I do think that that Americans are largely choosing to use bigger cars with bigger engines that they usually require. There should be a move to small engined, smaller and more efficient autos, but I don't see that in the US.
Just move to one of several cities where the combination of parking and environmental restrictions has had a noticeable impact. It has been done and it should and probably will be done to a greater extent over time.
The city where I used to live in the US, which probably has small cars as US cities go, is very comparable (in this respect) to the city I currently live in across the pond, which probably has large cars as European cities go.
