the characteristic axis of the light signal, determined by the manufacturer for use as the direction of reference (H = 0 C, V = 0 C) for photometric measurements and when fitting the reflex reflector to the vehicle
"Axis of reference" (or reference axis) means the characteristic axis of the light signal, determined by the manufacturer for use as the direction of reference (H = 0č, V = 0č) for photometric measurements and when fitting the lamp on the vehicle.