Presumably, if a specific person is a very good driver, entering an automated vehicle that is merely better than average driver, with no controls to interject, results in a net reduction of safety for this individual.
More specifically, what IF or rather WHEN there is an incident that could've been prevented by human interjection, but wasn't?
Other aspect is, why are we only ever discussing these separately? What is the safety of a automation-assisted human? Can we get to the point where safety is better than either system alone?