Introduction

We ought to plan the ideal of our city with an eye to four considerations. The first, as being the most indispensable, is health.

ARISTOTLE, Politics (ca. 350 B.C.)

Community design influences human behavior. The ways that cities, suburbs, and towns are designed and built impact the people who work, live, and play in them. The placement, layout, and design of transportation systems, of office complexes, of parks, and of the countless physical elements that make up communities result in real places that have real significance in terms of how we spend our time and what activities we engage in. Where people live, where they work, how they get around, how much pollution they produce, what kinds of environmental hazards they face, and what kinds of amenities they enjoy are a direct product of how communities are designed. This book is about how our communities influence one important type of behavior, physical activity, and the health outcomes that are associated with it.

Unfortunately, the great majority of Americans do not get enough physical activity to maintain their health over the long run. Physical inactivity is an enormous health problem in this country, contributing to, among other things, premature death, chronic disease, osteoporosis, poor mental health, and obesity. The environments in which most people spend their time—the modern American city and the suburbs and exurbs that have been the dominant form of development in this country for over a half century—are an important contributor to this problem. The cities and suburbs that we inhabit are not now, and have not been for a long time, places that encourage some critically important forms of physical activity. In short, our physical environment inhibits many forms of activity, such as walking, and has become a significant barrier to more active lifestyles.

A century ago, American cities were highly walkable places. They were compact. Commercial, retail, and even industrial operations existed in close proximity to housing, allowing people to walk to work or school or the store. Out of necessity, buildings and streets were designed to the human scale. Streetcar and trolley systems provided a major form of transportation for millions of passengers every day, in every major city in the nation, which meant that people had the means to make longer journeys without the use of a car. When combined, all of this produced environments in which someone could satisfy their basic daily needs within a comfortable walking distance of their home or within a distance reachable through a combination of walking and trolley riding.

Unfortunately, the burgeoning cities of the industrial era also brought with them a host of serious problems. They were dirty and polluted. They were crowded. Most importantly, they produced health problems for their inhabitants. The worst of these were the communicable disease epidemics—typhus, yellow fever, and all manner of other infectious diseases—that swept through them with frightening regularity. The very conditions that made the industrial city a highly walkable place, including its concentration of people, its mixing of uses, and its high density of buildings, came to be blamed—not quite accurately, as research eventually showed—for creating the conditions in which epidemics could occur. So during the nineteenth and early twentieth centuries, critics tore away at the intellectual foundation of the compact industrial city. They sought to replace it with a new paradigm, a new way of thinking about how to build cities. In the old city's place they created the modern decentralized city, where housing was separated from workplaces and buildings placed far apart from one another, separated by expanses of grass and trees. America's new cities of big lawns and big distances would, they hoped and expected, produce more healthy living. What resulted was the city that we are so familiar with today—dominated by suburbs, spread out, with different uses separated one from another and almost everything reliant on automobile travel. This mass suburbaniz ation also led directly to a decline, in terms of population, wealth, and public investment in the older, established central parts of most cities, resulting in the widespread abandonment of the fabric of the old walkable city.

Widespread criticism of this development model has appeared only during the last couple of decades. Much of it is a reaction to the omnipresent automobile congestion that is the hallmark of the decentralized city. Some of it is centered on the monstrous-yet-monotonous ugliness of the endless strip malls and parking lots that have proliferated from one end of the country to the other. Many people are concerned about the environmental consequences of the modern city. These concerns focus on the enormous amount of land consumed, the air quality problems produced by all of the cars needed to keep these cities running, the vast quantities of municipal water that is required to irrigate the lawns of the new suburban landscapes, or the rainwater that is wasted as polluted runoff from parking lots and streets. An even more recent source of criticism is from the field of public health, which is beginning to explore potentially uncomfortable linkages between the decentralized city and different indicators of health.

Physical Activity, Past and Present

In the old cities, getting enough physical activity during one's day wasn't an issue because it was as much a part of life as eating or sleeping. Today, physical activity has been engineered out of most aspects of life. Work is no longer physically demanding for most people and daily living patterns, from mowing the grass to cooking dinner to washing clothes, require significantly less manual effort than they once did. The modern city has changed all of this, creating environments in which it is less and less common to work physical activity into the everyday patterns of life. The dominant forms of community design have contributed to this decline by making walking and cycling for transportation difficult if not impossible. Many of the reasons why are clear to even the casual observer. Long distances between places mean that most people cannot walk or bicycle from one place to another. The streets and roads that connect these far-flung places are designed for cars, often making them unsafe and extremely unattractive for...