SDCL § 32-3-2.4: Farm vehicles exempt--Exceptions.

Any farm wagon, farm implement drawn by another vehicle, or farm vehicle which is designed and used primarily for tillage, harvesting, or transportation of agricultural products or farm property by or for agricultural producers is exempt from the provisions of this chapter, unless the farm vehicle is a stock trailer, gooseneck trailer, or semitrailer towed by a licensed motor vehicle on any public highway or a passenger vehicle, two- or three-axle truck, or semitractor.