Michigan Compiled Laws, Chapter 257. Motor Vehicles § 257.615

Sec. 615. (a) Imitation of traffic control devices. Except with authority of a statute or of a duly authorized public body or official, no person shall place, maintain, or display along any highway or upon any structure in or over any highway any sign, signal, marking, device, blinking, oscillating or rotating light or lights, decoration or banner which is or purports to be or is in imitation of or resembles or which can be mistaken for a 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 traffic control device or any railroad sign or signal, 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.

(b) Emergency vehicles; distinguishing lights; prohibited lights. No person shall place, maintain or display along any highway any blinking, oscillating or rotating light or lights sufficiently similar in color and design that they may be mistaken for the distinguishing lights authorized by law for emergency vehicles or that creates a hazard for the safety of drivers using said highways.

(c) Prohibited signs; public nuisance, removal. Every such prohibited sign, signal, marking, device, decoration or banner 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 to be removed without notice.

(d) Placement of street decorations and banners; obstruction of traffic lights and signals. Decorations or banners which may be placed over the traveled portion of any street or highway shall be placed not closer than 10 feet on either side of traffic lights or signals and shall be so placed as to not obstruct a clear view of such traffic lights or signals.