SDCL § 49-28A-1: Definition.

The term, "motor vehicle", as used in this chapter means any self-propelled or towed vehicle used on the highways in commerce to principally transport passengers or cargo:

(1) If the vehicle has a gross vehicle weight of ten thousand and one or more pounds;

(2) If the vehicle is designed to transport more than fifteen passengers, including the driver; or

(3) If the vehicle is used in the transportation of materials found by the United States Department of Transportation to be hazardous for the purpose of the Hazardous Materials Transportation Act, as amended (49 U.S.C. § 1801 et seq.).