"Bulk transfer/terminal system" means the diesel fuel distribution system consisting of refineries, pipelines, vessels, and terminals. Diesel fuel in a refinery, pipeline, vessel, or terminal is in the bulk transfer/terminal system. Diesel fuel in the fuel tank of any engine, or in any railcar, trailer, truck, or other equipment suitable for ground transportation is not in the bulk transfer/terminal system.
Ca. Rev. and Tax. Code § 60030