CR 202: Fatigue Expert Group: Options for Regulatory Approach to Fatigue in Drivers of Heavy Vehicles in Australia and New Zealand (2001)

Concern about the cost and impact of fatigue in the road transport industry and the effectiveness and relevance of traditional driving hours regulation has made this report of the fatigue expert group especially timely.

The Parliaments of both Australia and New Zealand consider fatigue in the road transport industry important enough to establish committees of inquiry into issues and possible solutions.

In February 2000 the National Road Transport Commission of Australia, the Australian Transport Safety Bureau and the New Zealand Land Transport Safety Authority jointly sponsored the establishment of a fatigue expert group to develop options for the medium term development of prescriptive hours of driving and work in the road transport industry.

The fatigue expert group comprised leading Australian and New Zealand experts in sleep, shiftwork and road safety who collaborated with the participating agencies and industry representatives to construct a set of evidence-based design principles for regulatory options.

The fatigue expert group's approach

The framework proposed by the fatigue expert group needs to be supported by other mechanisms to promote fatigue management. These other mechanisms include education, information, training, road treatments, technological aids and financial incentives/sanctions through workers compensation, vehicle insurance and safety management regimes.

The management of driver fatigue is not a matter for operators and drivers alone and the fatigue expert group emphasised the requirements and practices of others in the transport supply chain. The chain of responsibility provisions in current road transport legislation is designed to highlight that on-road performance is closely related to the decisions made by customers, consignors and loaders.

There are significant incentives in the social and economic profile of the transport industry for scheduling, trip planning and consequent driver practices that increase fatigue related risks. Competitive pressures, payment systems, contracting arrangements and even the unintended consequences of the current driving hours regime combine to create an environment in which fatigue has become an accepted part of industry practice.

The expert group was conscious of the need to provide a flexible and practicable framework in which fatigue could be actively managed by all those who are part of the supply chain.

The model of fatigue used by the expert group was centred on three primary factors that contribute to, and explain driver fatigue:

  • the need to ensure that drivers have adequate pportunities to sleep;
  • the need to take account of the circadian biological clock, which dictates that drivers cannot work or sleep equally well at all times of the day and night;
  • the need to address the fatiguing aspects of work demands, including the duration of work and the availability of breaks during work, which offer the opportunity for temporary recuperation from the effects of fatigue.

These factors are part of a more complex model for understanding fatigue. The core of this model is the need to provide adequate opportunities for restorative sleep and this is a fundamentally different orientation than prescribing limits to driving hours.

Principles for designing better regulations

On the basis of their own research and other national and international research the expert group identified five critical factors or principles that should be incorporated in any regulatory options. The factors are:


  • Minimum sleep periods, the opportunity for sleep and time of day influences

    A minimum sleep period in a 24-hour period is required to maintain alertness and performance levels. Continuous and undisturbed sleep is of higher quality and more restorative. The group concluded that the minimum sleep requirement in a single 24-hour period is six consecutive hours of sleep (although the average required on a sustained basis is about seven to eight hours).

    The group then considered the length of break that would enable the six-hour minimum which is necessarily longer than the six-hour sleep minimum period. Breaks need to take account of the activities of daily living including preparation for sleep and return to work. The impact of the circadian biological clock is critical in determining appropriate breaks in which sleep opportunity is possible. The group recommended the minimum sleep opportunity per 24 hours should be sufficient to allow for six consecutive hours of sleep.


  • The cumulative nature of fatigue and sleep loss

    Minimum sleep opportunities have to be considered over longer periods because of the cumulative nature of sleep loss and fatigue. The expert group agreed that the six hour minimum sleep requirement is adequate on one day, but not sufficient on an ongoing basis.

    Recovery sleep after an accumulated sleep debt is usually deeper and more efficient, and the lost hours of sleep do not need to be recovered hour-for-hour. Repaying the debt, to restore normal waking function, usually requires two nights of unrestricted sleep.

    As a consequence the group recommended that schedules should permit two nights of unrestricted sleep on a regular basis (preferably weekly) to provide drivers with the opportunity to recuperate from the effects of accumulating sleep debt.

  • Night work

    Driving at night was considered an important factor for the expert group as it brings together the elements that generate fatigue risks. Working at night produces an elevated risk of fatigue-related impairment, because it combines the daily low point in performance capacity with the greatest likelihood of inadequate sleep.

    The group concluded that the combination of risk factors associated with night driving should be recognised by ensuring that the length of breaks to enable sleep following night work are suitable and that opportunities for night sleep are available in a seven-day period. Additionally the group proposed a limitation to the number of hours (a limit of 18 hours) that could be driven in the 0000-0600 period after which two nights of unrestricted sleep should be available.

  • Duration of working time

    The expert group concluded that a "safe" threshold for daily working time on a sustained basis will vary according to other factors like time of day, but the upper limit is in the 12-14 hours zone. There was evidence that longer trips could be undertaken on a one-off basis but that repeated long trips rapidly escalated fatigue risk factors. Whilst the group believed flexibility for these longer trips should be provided they needed to ensure that long trips were not combined with risks associated with night driving and circadian low points.

    To underpin this short term flexibility, the expert group recommended that any one-off long trips involving over 12 hours work should not extend into the 0000-0600 period and that during a seven-day period there should be no more than 70 hours of working time.

  • Short breaks within working time

    The final factor noted by the expert group was making short breaks available as countermeasures to fatigue and the boredom and monotony associated with some driving tasks. These short breaks were not substitutes for the breaks to enable opportunity for minimum continuous sleep.

    Short breaks allow fatigue countermeasures like food, coffee and short naps to be utilised. The expert group agreed that breaks should be taken on a needs basis and that this discretion should be balanced by greater attention in scheduling to account for rest breaks.

    The expert group recommended that in a one-day period the driver should take non-work breaks equal to 10% of the total working time; these breaks should be taken at the discretion of the driver but they should not be accumulated to form long breaks. As a minimum, short rest breaks should include a non-work break of 15 minutes after every five hours work.

    A less flexible means of achieving non-work breaks equal to 10 per cent of total working time would be to require a 30 minute non-work break to be taken after every 5 hours of work.

Current driving hours regulations do not meet evidence based critical factors

The expert group's evidence-based critical factors are similar to those identified by expert panels in the United States and Canada and when applied to assess the current prescriptive driving hours regime highlight deficiencies including:

  • The maximum working (including driving) period in a day does not accommodate circadian patterns (time of day factors);

  • The minimum rest periods do not account for cumulative fatigue issues and the variable length of break required for adequate sleep opportunity at different times of the day;

  • The minimum rest periods do not accommodate the opportunity for night sleep;

  • The short rest breaks are arbitrary and do not allow breaks to be taken when they may be of most benefit.

The expert group's recommendations present challenges for industry and regulators

The expert group's primary focus was on the scientific basis for any regulatory options but it was cognizant of operational, social and economic cost-benefit and compliance dimensions. It gave consideration to a range of factors like journey completion issues, queuing and slotting, availability of rest stations, cost burdens and ease of enforcement.

It was recognised that some of the proposals may create challenges for current operational practices but the expert group was equally clear that improvement and reduced risk is dependent on some of those practices changing to accommodate the state of knowledge about fatigue. The need for change is not limited to the driving task but must encompass the supply chain.

These design principles should be considered in developing prescriptive traditional driving hours regulation or other options such as performance based regulations and codes of practice. To illustrate how the design principles could be applied, an indicative model was prepared by the expert group. The expert group saw this as one way of progressing the better management of fatigue but anticipated there would be other ways of putting the principles into practice.

Whilst the process of developing regulatory options involves robust examination of many factors and inevitable pragmatic compromises, the design principles set out in this report are considered fundamental to improved outcomes.

Type: Research and Analysis Report

Sub Type: Consultant Report

Author(s): D Dawson, A-M Feyer, P Gander, L Hartley, N Haworth, A Willamson, P Baas, D Nolan, B Moore, C Brooks, C Foley & B Bottomley

ISBN: 0 642 54478 6

ISSN: 0810-770X

Topics: Fatigue, Heavy vehicle

Publication Date: 01/02/01