31-5-218. Signals by hand and arm or signal lamps.
(a) Any stop or turn signal when required under this act shall be given either by means of the hand and arm or by signal lamps, except as otherwise provided in subsection (b) of this section.
(b) Any motor vehicle in use on a highway shall be equipped with, and required signal shall be given by, signal lamps when the distance from the center of the top of the steering post to the left outside limit of the body, cab or load of the motor vehicle exceeds twenty-four (24) inches, or when the distance from the center of the top of the steering post to the rear limit of the body or load thereof exceeds fourteen (14) feet. The latter measurement shall apply to any single vehicle and to any combination of vehicles.