Some people think that curtailing suburban sprawl through “smart growth” — transit-oriented development, walkability, higher densities, green building — is a theory-based movement dreamed up by a bunch of academically minded planners and architects. In fact real-world market forces, not theoretical, are making sprawl-producing planning, zoning and mortgage finance templates increasingly obsolete.
Until recently, these dominant templates embodied widely accepted planning conventions responsive to prevalent market conditions. For decades, subdivision development was America’s primary model for physical growth. New suburban communities encompassed thousands of low-density residential subdivisions comprising detached, single-family homes and the public infrastructure supporting them. Reaching ever farther into the countryside, they encircled older cities plagued by increasingly dysfunctional public education systems, rising crime and poverty rates and shrinking employment opportunities. Perceived as safe, attractive and affordable, suburbia was also where jobs were going.
Suburban planning and zoning templates were predicated on four key assumptions: that America had an unlimited supply of land; that automobiles and road building, thanks to inexpensive and presumably inexhaustible supplies of petroleum, would forever satisfy metropolitan transportation needs; that grouping homogenous land uses, not intermixing them, would best protect property values, especially for residences; and that the only way to realize the American dream was to own and inhabit a mortgaged house.
Today these assumptions have lost validity. Much of America’s land cannot or should not be developed. Dependency on oil and limitless use of cars pose daunting environmental, economic and geopolitical problems. Homogenizing and grouping land uses impede walkability, diminish transportation efficiency, waste energy and promote social segregation, all without necessarily enhancing real estate values. And when homeownership dreams recently became financial nightmares, many Americans discovered that having a house and a mortgage might not be all they were cracked up to be.
Yet market conditions are changing for another reason: demography. Regional and sub-regional populations are changing. Cities formerly shrinking in population, such as the District, are now growing. According to just-released 2010 census data, America’s demographic picture has markedly shifted in numbers geography and ethnic composition.
Whites have become a minority in many urban and suburban areas where Hispanic and Asian populations have steadily risen, and in some areas black population has decreased. The traditional nuclear family — mom, dad, two to three kids and one or two pets — is now a minority of America’s households. Today a majority of households are people, young or old, living alone; couples or sets of unrelated individuals of various ethnicities, ages and tastes; growing numbers of elderly requiring less dwelling space but more living assistance, and single, low-income parents struggling to support dependent children or perhaps a dependent adult.