There's evidence to suggest that America's already reached peak driving. The latest figures from the U.S. Department of Transportation suggest that vehicle-miles increased by 18.1 billion miles in 2013, just half a percent on the previous year. That's a rise, of course, but not enough to skew statistics showing that mileage has plateaued since its high mark in the mid-2000s:
Meanwhile, the U.S. population grew by about .7 percent in 2013, so per capita vehicle miles actually declined — for the ninth year in a row. Analyst Tony Dutzik writes that the latest per capita VMT rate is about 7 percent below its 2004 peak. In fact, when you adjust for the driving population, as financial advisor Doug Short has done, the 2013 VMT rate "is about where we were as a nation in January of 1995":
So if we really are driving less than we used to — or, at the very least, no more than we used to — when will we stop increasing road capacity? Traffic growth or decline is a notoriously difficult trend to forecast accurately. But given vehicle-mile trends, it stands to reason that sooner or later states and cities will warm to the possibility that maintaining existing roads is a wiser public investment than building new ones.
Chris McCahill at the State Smart Transportation Initiative points out that some places are already accepting this sea change. Back in 2009, for instance, the Maryland DOT projected 2 percent VMT growth through 2030 (below), citing "no clear evidence that Marylanders will continue to drive less in the future." Last month, however, it reversed course and not only acknowledged per capita VMT declines but omitted traffic projections.
Local officials can't help but notice the trend, too. At Sightline, Clark Williams-Derry tracks the enormous drop in traffic — 48,000 daily trips — that's occurred of late along Seattle's Alaskan Way Viaduct, an urban interstate that's being removed and replaced by a tunnel. Construction obviously has a lot to do with the decline, but peak driving might too, since the dip predates all the road work:
Sightline commenters make clear that the viaduct is very congested at times, so maybe more road capacity here will help. But the point made by Williams-Derry is that Seattle has adapted to the loss of 48,000 trips without much effort (a modest transit increase captured most of them). If officials had known that only 62,000 daily trips would remain in the viaduct corridor, would they have pushed for a multi-billion-dollar replacement tunnel or closed the gap with cheaper alternatives?
What all these data and charts point to are the merits of a fix-it-first road funding policy that puts road maintenance before road construction. For sure, we need a new source of funding, with the busted gas tax nearing its demise. It's also high time to challenge the idea that the amount of road funding we'll need in the future is the same as what we've needed in the past.