(1)    In this section, “flammable liquid” means any gasoline, naphtha, benzine, fuel oil, crude oil, kerosene or other liquid which has a flashpoint of 80 degrees Fahrenheit or less as determined by a Tagliabue or equivalent closed-cup test device.

   (2)   No person shall transport in or on any motor vehicle, trailer or semitrailer upon a highway any flammable liquid except by tank mounted on or attached to or structurally a part of such motor vehicle, trailer or semitrailer and which is plainly marked to show that flammable liquids are being transported therein.

   (3)   This section does not apply to transportation of flammable liquids as freight only by the consumer from the place of purchase to the place of consumption if such liquids are transported in drums or other containers having a capacity of not more than 100 gallons each and if the total amount of such liquids so transported in any one vehicle or combination of vehicles does not exceed 500 gallons.