Cities can be thought of as the absence of physical space between people and firms. As such, they exist to eliminate transportation costs for goods, people and ideas and transportation technologies dictate urban form. In the 21st century, the dominant form of city living is based on the automobile and this form is sometimes called sprawl.

In this paper, the researchers document that sprawl is ubiquitous and that it is continuing to expand. Using a variety of evidence, they argue that sprawl is not the result of explicit government policies or bad urban planning, but rather the inexorable product of car-based living. Sprawl has been associated with significant improvements in quality of living, and the environmental impacts of sprawl have been offset by technological change.

Finally, the researchers suggest that the primary social problem associated with sprawl is the fact that some people are left behind because they do not earn enough to afford the cars that this form of living requires.

In the early part of the 20th century, cities grew upward. Tenements and luxury apartment buildings replaced brownstones. Skyscrapers came to adorn urban landscapes. But at the end of the 20th century, urban growth has pushed cities further and further out. The compact urban areas of 1900 have increasingly been replaced by unending miles of malls, office parks and houses on larger and larger lots.

At first, people continued to work in cities but lived in sprawling suburbs. But the jobs followed the people and now metropolitan areas are characterized by decentralized homes and decentralized jobs. In 2003 America, urban growth and sprawl are almost synonymous and edge cities have become the dominant urban form.

Over the past century, urban growth has taken the form of sprawl. The move to cars and trucks was important not only because it reduced transport costs, but also because it eliminate the fixed costs of rail depots and ports. These fixed costs had been a major force driving agglomeration and their disappearance has enabled employment to decentralize.

Edge cities were made possible by the automobile and as long as the car remains the dominant transport mode, sprawl is likely to remain the dominant urban form.

The economic and social consequences of sprawl do not appear to be dire. Suburbanization is not linked to rapid decreases in intellectual creativity or to massive social unrest. Suburbs are actually more racially integrated than central cities. There is a transitional problem as the poor can not pay for cars and remain stuck in central cities and this surely deserves policy attention.

There are some market failures associated with sprawl. Highways have a common pool problem that is not shared by rail. Either we need to be accustomed to traffic jams, or we need to figure out how to be smarter about using electronic tolls to limit congestion. Pollution is an issue, but the phase-in of vehicle emissions control technology has reduced emissions per mile faster than vehicle mileage has increased.

Harvard University, John F. Kennedy School of Government - Department of Economics
Edward L. Glaeser (Researcher), tel. +1 617-496-2150

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01/05/2003

Edward L. Glaeser and Matthew E. Kahn

research

Urban Policy > Urban environment > Land use

Suburbanisation, Urban sprawl