I believe the only steer-by-wire model on the roads right now is some Infiniti. Even that has a clutch which engages the steering mechanically if the car loses power.<p>Electric cars potentially have additional braking redundancy. Even if the brakes failed entirely, they could drive the motor in reverse to stop the car. I don&#x27;t think any of them actually do this, since total brake failure doesn&#x27;t happen very often, but they could.<p>You pretty much have to trust the ECU. A failing ECU could just punch you in the face with the airbag and floor the accelerator. Fortunately, they seem to be pretty reliable.