S.D. Codified Laws § 32-22-16.3
No vehicle hauling agricultural products from farm storage or livestock from a farm is subject to enforcement action for violations not exceeding the legal limits imposed pursuant to § 32-22-16 or 32-22-21 by more than five percent. However, the vehicle is only exempt pursuant to this section within a range of fifty miles of the farm. The vehicle may not exceed the posted weight of any bridge or road. The weight tolerance authorized in this section is not applicable during spring load restrictions as set forth in § 32-22-24. If enforcement action is taken pursuant to this section, the fine or penalty shall apply to that portion of the load that is above the legal limit. The weight tolerance authorized in this section is not permitted on the interstate highway system. A violation of this section is a Class 2 misdemeanor.
SDCL 32-22-16.3