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Commercial driver’s license

CDL knowledge practice tests

To get a commercial driver’s license you pass one or more knowledge tests before the skills test. Which ones you take depends on the license class you want and the endorsements you need. Each state publishes a CDL manual that covers every knowledge test, and our questions are written from that manual with a manual reference for every answer.

Start with General Knowledge Which tests do I need?

Choose a CDL test

Every card opens the full practice test page: press Start test, then pick practice mode or exam mode.

  • General Knowledge

    The core CDL knowledge test every applicant takes: vehicle inspection, basic control, seeing, speed and space management, hazards, bad weather, emergencies, accidents and fires, and cargo safety.

    Topics: Vehicle inspection, Basic control and shifting, Seeing and communicating, Speed and space management, Hazards and distracted driving, Night, fog and weather, Railroad crossings and mountain driving, Emergencies, ABS and skids, Accidents, fires and alcohol, Cargo safety.

    • 113 practice questions

  • HazMat

    For the H endorsement: hazardous materials rules, communication rules, loading and unloading, bulk packaging marking, driving and parking rules, and emergencies.

    Topics: Intent of the regulations, Shipper, carrier and driver duties, Communication rules, Loading and unloading, Driving and parking rules, Emergencies.

    • 69 practice questions

  • Air Brakes

    Required to drive a commercial vehicle with air brakes without the air-brake restriction: system parts, dual systems, inspecting and using air brakes.

    Topics: Air brake system parts, Dual air brake systems, Inspecting air brakes, Using air brakes.

    • 45 practice questions

  • Combination Vehicles

    For the Class A license: driving combination vehicles safely, combination air brakes, trailer antilock brakes, coupling and uncoupling, and inspecting a combination vehicle.

    Topics: Driving combinations safely, Combination air brakes, Trailer antilock brakes, Coupling and uncoupling, Inspecting a combination vehicle.

    • 46 practice questions

  • Doubles/Triples

    For the T endorsement: pulling double and triple trailers, coupling and uncoupling, inspecting doubles and triples, and checking air brakes.

    Topics: Pulling double and triple trailers, Coupling and uncoupling, Inspecting doubles and triples, Doubles and triples air brake check.

    • 30 practice questions

  • Passenger

    For the P endorsement: vehicle inspection, loading and trip start, driving on the road, after-trip inspection, prohibited practices and brake-door interlocks.

    Topics: Vehicle inspection, Loading and trip start, On the road, After-trip vehicle inspection, Prohibited practices, Brake-door interlocks.

    • 30 practice questions

  • School Bus

    For the S endorsement: danger zones and mirrors, loading and unloading, emergency exit and evacuation, railroad crossings, student management, antilock brakes and special safety considerations.

    Topics: Danger zones and mirrors, Loading and unloading, Emergency exit and evacuation, Railroad-highway crossings, Student management, Antilock brakes, Special safety considerations.

    • 45 practice questions

  • Tank Vehicles

    For the N endorsement: which vehicles need it, inspecting tank vehicles, driving them safely, liquid surge, baffles and outage.

    Topics: Tank vehicle endorsement, Inspecting tank vehicles, Driving tank vehicles, Safe driving rules.

    • 28 practice questions

Passing score and number of questions

Passing score: at least 80% correct on each knowledge test, set by federal rule (49 CFR 383.135 (eCFR)). Number of questions: this varies by state, so check the CDL manual from your state’s licensing agency.

Not sure which tests apply to you? Our guide CDL Classes, Endorsements and Restrictions Explained sums up the classes, the endorsements and the knowledge test each one needs.

Why there is one page per CDL test, not one per state

State CDL manuals are built on the same national model, so the CDL knowledge content is largely the same everywhere. Instead of fifty near-identical state pages, we keep one complete, carefully checked page for each test. If your state’s manual differs on a point, your state’s manual wins.

How to use these practice tests

  • Read the matching section of your state’s CDL manual first.
  • Use practice mode to see the explanation and the manual reference after each question.
  • Switch to exam mode when you can score well above 80% without help.
  • Review every missed question against the manual section we cite.

More tips in our guide How to Study for the CDL Knowledge Tests.

Everyone starts with General Knowledge

It is the one CDL knowledge test every applicant takes.

Start the General Knowledge test