One issue might be heat . Heat and electronics dont go hand in Hand. Another thing to consider is that Using an Elecrical/Electronic device for braking is really not that useful as by braking we are losing the momentum gained by the motion of the car and in principle we are wasting the energy . Thus the best use of electronics in Braking would be to gain the lost energy back. That is what the new generation cars (read as Hybrid) like prius does . It uses the energy dissapated by the braking forces to regenerate the batteries . The new versions of BMW's are also going to have some thing similar to recharge the electrical system. This enables the BMW to have an alternator system on Demand so the engine is not taxed having to run the alternator at all times.
ON a different note
If your idea of an elecrical brake was some thing like using the electrical energy to stop the car then it was utilised in a Speed record attempt to stop the car. The brake principle they used was an electromagnet which was designed to slowly retard the speed of the Car using alternate elctromagnetic pulses. It was in principle the other way of the Maglev (Bullet trains of Japan) .
I guess i might have veered off topic so i am going to stop. If you need more gyan on the maglev i think wikipedia has some good reading material |