I have long expected that as automakers 'relaxed' their testing by not vetting such complex issues as software, and by accelerating the introduction of more and more technology at lower cost, that a decision would have to be made:
Do we increase cost and slow innovation by testing to what we suggest here to be FAA standards?
Increase cost and weight with backup/redundant systems?
Do we ask buyers to sign a disclaimer?
Do we confine rapid innovation to non-critical systems and fall back to robust, proven mechanical systems for acceleration/braking?
I do like Colin's suggesetion of a big red "STOP" button. If we can have that on a treadmill, why not a car?