Sprawling cities and spreading waistlines

The Centers for Disease Control and Prevention turn their attention to the connection between community design and people’s level of physical activity. For decades, health scientists have warned us that Americans are more sedentary and more obese than ever. The changing nature of work, the reliance on cars, the time spent in front of televisions and computers, the overconsumption of junk food — these are the usual suspects mentioned as contributing to this epidemic. Recently, however, researchers have begun to take a hard look at how the physical layout of our cities and neighborhoods might affect people’s health. The pursuit of data is gaining momentum. The Robert Wood Johnson Foundation has committed itself to funding research on the links between community design and health (see January/February 2001). More than 550 people gathered at a national conference on transportation and disease prevention in San Diego in January. On the federal level, the Centers for Disease Control and Prevention (CDC) have launched a new program, Active Community Environments (ACES), which seeks to identify specifically how land use and transportation affects behavior. ACES’ ultimate goal is to give people more opportunities to be physically active. These efforts come at the heels of last year’s report from the Surface Transportation Policy Project (STPP), Mean Streets 2000, which suggested that neighborhood and street design has a more immediate impact on health: death by accident. STPP ranked the 10 cities most dangerous to pedestrians, and almost all of them turned out to be Southern or Southeastern states where sprawling development has left pedestrians stranded on roads without sidewalks and far from schools and stores. Walking has become a dangerous business — per mile traveled, pedestrians are 36 times more likely to die in a collision than drivers, the report says. Walking has decreased but pedestrian fatalities have dropped only slightly. In 1997 and 1998, 13 percent of all traffic fatalities were pedestrians, the report says. And analysis of the cases where information was available, revealed that 60 percent of the accidents occurred in places where no crosswalks were provided. Lack of empirical data On the surface, the connection between community design and health seems straightforward. Says Richard Killingsworth, a health scientist with the CDC who spearheads the ACES program: “ Obviously, the way suburban developments are presently going up , with their lack of connectivity and a poor proximity to destinations of interest, does have an impact on one’s ability to walk or bicycle. We know that clearly.” Recently, newspapers across the country have featured almost identical anecdotes about suburban residents who have been embarrassed into exercising in a health club rather than walking in their neighborhood. Passing drivers repeatedly stop to offer a ride or ask if everything is all right. In some quarters, walking has come to be perceived as a suspicious activity — pedestrians must be either poor, lost, or mentally ill. Unfortunately, research on people’s walking and bicycling habits has been sporadic at best. “We have a lot of assumptions based on what is available through transportation and land-use studies,” Killingsworth says, but most of these studies focus on congestion or emission reduction and how people behave when they are in their cars. “The data on walking in this country is pitiful,” says Bill Wilkinson, Executive Director of the National Center for Bicycling and Walking. “We need good empirical evidence so we can nail down causalities.” The available data suggests that the decline in walking is substantial. According to the Nationwide Personal Transportation Survey, conducted every five years by the US Department of Transportation, the number of trips taken on foot has dropped by 42 percent in the last 20 years. Where is the link? Establishing a causal link between this decline and urban design has proved difficult. Lawrence Frank and Peter Engelke of the City and Regional Planning Program at Georgia Institute of Technology reviewed the literature on the subject in ACES’ first working paper, How Land Use and Transportation Systems Impact Public Health. They write: “Urban form variables themselves are difficult to disentangle. Those believed to influence the propensity to walk and bike, such as high density levels and grid street patterns, are often located in the same areas, making it difficult to determine which urban form factor is the more important. As a result of these difficulties, there is no universally accepted methodology in the scholarly literature for disentangling the influences of individual urban form variables on travel behavior.” One of ACES’ first task is to study why people choose to live in communities where opportunities for walking and bicycling are limited, Killingsworth says. “Are they self-selecting because those types of behaviors are not of interest to them, or if they did select a community with a high prevalence of walking or biking, would they be persuaded to engage in those behaviors?” he asks. In other words, would people behave differently in a mature new urbanist community? To find out, Killingsworth has sought the assistance of the Congress for the New Urbanism (CNU) in identifying communities for study. Hope VI projects, where many residents return to the same location to live in a radically different design, are of particular interest, he says. ACES is also working closely with the National Park Service, studying the proximity of parks and trails to residential communities and how people access these facilities. The program is developing a guide, Kids-Walk-to-School, that helps parents, community leaders, and health care practitioners promote walkable communities with safe routes to schools. “We’re looking at simple issues of decision making,” Killingsworth says. “How one decides to be physically active, and what cues are available to allow that to happen.” According to Frank and Engelke, people’s inactivity may be explained as a combination of personal barriers — such as lack of motivation, perceived lack of time, and family obligations — and environmental barriers, such as lack of sidewalks and bike lanes, lack of parks nearby, topography, and perceived safety of one’s neighborhood. Costs of car culture A 1990 comparison of travel behavior in Western industrialized countries shows just how insurmountable such barriers are in the US (see graph on page 16). While automobile use hit a low of 36 percent of all trips in urban areas in Sweden, it topped out at 84 percent in the US. Walking and bicycling accounted for only 10 percent of trips in the US, whereas in Denmark, the Netherlands, and Sweden, people used their bodies in more than 40 percent of all trips. The inactivity is taking its toll. According to Killingsworth, the CDC estimates that physical inactivity is a primary factor in 200,000 deaths annually, and some scientists conclude that it contributes to about 25 percent of chronic disease and 10 percent of the total number of deaths. “The financial consequences of this range from about $22 billion to $50 billion annually,” Killingsworth says. Only 30 to 40 percent of the US population engage in regular, sustained exercise, while another 30 percent are completely inactive. More than 50 percent are considered overweight. Killingsworth says these people can benefit greatly from integrating moderate exercise such as walking and bicycling into their daily routines, but if the environment is not right, it hinders them from doing so. Wilkinson of the National Center for Bicycling and Walking seems confident that the momentum of this new focus on physical activity can put a dent in the status quo. “In my experience, public health people are agents of change; they are going to raise questions,” he says, adding that transportation officials are generally much more conservative. City planning and public health came of age together in the 19th century, when both movements worked to repair the worst ravages of the urban slums created by the Industrial Revolution. Euclidian zoning was originally a means of protecting the welfare of the public by separating their homes from noxious uses. For the last 50 years, however, the paths of public health and planning crossed less frequently. Now they converge again, as evidence mounts that suburban design has contributed to a host of health problems.