About CDL Prep Hub

CDL Prep Hub is a free, independent study resource for U.S. drivers preparing for the Commercial Driver's License (CDL) knowledge exam. We publish practice questions, study guides, and state-by-state orientation pages so applicants can walk into the DMV — or the equivalent state agency — confident that they know the material the test is built from.

Our methodology

The federal government does not publish a single nationwide CDL exam. Instead, every state DMV writes its own knowledge test from a single source document: the AAMVA Model Commercial Driver License Manual, jointly maintained by the American Association of Motor Vehicle Administrators and the Federal Motor Carrier Safety Administration (FMCSA). We summarize and rephrase the content of that manual into multiple-choice questions covering every endorsement category — General Knowledge, Air Brakes, Combination Vehicles, Hazmat, Tanker, Doubles/Triples, Passenger Transport, and School Bus.

For every question we publish, we include a short explanation that points back to the underlying rule. The goal is not just to help you pick the correct letter on test day; it's to help you understand what the rule actually means so that the same concept, phrased differently, doesn't trip you up on the real exam.

Who we are

CDL Prep Hub is run by a small editorial team that has spent years working alongside transportation safety educators and ELDT (Entry-Level Driver Training) instructors. We are not a CDL school, we don't sell a course, and we don't take a referral cut for sending you to a training provider. The site stays free through advertising — placeholders for ad slots are visible in the HTML source, and they help cover hosting and editorial costs.

What we are not

CDL Prep Hub is not affiliated with FMCSA, AAMVA, or any state DMV. We are not a substitute for the official CDL Manual, and we are not a substitute for the in-vehicle training required by the federal ELDT mandate. Use this site as a study aid alongside, not instead of, the official manual published by your state DMV and the in-person training required for an initial Class A or Class B license, or for the Hazmat, Passenger, and School Bus endorsements.

Corrections and feedback

If you find an outdated rule, a question that no longer reflects current FMCSA regulations, or a typo in a state-specific page, please contact us. We update content on a rolling basis as the CDL Manual is revised.