[bcraven]

In UK my yearly MOT records how far my car has driven.

Taxing distance doesn't need to track _where_ the car has been, just how far it's gone.

[Ntrails]

I seem to recall when selling cars the V5 transfer also has a mileage (so easy to attribute)

It isn't precisely easy (MOT and tax timings won't line up etc) and arrears rather than advance etc. We definitely have enough data to do a fair approximation - just high operational overheads to collect

[kordite]

It's utterly insane, but there is no equivalent to the MOT in the US. There's an emissions test, but not a safety test. I don't know if mileage is recorded at the emissions test.

[amanaplanacanal]

That depends. Do you also tax when the car is driven outside the country?

[rdsubhas]

It's legitimate to track entry and exit on national borders though. A tax exception based on entry/exit times is doable and better than constant geo tracking.