Fatigue

Driver fatigue is a major factor causing road crashes and is more likely to be an issue in rural areas due to long trips and periods of continuous driving. It is particularly dangerous because fatigued drivers can’t judge their own level of tiredness.

Research shows that:

  • Not sleeping for more than 17 hours has an effect on driving ability the same as a Blood Alcohol Concentration (BAC) of 0.05.
  • Not sleeping for 24 hours has the same effect of having a BAC of 0.10, double the legal limit.

Causes and signs of fatigue

The four main causes of fatigue are:

  • lack of quality sleep
  • driving when you would normally be sleeping (1am-6am) or in the afternoon (2pm-4pm) when our biological time clock makes us feel tired
  • length of time driving
  • sleeping disorders such as sleep apnoea.

Signs of fatigue include:

  • constant yawning
  • drifting over lanes
  • sore eyes
  • trouble keeping your head upright
  • delayed reactions
  • daydreaming
  • difficulty remembering driving the last few kilometres
  • variations in driving speed.

How to avoid fatigue

  • Sleep uninterrupted for about 7 to 8 hours before your trip.
  • Aim to travel less than 8 to 10 hours each day.
  • Take 15 minute breaks at least every two hours. Get out of the car, get some fresh air and some exercise.
  • Share the driving and get your passengers to tell you if you are showing signs of tiredness.
  • Eat well balanced meals at your usual meal times and avoid fatty foods which can make you feel drowsy.
  • Avoid alcohol and medicines that can cause drowsiness.
  • Avoid driving at night. The chances of crashing are higher late at night and early morning.
  • Don’t begin your trip is after work as you will be tired already.

If you feel tired, pull over and have a power nap, otherwise you may experience dangerous microsleeps.

What are microsleeps?

  • Microsleeps are when you nod off and are unintended periods of light sleep that last a few seconds or several minutes. You may just lose attention and stare blankly or even close your eyes and your head might snap up.
  • Microsleeps are dangerous when driving. During a 4-second microsleep a car travelling at 100km/h will travel 111m while completely out of the driver’s control.
  • Microsleeps usually occur at times when you would normally be asleep or when you are tired and trying to stay awake.

Fatigue myths

  • Coffee doesn’t cure fatigue. It may be of benefit in the short term but its effects wears off quickly putting you at risk of crashing.
  • Playing music and fresh air will only have a short-term benefit in keeping you alert.