Driver fatigue

Fatigue is often ranked as a major factor in causing road crashes although its contribution to individual cases is hard to measure and is often not reported as a cause of crash. Driver fatigue is particularly dangerous because one of the symptoms is decreased ability to judge our own level of tiredness.

Fatigue is more likely to be a factor in crashes in rural areas as they can involve long trips and extensive periods of continuous driving, however anyone can be affected by fatigue.

Fatigue is often ranked as a factor in road crashes, although its contribution in individual cases is hard to measure and is often not reported as a cause of the crash. Preliminary analysis of fatal crashes in 2016 shows that at least 15 crashes were likely to be due to fatigue; this is compared to 10 crashes in 2015.

If you don't get enough sleep you go in to sleep debt and you owe yourself more sleep. The only way to repay this debt is by sleeping. Until you catch up on your sleep, you will have a greater risk of having a fatigue related crash.

Research has shown 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.


What causes fatigue?

There are a range of factors that can cause fatigue. The four main causes are:

  • lack of quality sleep
  • time of day driving when you would normally be sleeping (eg 1am-6am) or in the afternoon period (eg 2pm-4pm) when our biological time clock makes us feel tired
  • length of time performing the task
  • sleeping disorders such as sleep apnoea.
How do I know if Im fatigued?

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.

Most importantly if you feel tired, pull over and have a power nap, otherwise you may experience microsleeps which are dangerous while driving. Once you are fatigued the only cure is to stop and take a break.

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 drivers control.
  • Microsleeps usually occur at times when you would normally be asleep or when you are tired and trying to stay awake.
How do I avoid fatigue?
  • Get enough quality sleep before you begin driving. Be sure to have 7 to 8 hours of uninterrupted sleep before your trip.
  • The worst time to begin your trip is after work you will be tired already even though you do not realise it.
  • Aim not to travel more than 8 to 10 hours each day.
  • Take regular 15 minute breaks at least every two hours. Get out of the car, get some fresh air and some exercise.
  • If possible share the driving. Get your passengers to tell you if you look tired or if you are showing signs of tiredness.
  • Eat well balanced meals at your usual meal times. 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 much higher late at night and early morning.
Will coffee cure fatigue?
  • In the short term coffee may be of some benefit but its effects wear off and you are likely to suffer from sleep rebound putting you at risk of crashing.
  • The only cure for fatigue is sleep.
Will fresh air and loud music stop me from feeling fatigued?
  • Playing music will only have a short-term benefit in keeping you alert.
  • Fresh air will also only have short-term benefits in keeping you alert.
  • The only cure for fatigue is sleep.

What the Law says

On 29 September 2008 new nationally consistent laws regulating the working and driving hours of heavy vehicle drivers under the Road Traffic Act and Regulations were introduced.

The new laws consider the health and well-being of heavy vehicle drivers aiming to help drivers get home safely by requiring that all parties in the chain of responsibility take reasonable steps to prevent driver fatigue.

More information is available from the National Transport Commission website.


Offences under the new laws are classified according to the actual level of risk and the greater the risk involved, the more significant the penalties. Penalties will range from an infringement notice to court imposed penalties (maximum $50,000) and loss of demerit points.


Country Driving Hints

Roadside Rest Area Guide


National Transport Commission (RAA)

Latest news


All cars with “critical” defective Takata airbags to be refused registration in South Australia

07 Aug 2020

All remaining cars fitted with a critical defective Takata type airbag inflator will now be refused registration in South Australia from Monday, 10 August until they are rectified, to ensure the safety of all road users.


Safety label reminder for electric and hybrid vehicle owners

27 Jul 2020

As the popularity of electric and hybrid vehicles grows, DPTI reminds potential traders and buyers of the requirement to fix a safety label onto their numberplates.

News archive

Road safety works


McIntyre Road night works

17 Feb 2020

Works to improve ride quality will be undertaken on McIntyre Road between The Golden Way and Wright Road, commencing each night from 7pm, Tuesday, 18 February to 6am, Friday, 6 March, weather permitting.


11.6km of South Eastern Freeway to be resurfaced

04 Feb 2020

The South Australian Government is delivering $7.39 million worth of essential resurfacing works to five sections of the South Eastern Freeway between Mount Barker and Callington, with night works beginning this week.

Road safety works archive


Facebook Twitter YouTube