49 CFR § 384.204 - CLP or CDL issuance and information.
(a) General rule. The State shall authorize a person to operate a CMV only by issuance of a CLP or CDL, unless an exception in § 383.3(c) or (d) applies, which contains, at a minimum, the information specified in part 383, subpart J, of this subchapter.
(b) Exceptions -
(1) Training. The State may authorize a person who does not hold a CDL valid for the type of vehicle in which training occurs to undergo behind-the-wheel training in a CMV only by means of a CLP issued and used in accordance with § 383.25 of this subchapter.
(2) Confiscation of CLP or CDL pending enforcement. A State may allow a CLP or CDL holder whose CLP or CDL is held in trust by that State or any other State in the course of enforcement of the motor vehicle traffic code, but who has not been convicted of a disqualifying offense under § 383.51 of this subchapter based on such enforcement, to drive a CMV while holding a dated receipt for such CLP or CDL.