Holy shit!
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They've been doing it for years in Trucking. GPS,Cameras,Plates (on the road) and Quick Pass (Electronic Reader) for scales. No more "Drive Hard".
There's no need for RFIDs. Don't really need a license plate, even.
Your vehicle itself is enough of a signature to be uniquely identified. A scattering of cameras, a large database, and some decent software would do the trick.