The following description was taken from TIC: Code of Practice to ensure an adequate field and clarity of view

Truck manufacturers are required to meet a number of safety requirements contained in Australian Design Rules (ADRs). With respect to “field of view”, and visibility to the sides and front of the truck, there are two ADRs that are relevant; ADR 8/01 Safety Glazing Material, and ADR 42/04, /05 General Safety Requirements. These ADRs require a truck manufacturer to certify that the driver has an “ADEQUATE” field of view when seated in the vehicle with the seat belt fastened. It is essential that modifications are not made to the vehicle that results in the vehicle no longer meeting the requirements of the relevant ADRs.

With respect to this Code, that means reducing the luminous transmittance of the windscreen and side windows, and the “field of view”. Prior to development of this Code, there has been an increasing tendency to modify vehicles, by fitting a range of aftermarket components, that in many instances may cause the vehicle to no longer comply with the relevant ADRs. This can result in the driver having a reduced level of visibility and field of view, which could lead to an unsafe situation. The driver of the vehicle should have an unhidden view of the road and traffic ahead and to each aside of the vehicle. This Code has been designed to assist in maintaining and ensuring ongoing compliance for field of view.