I'm driving a car right now that was given to me by my BIL and when he had it he fell asleep at a stop sign and coasted through it. He ended up running into a pole on the other side of the intersection. He was stone cold sober. My point is that it is very easy to fall asleep when you are tired. My BIL fell asleep at a stop sign where there is no waiting time as opposed to a street light where you have to sit and wait momentarily. I know a few people that have fallen asleep while driving and I often get drowzy in fact while driving and I don't drink and drive at all.
Obviously I am not saying that Floyd wasn't drinking at all, but I am saying is that we can't assume that he had a "pretty high" BAC. He may have had a very high BAC, but he may also have just been exhausted. I don't trust the NFL's judgement for anything.