According to the
US Bureau of Transit Statistics for 2004 there are 243,023,485 registered passenger vehicles in the US. Out of these roughly 243 million vehicles, 136,430,651 (56.13%) were classified as
cars, while 91,845,327 (37.79%) were classified as "Other 2 axle, 4 tire vehicles," presumably
SUVs and
pick-up trucks. Yet another 6,161,028 (2.53%) were classified as vehicles with 2 axles and 6 tires and 2,010,335 (0.82%) were classified as "Truck, combination." There were approximately 5,780,870 motorcycles in the US in 2004, which accounts for 2.37% of all registered passenger vehicles.
According to cumulative data
[1] by the
Federal Highway Administration (FHA) the number of motor vehicles has also increased steadily since 1960, only stagnating once in 1997 and declining from 1990 to 1991. Otherwise the number of motor vehicles has been rising by an estimated 3.69 million each year since 1960 with the largest annual growth between 1998 and 1999 as well as between 2000 and 2001 when the number of motor vehicles in the United States increased by eight million.
[1] Since the study by the FHA the number of vehicles has increased by approximately eleven million, one of the largest recorded increases. The largest percentage increase was between the years of 1972 and 1973 when the number of cars increased by 5.88%.