No person shall park any truck or trailer, the gross vehicle weight rating of which exceeds 16,000 pounds, on the public streets of the Municipality, within any residential district, between the hours of 10:00 p.m. and 7:00 a.m. except for the purposes of actually taking on or letting off passengers or loading or unloading merchandise, and the vehicle, when so parked, shall be constantly attended by its operator.
(1974 Code Sec. 3-151)