A 8-year trendOur friends at Streetfilms have create a great video (below) that shows how Americans have, per-capita, been driving less and less since 2005. This multi-year trend cannot be explained away by only gas prices or the recession, though those have certainly played a role. There are also more profound societal changes that must be recognized, but sadly, urban planners and various levels of governments keep investing in transportation as if nothing had changed. This can't go on; we need much bigger investments in walking, biking, and mass transit to accomodate how people move around.
Cars are tools. Over time, we need them to run on clean energy. But even when they do, they'll still be good at certain things and terrible at others. If you live on rural Montana, you'll probably need a car to get around. But if you live in a dense urban area, walking, biking, and mass transit are much more sensible ways to get around (especially for commuting).