When reading discussions about sprawl, one thing often becomes painfully clear – no one quite knows exactly how to define sprawl.  Defining sprawl probably bears some similarities to Supreme Court Justice Potter Stewart’s famous definition of obscene pornography – “I know it when I see it.”   Indeed, when we’re talking about a qualitative measure of the built environment, it’s not particularly easy to come up with an authoritative definition.

First, I’d point out that when I talk about sprawl (as noted above), I’m talking about the built environment.   Too often, discussions get framed in polar terms – urbanity vs. sprawl, inner cities vs. suburbs, etc.  I don’t find any of these dichotomies are particularly useful in describing the built environment – not only do they not fit the complex patterns of development, but associations with inner cities or suburbs are too often charged with relatively unrelated social characteristics.

Sprawl is also not synonymous with suburbia, nor is it equal to a simple outward growth of an urban area.  Sprawl has four key characteristics, each of which are inter-related:

Density – sprawling development is typically low density, but land use patterns often prevent the positive externalities of density from accruing.

Segregation of land use – separating land uses into different parcels is both a product of lower densities and auto-centric design…

Auto-centrism – what distinguishes sprawl from just suburban growth is the focus on the automobile as the only real means of transportation.

Outward growth – the connotation of sprawling out, away from the city is only one factor of urban sprawl.  Sprawl often involves ‘leapfrog’ development away from the periphery.

Except for the outward growth, each of those points could be considered to be the opposite end of the spectrum for the 3D’s of Density, Diversity, and Design.

Cap’n Transit hits on some of these points – noting that all suburbs are not sprawl (and many of today’s urban core neighborhoods were once considered suburban development on the periphery):

Drum’s question actually shows that a lot of urban history is being forgotten. Most “urban cores” started out as bedroom communities. Greenwich Village, Brooklyn Heights, Long Island City and the Bronx were suburbs once. Hudson County, the part of New Jersey across the river from Manhattan, includes the four densest towns in the US, according to the 2000 census: Guttenberg, West New York, Union City and Hoboken. I’ve long thought that New York should just annex Hudson County as the fifth borough and be done with it.

If those are too “urban core” for you, consider these “streetcar suburbs” of Westchester County, all of whom have high-rise apartments walking distance from a commuter rail station, downtown shops and a supermarket: Scarsdale, where Garth Road is lined with seven- to ten-story luxury co-ops; Bronxville; the Fleetwood neighborhood of Mount Vernon; New Rochelle; Larchmont; and many more.

Oh, and for Jarrett, these Westchester suburbs all have twice-hourly trains to Grand Central Station six days a week, and hourly service on Sundays.

Most of these buildings were built years ago, between 1920 and 1960; for more recent dense suburb-building, see the claims for various DC suburbs. New Rochelle has also seen some recent high-rise transit-oriented development.