A person operating a motorcycle shall ride only upon the permanent and regular seat attached thereto, and such operator shall not carry any other person nor shall any other person ride on a motorcycle unless such motorcycle is designed to carry more than one person, in which event the passenger may ride upon the permanent and regular seat designed for two (2) persons, or upon another seat firmly attached to the rear or side of the operator. (1960 Code, Sec. 7-1405)