(A) Definitions.
(1) Truck tractor. Every motor vehicle designed and used primarily for drawing other vehicles and not so constructed as to carry a load other than a part of the weight of the vehicle and load so drawn.
(2) Semi-trailer. Every vehicle without motive power designed for carrying persons or property and for being drawn by a motor vehicle and so constructed that some part of its weight and that of its load rests upon or is carried by another vehicle.
(B) Parking restrictions. No person shall stand or park any truck tractor or semi-trailer on any public street within the RC, RE-1, RM, RS, or RD zoning districts for a greater period than is necessary for the reasonably expeditious loading or unloading of such vehicle.