S.D. Codified Laws § 32-22-32
All motor vehicles, trucks, trailers, and semitrailers used in transporting on the public highways articles consisting, wholly or in part, of any pipe, casing, rods, bars, finished lumber products, logs, poles, or piling, which are longer than eight feet, shall have them securely and tightly fastened to the front and rear of the vehicle by at least two separate iron chains, cables, or synthetic straps extending over and around the articles on the vehicle in a manner as to securely fasten the same to the vehicle and prevent lateral or longitudinal movement of the articles while being transported in the vehicle. The chains, cables, and synthetic straps used shall have a breaking strength of not less than fifteen thousand pounds. The provisions of this section do not apply to such articles if entirely enclosed, other than at top, within the confines of a rack or box mounted on such vehicles, and which articles, when loaded in such vehicle, do not extend at the highest point of the load two linear feet above the lowest point of floor or bed of such vehicle. A violation of this section is a Class 2 misdemeanor.
SDCL 32-22-32