No person shall operate the engine providing motive power, or any auxiliary engine of a motor vehicle with a manufacturer's gross weight rating of ten thousand (10,000) pounds or more for a consecutive period longer than twenty (20) minutes while such vehicle is standing and located within one hundred fifty feet (150') of property zoned and used for residential purposes except where vehicle is standing within a completely enclosed structure. This Section shall not apply to delivery or pickup vehicles that require the operation of the engine to unload or load their vending loads. (Ord. 80-8, 6-16-1980, eff. 7-1-1980)