Drowsy Driving

The U.S. National Highway Traffic Safety Administration (NHTSA) estimates that approximately 100,000 police-reported crashes annually (about 1.5% of all crashes) involve drowsiness/fatigue as a principal causal factor. A conservative estimate of related fatalities is 1,500 annually or 4% of all traffic crash fatalities. At least 71,000 people are injured in fall-asleep crashes each year. NHTSA estimates these crashes represent $12.5 billion in monetary losses each year.

Drowsiness/fatigue may play a role in crashes attributed to other causes. About one million crashes annually - one-sixth of all crashes - are thought to be produced by driver inattention/lapses. Sleep deprivation and fatigue make such lapses of attention more likely to occur.

Drowsiness, or fatigue can be caused by various medical sleep disorders, such as sleep apnea, narcolepsy, restless legs syndrome, and parasomnias (such as sleep walking). Fatigue is also a common outcome from insomnia, whether caused by a medical disorder or from everyday personal and work stress (National Sleep Foundation). In American's fast paced society, fatigue due to sleep loss has become an issue of great interest. Extreme fatigue can cause uncontrolled and involuntary shutdown of the brain--causing a person to lapse into sleep at any time, unaware of potential consequences. Motor vehicle crashes involving fatigue are a powerful example of this. NHTSA research shows that drivers are often unaware of their deteriorating condition or, when aware, often keep driving.

Who Is Most At Risk?

All drivers who are:
  sleep-deprived or fatigued 
  driving long distances without rest breaks
 
  driving through the night or at other times when they are normally asleep 
  taking medication that increases sleepiness, or drinking alcohol 
  driving alone 
  driving on long, rural, boring roads
 
  frequent travelers, e.g., business travelers. 
At Highest Risk for Drowsy Driving
  Young people (ages 16 to 29), especially males.
  Shift workers, students, or others whose sleep is disrupted by working at night or working long or irregular hours.
  People with untreated sleep apnea syndrome (SAS) and narcolepsy.
  People who drive between midnight and 6 a.m.
ÿ
  Drivers of passenger vehicles (95.9% of drowsy driver crashes) - not commercial truck drivers
(NHTSA drowsy driver technology program).
Prevention
Before motorists embark on their trips, they should:

Get a good night's sleep. While this varies from individual to individual, the average person requires about 8 hours of sleep a night.

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.

Schedule regular stops, every 100 miles or 2 hours.

Avoid alcohol and medications (over-the-counter and prescribed) that may impair performance. Alcohol interacts with fatigue; increasing its effects - just like drinking on an empty stomach.

Consult their physicians or a local sleep disorders center for diagnosis and treatment if they suffer frequent daytime sleepiness, have difficulty sleeping at night often, and/or snore loudly every night.

Once driving, motorists should:

Look for the warning signs of fatigue, for example, drivers who: 
  can't remember the last few miles driven 
  drift from their lanes or hit a rumble strip 
  experience wandering or disconnected thoughts 
  yawn repeatedly 
  have difficulty focusing or keeping their eyes open 
  tailgate or miss traffic signs
 
  have trouble keeping their head up 
  keep jerking their vehicles back into the lane.

Recognize that they are in danger of falling asleep and cannot predict when a microsleep may occur.

Not count on the radio, open window or other "tricks" to keep them awake.

Respond to symptoms of fatigue by finding a safe place to stop for a break.

Pull off into a safe area away from traffic and take a brief nap (15 to 45 minutes) if tired.

Drink coffee or a functional energy drink to promote short-term alertness if needed. (It takes about 30 minutes for caffeine to enter the bloodstream.)

A survey conducted by NHTSA in 2002 found that a significant number of drivers have experienced drowsy driving. Specifically:

Thirty-seven percent (37%) of drivers have nodded off for at least a moment or fallen asleep while driving at least once in their driving career. ÿMales (49%) are almost twice as likely to report having nodded off while driving than are female drivers (26%).

Eight percent (8%) had done so in the six months prior to the survey.

While slightly more than one in five (22%) drivers who recently experienced a drowsy driving episode report having been on the road driving for five or more hours, nearly half (47%) were driving for an hour or less. On average, these drivers were driving for almost three hours before they nodded off. Males had driven for about an hour longer than females on average (3.2 as compared to 2.2 hours). Drivers age 30 and over became drowsy in a shorter amount of time than younger drivers.

Characteristics of Drowsy Driving Trips
The average drowsy driving experience is associated with the following characteristics:

Driver averaged 6.0 hours of sleep the previous night (and 24% had slept fewer than five hours).

Driver had been driving for an average of 2.9 hours (but 22% had been driving for more than four hours).

Occurred while driving on an interstate type highway with posted speeds of 55 mph or higher (59%).

Nearly half (48%) nodded off between 9 p.m. and 6 a.m.
In the past five years, about 0.7% of drivers have been involved in a crash that they attribute to drowsy driving - amounting to an estimated 800,000 to 1.88 million drivers.

When asked what actions they take when they feel sleepy while driving, 43% of drivers report they pull over and rest or nap. Other key behaviors reported by drivers to combat sleepiness while driving include:

Open the window (26%).

Get coffee, soda, or caffeine (17%).

Pull over/get off the road (15%).

Play the radio loudly (14%).

 

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