Unfit to Drive

The content on this page includes amendments due to changes to the Heavy Vehicle National Law and Regulations that commence on 1 August 2026 and only relates to the new act. For more information, please see HVNL reform implementation.

This page provides information for drivers about the unfit to drive duty introduced following the 2025 amendments to the Heavy Vehicle National Law (HVNL).

What is the unfit to drive duty?

Under the HVNL, a person must not drive a heavy vehicle on a road while impaired by fatigue or unfit to drive.

The unfit to drive component expands on the existing duty not to drive while impaired by fatigue, recognising that a person’s health or fitness - not just fatigue - may impact their ability to drive safely.

The duty not to drive while impaired by fatigue or unfit applies to drivers of all heavy vehicles over 4.5 tonnes – not just those operating fatigue-regulated heavy vehicles.

When is a driver unfit to drive?

A driver is unfit to drive if at that time, they are not of sufficiently good health or fitness to drive the heavy vehicle safely. This may be due to physical or mental health conditions, temporary illness, injury, or the effects of alcohol and other drugs.

What does this mean for drivers?

The unfit to drive duty requires drivers to consider their health and fitness as it relates to their ability to drive the heavy vehicle safely.

Drivers must:

  • Ensure they are fit to drive before commencing driving
  • Not commence driving if they are unfit for any reason
  • Actively monitor their fitness to drive during a shift
  • Stop driving if they become unfit for any reason
  • If unfit, take appropriate action to ensure they are fit to drive before resuming their next shift

Similar to the duty not to drive while impaired by fatigue, this duty legally empowers drivers to stop driving if their health and fitness impacts their ability to drive safely.

Fitness to Drive and the Chain of Responsibility

While a person must not drive while unfit, parties in the Chain of Responsibility (CoR) must also ensure their business practices do not cause or encourage a person to drive while unfit and must empower them to stop driving when necessary. This includes ensuring drivers are fit to drive before they get behind the wheel.

Together, these duties support safer transport activities and aim to reduce the risk of incidents on our roads.

What are the risks of driving while unfit?

Being unfit can impair the critical functions required to drive safely, including seeing and perceiving the road environment, processing information, making decisions, and controlling the vehicle.

This can lead to unsafe driving behaviours such as:

  • Inappropriate speed or braking issues
  • Poor lane control
  • Reduced alertness and responsiveness to traffic and road conditions

These behaviours can significantly increase the risk of a near miss, incident, or crash.

Signs of being unfit to drive

Drivers can experience and exhibit a range of signs that may indicate they are unfit to drive. These signs can occur before, during or after driving and may reflect changes in how they are functioning.

Examples include:

  • Lack of alertness
  • Difficulty concentrating
  • Poor judgement or memory
  • Slower reaction times
  • Dizziness or light-headedness
  • Drowsiness or falling asleep
  • Blurred vision
  • Pain or discomfort
  • Impaired coordination or motor control
  • Psychological or emotional distress

If a driver notices any of these signs, or other adverse changes to their health and fitness, their ability to drive may be affected.

Examples of being unfit to drive

In addition to fatigue, there a range of factors related to a person’s health and fitness that can cause or contribute to being unfit to drive.

Examples include:

A medical episode or change in medical condition

Example - A hypoglycaemic episode (low blood sugar) that causes weakness, shaking, dizziness and light-headedness.

A physical injury or condition

Example - A lower back injury that causes significant pain, restricts movement, and affects concentration.

Being psychologically or emotionally distressed

Example - Experiencing a distressing event at home (e.g. family conflict or major life pressures) and becoming mentally preoccupied, leading to reduced situational awareness and impaired judgement.

A temporary illness

Example - Having a flu that causes drowsiness, body aches, headaches and exhaustion.

Being under the influence of alcohol, illicit drugs, or the effects of medication

Example - Experiencing side effects from a new medication that causes reduced alertness, slowed reaction times and impaired coordination.

Drivers should consider how any change to their health or fitness may impact their ability to drive safely.

Unfit to drive and other regulatory requirements

The unfit to drive duty operates alongside other HVNL duties and broader regulatory requirements. It does not override or exclude any other obligations for drivers or parties in the Chain of Responsibility (CoR).

Duty not to drive while impaired by fatigue (HVNL)

Managing fatigue is still a key obligation. The unfit to drive duty applies in the same way, if a driver is impaired by fatigue or otherwise unfit for any reason, they are legally required and empowered to stop driving.

Heavy vehicle licensing

States and territories set medical fitness to drive requirements for licensing purposes. Being medically fit for a heavy vehicle licence does not mean drivers are always fit to drive at any given point in time. Drivers may still be unfit to drive due to other factors (e.g. a medical episode or temporary illness/injury).

Work Health and Safety (WHS)

Workers and Persons Conducting a Business or Undertaking (PCBU) have duties to ensure health and safety at work. The unfit to drive duty does not replace driver’s, or their employer’s, safety responsibilities.

Managing fitness to drive

Managing fitness to drive involves continuously checking in with your health and fitness and taking immediate action if something changes. Similar to managing fatigue, it involves recognising and assessing how you feel and making a safe decision about being on the road.

Maintaining fitness to drive requires considering your health and fitness before, during and between shifts.

Before a shift

Before starting a shift, take the time to assess how you are feeling physically, mentally, and emotionally. Consider whether there are any changes to your health or fitness and whether these could affect your ability to drive safely.

For example, ask yourself:

  • Am I feeling tired, drowsy or exhausted?
  • Can I clearly sense and perceive my surroundings?
  • Am I alert and able to concentrate, make safe decisions, and respond appropriately?
  • Am I experiencing pain, discomfort or restricted movement?
  • Am I experiencing psychological or emotional distress?
  • Am I affected by alcohol, illicit drugs, or medications?

If something doesn’t feel right and you think it may affect your ability to drive safely, you must not commence driving.

Pre-shift self-assessment tools or checklists can help you to pause, reflect honestly and make an informed decision about whether you are fit to drive. These tools should support genuine self-reflection about your health and fitness and not treated as just a compliance exercise.

During a shift

Even if you were fit to drive at the start of a shift, your physical, mental and emotional state can change throughout. It’s important to monitor your fitness to drive throughout the shift and respond early to any signs which may impact your ability to drive. If you notice signs that your fitness to drive is becoming affected, stop at the first safe opportunity and reassess.

Between shifts

Fitness to drive can be affected by what happens outside of work. What you do after finishing work and between shifts can affect your ability to safely drive during the next shift.

Examples of how you can support your fitness to drive between shifts include:

  • Getting adequate and good quality sleep
  • Maintaining general health and wellbeing routines
  • Monitoring and managing any medical conditions
  • Understanding how alcohol and other drugs can affect your ability to drive

It's important to assess your fitness to drive before every shift. Being fit to drive during the previous shift does not guarantee you are fit to drive for your next shift.

Driver resources

The following resources can support drivers in managing their health, fitness and wellbeing:

Notifying an employer if you are unfit to drive

If you identify that you are unfit to drive for any reason, tell your employer and do not commence or continue driving. By doing so, you are fulfilling your legal obligations under this duty. Your employer is then responsible for taking appropriate action in response to this notification. They are also prohibited under the Primary Duty from requiring you to commence or continue driving if you are unfit to do so.

Chain of Responsibility Resources

The following resources can assist parties in the Chain of Responsibility to support fitness to drive: