Hooray for Sprawl: New Study Debunks "Smart Growth"

Carolina Beat No. 677:

By Michael Walden

June 06, 2003

Sprawl is a word that has acquired a negative connotation in our language. Mention sprawl and the immediate image in most minds is of subdivisions gobbling up farmland and pristine forests and causing commuters to
sit in time-wasting traffic jams to and from work. Many politicians say they are for “smart-growth,” which is a kind of fuzzy, ill-defined alternative to “nasty” sprawl.

Unfortunately, there has been little dispassionate, logical analysis of the causes and consequences of sprawl. But no more! Now there is a new study from the prestigious National Bureau of Economic Research that increases our understanding of sprawl. In Sprawl and Urban Growth, economists Edward Glaeser and Matthew Kahn debunk many of the myths about sprawl with rigorous analysis and empirical investigation. Sprawl is simply low-density development. Rather than economic activity being concentrated in central, high-density places, households and businesses are spread across the landscape in lower- density subdivisions and communities.

The driving force behind low-density development is households. Urban economists have long taught that households face a fundamental tradeoff in their residential location. They can live close to work and shopping on land that, because of its accessibility, is more expensive. In this case, commuting costs will be low, but housing costs will be high, thereby motivating less consumption of housing space. Or, households can live farther from work and shop on cheaper land, allowing them to afford more housing space but forcing longer commutes.

In horse and buggy days, when time costs of commuting were high, most households except farmers lived close to work and shopped in high-density dwellings. There was nothing romantic about living in crowded apartments on top of shops — it was a matter of economic necessity.

The development and proliferation of the automobile dramatically changed the economics of this tradeoff. Commutes that were previously unthinkable were now possible. The auto allowed households to “have their cake and eat it too.” The auto allowed households to move out of dense central cities, buy cheaper land, and therefore consume more space, and still have a reasonable commute to work and shopping. Plus, over time, many jobs and shopping followed households to the suburbs and reduced their commuting time.

Critics of sprawl argue that the government contributed to this low-density development by subsidizing roads. Not so, says Glaeser and Kahn. The vast majority of highway spending (70 percent) is financed by user fees in the form of gasoline taxes. In contrast, the subsidy rate of public transportation is much higher.

Even if one accepts that low-density development has occurred as a result of households making choices in their self-interest — that is, pursuing lower-cost land and greater housing space — there can still be negative consequences of these choices. Three often mentioned bad results from sprawl are greater commute times, reduced open space, and increased air pollution.

Glaeser and Kahn address each of these head on. Regarding commute times, they reveal a startling statistic. Average commute times to work are actually greater in more dense metropolitan areas than in less dense areas. A big reason is the inflexibility of mass transportation systems more commonly used in high-density metro areas. Mass-transit systems can’t deliver commuters from the doors of their residences to the doors of their work destinations.

Therefore, the total time of commuting using a mass-transit system includes the time of getting to the transit stop, the time on the transit vehicle, and the time getting from the transit stop to the destination. Autos are more time-efficient on the first and third components, and may also be more efficient on the second component when the multiple stops of mass transit systems are considered.

Glaeser and Kahn also show it’s incorrect to claim sprawl has significantly reduced the amount of open space in the country. Only 5 percent of the country is developed. The amount of land devoted to forests has actually been increasing. Furthermore, if residents desire more open space in their neighborhoods, they can accomplish this by voting for more public spending on park space or by participating in land trusts. Although low-density development is related to greater automobile use, technological advances have caused air pollution levels to fall in recent decades. Glaeser and Kahn call this the “greening of the automobile.” Automobiles are more environmentally friendly today than ever before, and the reductions in pollutant emissions per auto have more than offset the increase in driving.

The Glaeser and Kahn study makes clear households have generally benefited from sprawl. Indeed, sprawl has resulted from residents consciously making decisions to improve their standard of living. Certainly, low-density living isn’t the choice of every household, as witnessed by the increase in inner-city living by some middle- and upper- income households in recent years. But developers realize most households will trade a longer commute for more living space.

Consequently, any efforts to artificially limit sprawl will reduce the well-being of households, especially households that haven’t attained the dream of a single-family home in a low-density development. Such a move would be replacing the dreams of the many with the plans by the few.


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