You could probably match it to a single car owner but I'll bet you'd have a hard time matching it to a single person purely using data without some research, and people let other people borrow cars more frequently than mobile phones. Though you probably could fingerprint someone's driving style based on starts/stop cadence, turn velocity, routes, destinations, etc. and some insurance companies may already do it. They use this data to modify their clients rates automatically, already. That's why I opted to not use my housing insurer, Lemonade, to insure my car. I don't need surveillance capitalism invading yet another part of my existence.
In the case of red light cameras (https://www.thepublicdiscourse.com/2017/01/18093/), I think the legal consequences are so comparatively minor that nobody bats an eye when this gets flubbed. When it comes down to this being used as evidence in a major crime, that will probably be harder and surely defense attorneys will be all over it. From a commercial data privacy perspective, it's probably enough of an edge case that their customers wouldn't care much.
I think civil cases may be the more interesting venue for this inconsistency. I don't know if it's still true, but in file sharing cases, folks often didn't question the idea that an IP address could be mapped to a specific person. I'd guess this wouldn't be that much different than having a series of witnesses spotting a license plate without getting a clear view of the driver?
Strange times we live in.