Main Roads Heavy Vehicle Services (HVS) is pleased to advise that as part of our ongoing efforts to provide improved efficiency, we have included Tri Drive Combinations into the Prime Mover Combinations Operating Conditions and the Truck Combinations Operating Conditions. 

This means that operators of Tri Drive Combinations will now be covered by the Class 2 & 3 Orders and will no longer require permits if operating an approved vehicle combination within statutory mass limits. 

Refer to the Orders page on the Main Roads website for the latest Prime Mover Combinations Operating Conditions and the Truck Combinations Operating Conditions. 

For further information, please contact the Heavy Vehicle Services Helpdesk on 138 486 or email hvs@mainroads.wa.gov.au .

Heavy Vehicle Services

9 March 2026

Note: This HVS Update will be published for 1 month.