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Causes of driver fatigue and how to spot the most common signs

Posted by NOSA on Jan 29, 2018 11:45:00 AM

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Driver fatigue is a common danger for long-haul drivers. Driving while exhausted significantly increases the risk of a crash – it makes us less aware of what is happening on the road and impairs our ability to respond quickly and safely if a dangerous situation arises. In fact, it is believed to contribute to 30% of road crashes. That’s one out of every three road accidents.


What causes driver fatigue?


There are a few major causes of driver fatigue:

  • A lack of quality/quantity of sleep
  • Driving at times of the day during which you’d normally be sleeping


The consequence of both of these is a build-up of sleep debt. This is essentially sleep you ‘owe’ yourself. The only way to repay this debt is to sleep. Until you re-establish a pattern of regular and sufficient sleep, you are more likely to be at risk of being involved in a fatigue-related accident.


4 groups most at risk of driver fatigue


  • Young drivers: The combination of inexperience and night driving
  • Shift workers and those working extended hours: Shift workers are six times more likely to be in a fatigue-related crash, whether at work (operating machinery or vehicles) or while commuting
  • Commercial drivers: Long distance driving, often at night
  • Business travellers: Drivers suffering from jet lag and crossing time zones often suffer from restricted and/or poor quality sleep


6 factors that will increase the likelihood of driver fatigue


  • The length of time you’ve been awake (especially if it’s more than 17 hours)
  • The time of day: Your body and brain have a biological clock (circadian rhythm), which influences how alert or drowsy you are at certain times of the day
  • The quantity and quality of your last bout of sleep
  • Your level of physical or mental activity at the time (e.g. long, boring stretches of road make it difficult to maintain alertness and vigilance)
  • The presence of untreated sleep disorders (e.g. obstructive sleep apnoea or narcolepsy)
  • Sedative drugs


9 warning signs for a fatigued driver


It is very difficult for drivers to accurately assess their own level of fatigue. The ability to self-assess becomes increasingly impaired as you get more fatigued. If you, or your drivers, notice any of the following signs, you must stop and rest.

  • Difficulty focusing, frequent blinking, or heavy lids
  • Daydreaming, wandering or disconnected thoughts
  • Trouble remembering the last stretch driven
  • Missing exit or traffic signs
  • Yawning repeatedly or rubbing your eyes
  • Trouble keeping your head up
  • Drifting from your lane, tailgating, or hitting the side of the road
  • Feeling restless or irritable
  • Poor judgement and slower reaction time

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Topics: driving safety, fatigue management, long-haul driving, driver training

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