Suburbs, Sprawl, and Sustainability

Cities are living organisms. They grow, flourish, wither, and sometimes die. Throughout history, once-robust cities have reached points of economic obsolescence and have declined. Some vanish altogether, like Babylon and Ur. Others, like Venice, become essentially museums of themselves. Some survive, but shrink dramatically — like Detroit or St. Louis.

St. Louis, "the Gateway to the West," was once the greatest boomtown in America. Situated on the Mississippi, St. Louis saw the river as the forever-paramount avenue of commerce in the United States. But it turned out that railroads were more important than the river, and Chicago placed its bet on railroads. In the 1890s, St. Louis was the fourth-largest city in America. In 2014, it was the sixtieth-largest city in America, with about 318,000 people. Today, Mesa, Arizona, has nearly 150,000 more people than St. Louis.

As the world becomes ever more urban, the long-term prospects for the survival of individual cities is often critiqued, ranked, and debated. The term sustainability is the most frequent rubric of conversation. The new cities of postwar America generally fare poorly in these discussions. Built around the automobile and the single-family home, these cities are casually indicted for profligate resource consumption, low-density sprawl, and a mindless addiction to real estate development.

Even before Andrew Ross labeled Phoenix "the world's least sustainable place" in his 2011 book Bird on Fire, the city often served as an exemplar of such a place: isolated, dry, hot, and surely one of the most improbable and therefore least sustainable big cities on earth. Bill deBuys wrote about the city's impending doom from climate change: "If cities were stocks, you'd short Phoenix."

Despite the criticism of the "suburban cities" that arose in the last half of twentieth century America, Las Vegas, Phoenix, Salt Lake City, Dallas, Tucson, San Bernardino, and San Diego continue to be among the fastest growing places in the United States. In December 2014, the Economist looked at world cities. In a discussion of the planet's future, the "great urbanisation" (as they spell it) is frequently invoked: a world in which most people live in cities. The point of their analysis is that these global cities are looking increasingly suburban. Chinese, Indian, and Brazilian cities are all experiencing declines in density. Since 1970, Beijing's density has dropped by 75 percent. (Even at that, it is still about five times more dense than places like Phoenix.) Worldwide, the few cities that are becoming more dense are places like Los Angeles, Las Vegas, and Phoenix, which started out with very low density to begin with.

More than sixty years ago, the late Jane Jacobs examined the plight of American cities in one of the most insightful pieces of urban analysis ever written, The Death and Life of Great American Cities. The book is remembered as a screed against the perils of city planning, which she saw as an interference with the natural evolution of cities and the complex and intricate relationships among individual land uses. Today, her book tends to be remembered as a paean to places like Greenwich Village: pedestrian environments with a rich mix of uses; a layered texture of building types, sizes, and ages; and an ongoing generational drama played out in a largely unplanned "ballet of the street." Jacobs would not have liked places like Phoenix. Cities that grew in the latter half of the twentieth century were based not on intricate pedestrian interactions but on the convenience of automobiles. But perhaps Jacobs's greatest gift to thinking about the nature of cities was her application of observational logic to thinking about the way cities evolve, grow, and possibly die. She taught us that cities are the products of millions of individual decisions about how people want to live, to work, to recreate, and to interact. Those individual, incremental decisions are made in a particular context: an economic context as the city grows and matures; a technological context that exists for horizontal or vertical movement at different speeds and varying distances. Cities also evolve in a political context — a determination of how to negotiate the social contract between the needs of society and the rights of the individual.

Jacobs's observational insights were applied to the great industrial cities of America. Such cities were the products of the Industrial Revolution, the invention of the elevator, the streetcar, and the subway, and the employment of millions of workers in high-density production industries. She saw the problems created when those kinds of cities were subject suddenly to countervailing forces like the automobile, the airplane, and a political desire for more centralized planning.

It is possible to apply Jacobs's analytical tools to the cities that grew up later than did her favorite places. The same forces that operated to cause decline in the great cities of the nineteenth and early twentieth centuries were also operating to shape the cities of the latter half of the twentieth century. These changing forces dispersed populations that had previously been concentrated. The first, most obvious, and most examined of these urban change agents was the automobile, which made it possible for any given piece of property to be easily accessible with just a dirt road. The automobile served as an agent of destruction to the older industrial cities that had been built around streetcar commuting or pedestrian activity. Cars dispersed cities, causing a decline in the overall population density of older places. The automobile also begat the parking lot, an urban dead zone — hostile to pedestrians, hot, and uninviting.

City populations were also being dispersed by the growing dominance of the single-family detached home as a preferred lifestyle. The individual detached home had long been an aspirational goal of Americans, of course, but as the twentieth century rolled on it became attainable for ever-larger numbers. Together, the automobile and the single-family home would rewrite the nature of American urbanization.

While these forces were operating to disperse the American population, there were simultaneously countervailing forces in operation. The first of these was the rise of air travel as a dominant mode of interurban transportation. When the railroad became the means to getting from one place to another, small- and medium-sized cities were well served by tracks running through town with stops for goods and passengers. Air travel, on the other hand, is a force of concentration. Airports take a lot of room and cannot be too close together. The benefit of travel by air is speed, and landing too often results in slowing down that advantage.

As the American West began to urbanize, the region faced...