In Australia’s heavy vehicle industry, safety isn’t just a priority — it’s a legal obligation under Chain of Responsibility (CoR) and workplace health and safety (WHS) laws. While random drug and alcohol testing is standard across the sector, one of the most crucial — and often misunderstood — components of an effective testing program is reasonable suspicion testing.
This process allows supervisors to act when they believe a driver or employee may be impaired, ensuring risks are addressed before they reach the road, depot, warehouse, or loading zone.
When done correctly, reasonable suspicion testing protects staff, the public, and the business. When done poorly, it can expose organisations to legal, reputational, and compliance risks.
This guide walks transport supervisors and safety leaders through how it works — and how to implement it fairly and defensibly.
What is reasonable suspicion testing?
Reasonable suspicion testing (also called "for-cause testing") is initiated when there are observable signs an employee may be impaired by alcohol or drugs while at work or about to start work.
It is not guesswork, a “hunch,” or personal judgement — it is based on documented, objective evidence.
It complements other testing methods including:
- Random testing
- Pre-employment testing
- Post-incident testing
- Fit-for-duty checks
- Return-to-work testing
When should reasonable suspicion testing be used?
Reasonable suspicion testing is appropriate when there are behavioural, physical, or environmental indicators that suggest impairment.
Common signs include:
Behavioural
- Confusion or poor coordination
- Slurred speech or erratic behaviour
- Mood swings or aggression
- Difficulty following instructions
Physical
- Smell of alcohol or cannabis
- Glassy or bloodshot eyes
- Poor balance or slow reaction times
- Shaking, sweating, or drowsiness
Performance
- Repeated mistakes
- Difficulty operating machinery
- Unsafe driving or equipment handling
Environmental
- Empty alcohol containers in vehicle/cab
- Suspicious substances or paraphernalia nearby
Supervisor responsibilities in suspicion-based testing
Supervisors must handle these situations professionally and legally. Key responsibilities include:
- Observing and documenting signs objectively
- Removing the worker from duty safely (not punitive)
- Arranging testing promptly and discreetly
- Escorting the employee during the process
- Recording all actions and decisions
- Maintaining confidentiality
- Ensuring the worker gets home safely if removed from duty
This ensures employee dignity is protected while maintaining workplace safety obligations.
How to conduct reasonable suspicion testing — step-by-step
1. Observe
Identify concerning behaviour or indicators.
2. Document
Record observations with date, time, location, witnesses, and details.
3. Remove from duty
Privately escort the worker to a safe area.
4. Explain the process
State that testing is required under policy due to observed behaviours.
5. Conduct testing
Use approved equipment and trained personnel.
6. Take immediate action
If the worker tests positive, follow the policy (e.g., stand down, confirmatory testing, disciplinary/support process).
7. Record & store findings
Maintain secure records for WHS and audit purposes.
Why this matters — compliance & duty of care
Correctly performed reasonable suspicion testing helps organisations:
- Demonstrate WHS and Chain of Responsibility compliance
- Prevent impaired driving and machinery operation
- Protect public safety
- Reduce incident and insurance exposure
- Show fairness, transparency, and procedural integrity
In a safety-critical environment like transport, being reactive is not enough — supervisors must be prepared and trained.
Best practices for transport operators
- Train supervisors on signs of impairment
- Use an observation checklist template
- Keep breathalysers calibrated and test kits in date
- Use devices suitable for workplace compliance
- Maintain chain-of-custody procedures
- Store testing data securely and centrally
- Support employees with education and EAP pathways
Reasonable suspicion testing is not only a compliance tool — it helps build a culture where safety is taken seriously.
Final word
With professional supervision, documented procedures, and reliable testing tools, suspicion-based testing becomes a fair, compliant, and proactive safeguard — reducing risk across the entire transport chain.
And if you're updating your alcohol and drug procedures, building a testing program, or training supervisors, Andatech is here to support you.
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