Difficult Data to Understand: City Drivers Logging More Miles, Rural Drivers Fewer

"Urban driving is up 33 percent in that time; rural driving has fallen 12 percent," Henry Garbar writes for Slate. That is a huge change in vehicle miles traveled (VMT) and, while it's tempting to look for reasons in the classification of roads or in demographic change, those only account for part of the jump. "America’s cities (by which I mean, mostly, their sprawling exurbs) have grown by 19 percent in that time—meaning that bigger cities account for just 58 percent of the urban driving mileage increase," Garbar reports.

The missing 42 percent is hard to account for. It could be a result of transit decline, which is concentrated in cities, it could be that city drivers drive more when gas costs are lower, or it could have to do with the kinds of cities that are growing. "We know that urban growth—especially over the past few years—has been concentrated in sprawling Sun Belt metropolises, so it would make sense for driving to outpace urban population growth," Garbar writes.

Urbanists have long touted less need to drive as an advantage to city life. If cities and the way we use them continue to follow this trend, some of that advantage may whither away.