S.D. Codified Laws § 32-18-7
Every vehicle described in § 32-18-1 and combination of vehicles except special mobile equipment which includes vehicles not designed or used primarily for the transportation of persons or property and only incidentally operated or moved over a highway, including but not limited to: ditch-digging apparatus, well-boring apparatus, and road construction and maintenance machinery such as asphalt spreaders, bituminous mixers, bucket loaders, tractors other than truck tractors, ditchers, leveling graders, finishing machines, motor graders, road rollers, scarifiers, earth-moving carry-alls and scrapers, power shovels and draglines, and self-propelled cranes and earth-moving equipment, shall be equipped with service brakes complying with the performance requirements of §§ 32-18-8 and 32-18-9 and adequate to control the movement of and to stop and hold such vehicle under all conditions of loading, and on any grade incident to its operation. A violation of this section is a Class 2 misdemeanor.
SDCL 32-18-7