playing active sports in polluted areas. An academic study commissioned by SGA, Measuring Sprawl and Its Impact, shows that people in more sprawling places breathe more polluted air. The study found that the severity of ozone pollution is strongly related to the degree of sprawl. In fact the difference in ozone levels between the most sprawling and least sprawling metro areas is 41 parts per billion: enough to shift a metro area from ‘code green’ air quality status to an unhealthy ‘code red.’

Other pollutants emitted by cars, such as benzene and particulate matter, better known as soot, are associated with increased risk of lung and other cancers, particularly for those who live near major roadways. Ninety percent of total cancer risk in the Los Angeles Basin is attributable to toxic air pollutants emitted by mobile sources.

Traffic Safety

Traffic crashes are a leading cause of death and injury in the United States, with about 42,000 people killed every year, and people living in sprawling areas are more likely to die either as motorists or as pedestrians. Sprawling developments typically include high-speed roads that are more hazardous for people on foot and bicycle.

Residents of more sprawling areas are at greater risk of dying in a car crash, the research indicates. In the nation’s most sprawling region, Riverside CA, 18 of every 100,000 residents die each year in traffic crashes. The eight least sprawling metro areas all have traffic fatality rates of fewer than 8 deaths per 100,000. Again, see Measuring Sprawl and Its Impact for a metro by metro assessment

Creating Healthy Communities

Smart Growth communities can be places that improve public health by encouraging physical activity and social interaction, while reducing the negative impact of traffic. Since stores, schools, and offices are mixed in with each other and close together, people living in compact areas find it easier to walk rather than drive to eat, shop, get exercise, or even go to work. They use transit in greater numbers, and typically walk to and from stops. They can bike more comfortably, since streets generally have slower traffic and a grid pattern that offers varied routes. Smart growth reduces the amount of driving per person, helping clear the air and reducing the disruption of traffic.

Policy Initiatives

A number of initiatives are underway that directly address the health impacts of sprawl. As mentioned above, public health advocates are working to create communities friendly to Active Living. Communities working to revitalize main streets and create more walkable neighborhoods are using ‘traffic calming’ techniques to slow traffic and create a safer environment. On the federal level, a coalition of health and transportation groups is working to integrate health concerns into the next federal transportation bill, by improving support for walking and biking, creating a national Safe Routes to School plan, and considering health in the transportation planning process. You can read the group’s position statement under transportation policy options at: www.cspinet.org/nutritionpolicy/nana.html

Environmental health researchers are paying more attention to the potential for smart growth to improve human health by improving air and water quality.