It would appear the out of towners use those early morning hours to EVADE the locals!
Absolutely! That is why I make sure that I leave early enough to get through Atlanta by 0600 Hrs. I mean all the way through and out the other side by 0600 hrs.
Incidentally, my afternoon rides through aren't as bad, but I tend to plan my trips to pass through Atlanta between 1 and 3 PM. After 3 PM, you get the afternoon rush hour traffic.