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Rules of the road · about 2 min read

Tyres, collision duties and impairment

Understand the rule, its conditions and how to apply it

What you will learn

  • Explain the purpose of this rule.
  • Apply the procedure and recognise its limitations.

Purpose and essential terms

Tyres provide contact with the road. Visible tread and sound tyre condition matter for grip, especially in water. The reference requires at least 1 mm tread across the width and circumference for light vehicles and motorcycles above 50 cc. It sets a separate visible-pattern requirement for smaller motorcycles.

Inspect for uneven wear, cuts, exposed cords, damage and pressure problems using the vehicle’s instructions. A legal minimum tread number is not a guarantee of good wet-road performance or a reason to ignore tyre damage.

Key idea: Tyres provide contact with the road.

How to apply the rule

If involved in or contributing to a collision, stop immediately. Assess injuries and damage, summon appropriate assistance and give assistance you can provide safely. Do not move an injured person casually. Give the required driver, owner and registration details to a person with reasonable grounds to request them.

The manual includes reporting to a police station within 24 hours where the required information has not already been provided to an officer at the scene. For injury or death, vehicle-movement requirements apply; follow an officer’s direction and preserve or mark positions as required before authorised movement. Do not leave to avoid reporting.

Key idea: Stop and make the scene as safe as you can without exposing yourself to traffic.

Conditions and easily confused points

Do not drive while impaired by alcohol or drugs, including medication that affects safe control. Historical alcohol thresholds in the manual are not a safe drinking allowance and need current-law confirmation. The safest plan is not to combine drinking with driving.

Tyre maintenance prevents some risks; collision duties apply even when you believe another person caused the crash. Do not treat lack of blame as permission to leave.

Key idea: Apply the full rule to the actual vehicle, road and conditions.

Worked road situation

You are involved in a collision with apparent injuries.

  1. Stop and make the scene as safe as you can without exposing yourself to traffic.
  2. Call emergency assistance and help within your capability.
  3. Provide required details and follow reporting and vehicle-movement requirements.

Quick recap

  • Stop and make the scene as safe as you can without exposing yourself to traffic.
  • Call emergency assistance and help within your capability.
  • Provide required details and follow reporting and vehicle-movement requirements.

Practice questions on tyres, collision duties and impairment

1 What is the first action after being involved in a collision?

  1. Continue if your vehicle still runs
  2. Stop immediately
  3. Leave before someone asks for your details
Show the answer

Answer B: Stop immediately

The manual requires at least 1 mm tread for light vehicles and motorcycles over 50 cc, with separate rules for smaller motorcycles. After a crash, stop, check injuries, assist within your capability and provide required details. Follow reporting and vehicle-movement requirements. Never drive impaired by alcohol or drugs; check current legal limits, and do not treat a legal threshold as a safe drinking allowance.

Memory tip: Read the full rule, including its conditions and exceptions.

All vehicle codes

2 What assistance should you give after a crash?

  1. None unless you caused the crash
  2. Assistance you are capable of giving safely
  3. Move every injured person regardless of injury
Show the answer

Answer B: Assistance you are capable of giving safely

The manual requires at least 1 mm tread for light vehicles and motorcycles over 50 cc, with separate rules for smaller motorcycles. After a crash, stop, check injuries, assist within your capability and provide required details. Follow reporting and vehicle-movement requirements. Never drive impaired by alcohol or drugs; check current legal limits, and do not treat a legal threshold as a safe drinking allowance.

Memory tip: Read the full rule, including its conditions and exceptions.

All vehicle codes

3 May you drive while impaired by a drug with a narcotic effect?

  1. Yes, below the speed limit
  2. Yes, if it was prescribed
  3. No
Show the answer

Answer C: No

The manual requires at least 1 mm tread for light vehicles and motorcycles over 50 cc, with separate rules for smaller motorcycles. After a crash, stop, check injuries, assist within your capability and provide required details. Follow reporting and vehicle-movement requirements. Never drive impaired by alcohol or drugs; check current legal limits, and do not treat a legal threshold as a safe drinking allowance.

Memory tip: Read the full rule, including its conditions and exceptions.

All vehicle codes

4 What tread depth does the manual specify for a light motor vehicle?

  1. At least 1 mm
  2. At least 0.1 mm
  3. No visible tread required
Show the answer

Answer A: At least 1 mm

The manual requires at least 1 mm tread for light vehicles and motorcycles over 50 cc, with separate rules for smaller motorcycles. After a crash, stop, check injuries, assist within your capability and provide required details. Follow reporting and vehicle-movement requirements. Never drive impaired by alcohol or drugs; check current legal limits, and do not treat a legal threshold as a safe drinking allowance.

Memory tip: Read the full rule, including its conditions and exceptions.

All vehicle codes

More rules of the road chapters

Sources: NaTIS Rules of the Road, PDF pp. 41–42, sections 6.61–6.65; iDriving K53 manual, PDF pp. 91–102 (comparison; incomplete text extraction checked against official reference).

AceK53 is an independent study aid based on public road traffic manuals and is not an official test. Always confirm requirements with your driving licence testing centre.