39-13-03. Local parking regulations not enforceable where sign illegible or not in proper position

39-13-03. Local parking regulations not enforceable where sign illegible or not in proper position. Local parking and other special regulations are not enforceable against an alleged violator if, at the time and place of the alleged violation, an appropriate sign giving notice thereof is not in proper position and sufficiently legible to be seen by an ordinarily observant person.