Driving A Vehicle With Low Tyre Pressure

It is common for the driver of an off-road vehicle to deflate the vehicle’s tyres to create a better driving experience. Less tyre pressure allows the tyre to flex more, reducing the risk of damage from sharp objects and making for a smoother ride over rocks and corrugations. Drivers often travel at lower speeds off road, which also helps achieve these aims.

However, a police officer or transport officer has the discretion to issue a vehicle defect notice if the officer believes driving the vehicle with low tyre pressure is a safety risk.

Legislation about defective vehicles

Under the Road Transport Act 2013, a police officer or transport officer can inspect a vehicle to determine its identity, condition or registration status. The owner or operator of the vehicle needs to be reasonable in allowing such an inspection, or they face a maximum fine of 20 penalty units ($2200).

If a defect is found, the police or transport officer has three options. They can:

• issue a warning or a defect notice;
• impose conditions on the use of the vehicle;
• prohibit the use of the vehicle

If a person uses the vehicle contrary to conditions or a prohibition, they can be fined a maximum of 20 penalty units ($2200).

A defect notice can be a major or a minor one. A major defect notice is issued if continued use of the vehicle would pose an “imminent and serious safety risk”. A minor defect notice is issued if continued use of the vehicle “may constitute a safety risk”. A safety risk is defined as a danger to a person, property or the environment.

Tyre pressure

This is a measurement of the air in a pneumatic tyre, usually expressed as psi, or pounds per square inch. It is important safety consideration because sufficient pressure ensures tyres maintain the correct grip on the road surface and that they wear evenly. On regular road surfaces, deflated tyres can severely compromise the braking distance and handling capability of a vehicle, increasing the risk of a crash. Off-road however, deflated tyres are useful because they spread the vehicle’s weight over a larger area, allowing greater traction.

All car manufacturers must affix  a “tyre placard” to any new vehicle. The sticker provides information about the wheel and tyre requirements of the vehicle, including recommended pressure.

Off-road vehicle guides generally recommend 32-36 psi for driving on gravel, 15-25 psi on sand, 24-28 psi on rocks and 24 psi in mud.

Other tyre rules

The Australian Design Rules set legal safety standards for tyres in Australia. As well as adequate pressure, tyres must:

• have minimum tread of 1.6mm;
• include 4 evenly spaced wear indicators that show when the tyre tread has reached 1.6mm;
• be no more than 15mm bigger or smaller than the size listed on the vehicle’s tyre placard;
• be suitable for the rims to which they are fitted.

For advice or representation in any legal matter, please contact Armstrong Legal.