Pass Your CDL Knowledge Test the First Time
Free Commercial Driver's License practice tests covering every endorsement category — General Knowledge, Air Brakes, Combination Vehicles, Hazmat, Tanker, Doubles/Triples, Passenger, and School Bus — sourced from the official AAMVA CDL Manual used by every U.S. state DMV.
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Practice by Endorsement Category
Each test mirrors the structure and topic weighting of the official knowledge exam.
General Knowledge
The foundation test required for every CDL applicant, regardless of class or endorsement.
RequiredAir Brakes
Required to legally operate any commercial vehicle equipped with air brakes — most trucks.
EndorsementCombination Vehicles
Required for Class A drivers operating any combination of vehicles (tractor-trailer).
EndorsementHazmat
The H endorsement, required to transport hazardous materials in placardable amounts.
EndorsementTanker
The N endorsement, required to haul liquid or gaseous loads in bulk tanks.
EndorsementDoubles/Triples
The T endorsement, required to pull two or three trailers behind a single tractor.
EndorsementPassenger
The P endorsement, required for buses and other vehicles designed to carry 16+ people.
EndorsementSchool Bus
The S endorsement, required (in addition to P) to drive a school bus.
Practice by State
All practice questions are aligned with the AAMVA CDL Manual, the source document every state DMV uses to write its CDL knowledge exam. Pick your state to see all available practice tests.
Why Use CDL Prep Hub?
Built for working drivers. Studying for your Commercial Driver's License (CDL) takes time you may not have between shifts, family, and the drive itself. CDL Prep Hub is designed so you can knock out a 20-question round in less than ten minutes — on a phone, on a tablet, or on the desktop at the truck stop. Every question shows the correct answer instantly with a short explanation drawn from the source manual, so you learn the rule, not just memorize the letter.
Real questions, real sources. The federal government does not publish a single national CDL exam. Instead, every state DMV writes its own test from the same source: the AAMVA Model Commercial Driver License Manual, which is jointly maintained by the American Association of Motor Vehicle Administrators and the Federal Motor Carrier Safety Administration (FMCSA). That manual covers driver qualification, vehicle inspection, basic control, communicating, space management, night and adverse-weather driving, hazardous materials, air brakes, combination vehicles, doubles and triples, tankers, passenger transport, and school bus operation. Our questions cover every chapter.
How to use this site. If you are starting from scratch, begin with the General Knowledge test — every CDL applicant must pass it, regardless of license class. Then add Air Brakes if your vehicle has them (almost every commercial truck does), and Combination Vehicles if you are pursuing a Class A. From there, layer on the endorsements that match the job you want: Hazmat (H), Tanker (N), Doubles/Triples (T), Passenger (P), or School Bus (S).
Pick your state for the right details. While the questions come from the same source manual, fees, scheduling, and ELDT (Entry-Level Driver Training) requirements vary by state. The state pages point you at the right starting tests and answer the everyday questions about getting your CDL where you live.