While distracted driving is bad, there are other causes of car accidents that are just as dangerous. Like distracted driving, fatigued driving has increased steadily as a cause of car accidents. According to the National Sleep Foundation, while drivers of all ages drive while fatigued, about 55 percent of all drowsy driving crashes involve a driver under the age of 25. About half of all adult drivers in the United States admit to getting behind the wheel when sleepy and fatigued. About twenty percent said they have fallen asleep behind the wheel over the past year, and 40 percent admitted they have fallen asleep at the wheel at some point in their driving career.