I've yet to hear a convincing connection between driving down a public road and having privacy - in fact, the outside of a registered motor vehicle on a public road is about as non-private as you can expect.
You already have a unique plate tied to the registered owner of the car, and a range of court cases have held you can be stopped, ordered out of the car, questioned (by both police and immigration enforcement), etc.
It's not about your vehicle being seen in public at a single point in time, it's the fact that this system captures everyone's patterns of life. School, doctor, shooting range, church, play, protest. When, when, how often. All tracked and packaged up in a commercial database, without warrant or justification.
If you happened upon me on a public street, I'd say "that I'm here on this street now is not private information".
If you installed sensors across the entire city with 2-5 block resolution and could tell me everywhere I have been in the last 30 days (and hence where I'm liable to be tomorrow), I'd say "you are grossly violating my right to be secure in my person against unreasonable search - this is wrong".