The National Transport Commission (NTC) recently led a review of the Heavy Vehicle National Law aimed at improving safety and productivity for Australia's heavy vehicle sector. 

The review resulted in the following amendments to the Heavy Vehicle (Mass, Dimension and Loading) National Regulations that will come into effect on 1 August 2026:

• An increase of the general mass limits from 16.5t on a tandem axle group and 20t on a tri axle group, to 17t on a tandem axle group and 21t on a tri axle group.
• 7.0t on a single steer axle with ≥315mm tyres and 11.5t on a twin steer axle group with ≥275mm tyres on Euro VI (ADR 80/04) compliant trucks.
• An increase to the general length limits for certain vehicle combinations from 19m to 20m, including increased rear overhang limits and S-dimension limits, subject to specified requirements. 
• An increase to the tow mass ratio for a rigid truck and tag trailer combination, subject to minimum steer axle mass requirements.  

Refer to the NHVR Mass, Dimension and Loading Changes - Fact Sheet for further details. 

Main Roads Heavy Vehicle Services (HVS) will amend the relevant Order and Permit products to align with these National changes. HVS will then work with the Department of Transport and Major Infrastructure to amend the relevant WA legislation. 

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

Heavy Vehicle Services

27 May 2026

Note: This HVS Update will be published until 1 August 2026.