We're Americans. We travel whenever we damned well feel like it, without being detained, without explanation and without showing papers. It's our birthright.
If you don't like it, move. There is no shortage of third world pissholes and communist hellholes that violate those rights.
Stopping people in the streets and checking out the car for highway safety has been going on for as long as cars have been on the road.
You do not have a birthright to do anything with impunity on PUBLIC roads. I don't know where you get that from.