49 CFR § 391.11 - General qualifications of drivers.
(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.
(1) Is at least 21 years old;
(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;
(4) Is physically qualified to drive a commercial motor vehicle in accordance with subpart E - Physical Qualifications and Examinations of this part;
(7) Has successfully completed a driver's road test and has been issued a certificate of driver's road test in accordance with § 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 § 391.33.