The edge cases requiring immediate human attention are still too frequent for the human safety driver to be remote, as is the case in Phoenix. I think you can

The edge cases requiring immediate human attention are still too frequent for the human safety driver to be remote, as is the case in Phoenix. I think you can only determine that if you know how many times the human attendant takes over. Just having a human behind the wheel doesn't tell you much, I don't see how to get full self-driving without an intermediate step of human supervision.