5.8.3. The position, as regards width, will be determined from that edge of the apparent surface in the direction of the reference axis which is the furthest from the median longitudinal plane of the vehicle when referred to the overall width, and from the inner edges of the apparent surface in the direction of the reference axis when referred to the distance between lamps. Where the position, as regards width, clearly meets the requirements of the Regulation, the exact edges of any surface need not be determined. a0c0