Low-density development drives up infrastructure bills. Desperate for tax revenue because residential development does not pay for itself, politicians offer tax abatements and other inducements for footloose companies. Homeowner taxes soar to fill the gap, even while street repairs, schools and libraries suffer. Each decade property values crest in rings around the city centres. Those are the golden rings of values - feasting circles of profit for developers, contractors, bankers and real estate agents. Hypermobility of the suburban era - working, sleeping, playing, schooling at locations reached only by long auto rides - breaks down the sense of community and creates sterile environments.
Urban sprawl in the United States is also hard to slow because numerous government policies actively encourage it. For example, the current federal tax policy hits earnings and savings, while interposing preferences for selected economic activities such as home-buying or the bond issues that finance new sports stadiums, industrial parks and malls. This blend of incentives frequently overstimulates the exodus of population and jobs from central cities to outlying areas. More recently, a growing tendency of the federal government to impose on localities scores of unfunded mandates - requiring everything from costly "special ed" to separate storm-water sewers - indirectly abets sprawl. Wealthy jurisdictions may easily absorb these added burdens, but fiscally frail central cities often cannot. Forced to raise their local tax rates and cut essential services, these municipalities frequently end up driving more inhabitants and firms away to greener pastures.
In many developing countries, inter-city and rural-urban migration coupled with the natural growth of the urban population are causing cities to expand faster than the municipality can cope with. Unplanned urban expansion results in the creation of informal settlements and slum areas and causes a twofold problem. First, it decreases fertile agricultural land, and second, the disposal of both sewage and solid waste into irrigation canals creates negative environmental and operational effects on farming activities in the vicinity. For farmers the two main problems are pollution of irrigation water and the blockage of irrigation water pipes and openings.
The private New York Regional Plan Association, in 1929 and 1968 reports, called uncontrolled growth the greatest threat to the New York - New Jersey - Connecticut region. Officials failed to listen. Land was devoured 12 times faster than population grew. Suburbia became the region's engine of growth.
2. Urban sprawl divides people physically and spiritually, isolating the poor especially.
3. Restraints or guides on growth are routinely rejected as anti-business.
4. "Indiscriminate development on urban fringes is threatening areas which are predominately rural in character and is injurious to the central community," stated the New York Regional Plan in 1929.