Signs not to constitute traffic hazard. No sign or other advertising structure as regulated by any of the provisions of this chapter shall obstruct free and clear vision; or be at any location where, by reason of the position, shape or color, it may interfere with, obstruct the view of, or be confused with any authorized sign, signal or device; or make use of the word "STOP," "LOOK," "DRIVE-IN," "DANGER," or any other word, phrase, symbol or character in such a manner as to interfere with, mislead or confuse traffic.