Well.. I would say something nasty to you for something so stupid, but I won't.

You want to force everyone to take a 30min break automatically? How about i want to drive somewhere that takes 3h50 ? Or whst if there are more drivers in the car and we can stop for a quick change of drivers? Or.. whatever. I agree that driving without pausing and resting is bad but your solution is worse. It is my car, i should be able to stop whenever i want to, not when some system tells me to.