49 CFR § 381.200 - What is a waiver?
(a) A waiver is temporary regulatory relief from one or more FMCSR given to a person subject to the regulations, or a person who intends to engage in an activity that would be subject to the regulations.
(b) A waiver provides the person with relief from the regulations for up to three months.
(c) A waiver is intended for nonemergency and unique events, and is subject to conditions imposed by the Administrator.
(d) Waivers 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) § 390.19 Motor Carrier Identification Report;
(6) § 390.21 Marking of commercial motor vehicles;
(7) Part 391—Qualifications of Drivers;
(8) Part 392—Driving of Commercial Motor Vehicles;
(9) Part 393—Parts and Accessories Necessary for Safe Operation;
(10) Part 395—Hours of Service of Drivers;
(11) Part 396—Inspection, Repair, and Maintenance (except § 396.25); and
(12) Part 399—Step, Handhold and Deck Requirements.