Well, cars are very popular in general in the United States, and there exists a wide variety of vehicles on the road. According to Wikipedia, the country had an estimated 243,023,485 passenger vehicles registered in 2004. Americans prefer larger vehicles overall, and so SUVs (Sport Utility Vehicles) and pick-up trucks are very popular. According to Forbes magazine, in 2004 the 10 best-selling vehicles in America were:
1. Ford F-Series
2. Chevrolet Silverado
3. Dodge Ram pickup
4. Toyota Camry
5. Honda Accord
6. Ford Explorer
7. Honda Civic
8. Ford Taurus
9. Chevrolet Impala
10. Dodge Caravan