When comedian Tracy Morgan was hit and severely injured by a fatigued truck driver, the issues behind drowsy driving were put in the spotlight. Driver fatigue usually does not receive as much attention as drunk driving, but it can be just as dangerous. Here is what you need to know.

• It is more prevalent than you think. According to a 2005 poll by the National Sleep Foundation, 60 percent of adult drivers admit to driving while feeling drowsy, and more than one third say they have fallen asleep at the wheel. Four percent, or about 11 million drivers, said they had an accident or near miss because they were too drowsy to be driving. In countries with more reliable crash reporting systems than the United States, drowsy driving is known to be a factor in between 10 and 30 percent of all crashes.
• It is probably severely underreported. According to a conservative estimate by the National Traffic Safety Administration, 100,000 accidents per year are the result of driver fatigue, resulting in 71,000 injuries, 1,550 deaths and $12.5 billion in financial loss. However, the problem is likely much worse, because many sleepy drivers may not admit their states, and there is no test to determine a driver’s fatigue level as there is for alcohol intoxication.
• Some people are more at risk. Men are more likely to drive while fatigued than women, and young people (age 18-29) drive drowsy more often than other age groups. Late-shift workers, parents of young children and people with sleep apnea or other sleep disorders are particularly at risk.
• It is more dangerous than it seems. While people tend to recognize when they are sleepy, they also tend to misjudge how difficult it is for them to stay awake. The best thing for a driver to do when he or she recognizes drowsiness is pull over and take a nap. But many drivers respond by driving faster to get to their destination more quickly, increasing the danger. According to a study by the AAA Foundation for Traffic Safety, sleeping six or seven hours a night (instead of eight or more) can double the risk of a crash, and driving on less than five hours’ sleep increases the risk by four or five times.
• It can easily be as dangerous as driving drunk. An Australian study found that staying awake for just 18 hours created a level of impairment equivalent to a blood alcohol content of .05. After staying awake for 24 hours, the impairment level was equivalent to .10, above the .08 level at which it is illegal to drive.