Qualified is not a synonym for licensed. It is a defined state that must hold every day you drive, and § 391.11(a) puts the duty on both sides of the employment relationship: a person shall not drive a commercial motor vehicle as § 390.5T defines it unless qualified to drive one, and a carrier shall not require or permit a person to drive unless that person is qualified. Neither can rely on the other having checked.

§ 391.11(b) then sets seven conditions. Being at least 21 years old. Being able to read and speak English sufficiently to converse with the general public, understand highway traffic signs and signals, respond to official inquiries, and make entries on reports and records. Being able, by reason of experience or training or both, to operate the type of vehicle safely. Being physically qualified under subpart E. Holding a currently valid commercial motor vehicle operator’s license issued by ONE State or jurisdiction only. Not being disqualified under § 391.15. And having completed a road test and been issued a certificate under § 391.31, or having presented a license or certificate the employing carrier accepted as equivalent under § 391.33. Four of the seven can lapse without anything happening on the road — the medical certificate expires, a second license appears, a conviction disqualifies, the age condition never changes — which is why the rest of this chapter is about checking rather than about driving.

§ 391.13 adds a requirement Chapter 1 did not reach, and it is about cargo rather than credentials. To comply with §§ 392.9(a) and 383.111(a)(16), a carrier must not require or permit a person to drive unless that person can, by reason of experience or training or both, determine whether the cargo they transport — including baggage in a passenger-carrying vehicle — has been properly located, distributed and secured; and is familiar with the methods and procedures for securing cargo in or on the vehicle they drive. Note where it sits: this is a qualification requirement, not a driving rule, so a driver who cannot make that judgment is not qualified in the first place.