So, I should never drive? Not OP, but I experience the same thing. Driving just makes me tired. I've tried running A/C at full cold, caffeine, loud music, audiobooks, etc. Nothing helps. The strange thing is, outside of driving I don't get tired or want to fall asleep except at bedtime. I don't drive when I'm drowsy. Driving make me drowsy. The bad thing about it is I usually don't realize that I'm getting sleepy until after I've dozed off once. Then I've got to keep myself awake long enough to get to the next rest stop. 20 minute nap and I'm good to go for another few hours.