Every day millions of passengers put their lives in the hands of train conductors, bus drivers and the truck drivers who share the road with them. All of these jobs require long, monotonous hours with few breaks in between, which can sometimes lead to drivers falling asleep at the wheel.
When that happens, the results can be catastrophic. While some accidents are caused by simple fatigue, others are caused by an easily diagnosed and treated medical condition called sleep apnea.
Four people died and 63 were injured when a train on New York City's Metro North line crashed outside of the city after the train took a turn too fast and slipped off the rails. The cause of the accident