No truck used for transporting flammable liquids in bulk shall be left unattended on any street, highway, avenue or alley. Permission is granted, however, for stops for meals during the day or at night if the street is well lighted at point of parking.
Trucks used for transporting flammable liquids may be parked in open parking lots or on private property or in fireproof buildings for a period not exceeding two hours; provided, however, that trucks containing Class III liquids may be parked on the owner's business premises in buildings approved for such occupancy by the Fire Chief or his or her duly authorized agent.