According to the USDA’s 2010 National Resources Inventory, which tracks land use with satellite imaging surveys, the inflection point for suburban sprawl peaked in the mid-1990s, just as “smart growth” emerged onto the national scene — and before the giant housing bubble showered suburbs with seemingly limitless sums of capital. It’s been slowing ever since then, even though metro population growth moderated only slightly (see graphs on page 3). (Interestingly, non-metro population growth [including distant exurbs] in the 2000s fell much faster than metro population growth.)

It’s interesting that the slowdown in sprawl, like the slowdown in mall construction, presaged “peak car.” The directionality might be backwards: the 1980s cessation of massive freeway construction may have pushed many metro areas into some version of Marchetti’s Wall, whose daily-travel-time maximum creates a geometric limit for autocentric growth at the edge. Edge Cities, by relocating commercial uses into the inner suburbs, could only extend the outward trend so far; with a few notable examples, attempts at building Edge Cities in outer-ring suburbs has largely failed, since there’s no meaningful centrality amidst the undifferentiated masses of one-acre lots. Second-generation Edge Cities rarely thrived, because without new beltways there just wasn’t the population base to feed them.

To this day,* 80% of the office market in metro DC is within three miles of the Beltway. Joel Garreau wrote that in the late 1980s, Til Hazel “had major projects at half the exits on Interstate 66 from the Beltway to… Manassas,” but ultimately, that future didn’t pan out (with Reston-Herndon as the notable exception that proves the rule). Even in metro Boston, which uniquely among its East Coast brethren actually built an outer beltway, 73% of the office market is within the urban core or inner ring, and the urban core commands per-foot prices more than twice as high.

If you consider that the area of a circle grows with the square of its radius, a slowdown in the areas developed for sprawl would imply a much steeper decrease in the radius of metro expansion. This could imply another overlooked factor in the slowdown in VMT growth: since metro areas are no longer getting geometrically wider, thus distances between metro-area destinations are no longer growing as fast. As growth recentralizes, VMT can be expected to decline further. (A majority of the VMT benefits from central locations come from the fact that car trips are shorter; a minority of the befits come from a switch to other modes.)

* Using Cassidy Turley‘s submarket definitions.