Old news. Google: law enforcement herf gun or EMP gun.
Some police forces have had these since at least 2008.
Also, those arguing that this is unlikely because disabling a car this way could lead to collateral damage, are living in some nice rose-coloured world that isn't this one. So do Predator drone Hellfire missiles, or firing machine guns at a car driven by a couple of lady schoolteachers, and yet...
I had a conversation about 5 years ago with the manager of a vehicle service company that serviced Subaru and Mercedes cars. The stories he told me about electromagnetic susceptibility of cars, even Mercedes, convinced me that either the designers of car electronics are incompetent fools, OR there is an official policy of making modern cars deliberately vulnerable to HERF guns.
The second case sounds much more likely to me. (With a dash of the first mixed in.) Very useful for the State to be able to ensure that any consumer vehicle can be disabled from a distance. When they really want to stop them, in those special cases where a police chase isn't getting the job done.
Then again, there are other options now. Google Michael Hastings assassination, car computer remote control.
That manager drives an old, computer-free car, for the same reasons I do. And I'm a retired embedded microprocessor systems design guy. I'm NOT driving a car with any software involved in the car's function. Bad enough that my car has some electronics in the spark plug drive - that's probably enough to make it vulnerable to a HERF gun. But at least it's real 4WD, unlike my ex-wife's Honda CRV, in which the computer doesn't understand driving on sand, and the so-called '4WD' vehicle digs its front wheels floor-pan deep within a few meters of driving onto sand. No manual '4WD on' control either. Genius.