No provision of this chapter for which official traffic control devices are required may be enforced against any alleged violator thereof if, at the time and place of such alleged violation, any official traffic control device required by the provisions of this chapter or the Vehicle Code of the State is not in place and sufficiently legible to be seen by an ordinarily observant person.
(§ II, Ord. 539-NS, eff. August 21, 1975)