My car is going to start just fine without a GPS or national ID card.
What if they won't let you fuel without one of them?
Yeah things are not always that simple. First of all, when I said GPS devices, I didn't mean the fancy Garmin type things that display maps and help you find where you're going. They're talking about a "black box" that sits on the dash and tracks where you go. Instead of paying the 42 cents (or whatever) tax on a gallon of gas, you pay X amount per mile - the X being based on the type of road and how busy it is.
Now, I'm guessing that cops would be on the look out for vehicles that don't have the black box on the dash or there will be be some technological manner in which a cop driving nearby can determine if you're a "tax dodger". They can already do this in the UK with car insurance whereby the cop car driving behind you scans your license plate and automatically checks against a giant database to see if your insurance coverage is current and valid - I only found out about this when my dad told me he'd been pulled over - his insurance company had somehow not updated the record in the giant DB in time.
So I suppose they could scan your license plate as you're driving and determine the following:
1] You are insured
2] You have a valid MOT (inspection)
3] You have valid road tax / registration
4] Your black box is valid and working properly
5] The vehicle's registered owner is not on some "wanted" list
Also, just a note about the Hummer vs Hybrid thing and what is "fair". You have to remember that gasoline/road usage taxes are voluntary. There is nobody forcing you to own a vehicle, drive and pay those taxes. Therefore, the type of vehicle you drive is also voluntary - if driving a Prius gives some kind of "tax break" in that respect then that's simply encouraging people to be more environmentally friendly.