Modify a truck or heavy trailer

Requirements for modifying a heavy truck or trailer over 4.5 tonnes Gross Vehicle Mass (GVM).

The National Heavy Vehicle Regulator (NHVR) is responsible for the management of modifications to heavy vehicles and trailers in participating jurisdictions.

The participating jurisdictions are Victoria, Queensland, New South Wales, South Australia, Tasmania and the Australian Capital Territory.

The NHVR uses Approved Vehicle Examiners (AVEs) to certify and approve modifications to heavy vehicles and trailers. In Victoria, AVEs are referred to as VASS signatories who can issue a VASS Approval Certificate for modifications to both Victorian registered and interstate registered heavy vehicles and trailers that are accepted in all the participating NHVR jurisdictions.

Approval Certificates issued by interstate AVEs for Victorian or interstate registered heavy vehicles or trailers are accepted by VicRoads.

The guidelines for modifications or addition of components to heavy vehicles and trailers are outlined in the National Code of Practice Heavy Vehicle Modifications (VSB6).

Before performing modifications or adding components to your heavy vehicle or trailer it’s recommended that you discuss your plans with a VASS Signatory who will be able to provide you with advice related to your planned modification, making the process of obtaining a VASS Approval Certificate easier and ensure your vehicle or trailer will meet the Standards for Registration. 

If the description of your vehicle has changed as a result of modifications, VicRoads must be notified within 14 days of the change. See Notify VicRoads of changes and modification.

There are Vehicle Standards Information sheets (VSIs) which provide advice on some common modifications. A VASS Approval Certificate is not required if the modifications are made as per the allowances in:


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