49 CFR 391.11
(a) A person shall not drive a commercial motor vehicle unless he/she is qualified to drive a commercial motor vehicle. Except as provided in 391.63, a motor carrier shall not require or permit a person to drive a commercial motor vehicle unless that person is qualified to drive a commercial motor vehicle.
(b) Except as provided in subpart G of this part, a person is qualified to drive a motor vehicle if he/she--
(b)(1) Is at least 21 years old;
(b)(2) Can read and speak the English language sufficiently to converse with the general public, to understand highway traffic signs and signals in the English language, to respond to official inquiries, and to make entries on reports and records;
(b)(3) Can, by reason of experience, training, or both, safely operate the type of commercial motor vehicle he/she drives;
(b)(4) Is physically qualified to drive a commercial motor vehicle in accordance with subpart E--Physical Qualifications and Examinations of this part;
(b)(5) Has a currently valid commercial motor vehicle operator's license issued only by one State or jurisdiction;
(b)(6) Has prepared and furnished the motor carrier that employs him/her with the list of violations or the certificate as required by Sec. 391.27;
(b)(7) Is not disqualified to drive a commercial motor vehicle under the rules in Sec. 391.15; and
(b)(8) Has successfully completed a driver's road test and has been issued a certificate of driver's road test in accordance with Sec. 391.31, or has presented an operator's license or a certificate of road test which the motor carrier that employs him/her has accepted as equivalent to a road test in accordance with Sec. 391.33
[35 FR 6460, Apr. 22, 1970, as amended at 35 FR 17420, Nov. 13, 1970; 35 FR 19181, Dec. 18, 1970; 36 FR 222, Jan. 7, 1971, 36 FR 24220, Dec. 22, 1971; 45 FR 46424, July 10, 1980; 52 FR 20589, June 1, 1987; 59 FR 60323, Nov. 23, 1994; 60 FR 38744, 38745, July 28, 1995; 63 FR 33276, June 18, 1998].