TRUCK DRIVER ALERTNESS

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Defining the problem

• To reduce fatal crashes between trucks and other
  vehicles, a study was conducted to identify when
  most of the fatalities are occurring and under
  what circumstances.

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Whos at FAULT in fatal accidents involving
trucks other vehicles

• OTHER DRIVER AT FAULT 71
• TRUCK DRIVER AT FAULT 16
• BOTH DRIVERS AT FAULT 11
• NO ONE AT FAULT 2

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Truck Crash Statistics

• In two-vehicle fatal crashes between large trucks
  and passenger cars,
• 7 of the truck drivers were under 26 years old
• 2 were over 65
• Less than 1 had a BAC of 0.10 or greater

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Operator Fatigue

• A significant number of vehicle accidents are
  caused by
• Driver Fatigue
• Loss of Alertness
• Poor Performance at the Controls

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• Fatigue-Related Accidents Cause
• Fatality or severe injury
• Loss of corporate revenues
• Lower productivity
• Place operators privileges at risk
• Significant company liability exposure

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• Operator fatigue, is a state of mind and body,
  a response to continued physical or mental
  activity or sleep loss, is characterized by
  diminished ability to work, loss of attention,
  slower reactions, poor response, deterioration of
  attention or alertness, impaired judgment.

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• Fatigue can be caused by combinations of
  inadequate rest, sleep loss and/or disrupted
  sleep, displaced biological (circadian) rhythms,
  excessive physical activity or mental work, and
  general psychological stress.

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Physical Fatigue

• a temporary loss of muscle power to respond to
  demands
• a feeling of tiredness, soreness, or discomfort
• physical performance declines

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Mental Fatigue

• a feeling of tiredness after extended or
  repeated tasks particularly non-physical tasks
  such as driving
• may include feeling of monotony or boredom
  caused by lack of varied stimulation.

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Mental Fatigue

• negatively affects your level of alertness at
  the wheel leads to poor driving performance

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Chronic Fatigue

• a short term condition that can be relieved by
  adequate rest and sleep usually we can recover
  full alertness in just a few days with longer
  sleep (Sleeping longer on weekends, etc.).

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Chronic Fatigue

• results from repeated and cumulative stress
  some refer to it as Burnout
• may require extended break several days off

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Operator Fatigue Factors

• .Quality quantity of rest or sleep
• .Individual physical fitness
• .Individual endurance to demanding tasks
• .Environmental conditions of heat, humidity,
  cold, altitude, etc.
• .Performance on sustained work suffers before
  that on intermittent tasks
• AND
• Types of Tasks, Time-of-Day, Personal
  Motivation Individual Differences

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Operator Fatigue

• Sleep requirements differ for individual persons,
  and vary with age (infants, adolescents, young
  adults, mid-aged adults, seniors).

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Operator Fatigue

• Most adults maintain normal alertness, perform
  near their best, by obtaining 7- 8 hours of
  uninterrupted sleep every 24 hours.

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Operator Fatigue

• Some people get by with less sleep (5-6 hours)
  but often augment this sleep with naps.
• Others think they can get by with less sleep, but
  in reality, if their performance were measured it
  is degraded.

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Sleep Structure

• Normal nighttime sleep involves 4-5 repeated 90
  minute cycles of brain electrical activity (coded
  into 5 sleep stages) as we restore ourselves to a
  refreshed, alert state, or we recuperate from
  sleep loss and fatigue.

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Sleep Structure

• Rapid eye movement (REM) or dream sleep and slow
  wave sleep (stages 3 4 are deep sleep) seem to
  be the most recuperative.

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Continuity of Sleep

• A period of 4 contiguous hours of sleep permits
  several uninterrupted 90-minute cycles.
• Eight 1-hr sleeps are not the equivalent to a
  full 8-hrs of sleep. Intermittent, broken sleep
  is usually detrimental to alertness.

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Sleep Loss or Sleep Debt

• When we miss sleep required to maintain normal
  alertness, we accrue a SLEEP DEBT which
  accumulates each successive 24-hr day we
  shortchange ourselves of anticipated sleep
  (obtaining only 5 hrs one night minus our
  required 8 nets 3-hr sleep debt).

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Sleep Loss or Sleep Debt

• If after several days our sleep debt accrues to
  10-12 hrs sleep debt (more than one nights sleep
  loss) we begin to perform as if we missed an
  entire nights sleep.

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Recovery Sleep

• Paying off a sleep debt usually does not require
  a 1-for-1 replacement of hours missed sleep.

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Recovery Sleep

• A tired brain quickly goes into a sleep stages
  3 4 which makes efficient use of the first long
  duration sleep period

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Recovery Sleep

• Consequently, we spend a shorter time in the less
  restorative sleep stages (1 2), but more time
  in states 3, 4 and REM sleep

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Recovery Sleep

• After weekly sleep debt of 15 hrs we might make
  up a debt with one or two long duration recovery
  sleeps (10 hrs) on the weekend.

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Rest Breaks

• Rest may be a break in activity, or simply a
  change of pace or even a change in activities.
• Rest breaks permit us to restore our energy,
  break the monotony, or give our bodies and minds
  relief.

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Rest Breaks

• Frequent Rest Breaks Can Be Helpful in Any
  Sustained Work.
• But Rest Is Not the Same As Sleep,
• And It Will Not Substitute for Needed Sleep.

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Circadian Rhythms

• our physiological behavior patterns repeat
  daily in synchronization with our internal
  biological clock.

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Circadian Rhythms

• body core temperature, urine production,
  hormonal excretions, digestive processes etc.
  Repeat at the same time each day.

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Circadian Rhythms

• as we wake up from a nights sleep, our body
  temperature begins increasing, and gradually
  rises through the day until about 1 to 3 PM when
  it levels off somewhat.

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Circadian Rhythms

• being awake past mid-night after no sleep
  results in feeling groggy, less alert, and
  performance is considerably degraded in this
  circadian low period (midnight to 4 AM) when our
  brain would prefer to be asleep.

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Performance Implications of C-R

• best time to obtain sleep is during the C-R lows
  (afternoon siestas or naps are valuable).
• if you cannot sleep during the C-R lows, taking
  a rest break will be beneficial

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Work Shift Changes

• sleeping, working, and eating meals on a new
  schedule requires a period of from one to three
  weeks for the body to adjust to the new rhythm, a
  period during which the worker is likely to
  experience Shift- Lag much like trans-meridian
  travelers experience Jet Lag.

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Work Shift Changes

• forward shift rotations are easier than
  backward rotations.
• as an example, it is generally easier to adjust
  to flying westward by staying awake longer that
  day.

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Keep In Mind

• sleepiness and fatigue can be a serious threat
  to safe vehicle operation.
• fatigue is physiological and can be can be
  affected by our psychological factors.

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Keep In Mind

• plan ahead to get enough sleep
• be aware of the brain body principles of
  fatigue and sleep loss

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Keep In Mind

• plan ahead, both at home, and on long trips,
• implement fatigue countermeasures