The Heavy Vehicle National Law (HVNL) imposes a series of prescriptive work and rest hour limits designed to ensure that heavy vehicle drivers are not adversely affected by fatigue. In addition, the HVNL prevents parties in the chain from requiring or rewarding drivers to drive in breach of their work and rest hours.

The thinking behind the work and rest hour requirements is that if drivers have X hours rest (or at least, X hours of non-work), then they will be fit to perform Y hours work. Sounds simple, perhaps too simple.

Just because someone rests or doesn't work for X hours doesn't necessarily mean that they are fit to perform Y hours work. The simple work/rest equation doesn't take into account things such as the time when rest is taken or work performed (i.e. shift work), what other activities are performed or pressures faced during 'rest' time (e.g. a big weekend or family medical stresses) or the differences in people's physiology (e.g. I am a morning person, my brain starts to power down as of about 4pm, regardless of how much I sleep).

For these reasons, the HVNL also prohibits drivers from driving or any party in the chain from requiring or rewarding drivers to drive when they are 'impaired by fatigue', meaning where a driver's ability to drive safely is adversely affected by fatigue. This is a catch-all, that covers situations where the work/rest hours limits may be satisfied, but a driver is still not fit to drive.

This is also one of the hardest aspects of the HVNL to assess and manage, as it is very individual and point-in-time specific. But, what if you could materially reduce the risk of drivers being 'impaired by fatigue' at a business level, to help minimise the chance of any specific driver being impaired by fatigue at any given point-in-time?

A recent project by a group called Circadian highlights the performance-based considerations that can help manage fatigue. Within the operations of a transport operator, they started by considering any elements of the business which inherently raised the risk of fatigue, such as:

  • the nature of the business of the transport operator (e.g. long-distance)
  • the scheduling of trips, in particular the sequencing of types of trips and back-to-back sequencing
  • the day-to-day decisions of drivers in managing their journeys and work/rest time.

Circadian identified the business/schedule/driver behaviour scenarios and combinations that gave rise to the highest risks of fatigue and tabled these as the targets for intervention and risk management.

An intervention program was then developed, which looked at changes that could be made to the business practices surrounding those high risk factors and combinations, such as:

  • educating schedulers on the fatigue-impact of their decisions (e.g. 'mix a job, schedule and driver like this and you produce an intoxicating blend of fatigue')
  • adjusting the timing and duration of daily and weekly work patterns
  • providing two consecutive nights of rest
  • avoiding rapid rotations in start times
  • reducing consecutive work shifts.

The results were fairly impressive, including:

  • a reduction in driver risk scores (per Circadian's formula) from 47 to 29 in the first nine months
  • a drop in high risk fatigue scores from 28.9 per cent to 3.9 per cent
  • an 80.9 per cent drop in the incidence of 'loss-of-attention' incidents
  • a 66.7 per cent drop in the average cost and severity of vehicle incidents
  • a significant drop in insurance claims.

The above assessment and outcomes were the result of taking a performance based approach to fatigue management. Rather than merely painting by numbers (or work/rest hours), the transport operator looked at what changes they could make to the factors that were most likely to contribute to fatigue throughout their operations, resulting in a business and driver base that was inherently less risky than previously.

This is exactly what is required under the HVNL and, when you look at it, is not as difficult as you might have thought.

This publication does not deal with every important topic or change in law and is not intended to be relied upon as a substitute for legal or other advice that may be relevant to the reader's specific circumstances. If you have found this publication of interest and would like to know more or wish to obtain legal advice relevant to your circumstances please contact one of the named individuals listed.