The Problem of Fatigue and Drowsy Driving in the U'S'

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The Problem of Fatigue and Drowsy Driving in the
U.S.

• John Caldwell, Ph.D.
• Air Force Research Laboratory
• Brooks City-Base, TX
• john.caldwell_at_brooks.af.mil

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Fatigue is a problem throughout America

• In the past century, Americans have reduced their
  sleep time by 20 (from 9 hrs down to 7 hrs a
  night).
• Since 1969, we have added 158 hours a year to our
  working and commuting time.
• Over 25 million people now routinely engage in
  shift work.

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Complaints about sleepiness are growing across
the U.S.

• Only a half of all adults are satisfied with the
  amount of sleep they get (they are getting an
  hour a day less than what is recommended).
• More than one-fourth say that they are sleepy at
  work 2 days per week or more.
• Ten percent occasionally or frequently fall
  asleep at work.
• One out of five say they make errors at work due
  to sleepiness.
• Many admit that on-the-job sleepiness impairs
  concentration, lowers productivity, and degrades
  work quality.

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Much of this sleepiness is simply due to chronic
sleep restriction
VIGILANCE TASK PERFORMANCE
Balkin et al., 2000
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Sleepiness creates particular problems late at
night

• Since fatigue is a function of hours awake and
  time of day, alertness suffers the most late at
  night
• Micro-lapses into sleep are rare during the
  daytime (even between 1700 and 2200).
• Unintentional sleep episodes steadily increase
  between 2400 and 0800.
• Increased lapses at night partially explain why
  accident rates often are higher at night.
• Night workers are more likely to make a variety
  of performance errors than day workers due to
  sleepiness.

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Alertness and performance are clearly influenced
by time of day
11000
10000
9000
Meter Reading Errors
8000
7000
6000
5000
4000
Midnight
6 a.m.
6 p.m.
Noon
Midnight
Time of Day
Mitler et al., 1988
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Fatigue has become a major problem on U.S.
highways

• Tour bus crashes in 98 and 99 focused attention
  on hours of service regulations for drivers
• Insufficient rest is thought to be responsible
  for driver errors.
• Fatigue made the top 10 list of transportation
  safety issues because of trucker crashes
• Thirty-one percent of all trucker fatalities are
  fatigue related.
• Driver drowsiness causes 100,000 accidents, 1,500
  fatalities, and 71,000 injuries annually, and
  costs the U.S. 12.5 billion a year!

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Driver sleepiness has reached alarming proportions

• A 1999 National Sleep Foundation survey of the
  general public found
• 62 reported driving drowsy in the past year
• 27 had actually dozed off at the wheel
• 23 knew someone who had experienced a
  fall-asleep crash
• Fatigue-related crashes are especially frequent
  at times that coincide with low points in the
  bodys circadian cycle

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Fatigue-related collisions increase at certain
times
2 AM
2 PM
Source M.M. Mitler, M.A. Carskadon, C.A.
Czeisler, et al.
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Unfortunately, crash statistics seriously
underestimate the problem

• Only half of crashes are reported (Miller, 1991)
• 6 states do not have fatigue codes (NSF, 1998)
• Most police are not trained to detect fatigue
• There is no objective measurement (e.g., blood
  test)
• Self-reporting tends to be inaccurate
• Drowsiness is often linked to other factors
  (e.g., alcohol, drugs)

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One drivers experience with drowsy driving
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Increased litigation and civil penalties have
made falling asleep at the wheel no laughing
matter
Thag Anderson becomes the first fatality
as a result of falling asleep at the wheel.
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Families have been devastated by drowsy driving
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Commercial and Govt organizations are getting
the message they can be held liable for driver
fatigue
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Individual drivers are learning that falling
asleep is no excuse
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Characteristics of drowsy driving crashes

• Most happen between midnight 600am in the
  midafternoon (circadian dip)
• The driver is alone and more likely to be male
• A single vehicle drifts off the road and hits a
  stationary object
• Most are rear-end or head-on collisions
• There is no evidence of braking or evasive
  maneuvers
• Many involve serious injuries and/or fatalities

(Pack, 1995)
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Risky situations

• Think twice about getting behind the wheel if
• You are sleep-deprived or fatigued (whether from
  shift work, sleep deprivation, or chronic sleep
  restriction)
• You know you are suffering from insomnia, poor
  quality sleep, or a sleep debt
• You plan to be driving long distances without
  proper rest breaks
• You will be driving through the night, the
  mid-afternoon or when you would normally be
  asleep

(Knipling, 1994)
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Risky situations (cont.)

• Think twice about getting behind the wheel if
• You are taking sedating medications
• You have been working more than 60 hours a week
• You are working more than one job and your main
  job involves shift work
• You have been drinking even small amounts of
  alcohol
• You will be driving alone or on a long, rural,
  dark or boring road

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Certain demographic groups are of particular
concern

• Young people
• Shift workers
• Commercial drivers
• People with undiagnosed or untreated sleep
  disorders
• Business travelers
• The elderly

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What are the warning signs of highway drowsiness?

• Difficulty focusing or keeping eyes open
• Trouble keeping your head up
• Yawning repeatedly
• Wandering, disconnected thoughts

• Feeling restless or irritable
• Trouble remembering the last few miles driven
• Drifting from your lane
• Tailgating or missing traffic signs of exists

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As individuals, what can we do to protect
ourselves?

• Before a trip, be sure to
• Get a good nights sleep
• Travel with a companion
• Schedule regular stops every 100 miles or every 2
  hours
• Avoid alcohol and sedating medications
• During a trip, if you do feel drowsy
• Stop driving and find a safe place to take a nap
  or spend the night
• Drink coffee or consume a caffeinated drink
• Get off the road if you hit shoulder rumble
  strips

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As professionals, what can we do to help everyone
else?

• The first key is education!!
• The National Sleep Foundation has a number of
  resources check out www.sleepfoundation.org
• Educational materials can inform everyone of the
  facts
• Professionally-produced videotapes and
  informative talks can bring the message home
• Next, we should make sure and design highway rest
  facilities that appeal to those most at risk!!
• If they dont like their rest facility options,
  theyll just keep going until their physiology
  (or a bridge rail, telephone pole, or an oncoming
  car) stops them!

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US Air Force Research Laboratory Aviation
Sustained Operations Team
State of the Art Fatigue Management for Americas
Air Force
For more information, contact Dr. Lynn Caldwell
at 210-536-3640 or lynn.caldwell_at_brooks.af.mil Dr.
John Caldwell at 210-536-8251 or
john.caldwell_at_brooks.af.mil