In what Sightline's Clark Williams-Derry calls "perhaps the most compelling piece of evidence I’ve seen suggesting that there’s been a profound a generational shift in America’s driving habits," data from the Transportation Research Board shows that between 2001 and 2008, everyone drove less---but younger people drove dramatically less, signaling a major shift away from driving among Americans between 20 and 40.

Some portion of this trend may be simple economics: the recession of 2008 may have hit younger folks a bit harder than the recession of 2001. (The fact that both surveys were taken in the midst of a recession was just pure dumb luck.) And there are still all sorts of questions about what’s at the root of this trend: is it young folks substituting life online for life behind the wheel?  Environmental concerns dampening their enthusiasm for cars? More young people choosing to live car-lite city lifestyles? I’m sure there are dozens of theories out there, and probably many that have a grain of truth.

Meanwhile, the New York Times reported yesterday that although gas prices are cheaper than they were a year ago, people overall are still driving less.