Fatigue Problems and Countermeasures

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FatigueProblems and Countermeasures

• Ken Smith, FACRS
• Smithworks Consulting

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Introduction

• Begin with the premise that because of the kind
  of travel being discussed today, there is a
  strong likelihood that fatigue plays a big part
  in crashes
• Good guess that not less than 20
• Hence fatigue is a real problem with real
  consequences in terms of road trauma

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Defining Fatigue

• Define so that fatigue is distinguished from
  other means of impairment, even if the effects
  are the same
• Should describe the state of a person, identify
  the cause of that state and, as far as possible,
  have the same meaning as is ascribed to it be
  most of the population (Job Dalziell)
• A short one result of inadequate rest over a
  period of time and leads to physical and mental
  impairment (Neville)
• Applies to all people not just professionals like
  truck drivers

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Fatigue and crashes

• Certain kinds of crashes said to be fatigue
  related or characteristic
• Severe, running off the road or colliding with
  vehicle or object, especially with no evidence of
  braking or swerving crashes occurring at high
  risk times such as early morning or mid afternoon
• Important feature these are derivative a guess
  after the event, so there is great uncertainty
  about just how much fatigue contributes to
  crashes
• Figures of 4-30 cited one restricted definition
  (Dobbie) estimated 16.6 Sweatman et al thought
  up to 60 could have involved some element of
  fatigue
• No one knows but it is probably more than our
  best guess. Fatigue could be as big a killer as
  alcohol

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But wait, theres more

• This is fatigue through sleep deprivation
  crashes we identify as fatigue related almost
  certainly result from the driver actually falling
  asleep, whether microsleep or longer
• There is also hypovigilance or white line fever
  result of lack of stimulation or simple boredom
  (see CARRS-Q)
• In this situation with lack of stimulation the
  brain progressively shuts down functions it
  doesnt need for the immediate task
• Unaroused states can be just as dangerous as
  sleep deprivation or work induced fatigue if they
  mean loss of attention and consequent failure to
  perceive hazards and slowness to react
• Can maintain vehicle control but impair
  perception and collision avoidance ability (Swann)

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So why is fatigue such a big risk?

• Misunderstanding of the nature of fatigue
• Perception that it applies only on long distances
• Like alcohol, fatigue affects cognition
• Therefore cannot trust own judgement
• The fact that a person is becoming impaired by
  fatigue is masked in the same way as impairment
  from alcohol consumption.
• Misunderstanding of the effect of sleep loss or
  sleep deprivation
• Misunderstanding and underestimation of the
  effects of everyday activities

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Some facts about the nature of fatigue

• The body is governed by inbuilt biological
  rhythms attuned closely if not precisely to the
  cycles of day and night.
• Work is best performed during the day when the
  bodily system is (other things being equal) awake
  and alert
• The best sleep is obtained at night when there is
  a strong propensity to sleep.
• Rest and sleep at times of the day when sleep is
  less efficient than at night may be shorter
  because of disturbances and interruptions, and
  may be less restorative.
• Length of time awake (and hence time since sleep)
  may be a more important factor in fatigue than
  the amount and duration of work (Fatigue Expert
  Group)

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Risk factors

• So the risk factors for fatigue affect all of us
  in our everyday activities
• Recall the research that found that 17-19 hours
  continuous wakefulness results in the same
  impairment as being at 0.05
• So leisure activities young people are
  especially at risk, especially since they really
  have greater need for sleep
• Little literature on effect of work on driving
  but work that is stressful and demanding means a
  tired worker on the way home will have impaired
  driving capacity
• Sleep deprived mothers are probably at very high
  risk, especially since they often have little
  prospect of breaking the cycle
• And of course shift workers probably
  permanently fatigued to some extent

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Its obvious, but . .

• Two real issues knowledge and attitude
• Firstly, insufficient knowledge about the issues.
  Too much emphasis on long distance, not enough
  about fatigue causes and impairment effects.
• Insufficient understanding about how fatigue and
  sleepiness can impair driving
• Insufficient understanding of cognitive effects
• Mistaken perception that can identify sleepiness
  when it comes
• Attitude
• Reluctance to stop, including transient effects
  such as weather or no good place to stop
• Simple desire to press on and finish the journey

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Survey findings - RACV

• Drivers 18-25 less likely to take rest breaks
  than older drivers, as were those who drove long
  distances frequently
• They ranked inattention or inexperience (third)
  higher than fatigue (fifth) as contributors to
  crashes
• 48 wanted to get to destination as quickly as
  possible on long trips
• 41 only stopped for petrol or a toilet break
  rather than a rest
• 9 only stopped driving when they had nearly
  fallen asleep at the wheel
• 7 thought breaking a drive to have a rest was
  just a waste of time (RACV reported RS2004)

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Survey findings - Bartlett

• Sometimes confused and insufficient knowledge by
  17-25 year olds on amount of sleep they needed,
  and on countermeasures for sleepiness (Bartlett
  reported RS2004)
• Both surveys suggested that urban residents who
  take long journeys less frequently take more rest
  breaks
• But crash data suggests that many just want to
  get to their destination as quickly as possible
• Reasonable supposition that many of those will be
  fatigued when they begin and less inclined to
  take rest breaks

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Implications

• There is scope for deeper and more extensive
  public education on the nature and causes of
  fatigue and, especially, impairment.
• If we are talking about a problem that is
  potentially as big a killer as alcohol, then we
  need to treat it just as seriously.
• Extensive public education should be directed
  towards changing public perceptions and
  encouraging behaviour change
• Billboards and catchy TV commercials about
  microsleeps are far from enough

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What about enforcement?

• Enforcement always part of the behaviour
  modification package
• But we dont have an easily applied standard like
  a breath test
• Some equipment has been developed for truck
  driver survey work but not for general use
• We need to be able to identify and measure before
  we can even create an offence of fatigue
  impaired driving
• Need some measuring stick before we could even
  make effective use of, for example, negligent
  driving provisions

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Technology?

• A good deal of research here but none of it yet
  satisfactory
• Warning and ultimately control systems
• Eye blink, head movement, steering/throttle
  control, lanekeeping have all been subject of
  trials
• TAC SafeCar has used headways and speed
  monitoring
• Big problem is a system sensitive enough to
  detect impairment before it becomes dangerous but
  to not give false positives
• An ideal system would meet these requirements,
  cover all forms of impairment and be downloadable.

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Some strategies we could consider

• Actively promote our towns as rest stops food,
  fuel, parks to relax with facilities
• Information in tourist brochures fatigue
  contributors and precursors, impairment effects
• Develop and promulgate tactics to help people
  maintain vigilance
• Identify and promulgate tactics to detect the
  onset of sleepiness and loss of alertness
• Identify things that inhibit or degrade alertness
  and vigilance and circumvent or remove them

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Further information

• Copy of the full paper
• Copy of these slides
• Smithworks Consulting
• smithworks_at_aapt.net.au