Code of Federal Regulations Title 43. Public Lands:  Interior § 43.8365.1–3 Vehicles

(b)(1) The operator of a motor vehicle is prohibited from operating a motor vehicle in motion, unless the operator and each front seat passenger is restrained by a properly fastened safety belt that conforms to applicable United States Department of Transportation standards, except that children, as defined by State law, shall be restrained as provided by State law.

(2) Paragraph (b) applies on public lands, or portions thereof, that are located within a State in which there is no State law in effect that requires the mandatory use of a safety belt by the vehicle operator and any front seat passenger. It also applies on public lands, or portions thereof, located within a State in which the mandatory safety belt law of the State does not apply to the public lands or in which any provision of State law renders the mandatory safety belt law of the State unenforceable by the authorized officer as to acts or omissions occurring on the public lands.

(3) This section does not apply to an operator or a passenger of a motor vehicle occupying a seat that was not originally equipped by the manufacturer with a safety belt, nor does it apply to an operator or passenger with a medical condition that prevents restraint by a safety belt or other occupant restraining device.

(4) An authorized officer may not stop a motor vehicle for the sole purpose of determining whether a violation of paragraph (b)(1) of this section is being committed.