All vehicles with a gross vehicle mass over 12 tonnes and trailers with a gross trailer mass over 10 tonnes mustbe fitted with retroreflective rear marking plates.
Rear marking plates may also be fitted to any motor vehicle with less than 12 tonnes gross vehicle mass or to any trailer with less than 10 tonnes gross trailer mass.A special turning concession applies to vehicles or vehicle combinations over 7.5 metres long which display a prescribed sign at the rear with the words “DO NOT OVERTAKE TURNING VEHICLE”. This sign may be either a separate sign or can be combined with the marking plate on the left hand side.
This sign has the words DO NOT OVERTAKE TURNING VEHICLE, ensures that your van is compliant with the regulations and helps to raise awareness for drivers behind you. made of class 1 reflective material and is 300x100mm and the writing is 50mm.
Not having “DO NOT OVERTAKE TURNING VEHICLE” sign on these vehicles and crossing lanes is illegal.
For more information see http://www.infrastructure.gov.au/roads/vehicle_regulation/bulletin/pdf/vsb_12.pdf