Oh, and my prediction on how the above question will play out: For decades OEMs will tell users, "Don't take fucking naps. Pay attention. if the autonomy system fails and you don't catch it, it's on your dumb ass."
Much to Aldarion's dissent, a big part of autonomy development is a camera in the cabin monitoring the driver. In cars that actually care about safety (ex: volvo), expect to see some nanny-cam that bitches and moans when it detects the driver isn't paying attention. After enough autonomy failures this might become a feature required by government.