A new study suggests that missing an hour or two of sleep can double your chances of a car crash the following day. Driving with only four to five hours of sleep quadruples that risk and is comparable to driving with a blood alcohol level considered legally drunk, according to researchers with the AAA Foundation for Traffic Safety. \u00a0It is believed that the risk of sleep-impaired driving has long been underestimated. National sleep organizations recommend that healthy adults get seven to nine hours of sleep each night. Teens, young adults and those recovering from a sleep deficit many need even more. Too often drivers put themselves behind the wheel without adequate sleep and that slows reaction times, decreases response accuracy and leads to lapses in attention. In an analysis of more than 4,600 crashes, sleep deprived drivers\u2019 crash risk increased steadily with fewer hours of sleep compared to those who got seven hours or more. Younger and older drivers were the most culpable in drowsy driving-related accidents. Adequate sleep should always be a priority before getting behind the wheel of a car or other vehicle.