Those cars in Atlanta appear to be on both sides of the road, though.
I'm not puzzled that some people abandoned cars -- either running out of gas, or somebody in the car trollifying, would explain that. I'm puzzled that other people didn't try to drive around them and fill up the other lane, shortly after which the same problem would occur in the other lane, resulting in abandoned cars on both sides of the road.
A clearing operation some time later would indeed explain it. They wouldn't have needed to clear the whole road, just the places such as bridges where tanks couldn't just go around through the fields.