I take a flight between Seattle, WA and Atlanta, GA on a fairly regular basis, which is 5 hours going east, 5.5 hours going west. I can sit through the entire flight without having to piss.
3 hours in a car isn't a problem for me, either. I can't speak for the driver of a race car, as that's a whole different animal. I can see how someone could drive the entire race without a bathroom stop.