motor vehicle
(7) Motor vehicle .— The term “motor vehicle” means any vehicle, self-propelled or drawn by mechanical power, designed and operated principally for highway transportation of property or passengers, excluding— (A) a vehicle designed or used for military field training, combat, or tactical purposes, or used principally within the confines of a regularly established military post, camp, or depot; and (B) a vehicle regularly used by an agency to perform investigative, law enforcement, or intelligence duties, if the head of the agency determines that exclusive control of the vehicle is essential for effective performance of duties.
Source
40 USC § 102(7)
Scoping language
None identified, default scope is assumed to be the parent (subchapter I) of this section.