Sleep deprivation can result from undiagnosed or untreated insomnia or sleep disorders such as sleep apnea, restless leg syndrome and narcolepsy. The consequences of sleep deprivation can be dangerous and particularly lethal on the road. Recent National Sleep Foundation polls found that more than one-half of adult drivers – 100 million people – reported they drove while drowsy in the past year. Nearly 20 percent said they actually fell asleep at the wheel. The National Highway Traffic Safety Administration estimates that at least 100,000 police-reported crashes and 1,500 deaths occur in the United States each year because of drowsy driving. Daytime sleepiness increases the likelihood of accidents, hinders productivity and makes relationships more difficult.