As I've stated before when I make very occasional posts, I am not a pilot and will not comment on piloting issues - I am a Position Navigation and Timing Technologist with particular interest in testing navigation systems with emphasis on security (and of course evaluating the effectiveness of highly automated systems and how to test them). I suggest that some of you might appreciate reading the NTSB investigation into the recent (and fatal) accident between a highly automated car and a tractor/trailer in Florida. It highlights many of the issues associated with autonomous vehicle navigation - and also the issues around developing a navigation system suitable for use in dynamic traffic situations that does not require human intervention at some point.... As I have less than 10 posts I can't provide a link to the report but its reference is NTSB/HAR-17/02. If you think it worthwhile, perhaps someone else could post the link?