Yes, automated systems will also do unpredictable things - the point I was (poorly, as it were) trying to make was that the mix of autopilots and humans are likely to create new problems; without being able to dig it out now, I remember a study which found that humans had problems interacting with autonomous vehicles as the latter never fudged their way through traffic like a human would - say, approaching a traffic light, noting it turned yellow - then coming to a hard stop, whereas a human driver would likely just scoot through the intersection on yellow. Result - autonomous vehicles got rear-ended much more frequently than normal ones.

So - humans need to adapt to new behaviour from other vehicles on the road.

When ALL vehicles are L5, though, they (hopefully) will all obey the same rules and be able to communicate intent and negotiate who goes where when /prior/ to occupying the same space at the same time...