The only one I’m aware of is a factory installed program integrated into the stability control system of some high end German cars. I think it’s Mercedes Benz that does this. It detects lack of proper driver input which could be caused by drowsiness, corrects the car’s course to keep it in its own lane, and beeps at you and turns on a dashboard light that looks like a cup of coffee. This is a new feature, and you will probably be looking at $25-30k for a car with this option. As you noted, anyone who cannot stay awake during sustained driving does not need to be doing any sustained driving. She should find someone else to help her drive if she has to travel longer distances. Even professional over the road truckers are only allowed to drive a maximum of ten hours a day to prevent accidents caused by drowsiness.