Building Or Designing Healthy cities

Introduction

Town plans guide the physical development of a community over time and may affect cancer risk in a variety of ways. The most studied relationship involves the influence of the physical environment on risk of obesity, which is a well-established risk factor for certain cancer types, including colon, gallbladder, endometrial, prostate, kidney, and postmenopausal breast cancer. Obesity is, in turn, influenced by lack of energy balance as determined by physical activity and food choices.

Town plans can act to create Cities that support physical activity by increasing access to places where physical activity occurs such as parks, green space, trails, and recreation centers or by providing the opportunity for active travel, such as walking and bicycling. Cities that support active travel may also generate less driving and therefore lower the presence of cancer-causing air and water pollutants attributable to petroleum-powered automobiles; they also may necessitate less pavement, which exacerbates pollution through storm water run-off and heat island effects. Town plans may also affect health outcomes by influencing the nature of access to healthy and unhealthy food choices.

Alternatively called General Plans or Comprehensive Plans, Town Plans provide a long-term vision for the community and outline strategies for achieving that vision. The land use map is usually a central part of the town plan: It shows what kinds of land uses are to be located where in the city in the future. The town plan is usually implemented through the land development code, which regulates private activities, and the capital improvement program, which dictates public investments. In broad terms, these tools together determine the location, intensity, and type of development and the provision of infrastructure and services in an urban area.

Discussion

One way that traditional town planning practices contribute to cancer risk is through excessive separation of land uses. Traditional zoning practice involves the definition of zoning districts in which a limited range of land uses are allowed. Residential areas are segregated from commercial and industrial areas, and more specific classifications restrict what kinds of residential or commercial or industrial activities are found in each area. Newer areas built under these rules have a greater separation of land uses than older areas built before more restrictive zoning ordinances. Although some separation can be justified on health grounds (e.g., locating factories away from schools and homes), the degree of separation built into zoning codes in the United States is probably much greater than it needs to be, limiting the potential for walking and bicycling.

The problem of land use separation is often compounded by the layout and design of the local street network. In their land development codes, cities have traditionally adopted the concept of a street hierarchy, with high-speed, high-traffic freeways at one end of the hierarchy and slow-speed, low-traffic cul-de-sacs at the other. Although this approach means lower levels of traffic within neighborhoods, it also makes for convoluted routes through neighborhoods for drivers as well as pedestrians and bicyclists. Standards for street design have also been problematic. For decades, residential ...