(a) Drivers. No driver shall operate a commercial motor vehicle, and a motor carrier shall not require or permit a driver to operate a commercial motor vehicle, that has a seat belt assembly installed at the driver's seat unless the driver is properly restrained by the seat belt assembly.

(b) Passengers. No driver shall operate a property-carrying commercial motor vehicle, and a motor carrier shall not require or permit a driver to operate a property-carrying commercial motor vehicle, that has seat belt assemblies installed at the seats for other occupants of the vehicle unless all other occupants are properly restrained by such seat belt assemblies.