I fell asleep because I was tired from doing homework and what not, but what made me really sleepy was the lack of traffic, intersections, and street lights.
I drove down to Tampa Bay last June, 13 hours down non stop, and almost 20 hours on the way back and I didn’t fall asleep at all.
Treads4Heads: As far as your gf, just dont let her drive long distances I’d say. No medical help needed because when you are sitting in the same spot when you’re tired, you are going to fall asleep unless something keeps you awake. I.E. friend, traffic, curvy roads, cocaine (energy drink!), things of that nature.