Whenever the load or any projecting portion of any vehicle shall extend beyond the rear or the bed or body thereof the operator shall display at the end of such load or projections, in such position as to be clearly visible from the rear of such vehicle, a red flag being not less than twelve (12) inches square. Between one-half (1/2) hour after sunset and one-half (1/2) hour before sunrise there shall be displayed in place of the flag a red light plainly visible under normal atmospheric conditions at least two hundred (200) feet from the rear of such vehicle.