Driving under the influence.
Drunk driving is a factor in nearly half of all fatal accidents and causes numerous crash injuries every year. However, alcohol is not the only substance that can impair a driver’s ability to operate a vehicle. Prescription medications, illegal narcotics, and over-the-counter medicines can all cause confusion, drowsiness, and poor decision-making.
Even if a tired driver is able to avoid falling asleep while driving, he or she may have slower reaction times than an alert driver, making it more difficult to respond to sudden road hazards.