49 CFR § 381.300 - What is an exemption?
(a) An exemption is temporary regulatory relief from one or more FMCSR given to a person or class of persons subject to the regulations, or who intend to engage in an activity that would make them subject to the regulations.
(b) An exemption provides the person or class of persons with relief from the regulations for up to 5 years, and may be renewed, upon request, for subsequent 5-year periods.
(c) Exemptions may only be granted from one or more of the requirements contained in the following parts and sections of the FMCSRs:
(1) Part 380—Special Training Requirements;
(2) Part 382—Controlled Substances and Alcohol Use and Testing;
(3) Part 383—Commercial Driver's License Standards; Requirements and Penalties;
(4) Part 384—State Compliance with Commercial Driver's License Program;
(5) Part 391—Qualifications of Drivers;
(6) Part 392—Driving of Commercial Motor Vehicles;
(7) Part 393—Parts and Accessories Necessary for Safe Operation;
(8) Part 395—Hours of Service of Drivers;
(9) Part 396—Inspection, Repair, and Maintenance (except for § 396.25); and
(10) Part 399—Step, Handhold and Deck Requirements.