Anywhere in aviation it's redundant transducers (the thingies that transform rotation into some sort of signal), redundant flight law computers implemented by independent teams on dissimilar hardware, a stupidly robust vote/compare module, I think mostly analog, and usually a last resort direct mode.

When all of that is implemented in cars and weathers for 10-20 years I might consider it.

Otherwise, seeing as Toyota's regen braking code had like 10k global variables, I'm not touching that with at 10 foot pole.

Acceleration/braking can be quite bad but there's normally neutral and ignition switches. With steering there's literally nothing between you cruising along a highway and you splattered on some concrete pillar 200ms later.