Whenever a vehicle is parked or stopped upon a highway whether attended or unattended during the times mentioned in section 684, there shall be displayed upon the left side of such vehicle 1 or more lamps projecting a white or amber light visible under normal atmospheric conditions from a distance of 500 feet to the front of such vehicle and projecting a red light visible under like conditions from a distance of 500 feet to the rear, except that local authorities may provide by ordinance that no lights need be displayed upon any such vehicle when parked in accordance with local ordinances upon a highway where there is sufficient light to reveal any person within a distance of 500 feet upon such highway.