What is the Unfit to Drive duty?
Short answer
A person must not drive a heavy vehicle on a road while impaired by fatigue or otherwise not of sufficiently good health or fitness to drive it safely.
Plain English
The duty applies to drivers of all heavy vehicles, not only fatigue-regulated vehicles above 12 tonnes. A driver can be unfit because of fatigue, illness, injury, physical or mental health, alcohol, other drugs or another condition that affects safe driving.
Compliance with a work and rest table does not prove the driver is fit. The HVNL expressly allows a court to find a driver impaired or unfit even where the driver complied with maximum work and minimum rest requirements.
What this means operationally
Drivers must stop and report when they are not fit to continue. Operators and other parties should provide a no-penalty reporting path, competent escalation, safe alternatives to driving, and schedules and contracts that do not pressure a person to continue. A fitness concern should be assessed on the actual risk, not dismissed because the work diary is technically compliant.
Who it applies to
Every driver of a heavy vehicle on a road in an HVNL jurisdiction, plus businesses and people whose requests, contracts or transport activities can cause or encourage unsafe driving.
Example
A driver has complied with Standard Hours but develops severe vertigo. The driver must not continue, and the operator must arrange a safe response rather than insist that the delivery window be met.
Exceptions and traps
This is a fitness-to-drive duty, not a diagnosis rule. Medical decisions should use appropriate clinical advice and the national Assessing Fitness to Drive standards. Western Australia and the Northern Territory have separate domestic road laws.
What changed
From 1 August 2026, s 228 expressly applies to driving any heavy vehicle while impaired by fatigue or unfit to drive, and the supporting provisions define and explain the broader fitness concept.
Previous rule
The former s 228 offence was focused on driving a fatigue-regulated heavy vehicle while impaired by fatigue and did not express the broader unfit-to-drive duty in the current form.
Legal foundation
Heavy Vehicle National Law ss 26C, 26E and 220-228
Sources & primary documents
- www.legislation.qld.gov.au/view/whole/html/inforce/current/act-2012-hvnlq
- www.nhvr.gov.au/safety-accreditation-compliance/human-factors/unfit-to-drive
- www.nhvr.gov.au/safety-accreditation-compliance/fatigue-management/duties-for-managing-fatigue-and-fitness-to-drive
WWTG verification: Queensland legislation, NHVR
Frequently asked questions
Which vehicles are covered?
The duty applies when a person drives a heavy vehicle on a road, generally a vehicle above 4.5 tonnes, not only a fatigue-regulated vehicle.
Can a driver be unfit even after enough rest?
Yes. Illness, injury, physical or mental health, alcohol, other drugs and other conditions can affect safe driving.
Does a compliant work diary prove fitness?
No. A driver may still be impaired by fatigue or unfit despite complying with recorded work and rest limits.
What should an operator do when a driver reports unfit?
Stop the driving task, assess the risk, arrange a safe alternative and address any schedule or work factor contributing to the problem.
Can a contract require a driver to continue?
No. The HVNL prohibits requests and contracts that cause or encourage driving while impaired by fatigue or unfit to drive.