§ 70.33  NECESSITY OF SIGNS.
   No provision 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 an ordinarily observant person. Whenever a particular section does not state that signs are required, the section shall be effective without signs being placed to give notice thereof.
(`90 Code, § 11-184)