D.C. Mun. Regs. tit. 18, § 2215
2215.1 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.
2215.2 If a motorcycle is equipped to carry more than one person, the passenger may ride upon the permanent, regular seat if designed for two (2) persons, upon another seat firmly attached in a position to the rear or side of the motorcycle and provided with foot rests and handgrips, or in a side car attached to the motorcycle.
2215.3 No person shall operate or ride upon a motorcycle unless wearing a protective helmet in the manner for which the helmet was designed and of a type approved by the Director. [See chapter 7]
2215.4 No person shall operate a motorcycle unless he or she wears goggles or a face shield of a type approved by the Director. [See chapter 7]
2215.5 The provisions of § 2215.4 shall not apply to an operator of a motorcycle equipped with a wind screen or shield of a type approved by the Director in accordance with chapter 7, nor shall it apply to an operator of a motorcycle who wears spectacles with safety glass lenses during the operation.
2215.6 The provisions of the Point System Regulations for the District of Columbia, shall not be applicable to violations of this section.
SOURCE: Commissioners' Order 274, 310/949 effective September 1, 1949, 17 DCRR § 110 (October 19, 1970).