Driving while struggling to stay awake has the same effect as driving drunk. Reaction time slows, focus slips and controlling the steering wheel and braking becomes difficult.
A car traveling at highway speeds covers the length of a football field in a few seconds, so closing one’s eyes for longer than blink creates extreme hazards. During that brief period, a drowsy driver can miss a stop sign or red light, drift out of his or her lane, or come up on a line of slowing or stopped traffic.
Plus, a driver who jerks awake to immediately see an impending crash is likely to respond inappropriately. Panic braking and jerking on the steering wheel cause many collisions.