Section 321.259 - Unauthorized signs, signals, or markings1. No person shall place, maintain, or display upon or in view of any highway any sign, signal, marking, or device which purports to be or is an imitation of or resembles an official parking sign, curb or other marking, 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, if such sign, signal, marking, or device has not been authorized by the department and local authorities with reference to streets and highways under their jurisdiction and no person shall place or maintain nor shall any public authority permit upon any highway any traffic sign or signal bearing thereon any commercial advertising. This shall not be deemed to prohibit the erection upon private property adjacent to highways of signs giving useful directional information of a type that cannot be mistaken for official signs.2. Every such prohibited sign, signal, or marking is hereby declared to be a public nuisance and the authority having jurisdiction over the highway is hereby empowered to remove the same or cause it to be removed without notice.C39, § 5019.08; C46, 50, 54, 58, 62, 66, 71, 73, 75, 77, 79, 81, § 321.259Nuisances in general, chapter 657