§ 18-152  NECESSITY OF SIGNS.
   No provisions of this chapter for which signs are required shall be enforced against an alleged violator if, at the time and place of the alleged violation, an official sign is not in proper position and sufficiently legible to be seen by an ordinarily-observant person. Whenever a particular section does not state that signs are required, such section shall be effective even though no signs are erected or in place.