Baph

Not really, as you're still free to walk/catch a bus etc. It's only the method of movement that's restricted, and then only by the size of your wallet.

Good plan, but if they use even half decent GPS gear, that won't work. Now, don't tell anyone to open the box & put tin foil over the back of the PCB... I'll earn a mint doing that (before it's a legal requirement to have the black box officer!!).

If it's going to work, it'll have to be along the lines of the already existing Tracker (used for tracking stolen vehicles). But as evidenced on the .org before, even those can be beaten.

EDIT: Double-taxation? I'd say it's tripple. Fuel tax depending on how much of it you burn, road tax depending on how quickly you burn fuel, and "pay as you drive" for how much of the road you drive on, and at what time.