The U.S. Centers for Disease Control and Prevention considers insufficient sleep to be a public health problem. An estimated 50 to 70 million American adults have a sleep disorder, according to the Institute of Medicine. Countless more suffer from insufficient sleep for a variety of reasons, from irregular work schedules to personal behavioral choices. The CDC estimates that one-third of Americans are not getting enough sleep on a regular basis. Whatever the cause, insufficient sleep is a known risk factor in motor vehicle crashes. The less sleep a person gets, the more likely he or she is to get into a car accident.