I'm guessing you haven't driven in certain areas of the country.
So, you just made the argument for geo-fencing for limiting vehicle speeds didn't you?
Perhaps higher speed limits in remote areas where traffic is far and few in between and distances are great.....and limited to much lower speeds where there is more traffic or congestion?
Some of the posts gave me a great idea....incorporate speed reduction capabilities into ALL vehicles, then implement them based on driver record. So what if it follows the vehicle in the beginning? That driver is still most likely to be driving a vehicle registered to his or her name. Perhaps later incorporate transponder chips (similar to what's already in use for vehicle security), that is embedded into the Driver license.
No driver license....car won't start. Now if the driver keeps circumventing the laws or restrictions, then let the courts deal with them accordingly.
Not advocating it....just saying how it "might" be done.