When official signs or curb markings have been placed by the traffic engineer to prohibit stopping, standing or parking a vehicle in a certain place for any time longer than two hours between the hours of 8:00 A.M. and 5:00 P.M. of any day except Saturday, Sunday or any holiday set forth in Chapter 1 of this code, it is unlawful for an operator of a vehicle to stop, stand or park his vehicle in violation thereof. (Ord. No. 1111, § 6.)