There is a significant increase in the risk of you being involved in a crash if you are becoming tired when driving. When you are starting to become tired you can't concentrate properly on your driving and so you can't respond as quickly and safely as you should.
Driver fatigue contributes to more than 25 per cent of road crashes in Victoria.
This section will tell you what causes fatigue and how to avoid it. Microsleeps, sleep apnoea and the problems of shiftwork are explained.
What causes fatigue?
Signs of fatigue
How to avoid fatigue
Microsleeps
Shiftwork and fatigue
Sleep apnoea — a sleep disorder
Fatigue can be caused by:
- lack of quality sleep
- driving at times when you are normally asleep (eg 1am – 6am) or in the afternoon lull (1pm-5pm), when our biological time clock makes most of us feel sleepy
- having a sleep disorder such as sleep apnoea. Symptoms of sleep apnoea include heavy snoring broken by sudden periods of silence, restless sleep and constantly being tired during the day.
Research has shown that going without sleep for 17 hours has the same effect on driving ability as a Blood Alcohol Concentration (BAC) of .05, which is over the legal limit. Going without sleep for 24 hours has the same effect as a BAC of .1, which is double the legal limit.
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If you are tired, pull over and have a powernap. Otherwise you may experience dangerous microsleeps and other signs of fatigue including:
- constant yawning
- drifting in the lane
- sore or heavy eyes
- trouble keeping your head up
- delayed reactions
- daydreaming
- difficulty remembering the last few kilometres
- variations in driving speed.
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If you don’t get enough quality sleep you go into debt – you ‘owe’ yourself more sleep – and the only way to repay this debt is by sleeping. Until you catch up on your sleep, you have a greater risk of having a fatigue-related crash.
Before you start driving:
- make sure you regularly get enough sleep
- be aware of your biological clock, namely that you are at an increased accident risk when driving between 1am-6am and 1pm-5pm
- don’t start a long trip after a long day’s work.
When you are driving:
- Take a powernap if tired. Research shows that even a small sleep — or powernap — of 10 minutes can significantly reduce your chances of a crash caused by fatigue.
- Cool the car interior.
- Don’t drink alcohol.
- Take regular rest breaks to help reduce the effects of fatigue.
- Eat proper and well-balanced meals, preferably at your normal meal times.
Remember that once you are fatigued the only cure is sleep!
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Microsleeps, known as ‘nodding off’, are unintended periods of light sleep that typically last between 2 and 20 seconds. You lose attention and may stare blankly, close your eyes or find your head snapping upright.
Microsleeps are likely to occur when a driver is driving at the times they would normally be asleep and when they are tired and trying to stay awake.
The danger for fatigued drivers is that during a microsleep a driver does not react to a hazardous situation and will not see a red light, or notice that the road has taken a curve or that their vehicle has travelled to the incorrect side of the road.
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Shiftworkers are six times more likely to be involved in a fatigue related road crash than other workers. They are at a greater risk when they:
- drive when their body clock is saying they should be asleep
- not getting enough quality sleep, as daytime sleep is not as high a quality as night time sleep.
Fatigue has a direct impact upon workplace safety and productivity. It is the responsibility of employers and employees to protect themselves, their colleagues and other road users:
- Employers may have a duty of care to protect employees who suffer from fatigue.
- Employees may have Occupational Health and Safety obligations to advise their employer of their fatigue.
- Shiftworkers are at a significant risk of an accident particularly when traveling home from shiftwork.
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Sleep apnoea, which means lack of breath, results in three times higher a risk of having a road crash.
Characteristics of sleep apnoea:
- being constantly tired during the day
- struggling to keep awake during the day
- affects up to 15 per cent of adults
- many sufferers are middle-aged males who are often overweight, with symptoms of snoring, restless sleep and pauses in breathing lasting from 10 to 90 seconds while asleep
- contributes to high blood pressure, heart disease, stroke and depression.
There are a range of treatments available. If you think you may suffer from sleep apnoea, consult your local doctor.
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