Driver Fatigue

Fatigue - the facts

Tiredness is one of the major causes of road crashes making driving while sleepy as dangerous as speeding, or driving under the influence of alcohol.

The gist of it
  • If a driver hasn’t had enough sleep, or is driving at a time when they would usually be asleep, sleepiness becomes a risk factor that compromises the safety of that trip
  • Crashes that occur because the driver has fallen asleep are often very severe because the driver is unable to do anything to avoid or prevent the crash.
  • Circadian rhythms are our in-built body clock that determine when we’re at our most alert, and most sleepy. Generally, humans are programmed to feel very sleepy between 2am and 4am, and then again between 2pm and 4pm. Sleep-related car crashes peak during these times.

The Issue - Fatigue effects core skills needed for driving

  • attention span
  • reaction times
  • assessment of potentially dangerous situations
  • ability to control speed
  • ability to control the car and keep it within a lane

Calling the shots - It's up to drivers to recognise the signs and pull over

  • drifting in the lane or over lane lines
  • speeding up or slowing down without reason
  • yawning and head nodding
  • a feeling of drowsiness and having heavy eyelids
  • blinking more than usual
  • sense of restlessness and boredom
  • microsleeps (a very brief sleep episode that may last just a few seconds)

Who's at risk - fatigue can affect any driver, regardless of experience. Some drivers are particularly at risk

  • Shift workers are more likely to have disrupted sleep patterns, which are a significant contributor to fatigue
  • Young people are often at a stage of life that includes frequent late nights and driving at irregular times

In recent years fatigue has been considered a primary contributory factor in road crashes.  Fatigue-related crashes are often more severe than other crashes as drivers’ reaction times are often delayed or drivers have not employed any crash avoidance manoeuvres.  Yet still, many drivers believe they can push through the symptoms.

There are common myths about driver fatigue, but they are easily busted by the facts.

Myth vs Fact


Sleep is the only cure for tiredness. If you find yourself starting to rely on caffeine and other distractions to keep you awake, you need to stop and rest, or change your plans.


Loss of concentration and delayed reactions are just as fatal on a short trip as a long one. A significant number of fatigue-related crashes happen within 25km of the start of a journey.


Even as little as two hours less sleep than usual on just one night can affect your reaction time, mental functioning, memory, mood and alertness.

Safety Checklist

Here's a few things you can do to stay on top of driver fatigue.

  1. Get enough sleep on a regular basis. If you go without enough sleep for several night in a row, you’ll develop a sleep debt. If that gets too large, your brain will react by going to sleep involuntarily snatching microsleeps. These may just last for a few seconds, but that’s all it takes for something to go wrong while you’re driving.
  2. Avoid driving at times when you would usually be asleep, that includes late nights after a full day of work or study, and very early mornings.
  3. Learn to recognise your own sleepy signs (study the list above).
  4. Take frequent breaks on long trips (once every two hours is recommended).
  5. Share the driving if you can.
  6. Some medications can make you feel tired, check with your doctor to understand what this means when getting behind the wheel of a car.
  7. If you find yourself losing concentration, pull over and rest.