Sec. 12. Other than official traffic signs prohibited.
No unauthorized person shall erect or maintain upon any highway
any warning or direction sign, marker, signal or light in imitation
of any official sign, marker, signal or light erected under
the provisions of this article, and no person shall erect or maintain
upon any highway any traffic or highway sign or signal bearing
thereon any commercial advertising; provided, that nothing in
this section shall be construed to prohibit the erection or maintenance
of signs, markers or signals bearing thereon the name of
an organization authorized to erect the same by the state highway
commission, mayor or city manager. (Id., § 489(60).)
