Except during times other than stated on the parking meter as operating hours, it shall be unlawful for any person to cause, allow, permit or suffer any vehicle to be parked, whether occupied or not, in any parking space provided for by this article, beyond the period of time established by the duration of the parking meter, or by any notice on the parking meter limiting the period of time a vehicle may remain parked in such a space. The insertion of additional coins after such time has elapsed does not extend the allowable time a vehicle may remain parked in the same space. This section shall not be interpreted to permit parking in meter spaces that are otherwise restricted by official signs. (1978 L.M.C., ch. 7, § 2.)