Wrap the car in a large faraday cage? As a general rule it should be assumed that any device with a direct to internet connection capability has the potential to track the user, even of it's at a very course level like IP history that in theory could be made more precise if the ISP was inclined to keep tabs on a mac address.

My own vehicle has the ability, if not the subscription, to use one of those manufacturer sponsored satilite connections. Plenty of new vehicles have such things as paid DLC and just lock it up behind software but the hardware is still there. Physical interferance through disconnecting the relevant modules in a clean reversible way has potential for some enterprising sort to either open a school or a specialty repair shop. Now if we could just do something about the phone the driver has with them at the same time.