The CDL Combination Vehicles test

The Class A test

Pull a trailer heavy enough and the license class changes, and this is the knowledge test that comes with it. A driver staying in a straight truck does not need it.

Three subjects, which is the fewest of the eight

49 CFR 383.111(c) names coupling and uncoupling, vehicle inspection unique to combinations, and general operating practices and procedures. That is the whole federal list.

Why so few, and what it means for studying

A short list is not a short test. It means the questions crowd into a narrow space, so the detail asked about each subject goes deeper than it would on a broader paper. Coupling in particular is a sequence with a right order, and a test built on three subjects has room to ask about the middle of that sequence rather than only the start and the end.

The inspection subject is the one people underestimate

It is not a general inspection question with a trailer attached. The regulation says inspection unique to combinations, which means the coupling itself, the air and electrical lines running between the units, the landing gear, and the points where two vehicles become one. Those are the items a straight-truck inspection never covers.

Passing it

Three choices a question, 80% to pass. Our own forms run twenty questions, which is our length. New York publishes no count for this test, so any figure you are given for it is either another state's or somebody's estimate.