How are they going to know? I’m betting that they are going to require all cars to have a transponder that sends the mileage to Central Computer every time you go through an intersection.
I can guarantee that “self driving” cars will be reporting their mileage to Central Computer every step of the way. Additional bill at the end of the month.
They have to finance reparations somehow. They will tax the ones who go to work an additional amount for mileage so they can pay the ones who don’t go to work to sit home, swig malt liquor, and hate the ones who do go to work.
Both of my vehicles are monitored by the manufacturers already. They tell me, by email, each month, what my mileage is until the next maintenance requirement.