The hole in DOT rules and regs works like this: Drive all night to deliver load, sleep at 5 am. Sit all day and night with no work, new load at 5 am. So sleep schedules are always flip flopping. This driver fell asleep. Think of it this way: as you tire your IQ falls this driver already started with a low IQ so was driving with monkey level thinking. That's why he was able to keep it straight in the wrong lane.