(A) No person shall stop, stand, or park a vehicle for any purpose or length of time other than for the expeditious unloading and delivery or pick-up and loading of materials in any place marked as a freight curb loading zone during hours when the provisions applicable to such zones are in effect. In no case shall the stop for loading and unloading of materials exceed 30 minutes.
(B) The driver of a passenger vehicle may stop temporarily at a place marked as a freight curb loading zone for the purpose of and while actually engaged in loading or unloading passengers when such stopping does not interfere with any motor vehicle used for the transportation of materials which is waiting to enter or about to enter such zone.
(`90 Code, § 20-137)