Dangers of Driving While Drowsy


he National Highway Traffic Safety Administration estimates that drowsy driving results in 1,550 deaths, 71,000 injuries and more than 100,000 accidents each year.

Nearly nine out of every ten police officers reported they had stopped a driver who they believed was drunk, but turned out to be drowsy.  The AAAFTS survey also indicated that:

Younger drivers age 16-24 were nearly twice as likely to be involved in a drowsy driving crash as drivers age 40-59,

About 57 percent of drowsy driving crashes involved the driver drifting into other lanes or even off the road.

More than half (55%) of those drivers who reported having fallen asleep while driving in the past year said that it occurred on a high-speed divided highway.

More than half (59%) of those drivers who reported having fallen asleep while driving in the past year said they had been driving for less than an hour before falling asleep; only one in five reported they had been driving for three hours or longer.


Drowsy driving is operating a motor vehicle while sleepy, fatigued or “tired/exhausted”.  Sleepiness and driving is a dangerous combination. Most people are aware of the dangers of drinking and driving but don’t realize that drowsy driving can be just as fatal. Like alcohol, sleepiness slows reaction time, decreases awareness, impairs judgment and increases your risk of crashing.1

The potential to fall asleep behind the wheel can’t be judged by the operator – they simply fall asleep and typically lose control of their vehicle.

This training topic looks at the underlying causes of “drowsy driving”, who may be at greatest risk, warning signs, and potential countermeasures.

The Causes and Effects of Drowsy Driving

There are many contributing factors that lead to drowsy driving:

Driving between midnight and 6 a.m.; driving a substantial number of miles each year and/or a substantial number of hours each day; driving in the mid-afternoon hours (especially for older persons); and driving for longer times without taking a break

Poor quality sleep (waking up multiple times during the night)

A general lack of sleep (i.e. “chronic sleep debt”)

Working a constantly changing schedule that directly interferes with getting a good night’s sleep (i.e. shift work) or

dealing with undiagnosed or untreated sleep disorders

The use of sedating medications or the consumption of alcohol when already tired.

Everyone can suffer from “tiredness”.  It is caused by three categories of stress factors:

1) physical environment – exposure to extreme temperatures and even vibration or noise

2) physical condition - poor or inadequate sleep, medications and alcohol, or medical conditions that interfere with sleep such as sleep apnea

3) prolonged periods of emotional upset (anger, fear, frustration, etc.)

Employees who drive as part of their job are exposed to many of these factors every day.  The National Sleep Foundation points out that driving while drowsy is similar to driving under the influence of alcohol in that “sleepiness slows reaction time, decreases awareness, impairs judgment and increases your risk of crashing.”  Additionally, drowsiness can affect vision, information processing and short term memory (ever get home late at night and can’t remember the last several miles of your trip in detail?)  The effects of being awake for 18 hours are very similar to having a Blood Alcohol Concentration of 0.08 (legally impaired/intoxicated).

“At-Risk” Populations

Some folks are more “at-risk” to have or develop problems with drowsy driving.  Most research points to young people (under 26 years old), shift workers (working the night shift increases risk by nearly six times), commercial drivers (especially long-haul operators with varied hours), persons with undiagnosed or untreated sleep disorders, and business travelers who may spend a lot of time driving or may be “jet-lagged”.

Avoiding “Drowsiness”

Although getting a good night’s sleep (7-9 hours) on a regular basis is probably the most obvious way to avoid the problem, there are many things that keep us from ideal sleep patterns. Here are some tips that should help combat drowsiness:

1. Proper Nutrition - Do your best to eat a well-balanced diet that includes a reasonable balance of the major food groups.

2. Adjust Your Sleep Environment - Check for noise, poor ventilation, high or low temperatures, and bedding firmness, etc.

3. Maintain Fitness - plan your exercise program to build your stamina.  Trainers at your fitness center should be able to help you adjust your program.

4. Reduce Any Excess Weight – Any excess pounds can contribute to poor sleep quality or lack of sleep.  In some cases, it may also contribute to a serious medical condition called “Sleep Apnea” which involves not getting enough oxygen when you sleep.

5. Adjust Your Sleep Pattern and Get Adequate Sleep - Experiment by sleeping more or less, going to bed earlier or later, to discover proper sleep time.  Most adults need 7-9 hours to maintain proper alertness during the day

6. Time Management and Relaxation – Planning your days and nights to avoid stress and rushing can be helpful.  Schedule proper breaks—about every 100 miles or 2 hours during long trips

7. Reduce Your Regular Use of Caffeinated Beverages. Caffeine is a drug that may overstimulate the body and mind, interfering with sleep and increasing anxiety.

8. Quit Smoking and Avoid Alcohol – Both nicotine and alcohol can interfere with sleep, especially when consumed near bedtime.

Warning Signs

Most people can not tell when they are falling asleep while driving.  In fact, half of all responses in a recent survey of drivers who had been in drowsy-driving crashes said they felt "only slightly sleepy" or "not at all sleepy" right before the crash.  Common warning signs include:

You find yourself drifting from your lane or tailgating

You miss signs or drive past your exit

You have trouble keeping your eyes open and focused

You yawn frequently or rub your eyes repeatedly (blink hard to refocus)

You can’t keep your head up (head nodding)

You daydream or have wandering, disconnected thoughts

You drift off the road and hit the rumble strips

If you recognize any of these symptoms, you could be in danger of falling asleep.  What can you do?  Consider these strategies:

1. Sleep – even a short nap (in a safe place such as a rest area) can help especially when followed by exercise to wake up.  We’ll say it again; make sure you use a secure rest area – not the side of the road where another vehicle might collide with your vehicle.

2. Exercise – get out of the vehicle and walk, stretch and move your body to wake up.  Take driving breaks (every 100 miles or every two hours) to stretch your legs and get your blood moving, heart pumping, etc.

3. Companions - When possible, travel with a companion who will stay awake with you to monitor your driving and talk to you.

4. Timing - Try to avoid “sleepy” times of the day – after dark and especially after midnight are peak times for your body to decide to sleep – and when most “drowsy driving” crashes occur.

5. Careful consumption of caffeinated beverages – many drivers expect to use coffee or colas to wake up, but its effects take time (20-30 minutes) to hit your system and usually wear out after the first couple of drinks.  These drinks are no substitute for adequate sleep, may not prevent nodding-off, and may provide a false sense of security.