HVNL: fatigue – more than just work and rest hours?

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