You know that's already happening right? For example, SunPass in FL will bill you by your license plate as you go through automatic readers, and mail you a bill to California if that is where your car is registered.

The 'mass' in 'mass surveillance' is a matter of degree. Most roads are not presently toll roads. Most are not presently tracking all cars that drive on them.

I don't find 'some surveillance happens already, so we may as well go all in' a compelling argument.

Mass surveillance is about indiscriminate surveillance(recording everyone that comes through in case a bad guy comes through), as opposed to specific surveillance(trailing a mobster to see where he goes). You can have mass surveillance on some roadways without most roads being surveilled.

You can have mass surveillance at a stadium and no surveillance outside the stadium. Likewise, you can have mass surveillance on a toll road and not on county roads.

Part of your point was the difficulty of inter-state cooperation in this regard, which is incorrect, or at least the difficulty has already been overcome, because this data has been shared with SunPass for ~20 years.

And no one made an argument that because we have a little we should have a lot. My point was that what you find intolerable of is already happening.