Automobile means a 4-wheeled vehicle that is propelled by conventional fuel, or by alternative fuel, manufactured primarily for use on public streets, roads, and highways and having a gross vehicle weight rating of less than 10,000 pounds, except:
(1) A vehicle operated only on a rail line;
(2) A vehicle manufactured in different stages by two or more original equipment manufacturers, if no intermediate or final-stage original equipment manufacturer of that vehicle manufactures more than 10,000 multi-stage vehicles per year; or
(3) A work truck, as that term is defined in this section.
10 CFR § 490.2
The following definitions apply to this part -