D.C. Mun. Regs. tit. 18, r. 18-2102
No person or authority shall place or maintain any traffic control device upon any street or highway within the District except by permission of the Director of the Department of Public Works.
No person shall place, maintain, or display upon or in view of any highway any unauthorized sign, signal, marking, or device which purports to be, is an imitation of, or resembles an official traffic control device or railroad sign or signal; or which attempts to direct the movement of traffic; or which hides from view or interferes with the effectiveness of any official traffic control device or any railroad sign or signal.
No person shall place or maintain, nor shall any public authority permit, upon any highway any traffic sign or signal bearing any commercial advertising.
The provisions of this section shall not be considered to prohibit the erection upon private property adjacent to highways of signs giving useful directional information which are of a type that cannot be mistaken for official signs.
Each prohibited sign, signal, marking, or device is hereby declared to be a public nuisance and the authority having jurisdiction over the street or highway is hereby empowered to remove the same or cause it to be removed without notice.
D.C. Mun. Regs. tit. 18, r. 18-2102