Earlier quoted context omitted.
People are afraid of planes because if the power goes out, you die. On the ground, if the power goes out on your driverless car, you cruise to a stop.
And if you cruise to a stop in the middle of a train crossing? Or if the steering shuts down while on a long curve next to a cliff?
Steering doesn't shut down, it just goes from easy to hard. If the car is in motion it requires very little energy to turn.