It shall be unlawful for any person to supply or permit to be supplied with gasoline, kerosene or other flammable fluid of known dangerous character, any motor vehicle or other mechanism powered by an internal combustion engine of which the gasoline, kerosene or other flammable fluid shall be the fuel, on the roadway, sidewalk or parking of any street, avenue or road, or in or on any alley or public driveway, or in any vacant lot or plot of ground adjoining the roadway, sidewalk or parking of any street, avenue or road, or any alley or public driveway within the Montgomery County Suburban District, except in case of an emergency. (Mont. Co. Code 1965, § 114-3.)