> You contend that there are millions of people who knowingly drive while tired enough to fall asleep at the wheel and with a history of doing so?

Yes? There are even millions of people who drive drunk every year, which is a far more conscious choice to endanger other people than someone driving home after long, late shift.

15 million people work a night shift. If 10% of them drive home drowsy one night per year, you're already at millions.