I don't think Americans really need to do anything personally. I think the primary issue is the lack of public transportation here in America. We need leadership on this from the top so that we can catch up to the rest of the world. You can go anywhere in Europe in hours on a train. I know America is big but we are still (perhaps) the richest country in the world and we can implement a quality public transportation system. It would even help the economy by providing jobs, just like all of the infrastructure projects of the new deal did.
Besides public transportation though, just working on our infrastructure would help with fuel saving. Sitting in traffic all day doesn't help MPG. Hell, sometimes I wish I had an SUV for some of the roads here in Pittsburgh, with the potholes its like I am driving through in Iraq. Also, my beef isn't really with all SUVs. I mean the Traverse gets what 33/mpg? I am talking about the people who drive Escalades to and from work and don't haul anyone around.