Signs not to constitute traffic hazard. No sign or other advertising structure as regulated by this chapter shall be erected in such a manner as to obstruct free and clear vision; or 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 traffic sign, signal or device; or which makes use of the words "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.