Fatigue is the direct cause of up to 65 per cent of all haul truck accidents in surface mining operations and is responsible for 30 per cent of all road fatal accidents, according to the Australian Safety Transport Bureau (ASTB). Fatigue is four times more likely to contribute to workplace impairment than drugs or alcohol.

While these are frightening statistics, they are undoubtedly gross underestimations of the extent of the problem for a number of reasons. The main reason is that drowsiness at the time of the accident cannot be measured or verified after the fact by a blood or breath test and in fatal motor vehicle crashes, sleepiness (unlike alcohol) does not show in an autopsy. This leaves very little data on which to base a conclusion on the role drowsiness or sleep plays in accidents.

We know fatigue and drowsiness affects even those with the best training and years of experience. Human error as a result of drowsiness is not fundamentally a behavioural problem, it's a problem of human physiology.

It is important to understand that drowsiness is more than "feeling tired". Drowsiness has measurable cognitive and physiological effects in reducing one's ability to perform tasks.

The direct impact of drowsiness on work performance includes the inability to focus or concentrate, taking longer to perform tasks, slowed reaction times, increased irritability and reduced alertness.

The implications of these symptoms on safety in the workplace are obvious. The ability to recognise a dangerous situation, react to or solve a problem is all sub-optimal.

Would you let a drunk driver behind the wheel of a 50 tonne haul?

Beyond stating that drowsiness can reduce your reaction times or hand-eye co-ordination, we can now indicate to what extent. Research has shown that being awake for 17 hours has a physiological effect on your focus akin to a blood-alcohol level of 0.05; being awake 20 hours is equivalent to having a blood-alcohol level of 0.11. No organisation would knowingly allow a staff member to perform a safety-critical task within an hour of consuming four or five beers.

Monitoring fatigue/drowsiness

As a significant occupational health and safety issue, fatigue management becomes crucial where workers are driving, operating heavy machinery, or working shifts. However, despite mining companies' attempts to manage the situation through education, policies and procedures, there are still people falling asleep, said David Edwards, an ergonomics research engineer who works at Caterpillar Safety Services Division.

It is often difficult for drivers/operators to assess the risks of their drowsy driving at the time because often they are not aware that they are dozing at the wheel until after they rouse and suddenly recognise what has happened.

Focusing on the need for an objective means to monitor the operator/driver's state of drowsiness, Optalert has developed a drowsiness monitoring technology that takes the 'guess work' out of drowsy driving.

The Optalert system encompasses a pair of innovative glasses connected to a Vehicle System. Optalert serves as a personal safety device giving operator/driver's warnings of their drowsiness, when it first begins, and before it reaches a dangerous level. This dramatically reduces the risk of fatigue related accidents. The system also records the operator/driver's fatigue data over a period of time (days, weeks, months), supplying crucial monitoring input that can be optimised to tailor personal and corporate fatigue management policies.  

Effective fatigue management should involve a range of strategies from fitness for duty tests through to the development of education and training programs. Programs should be based on monitoring data, collected in real time.

Tailored fatigue management policies and programs are bound to improve performance and reduce the risk of fatigue-related accidents.

To learn more about the Optalert system visit www.optalert.com or call 1300 678253.

Dr. Andy Tucker, PhD. is a senior scientist at Optalert.