The United States Department of Transportation, [Bureau of Transportation Statistics (BTS) reports][1] that there are 272,480,899 vehicles that are registered for for highway use [as of 2017][2]. An additional 63,759 mass transit buses are also registered. Given a population estimate of 327,167,434 [as of July 1, 2018][3] of which 22.4% are below the age of 18, that gives a population of about 253,881,929.

That makes the claim to be **plausible** with about 1.07 registered highway vehicles in the United States, with a nominal increase if mass transit vehicles are included.


  [1]: https://www.bts.gov/content/number-us-aircraft-vehicles-vessels-and-other-conveyances
  [2]: https://www.bts.gov/sites/bts.dot.gov/files/table_01_11_053019.xlsx
  [3]: https://www.census.gov/quickfacts/fact/table/US/PST045218