Careful with that statistic. People might think that we have more trucks on the road than cars which is far from the truth. Its mostly that there are really only about 10 models of trucks and probably closer to 100 cars.
So, you can skew the stats however you want depending on how you want to look at it. Overall cars are actually the lesser-selling segment in the US.
1. http://online.wsj.com/mdc/public/page/2_3022-autosales.html#...