No person shall permit any truck or other vehicle
designated to transport flammable or toxic substances, and carrying
such substances, to be parked within 200 feet of any residential zone,
except when making a delivery of such substances to a residential
dwelling. If any truck or other vehicle is being used to deliver said
flammable or toxic substance, it shall be permitted to park in the
vicinity of the delivery place only for such time as is necessary
to make such delivery.