Changes in Trailer Definitions with QLD Transport and Trailer Roadworthy Certification.

Changes to trailer definitions

The inspection categories for light and heavy trailers will change. The current definition of under or over 3.5t Aggregate Trailer Mass (ATM) will be changed to under or over 4.5t ATM.

The only trailers that will be affected by the change are those between 3.5t and 4.5t ATM that will no longer require a certificate of inspection (COI). The light trailer inspection category—between 0.75t and 4.5t ATM—will require a safety certificate only when it is sold or transferred to another entity. The heavy trailer category, those over 4.5t ATM, will continue to require a COI.

Hard copy inspection certificate books will be updated to reflect the change from 3.5t ATM to 4.5t ATM. However, you can continue to use your existing light trailer safety certificate books to issue safety certificates to trailers between 3.5t and 4.5t ATM until you purchase the new books.

From 26 March, if AEs use ICO to issue inspection certificates, and the trailer being inspected is already recorded in TMR’s registration system, ICO will verify trailers between 3.5t ATM and 4.5t ATM as a light trailer and issue a safety certificate. The AE should check that the customer is planning to sell the trailer and if not, advise them that a COI is no longer needed.

If the trailer is not recorded in TMR’s registration system, AEs can issue a manual (unassigned) safety certificate in ICO. This is done by selecting the light trailer inspection type for all trailers over 0.75t ATM up to and including 4.5t ATM. The AIS and the AE conducting the inspection must both be accredited with the light trailer inspection type. All trailers over 4.5t ATM must be issued a COI.


With over 20 years experience in the Automotive and Motorcycle industries Michael has the knowledge and knowhow. From performance & handling, Buying on your behalf ( locating vehicle, Inspecting vehicle, negotiating the deal, complying and delivering to your door), Pre Purchase Inspections, mod plating to roadworthy’s Michael has you covered.