According to the national code of practice (VSB12), all motor vehicles over 12 Tonne GVM and all trailers over 10 Tonne GTM need rear safety signage of a specific form.
Plate selection and Combination – VSB12:
- Vehicles or combinations with a combined length of 7.5m or more must be fitted with “DO NOT OVERTAKE TURNING VEHICLE” signage. If less than 7.5m do not fit “DNOTV” signage.
- If space permits on the rear of the vehicle:-
- Use Category 33 and 34 plates as first choice. https://www.tegral.com.au/product/rmp-dnotv-class-400-aluminum-300mm-x-400mm/
- Use additional strip plates, if possible, for added visibility. https://www.tegral.com.au/product/strip-rmp-class-400-aluminum-4-piece-400-x-100mm/
- If Category 33 plates are selected:
- Use them in correct configuration with either 31L or 33L plates.
- Use additional strip plates, if possible, for added visibility.
- If Category 34 plates are selected:
- Use a 33 plate on the right hand with a 34A plate on the left or use 34 plates on both sides.
- Use additional strip plates, if possible, for added visibility.
- Category 34 plates cannot be used on a vehicle/combination that is less than 7.5m in length.
- If rear of the vehicle cannot support Category 33 and 34 plates:
- Use the Category 161 strip plate as space permits.
- Use them in conjunction with either 31L or 33L plates if required.
- If a single 161 plate cannot be used:
- Use the correct combination of 81 and 41 plates.
- Use these in conjunction with 31L and 33L plates.
- If vehicle is a prime mover, lead semitrailer or converter dolly:
- Use 615 plates only.
- Use in conjunction with 31L and 33L plates if required.
https://www.nhvr.gov.au/files/202007-0849-vsb12-national-code-of-practice-rear-marking-plates.pdf