What about an AI that refuses to start for a drunk driver? Boom, problem solved at the fraction of complexity and no innocent people get butchered up in the testing phase of a software that simply can’t reliably work with current tech.
But as for the very specific emergency case while you are drunk, it could be overridden with some visible sign turning on notifying other drivers - but it would need some law background, so eg. a cop can escort you in that case, etc. But tesla’s fake self-driving doesn’t help anyone.