A study by two researchers in Journal of the American Planning Association has proven what we already knew: that sprawl begets sprawl.
The authors found that “adding one large subdivision event within one-quarter mile of the parcel in the previous period was associated with a 42 percent increase in the odds of the parcel subdividing.” In other words, we’re much more likely to see a new subdivision cropping up near a recently built one than we are to see it where there has been no previous development. Or, put yet another, perhaps unsurprising, way: sprawl spreads.
Wilson and Song found a number of other factors that increased the likelihood of new development, including being near the I-485 freeway, being near a rail corridor, and being near demolition activity, but none of these was as influential as being near previous development. (Emphasis mine)
Meanwhile, the 2010 Census has found increased density along the Washington, DC Metrorail lines. It’s a reversal of the 1990s trend that saw so much sprawl outside the Beltway:
(T)he areas of Northern Virginia that saw the greatest percentage growth between 2000 and 2010 were all clustered around Metro stations — in Arlington along the Rosslyn-Ballston Corridor (Orange Line) and in Crystal City (Yellow and Blue Lines); in Alexandria near Van Dorn Street Station (Blue Line) and Eisenhower Avenue (Yellow Line); and in Fairfax County near Vienna/Fairfax Station (Orange Line). As other areas of close-in Virginia have been fully developed, these station area zones have densified through the coordinated planning decisions of city officials, the availability of rail rapid transit, funds from developers, and a clear interest of a large portion of the population to inhabit the new buildings.
In the case of the Rosslyn-Ballston Corridor, the Census Blocks within closest proximity of the five Metro stations along the Orange Line absorbed more than 70% of Arlington County’s growth, increasing by 12,816 people compared to Arlington’s expansion by 18,174 people towards a total population of 207,627. These 1.47 square miles arrayed linearly — a small percentage of Arlington’s 26 square miles — now represent more than 17% of the county’s population, compared to about 12% in 2000. (Emphasis mine)
The old growth paradigm — in which cities must grow suburbs like colonies of mushrooms — isn’t sustainable, and is actually more expensive than the density model. Mile for mile, money spent on new roads for new development creates fewer jobs than mass transit, too (.PDF). In fact, one can look on the age of subprime NINJA (No-Income, No Job or Assets) mortgage loans as an enormous, busted national investment in sprawl. Time for a different paradigm.
