January 10, 2023
What do we know about driver or machine operator fatigue?

Whatever the source – lack of or poor-quality sleep, long hours of work or driving, shift work, stress, or sleep disorders – fatigue affects your ability to drive safely. Driver fatigue is a major workplace safety risk. The good news: a fatigue risk management system can help employers and workers to reduce the risks of driver fatigue.


The Numbers

  • As many as one in five fatal crashes in the general population involve driver fatigue.1
  • Companies use a fatigue risk management system to promote alertness among workers, identify fatigue-prone tasks, and lessen fatigue and its potential consequences.2
  • After 17 consecutive hours awake, impairment is equivalent to having a blood alcohol content (BAC) of .05. After 24 hours awake, impairment is equivalent to a BAC of .10.3
  • A survey of the U.S. workforce found that 37% of workers got less than the recommended minimum of 7 hours of sleep.4
  • Most adults need 7 to 9 hours of sleep each day.


1Tefft BC [2014]. Prevalence of motor vehicle crashes involving drowsy drivers, United States, 2009-2013. AAA Foundation for Traffic Safety.
2Lerman SE, et al. [2012]. Fatigue risk management in the workplace. Journal of Occupational & Environmental Medicine 54: 231-259.
3Dawson D, Reid K [1997]. Fatigue, alcohol, and performance impairment. Nature Jul 17;388(6639):235.
4Shockey TM, Wheaton AG. Short Sleep Duration by Occupation Group — 29 States, 2013–2014. MMWR 2017;66:207–213.
5National Sleep Foundation. How Much Sleep Do We Really Need?


The Causes

  • Being awake for many consecutive hours.
  • Not getting enough sleep over multiple days.
  • Time of day: Your body has a sleep/wake cycle that tells you when to be alert and when it’s time to sleep. The urge to sleep is the most intense in the early morning hours.
  • Monotonous tasks or long periods of inactivity.
  • Health factors such as sleep disorders or medications that cause drowsiness.


The Effects

Fatigue impairs your ability to safely perform tasks, including driving or operating machinery. When you’re driving, fatigue causes you to:

  • Nod off.
  • React more slowly to changing road conditions, other drivers, or pedestrians.
  • Make poor decisions.
  • Drift from your lane.
  • Experience “tunnel vision” (when you lose sense of what’s going on in the periphery).
  • Experience “microsleeps” (brief sleep episodes lasting from a fraction of a second up to 30 seconds).
  • Forget the last few miles you drove.


Excerpt from The National Institute for Occupational Safety and Health (NIOSH), “Driver fatigue on the job”.