(1) No person shall stop, stand, or park a vehicle for any purpose or period of time other than for the expeditious unloading and delivery or pickup and loading of property in any place marked as a loading zone during hours when the provisions applicable to such zone are in effect. In no case shall the stop for loading and unloading of property exceed thirty minutes.

(2) The driver of a vehicle may stop temporarily at a loading zone for the purpose of and while actually engaged in loading or unloading passengers when such stopping does not interfere with any vehicle which is waiting to enter or about to enter such zone to load or unload property.