Heavy vehicles

Heavy Vehicle Classification

All vehicles with a gross vehicle mass greater than 4.5 tonnes are classified as heavy vehicles. Heavy vehicles operated in a combination less than 19 metres in length, 2.5 metres width, 4.3 metres height and 42.5 tonnes gross mass are considered "as of right" vehicles and have unrestricted access to the road network. Heavy vehicles exceeding these mass or dimension limits are required to operate under a Notice or Permit issued by Main Roads WA.

Standards

The Vehicle Safety Branch is involved in setting standards for these vehicles and approving modifications. To assist in this process we consult extensively with interested parties including industry.

Heavy vehicle modifications

Heavy vehicle modifications can be carried out by Authorised Modifiers under the Authorised Modification Scheme (see below) or by individuals who obtain a modification permit from the Manager, Technical Section, Vehicle Safety Branch (telephone: 13 11 56).

Generally, modifications are subject to a vehicle examination prior to final approval.

For more information on heavy vehicle modifications go to the Heavy Vehicle Modifications Scheme on the DOTARs website.

In-Service Compliance

Compliance with the regulations is assessed by roadside inspections carried out by the Main Roads Heavy Vehicle Road Transport Compliance Unit and the WA Police Service.

Vehicles found to be un-roadworthy are issued with a compliance notice, which requires that the vehicle be submitted for inspection by a Department Vehicle Examiner or an Authorised Vehicle Examiner.

Heavy vehicles mass and loading

Western Australia has adopted the Road Transport Reform regulations for Mass and Loading and for Dimension Limits.

Performance-based standards

Performance-based standards provide boundaries of acceptability within which a manufacturer or user can operate.

This method of operation has advantages for both manufacturers and users as it provides a very high level of flexibility and does not choke innovations as much as prescriptive regimes.

The National Transport Commission Load Restraint Guide is a good example of performance-based standards. The load restraining devices must be capable of withstanding a multiple of the mass load specific to a particular direction. For example, the restraints must be able to withstand 0.8 times the mass of the load in the forward direction and the user or operator is free to use any type of restraining system that meets this restraining load specification.