Edit: thank you everyone for your replies. i will not officially close the thread but i got some good information from everyone. i think my theory was disproven. ---- When i was a baby my parents would get frustrated i didnt take naps well and would drive me around the block until i fell asleep in a car seat. I dont know if its because of that or if its because woman are naturally bad drivers or some other thing, but now as an adult, even if i get good sleep i will have moments when im driving where my vision will shake and i have to hit myself to stay awake otherwise i will then black out for a second (dozing off) and have to force myself awake before i hit traffic. the only time i do not have this issue is if i havnt driven in a long time or if im not going for a long drive. i mostly had this issue when i was working, going to school, and was on the road all the time fairly sleep deprived, but even in that time period i would still black out if i was well rested. I do not have that issue now but im a stay at home mom with a rare reason to drive.