The New England Journal of Medicine reports on a study which concludes that medical interns who have been "working for 32 consecutive hours with only two or three hours of sleep" are twice as likely to get into car accidents on the way home from work. 

The study, conducted by researchers at Harvard Medical School, also concluded that when medical interns who work for more than 24 straight hours are more inclined to make "serious medical errors".

Read more here.

I have concluded, in my own parallel study, that researchers are Harvard Medical School have way too much time on their hands.