As a denizen of northern Virginia I'll note that I'm a huge fan of the VRE. Driving within the beltway is miserable and I prefer public transit whenever I can.<p>I have to reach the Madison building every few weeks and I can generally make it by driving down the street to the Manassas Park station and riding to L'Enfant Plaza, where I can jump to the metro. The whole trip takes hour: I can leave at 7:45 and be sure of getting there before 9:00. In contrast, my boss leaves the house at 6:30 and heads to the Vienna metro (the westmost point of the DC metro) and arrives around the same time I do. He has to leave early because there is no parking at Vienna after 7:30. Both of us live near enough to each other that our commutes comparable.<p>The worst traffic in the US is caused by commuters and most of that is due to the vast amounts of sprawl. It's not always feasible to live within reasonable distance of your place of work and that leads to people needing drive farther and longer, leading to more traffic over-all. Things like commuter trains help a lot because the infrastructure is mostly in place and they can go faster and cover more ground than metros but it won't help until people start living a little closer together.