Maryland Code, Transportation § 22-204

(a) Except as otherwise provided in this section, after June 1, 1971, every motor vehicle, trailer, semitrailer, and pole trailer, and any other vehicle that is being drawn at the end of a combination of vehicles, shall be equipped with at least 2 tail lamps mounted on the rear, which, when lighted as required in § 22-201.1 of this subtitle, shall emit a red light plainly visible from a distance of 1,000 feet to the rear.

(b) Every motor vehicle, trailer, semitrailer, and pole trailer, and any other vehicle that is being drawn at the end of a combination of vehicles, and that was manufactured or assembled before June 1, 1971, shall have at least 1 tail lamp mounted on the rear which, when lighted as required in § 22-201.1 of this subtitle, shall emit a red light plainly visible from a distance of at least 300 feet to the rear.

(c) On a combination of vehicles, only the tail lamps on the rearmost vehicle need actually be seen from the distance specified in subsections (a) and (b) of this section.

(d) On vehicles equipped with more than 1 tail lamp, the lamps shall be mounted on the same level and as widely spaced laterally as practicable.

(e) Every tail lamp on every vehicle shall be located at a height of not more than 72 inches nor less than 20 inches.

(f) Either a tail lamp or a separate lamp shall be constructed and placed to illuminate, with a white light, the rear registration plate and render it clearly legible from a distance of 50 feet to the rear. Any tail lamp or tail lamps, together with any separate lamp or lamps for illuminating the rear registration plate, shall be wired to be lighted whenever the head lamps or auxiliary driving lamps are lighted.

(g) Notwithstanding any provision of this section to the contrary, special mobile equipment that is being drawn at the end of a combination of vehicles is not required to be equipped with tail lamps unless: