问答题

Even on paper, urban sprawl looks ugly. It looks more so from the 110th floor of Chicago’s Sears Tower. From there you can survey, into the misty distance, a metropolitan area that now encompasses no fewer than 265 separate municipalities and covers 3,800 square miles in six northeastern Illinois counties.
The expansion of the region is sometimes described as growth. More accurately, Chicago has simply spread out. Between 1970 and 1990 the population of the metro area increased by only 4%, while land used for housing increased by 46%. More telling, land used for commercial development increased by a whopping 74%.
The drawbacks of sprawl need no repetition: the isolation of less mobile (usually poorer) groups in the inner cities, and the premature abandonment of infrastructure. Worse, these problems are now overtaking the very suburbs that were once supposed to escape them. Between 1970 and 1990, the city of Chicago lost 17% of its population while the suburbs gained by 24%. But the inner suburbs lost people too. Over the past ten years, 70 inner-suburban towns have lost residents to towns on the periphery.
A recent series in the Chicago Tribune, "The Graying of Suburbia", documented the population decline of inner-ring towns ranging from dilapidated Dolton and Harvey to relatively up-market Elmhurst and Skokie. In the harder-hit cases, population loss has been compounded by falling property values along with rising crime and unemployment. (Several inner suburbs have banned out-door "For Sale" signs to curb the growing sense of panic.) Their fate contrasts with Naperville, a booming outer suburb, which is currently developing a 10,000- acre site for 22 more housing tracts and several shopping malls. Since 1980, Naperville’s population has more than doubled.
The expanding towns on the edges make no apology for their prosperity. Sprawl is natural, they argue ; Americans live in smaller households ( true-house-holds increased by 20% when population grew by only 4%) and they want bigger houses (also true—and they want three-car garages ). Businesses in turn follow the outwardly mobile workers. They also appreciate the cheaper land and better roads. As a case in point, ask Sears. The very company that built the magnificent downtown skyscraper relocated 5,000 workers to the outer suburb of Hoffman Estates in 1992.
Critics of sprawl argue that government deals an unfair hand. An article published this summer by the Federal Reserve Bank of Chicago shows that various incentives in the federal tax code, including the deductibility of mortgage payments, promote over-consumption of housing. The code also allows taxpayers to defer capital-gains taxes if they buy a new home of equal or greater value, which pushes buyers towards higher-priced houses—most of them on the edges of cities. Another subsidy is provided for cars, the sine qua non of suburban life. By some estimates, existing taxes on motorists cover only 60% of the real costs of government road-related services.
Far from expanding under one central authority, almost all metro areas are tended by a hotch-potch of city, town and other smaller governments. (Metropolitan Chicago has over 1,200 separate tax districts, more than any other in the country.) The quality of the services provided by these governments depends on the quality of the local property that they have to tax; so aggressive jurisdictions offer rebates or subsidies to win juicy new developments.
The outcome, on one front, is often the premature development of new land. Towns on the outskirts, armed with subsidies and plenty of space, lure development away from the center. In the past 20 years 440 square miles of farmland have been developed, with sites further in are abandoned. The city of Chicago alone has over 2,000 vacant manufacturing sites.
Tax-base competition also encourages sprawl in other ways. When the taxing jurisdictions are so small, the departure of wealthier residents and business increased the strain on those left behind. Taxes must go up just to maintain the same level of services. Thus in Harvey, a declining suburb, the property tax on a $ 50,000 house is $1,400—whereas in booming Naperville, if it had such cheap houses, the rate would be around $900. At the same time, the Harvey property taxes do not stretch very far. Last year, the local school district was able to raise only $1,349 per elementary school pupil, compared with $7,178 in wealthy Wilmette. Although state funds help to even things out, the disparities become another reason to move.
Over the long term, there is a chance that sprawl will not go unmanaged for ever: that the price of inner-city decline will eventually become too high. But it has not reached that point yet. The inner areas would like to see a regionally coordinated effort to pursue economic development (to diminish tax-base competition), or a region-wide sharing of commercial tax revenues, as has been tried to good effect in the Minneapolis—St Paul metropolitan area. But the deeper incentives to sprawl will still remain. Subsidies for home ownership are well guarded by lobbyists in Washington, and local governments are rightly jealous of their self- determination. For the time being, metropolitan areas like Chicago will just keep expanding. So what if it means loosening another notch on the belt

Why is the inner city losing its population