It doesn't invalidate the numbers if they were in ideal conditions, but it certainly means you cannot compare them to regular human drivers. That 500k number is the average from all kinds of different driving conditions. You would have to find a set of data where the humans also only drove in ideal conditions and see if the rate is any worse. I agree with the original poster and that there's not enough evidence to say that machines will be better than humans with the current technology being used.