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Drowsy Driving

Left untreated, snoring and sleep apnea result in chronic sleep disruption and excessive daytime sleepiness. Excessive sleepiness can cause slowed thought processes, poor memory, delayed reaction time and difficulty concentrating.

Inadequate sleep, shift work, jet-lag and sleep-disordered breathing have been implicated as factors contributing to sleep-related accidents.

If you're driving tired… you're driving impaired.


Drowsy drivers put themselves and other road users at risk. Fatigue affects our ability to drive by slowing reaction time, decreasing awareness and impairing judgment.


Most of us have driven tired or sleepy. Many think that just because we haven't been drinking, we are OK to drive. But the evidence shows that an over-tired driver can be as dangerous as a drunk.


Many who would never drink and drive think nothing of hitting the road exhausted. According to the Traffic Injury Research Foundation an alarming 20% of Canadians admit to falling asleep at the wheel at least once a year.


Canada's official road safety agency estimates fatigue is a factor in 19% of fatal collisions and 23% of crashes where no one dies.


Snorers are 3x more likely to have a single or multiple motor vehicle accidents.


Snorers with mild SDB are 7x more likely to have multiple motor vehicle accidents.


Male snorers have 3 x the risk of occupational accidents


Who's more likely to drive drowsy?

  • Commercial drivers

  • Shift workers (work the night shift or long shifts)

  • Drivers with untreated sleep disorders such as sleep apnea

  • Drivers who use sedating medications

  • Drivers who do not get adequate sleep




According to the National Sleep Foundation’s 2005 Sleep in America poll, 60% of adult drivers – about 168 million people – say they have driven a vehicle while feeling drowsy in the past year, and more than one-third, (37% or 103 million people), have actually fallen asleep at the wheel! In fact, of those who have nodded off, 13% say they have done so at least once a month. Four percent – approximately eleven million drivers – admit they have had an accident or near accident because they dozed off or were too tired to drive.

How dangerous is it to drive while drowsy?

Laboratory research suggests that driving while sleepy can be as dangerous as driving while drunk. One study of healthy young adults found that performance on a driving simulator after 18 hours of being awake was equally impaired as a blood alcohol concentration (BAC) of 50 mg%, or slightly less than the legal limit. After being awake all night, driving performance was as bad as a BAC of 80 mg%, which is the “legal limit”. Other research has found that reaction time, one of the skills critical to driving, is more impaired in patients with untreated sleep apnea than healthy individuals who are legally intoxicated.

Drowsy driving is implicated in an estimated 20% of motor vehicle accidents making it a significant contributor to accident related injury and death.1 Fatigue related to driving at night and restricted sleep greatly increases the risk of a motor vehicle accident. Accidents are 5.6 times more likely to occur between 2 and 5 o’clock in the morning and 8 times more likely when driving while sleepy. The incidence of sleep related motor vehicle accidents is higher in drivers who report sleeping less than seven hours per night on average. One study found that after a single night of restricted sleep (5 hours) drivers showed significantly reduced performance in a driving simulator. 2

The American Academy of Sleep Medicine, President Dr. Sam Fleishman, described that, "Drowsy driving is a serious risk to personal health and public safety, and snoring is an important warning sign that should not be ignored." 3

The American Automobile Association (AAA) estimates that one out of every six (16.5%) deadly traffic accidents, and one out of eight (12.5%) crashes requiring hospitalization of car drivers or passengers is due to drowsy driving. The full national sleep foundation white paper is available HERE.

The AASM released a free online presentation about drowsy driving that describes the signs, causes and effects of driver fatigue.



Tips to Avoid Drowsy Driving


Sleep                     Get enough sleep – most people need 7-8 hours of sleep per day to function well

Companion         If you’ve only had a few hours of sleep have someone else drive. Plan to drive long trips with a                                                  companion. Passengers can help look for early warning signs of fatigue or switch drivers when needed.                                  Passengers should stay awake to talk to the driver.

Nap                      Take a nap before driving & after every 2 hours of driving

Plan                      Take a break every 2 hours for a stretch & fresh air.

                              Drive during daylight hours

Caffeine              Consume the equivalent of two cups of coffee. e.g. soft drinks, energy drinks, coffee, tea, chewing gum,                                   tablets; for best results, try taking caffeine and then a short nap to get the benefits of both.

Alcohol and medications, whether over-the-counter or prescribed, may impair performance. Alcohol interacts with fatigue, increasing its effects. Antidepressants, anti-anxiety, sleep aids and pain relievers; can all contribute to drowsiness.

Signs That Should Tell A Driver to Stop & Rest


  • Difficulty focusing, frequent blinking, or heavy eyelids

  • Daydreaming; wandering/disconnected thoughts

  • Trouble remembering the last few miles driven; missing exits or traffic signs

  • Yawning repeatedly or rubbing your eyes

  • Trouble keeping your head up

  • Drifting from your lane, tailgating, or hitting a shoulder rumble strip

  • Feeling restless and irritable


If you have even one of these symptoms while driving, you may be in danger of falling asleep. Pull off the road and take a nap.



1. Horne JA, Reyner LA: Sleep related vehicle accidents. BMJ  1995; 310:565-567.

Philip P, Vervialle F, Le Breton P, et al: Fatigue, alcohol, and serious road crashes in France: factorial study of national data. BMJ  2001; 322:829-830.

Connor J, Norton R, Ameratunga S, et al: Driver sleepiness and risk of serious injury to car occupants: population based case control study. BMJ  2002; 324:1125.

2. Banks S, Catcheside P, Lack L, Grunstein RR, et al: Low levels of alcohol impair driving simulator performance and reduce perception of crash risk in partially sleep deprived subjects. Sleep  2004; 27(6):1063-1067.

3. Centers for Disease Control and Prevention: Drowsy Driving – 19 States and the District of Columbia 2009-2010. January 4, 2013; 61(51);1033-1037.

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