Pass Your CDL Knowledge Tests

Practice tests built like the real ones, for all eight CDL tests. 2,065 questions with three options each, as on the real test. Every answer explained in plain English, with the rule behind it: free with an account.

Choose Your Test

• General Knowledge: The General Knowledge test every CDL applicant takes. Sample questions · Topic Study
• Air Brakes: The Air Brakes test, for vehicles with air brakes. Sample questions · Topic Study
• Combination Vehicles: The Combination Vehicles test, for a Class A license. Sample questions · Topic Study
• Hazardous Materials: The Hazardous Materials test, for the H endorsement. Sample questions · Topic Study
• Tank Vehicles: The Tank Vehicles test, for the N endorsement. Sample questions · Topic Study
• Doubles and Triples: The Doubles and Triples test, for the T endorsement. Sample questions · Topic Study
• Passenger: The Passenger test, for the P endorsement. Sample questions · Topic Study
• School Bus: The School Bus test, for the S endorsement. Sample questions · Topic Study

Guides

• CDL Permit Test: Which knowledge tests you need for a commercial learner's permit (CLP) for Class A or B, the permit's rules, and practice tests built like the real ones.
• How to Get a CDL: The steps to a commercial driver's license: medical card, permit and knowledge tests, entry-level training, the skills test, with the federal rules for each.
• CDL Classes and Endorsements: Class A, B and C CDLs, the H, N, P, S, T and X endorsements and the restriction codes, and the tests each one needs.
• CDL Rules: The federal rules CDL drivers are tested on: hours of service, alcohol, phones, rail crossings, warning triangles, the medical card and disqualifications, each with its section.
• DOT Physical: What the DOT physical checks (vision, hearing, blood pressure, diabetes), who can do it, how long the medical card lasts and what changed in 2025, with the federal rules.
• Truck Driver Pay: Truck driver pay from the Bureau of Labor Statistics: a $58,640 median in May 2025, the top-paying states, bus driver pay and the CDL each job needs.
• Pre-Trip Inspection: What the CDL pre-trip inspection test covers, the parts to check before every trip, tire tread limits and the numbers for the air brake check.
• Hazmat Endorsement: The steps to the H endorsement: TSA's security threat assessment and its fee, hazmat training and the knowledge test, and who qualifies.
• ELDT: Who needs entry-level driver training, what the theory and behind-the-wheel parts cover, whether theory can be online, and the Training Provider Registry.
• Drug and Alcohol Clearinghouse: What FMCSA's Clearinghouse records, when your state and employers check it, registering, and how a violation comes off your record.