All vehicles on Australian roads are subject to rules and regulations designed to promote safe road use. However, regulations applying to vehicles towing trailers have sometimes varied between the States and Territories, making life for interstate travellers somewhat confusing.

In an attempt to remedy this situation, new regulations were introduced in December 1998 that nationalised the speed limits applicable to vehicles towing trailers and to the maximum ATM.

Speed Limits

For a motor vehicle and trailer combination that has a GCM of less than 4.5 tonnes, the posted speed limits apply - unless the manufacturer of the towing vehicle has stipulated a lower towing speed limit. The only exception to this is in Western Australia where the maximum speed limit is 100km/h for vehicles towing a trailer with an ATM of over 750kgs.

However, if you are a Provisional license holder, you should check with the individual States or Territories to ascertain what towing laws apply to you.

Maximum Trailer Mass

Throughout Australia, the allowable maximum mass for the trailer is either the capacity of the tow vehicle's towing attachment or the towing limit specified by the vehicle manufacturer for the towing vehicle, whichever is the least.

If the vehicle's manufacturer has not made a recommendation as to the towing mass, then the following rules apply. A vehicle may tow a laden trailer of up to one and a half times the unladen mass of the tow vehicle, provided that the towbar is rated accordingly and the trailer is fitted with brakes that comply with the requirements stipulated in the Australian Design Rule ADR38. If the trailer is not fitted with brakes, then the maximum mass must not exceed the unladen mass of the motor vehicle. The unladen mass of the vehicle can be found in the vehicles handbook, or check with your dealer. All trailers with a GTM exceeding 750kgs must have brakes.