I just watched a video that shows numerous ways police can stop a fleeing vehicle. I especially like RF SAFE STOP. It uses a remotely controlled series of RADIO FREQUENCIES to shut off the fleeing cars electronics.
RF SAFE STOP is designed to do one thing and one thing only ... fry the electrical system of cars. Pure genius ! I can't imagine what thieves, gangs or carjackers would do with such a device.
Consider the possibility that it's the driver, not the car, that is the problem. Being able to run at high speeds can alleviate traffic congestion by allowing more cars through per time unit (e.g., The efficiency and relative safety of the German autobahn)
Noting there are already EMP shielding devices already on the market, it would be easy for gangs to get hold of devices that would stop an unprotected car at convenient spots for the purpose of robbing or carjacking the unsuspecting motorist.
Years ago on the television series called Leverage, I think, they showed a device that used a micro EMP to totally disable any vehicle it was aimed at, except of course a horse and buggy. The u.s.government has experimented or developed an emp also to disable flying objects that have electric circuits, like drones or airplanes or flying donkeys.... haha... no, not that last one, not yet....
You likely already know that car dealers, selling cars, can and do routinely disable vehicles no matter how far away they are, with a "flip of a switch", through various electronic means and programs they have, and that directly access the vehicle's 'brain', etc. The police might enlist such services , if they want to, but maybe not legally yet, or just in some times and places.
Yes, the technology is there, but I don't believe it's a good move to give the police the power to use it just because it's technologically possible.