SDCL § 32-20-6.1: Operator and passengers restricted to permanent and regular seats--Violation as misdemeanor.

A person operating a motorcycle shall ride only upon the permanent and regular seat attached thereto, and such operator may not carry any other person nor may any other person ride on a motorcycle unless such motorcycle is designed to carry more than one person, in which event a passenger may ride upon the permanent and regular seat if designed for two persons, or upon another seat firmly attached to the motorcycle at the rear or side of the operator. A violation of this section is a Class 2 misdemeanor.