(a) “Tank vehicle” means any vehicle other than railroad tank cars and boats, with a cargo tank mounted thereon or built as an integral part thereof used for the transportation of flammable liquids. Tank vehicles include self-propelled vehicles, and full trailers and semi-trailers without motive power and with wheels carrying either part or all of the load.
(b) Tank vehicles used for the transportation of flammable liquids shall be constructed, maintained and operated in accordance with nationally recognized standard practice as specified in section 609 of this title.