Devices may be available, but when I say working on it I more mean getting around the Fourth amendment. Or does that one count anymore?
By the way, I assume even if the devices are installed at the factory it’ll be too easy for drivers to interfere with them. Traffic cameras don’t seem up to the job. I imagine roaming robot spy planes.
Pay by the mile is a reality on “express” toll lanes on several Atlanta interstates. They are using transponders right now, and compliance doesn’t seem to be an issue. Billing is automatic to your credit card.
The statewide thing will be a combo GPS and transponder system that periodically reports miles driven since the last data collection point.
I am not in this field, but am good friends with someone who is.