(1) Whenever a requirement is stated as to the distance from which certain lamps and devices shall render objects visible, or within which lamps or devices shall be visible, those provisions shall apply during the times stated in section 49-903, Idaho Code, in respect to a vehicle without load when upon a straight, level, unlighted highway under normal atmospheric conditions unless a different time or condition is expressly stated.
(2)  Whenever a requirement is stated as to the mounted height of lamps or devices, it shall mean from the center of the lamp or device to the level ground upon which the vehicle stands when the vehicle is without a load.