Ala. Code § 32-5-211

Whenever the load of any vehicle shall extend more than four feet beyond the rear of the bed or body of the vehicle, there shall be displayed at the end of the load in a position which shall be clearly visible at all times from the rear of the load a red or orange flag not less than 12 inches both in length and width. Between one-half hour after sunset and one-half hour before sunrise there shall be displayed at the end of any load a red light or amber strobe light plainly visible under normal atmospheric conditions at least 200 feet from the rear of the vehicle. Any person violating this section shall be guilty of a misdemeanor and upon conviction shall be punished as provided in Section 32-5-311.