I googled it up and 209M adults vs 183M passenger vehicles. In the USA registration wildly varies by state and the actual stat is a quarter billion "vehicles"

I googled it up and 209M adults vs 183M passenger vehicles. In the USA registration wildly varies by state and the actual stat is a quarter billion "vehicles" but in my state every non-rowboat boat is a registered vehicle (although essentially unenforced for small sailboats and inflatables) and every boat trailer is yet another vehicle and every RV is a registered license plated vehicle and every trailer and etc. My parents never owned more than one car although they had five "registered vehicles" at one point. Also any commercial vehicle that drives on public roads, in my state this includes SOME farm tractors and other farm equipment. Needless to say every motorcycle and moped is a registered vehicle, and in my municipality, resident bicycles are technically required to be registered although never enforced. Nationwide there's about 70M "things that move and pay registration tax and are not cars" that are registered as vehicles. Very near one per adult. As a check on the figures, note there's only 105M "housing units" in the USA, so when you see strange figures reported about 300M to 400M vehicles its obvious that the average house does not have four cars parked in front of it, and that figure includes scrapped cars in junkyards and railroad cars and minecarts and things like that.