We have the right to own a gun, but in most of the US owning a car is a necessity. There is some route available in most states but it's incredibly cumbersome compared to something like making your own gun.
Hypothetically, "Motorized transportation, being necessary to the mobility of a free State, the right of the people to keep and drive automobiles shall not be infringed."
Imagine the vehicles we would have. For one thing, the impossible-to-meet CAFE standards, which make it economically infeasible to sell compact pickup trucks in the U.S., would probably have been declared unconstitutional. On the other hand, laws requiring seatbelts and airbags probably would have also been unconstitutional.