In just 15 years, between 1982 and 1997, the amount of urban and built-up land in the United States grew by almost 40 percent - two and one-half times faster than the population. More than half of that growth took place recently in the five years between 1992 and 1997.

American cities seem to be spilling over their traditional boundaries and covering surrounding areas with low-density development at an astounding pace. More than 100,000 new homes were built in 21 metropolitan areas, including Boston, between 1990 and 1997. Most of this construction took place in medium- and lower-density counties at the metropolitan fringe.

At this pace, development is changing the landscape before people's eyes. Cities, suburbs, and neighboring rural areas are all feeling the impact - albeit differently. For many cities, it has meant concentrated poverty and decay at their core. Although some - like Boston - are doing better than they have in years, many are still struggling to revitalize themselves as jobs continue to grow at faster rates in the suburbs. In older suburbs, being sandwiched by new development has brought increased traffic, pollution, and the problems that initially affected inner cities. And those who earlier moved out to enjoy closer access to countryside and natural beauty are seeing those very qualities fade as others attempt to enjoy them.

Little wonder, then, that urban sprawl has been in the national spotlight in the last couple of years. Voters approved over 160 sprawl - related ballot measures in state and local elections in 1998, ranging from managing growth and improving livability in specific communities to New Jersey's unprecedented ballot approval of a $1 billion bond to preserve open space. Both Time and Newsweek ran feature stories on sprawl in 1999. And Vice President Al Gore has made sprawl central to his presidential bid.

In spite of this national attention, however, sprawl is not well understood and the magnitude of the problem is hard to assess. For one thing, land is abundant in the United States. Although three million acres of rural land were lost to development each year during the 1990s, only 7 percent of nonfederal land in the country is built up, according to the U.S. Department of Agriculture. Most agree that, even in the face of rapid development, urbanization is not a threat to food production nationally for the foreseeable future. Moreover, if a majority of Americans have chosen bigger houses in larger lots over denser homes in traditional cities, then obvious private benefits are involved in this pattern of development.

Yet, there is a sense in which sprawl is wasteful. As people abandon the city - and increasingly in the inner suburb - by moving farther out, some city problems become worse and infrastructure is duplicated or abandoned. And the way in which development takes place - regardless of how much land is available - can impose costs on others. Sprawling, low-density development has been associated with traffic congestion, tax increases, greater cost of providing services, environmental degradation (i.e., air pollution, water quality), inner-city decay, and reduced access to open space.

But the relationship between sprawl and these issues is hard to disentangle. Sprawling development is a pattern that results from complex interactions among the availability of resources, changes in technology, public policies, and private tastes. To better understand sprawl, one must attempt to isolate the specific characteristics of development that lead to particular negative consequences and determine who bears the costs.

WHAT IS THE PROBLEM?

One of the greatest difficulties in dealing with sprawl is that there is no consensus about what it is. Like pornography, it is something that people claim to recognize when they see it but cannot precisely define. Experts in the field consider sprawl to be - at a bare-bones level - unconstrained, low-density development that jumps over undeveloped areas in a "leapfrog” fashion. But, the meaning of "low” density varies by region. "The single-family detached housing on the order of 5,000- to 10,000-square-foot lots that you find in Maine's more traditional residential neighborhoods would be considered extremely wasteful in other parts of the country,” says Beth Della Valle of Maine's State Planning Department.

So, while people claim to recognize sprawl when they see it, they often don't recognize the same thing. Even experts in the field debate whether or not Los Angeles is characterized by sprawl. The confusion occurs because people associate with sprawl a number of other characteristics that go beyond density. These traits are much harder to quantify and measure precisely, and they often have a subjective element to them. But being clear over what they are is important, because policies to address sprawl cannot easily address all of them. And, in some cases, policies that speak to one area of concern can end up having an adverse effect on other aspects.

For instance, when people say they are against sprawl, part of what they are reacting to is a lack of access to open space. Green areas provide opportunities for recreation and variety to a built-up environment that can otherwise seem never-ending. Thus, some measures proposed to address sprawl attempt to include public parks and green spaces in city design. Yet, doing this could actually lower the density or increase the absolute area a city occupies.

Similarly, there is an aesthetic component to the reaction against sprawl. Some people link sprawl with the unsightly results that haphazard development can have, especially when it leads to the inappropriate mix of commercial and residential uses. Yet others, object to monotony of design - a landscape of single-family homes and "big-box” retail establishments which makes different areas of the country lose their distinctiveness. Addressing these concerns might involve changing zoning laws or attempting to generate unique architectures and not deal at all with the density of development. Likewise, measures to increase density would not necessarily produce environments of greater visual appeal and variety - and could lead to greater proximity among different uses.

Others dislike sprawl because they equate it with racial and economic segregation. When poverty becomes isolated in inner cities, and better schools and employment opportunities are found in the outer layers of a metropolitan area, the city's spatial distribution seems to stack the deck against those already disadvantaged. Yet, the relationship between sprawl and urban decline has not been proved. After running hundreds of regressions trying to relate urban decline to measures of sprawl, Anthony Downs of the Brookings Institution concluded there was no significant relationship between the two. "This was very surprising to me and went against my belief that sprawl had contributed to concentrated poverty, and therefore to urban decline,” he writes.

On the other hand, some of the measures to make cities more compact run the risk of worsening equity issues. Urban growth boundaries, such as those drawn around Portland and other cities in Oregon, limit the land available for development. Such land restrictions can have the unintended effect of decreasing housing affordability as cities approach their limits and land prices appreciate. Unless other measures are taken, low-income residents would take the hardest blow and could potentially even be driven out altogether.

And the association between sprawl and racial segregation cannot be generalized. The tendency of white and middle-class families to leave racially mixed, largely urban school districts is one factor that historically has fueled sprawl. But sprawl can also take place independent of race. In Maine, where the population is largely white, the outward movement of people from the cities has been well documented. In a survey of recent homebuyers conducted by the Maine State Planning Office, 42 percent reported moving out to rural or suburban places, while only 5 percent moved into town settings. Crime or bad schools - issues reported in national surveys, which in some cases are associated with poverty and often tinged with racial prejudices - were not among the reasons Maine homebuyers cited for their outward movement. Instead, they reported moving out to escape crowded, noisy, and traffic-congested settings.

In fact, traffic congestion itself offers a good example of the confusion that occurs when people equate something with sprawl that is not directly related to the density of development. Traffic congestion - together with long commutes - are seen as some of the more damaging consequences of our car-dependent, spread-out pattern of development. Commute times and vehicle miles traveled are commonly used as indicators of the sprawl problem. And, measured by that standard, sprawl has worsened considerably. The miles Americans travel in their cars each year have grown even faster than developed land and much, much faster than the population.

But, while spread-out development would certainly not be possible without the car, the relationship between expanding cities and commute times or congestion is not simple. As cities grow, they tend to go from having a single center of concentrated activity downtown to having several smaller nodes, including some outside the city proper. This means that people are often commuting between suburbs, so living outside the central city does not necessarily entail a longer commute. Similarly, living in the city or high-density suburb doesn't mean less traffic. It is precisely when suburbs are becoming more populated that traffic congestion becomes an issue.

Finally, when people complain about sprawl sometimes they are really discontent with growth. Those in areas with high-population growth see the fabric of their community transformed by newcomers, and growth and sprawl become impossible to disentangle. Yet, the debate about sprawl intends to tackle the costs and benefits of the way we grow rather than the impact of growth itself.

The fact that "sprawl” is so interrelated with growth, homogeneity, congestion, and racial and economic segregation has confused efforts to understand it, let alone address its attendant problems. But, the fact remains that, when we are talking about sprawl, what we want to understand - at a minimum - is the impact of unlimited low-density development that leapfrogs over undeveloped land.

WHO PAYS?

Although the very term is pejorative, not all that is associated with sprawl is negative. People have always enjoyed being closer to the countryside and having greater space. According to Lewis Mumford's classic The City in History, the suburb became visible almost as early as the city itself. When British archaeologist Leonard Woolley excavated the 4,500 year-old Mesopotamian city of Ur (the Biblical city that was home to Abraham), he found remains of developments scattered as far as four miles away.

While sprawl has a long history, its spread in the United States is both relatively recent and unprecedented. It has been made possible by great technological change and our greater affluence. Americans have increasingly embraced their cars and suburban dream homes, especially after the Second World War.

Not only do Americans love their homes, but they also love them to be bigger. Given the choice of using $100,000 to buy a home in an urban or a village area close to public transportation, work, and shopping or a larger house in an outlying area with longer commutes and more yard space, 74 percent of Vermonters would choose the larger home. These choices, expressed in a survey conducted by the Vermont Forum on Sprawl, are common across the nation. In addition, people cherish safe streets and good schools, which a majority have equated with moving to the suburbs.

But the main question is whether Americans impose costs on others when they choose the larger house in the outskirts. Many researchers suspect that the answer is yes, that they are not paying the full cost of their actions.

But no one has been able to estimate the extent to which this is so. One example is the home mortgage interest deduction. More expensive houses are more likely to incur higher interest costs, and the value of the deduction is greater for high-income homebuyers. Because of this, researchers think that the deduction offers an incentive to purchase more expensive housing that is sometimes located outside of urban areas. But no one has directly estimated how much this tax preference actually affects the geographic spread of new housing.

Development on the fringe is also potentially being subsidized in the provision of public and private services. According to Robert Burchell of the Center for Urban Policy Research at Rutgers University and other researchers, low density development is linked with higher infrastructure costs in local and regional roads, water and sewer systems, and schools. It can also result in higher costs in the delivery of services such as telephone, mail, gas, and electricity to customers in the urban fringe. Do those who live on scattered or fringe development pay for those increased costs? Again, the answer is hard to calculate with accuracy. In some cases, localities charge developers exaction fees to cover these costs, which are then passed on to consumers in the price tag of their houses. But, when this does not happen, other people bear part of the expense of the new suburbanites location decision.

Public education in Maine offers a vivid example. While the student population in elementary and secondary public schools in the state declined by 27,000 between 1970 and 1995, $727 million was committed to new school construction and additions between 1975 and 1995, according to Evan Richert, director of the Maine State Planning Department. The new capacity was needed simply to serve existing students whose families had moved. Part of the tab for such new infrastructure was picked up by state funds. Because the old schools left behind in the cities had fewer students, this also implied higher per-pupil costs for maintenance in existing schools. At the same time, state and local spending on busing children went from $8.7 million to $54 million. "In a different world, the $54 million could be used to equip every student with access to state-of-the-art computers, Internet connections, and science equipment,” says Richert.

Other costs are also hard (or even harder) to calculate. Development - especially when it occurs in a scattered fashion - harms the environment by fragmenting wildlife habitats and thus places particular species in danger of extinction. It is not clear how to place a dollar value on such damage, yet the harm is borne by the animals and all human society - present and future. Similarly, researchers say that widely spread development that requires more pavement has a greater impact on water quality than more compact development. Runoff from impervious surfaces is a significant source of water pollution affecting habitats in streams and rivers as well as our own sources of drinking water, but the cost is difficult to assess.

THE FOUR-WHEELED CULPRIT

Probably the most agreed-upon source of encouragement to sprawl lies in our favorite mode of transportation. Sprawl would not be possible without the car. And, "motor vehicle use in metropolitan areas is vastly underpriced," says economist Edwin Mills. Figures of the extent of subsidies to car use vary widely depending on whether items such as the costs of accidents and "global warming" damages are tallied. But just looking at public expenditures for highway infrastructure and services, a federal study found that car users paid for only 62 to 72 percent of total expenditures in 1990.

Over a long enough period of time, this type of subsidy has probably affected the way cities developed. European cities have remained more compact than most U.S. cities, partly because they have made higher investments in mass transit and charge much higher prices for automobile use, according to Pietro Nivola, a senior fellow at the Brookings Institution. "Thanks to scant taxation of gasoline, the price of automotive fuel in the United States is almost a quarter of what it is in Italy. Is it any surprise that Italians would live closer to their urban centers, where they can more easily walk to work or rely on public transportation?" he asks.

Use of the car also imposes costs not covered by drivers such as air pollution and traffic congestion. People who choose to live farther out from the city and drive to work suffer some of the congestion consequences of that decision. But they do not pay for the cost they impose on other drivers, as each additional car lowers the travel speeds and increases congestion for everyone on the road. Similarly, drivers do not have to pay for the pollution that they create in the air everyone breathes.

For Mills, it is subsidies to the car and not sprawl per se that account for the bulk of current problems. Rather than restricting urban growth in any way, the best way to deal with the problems associated with sprawl, according to Mills, would be to raise the cost of fuel by about 150 percent so as to cover the full costs of using the car. In this way, decisions about driving would become more efficient and distance from work would factor more heavily in peoples housing decisions. Congestion would be mitigated (provided that road capacity is expanded to the right amount) and pollution would also be reduced. However, it is difficult to say precisely how much impact such a measure would have on urban form. Mills himself thinks that "any effect on suburbanization would be incidental, and would probably be minor."

THE LONG VIEW

Like other sweeping and radical plans to deal with sprawl, Mills proposal would undoubtedly incur some opposition. Although Mills suggests replacing other taxes with the new fuel tax, he acknowledges that it would be politically unpopular, as "Americans dislike tax increases, and no elected official or government can guarantee that the higher fuel tax would be offset by a permanent reduction on any other tax." (Also, even if total taxes were unchanged, tax burdens would shift, and drivers would pay much higher taxes.)

But beyond attitudes toward taxes, it is hard to make a case for changing a way of life that touches on many of Americans" most cherished notions, when we can"t tell them exactly how much damage they are causing. While most sprawl experts may believe that we are subsidizing outward development in one form or another, quantifying the extent of the subsidy is a big leap.

Yet, tackling sprawl requires that individuals consider the impact of their actions on society. No one likes to see his or her own move to the suburbs as contributing to sprawl. Sprawl is always what someone else is doing. "When voters oppose construction of new housing subdivisions, what they mean is that everybody else should live in higher-density circumstances. They certainly do not mean they are willing to have their own lots carved up to put in more housing per acre," writes Gregg Easterbrook in a recent issue of Housing Policy Debate.

Even if we were able to calculate and charge precisely the right price for low-density development, it is difficult to determine to what extent that would change our growth pattern. Costs are not the only factor that figures in on the decisions people make. The preference for a single-family detached house with a big backyard is deeply embedded in the American psyche. People may choose to limit their consumption of other goods and continue to purchase something close to their ideal home, even if it costs more.

Perhaps the concept of sprawl, because of its complexity, does not offer the best framework to deal with the short-term quality-of-life problems people are concerned about. And it might be easier to deal directly with issues such as traffic or inner-city decay - with an awareness of the consequences that the measures taken might have on other aspects or our lives. But in the long run, thinking about how we have developed thus far can help us to see where we are going. Unless we begin to think in a systemic way, it is unlikely that we will build a different future.

SPRAWL IN NEW ENGLAND

When people think of sprawl, New England is not the first region to come to mind. Blessed with beautiful forests, mountains, and coasts, as well as villages and cities steeped in history, New England has an identity of its own. A large share of the area's development took place in traditional towns and cities before car use became so widespread. And, over the last 50 years, the region's population growth tended to be slower than the nation's, so suburban development tended to be more gradual and incremental.

But the difference between New England and other regions of the country is only a matter of degree. "We haven't made such a mess of our land and waterways, but the trends are going in the wrong direction," says Scott Wolf of Grow Smart Rhode Island, a community interest group concerned about development in the state.

In fact, given its population growth, the region has been developing in a more expansive way than the nation. Between 1982 and 1997, New England consumed land at almost six times the rate of population growth, while the U.S. consumed land at two and one-half times the rate of population growth.

Rhode Island is a case in point. In the 10 years between 1987 and 1997, the developed area in the state increased by over 27,000 acres - more than twice the size of Providence - even though the population of the state decreased during that time. Jim Dodge, CEO of Providence Energy Corporation, founded Grow Smart Rhode Island after seeing the impact that such expansion was having on one of his companies. Although its customer base was growing at only about one percent a year, Providence Gas had to spend $18 million on new pipelines and equipment because its customers were moving to previously undeveloped areas.

Boston does not fit easily into the image of inner-city abandonment and decay that is often associated with sprawl. The city boasts thriving, well-preserved neighborhoods, such as Beacon Hill, and the greater concern has been over the impact of gentrification on low-income residents. Yet, the metropolitan area has experienced a pattern of outward expansion with decreasing population density Between 1990 and 1998, the city lost 16,000 residents while the surrounding areas gained 124,000, according to the Joint Center for Housing Studies at Harvard University.

A large part of that growth has taken place in southern New Hampshire and in the south coastal area of Massachusetts, which has been the fastest-growing area of the region. In turn, New Hampshire's Rockingham and Hillsborough Counties, on the border with Massachusetts, absorbed more than half of the new homes built in the state between 1980 and 1998.

And sprawl in New England has not been limited to the larger urban centers. In the more rural parts, sprawl is associated with struggling town centers, as a large share of business has migrated to the regional malls and superstores close to the highways. In addition, residential development has been altering the rural character of areas where large-lot houses replace the farms and woodlots of the working landscape.

"We know that we are going to have to grow and people are going to continue to come here,"says Steve Whitman of the New Hampshire Office of State Planning. But the issue for New England as a whole is how to accommodate that growth without losing the area's particular character.

SMART GROWTH IN MAINE

Rather than try to shape or limit urban growth exclusively through regulations and directives, Maine is launching a strategy that aims to go straight to the decisions people make in the market.

To achieve this, state planners first set out to understand what drives people to move to more remote settings and whether some people would consider staying in a built-up area. The Maine State Planning Office surveyed more than 600 recent homebuyers in late 1998 and found that the most frequent complaints about city living had to do with the lack of privacy, the crowding of houses and people, the level of noise, and the lack of access to nature and wildlife.

State planners also asked homebuyers what their ideal living environment would be. Over half of those surveyed showed clear preferences that were consistent with moving out. For instance, about 23 percent - mostly middle-to-upper income homebuyers without children at home-expressed a strong desire to have nature right out their back door and preferred little interaction with their neighbors.

But, others seemed amenable to denser living arrangements. About a quarter of the market, mainly middle-aged and middle-income families, said they valued a sense of community, intimacy with neighbors, and proximity to stores and services. They preferred being close to gyms, ball fields, theatres, and cultural activities, as opposed to having outdoor recreation outside their back door.

Nonetheless, a large share of these respondents moved to suburbia. Confronted with older in-town neighborhoods afflicted with noise, traffic, and deterioration, say planners, many consumers see few alternatives but to move out to the typical suburban large-lot, detached, single-family home. Regulatory mandates - such as minimum-lot sizes - by and large prohibit alternative neighborhoods. And spread-out development has been the accepted wisdom for several decades. This leaves builders with little incentive to undertake riskier unconventional projects that may better suit these homebuyers' needs.

"About 37 percent of Maine's public might be ready for something different if it were available," says Elizabeth Della Valle, of the Maine State Planning Office.

So, Maine's planning office is working on expanding available choices. Their goal is to use better urban design to address the issues that are pushing people out of built-up areas by promoting the construction of what they call "Great American Neighborhoods. "Based on traditional towns and villages, these neighborhoods ideally will be relatively dense - a ten-minute walk across - and will be built around a civic core such as a library or a school. They will include open space, such as a town green, and small-scale commerce. They will also have a decidedly Maine slant. "We are talking probably of lower densities than what would be acceptable in Atlanta, and the neighborhood has to have linkage to nature," says Della Valle.

Such development would help to limit sprawl - without limiting growth - by promoting more compact developments while addressing some of the lifestyle concerns people are worried about.

The "Great American Neighborhood" is part of a larger strategy to deal with sprawl. The state's planners are also looking for ways to minimize state subsidies for sprawl. For instance, they are considering directing state funds for infrastructure development only to locally designated growth areas to avoid stimulating urbanization in unwanted localities. The state will also be using a voter-approved bond issue to raise $50 million for the preservation of undeveloped land.

The next step in the promotion of "Great American Neighborhoods" will be an informational and marketing campaign designed to present the survey findings and convince homebuilders that there is a demand for this alternative. The planners will also use the information to lobby towns to reform their ordinances.

But, the most convincing argument will be built on bricks."Our immediate ambition is to get a few of these on the ground so that people can see with their own eyes," says Evan Richert, Director of the Maine State Planning Office.But, the most convincing argument will be built on bricks."Our immediate ambition is to get a few of these on the ground so that people can see with their own eyes," says Evan Richert, Director of the Maine State Planning Office.