Where partial fulfilment is deemed acceptable, retro-reflective devices like retro-reflectors of class IVA of UN Regulation No. 3 or 150 or brackets containing retro-reflecting material compliant with photometric requirements of Class C of UN Regulation No. 104 or 150 may substitute part of the required conspicuity markings. In this case, at least one of these retro-reflective devices shall be installed per 1,500 mm. a8c0
Where partial fulfilment is deemed acceptable, retro-reflective devices like retro-reflectors of class IVA of Regulation No. 3 or brackets containing a0c0