No person shall park a vehicle with any portion thereof projecting into any alley entrance. No person shall park a vehicle in any alley, except for the purpose of loading or unloading during the time necessary to load or unload, which shall not exceed the maximum limit of one-half hour. Every vehicle while loading or unloading in an alley shall be parked in such manner as will cause the least obstruction possible to traffic in the alley.
Penalty, see § 5-901