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  • Based on 2025 ON commercial driver's licence manual
  • Updated for May 2025

FREE Ontario Class D/DZ Licence Practice Test

Getting your Ontario Class D Commercial Licence with a Z endorsement requires a little multitasking. While there are several requirements you must meet, you must pass both the Ontario Class D Commercial Knowledge Licence Test and the Z Endorsement Test for air brakes. The Class D official knowledge test focuses on road rules, road signs, trucking signals, and safe trucking techniques. Meanwhile, the Z endorsement test seeks to verify your knowledge of air brake operation and inspections. Before navigating the Montreal River Hill, you’ll want to approach it in a safety-first manner. The best way to prepare for these challenges is to get comprehensive instruction on these topics to fuel your success.

Combining essential information for both tests, our Ontario Class D/DZ Commercial Licence Written Practice Test allows you to make efficient use of your study time. The written practice test will provide an assessment of your knowledge level to determine your readiness and track your progress in exhibiting the skills needed to pass the official knowledge and endorsement tests. It contains 25 questions, similar to the ones on the official knowledge test, to direct your attention to topics you should study more. You will gain the advantage of targeting the areas where you need improvement without rehashing the information you already know. It’s a winning strategy that will increase your chances of passing both tests on your first attempt.

The Ontario Class D/DZ Commercial Licence Practice Test will provide extensive instruction using reliable information to help you fully develop your driving skills. It is based on the most recent Ontario Ministry of Transportation (MTO) Truck Handbook, the most authoritative source available. Employing an interactive approach that addresses your specific needs, the practice test is designed to deliver exceptional results. You can’t depend on other on-line resources, such as study guides, to speak to your specific needs. Study guides merely teach you to memorize the answers to the questions and will not help you understand how to correct wrong answers. If you get a question wrong on the practice test, a detailed explanation of the correct answer is given. The information provided expands your knowledge by helping you understand the logic supporting the answer. Your ability to process and apply the information will be invaluable in your efforts to correctly answer the minimally required 80% of the questions on the official knowledge and endorsement tests. The practice test feeds your desire to learn more about the skills that make you a professional driver. You can rely on the practice test to deliver instruction worthy of the master class.

Pickle Lake may be the “last frontier,” but the first step to developing outstanding driving skills is to take the practice tests at https://tests.ca/ontario.
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  • Perfect for first-time and renewal commercial applicants, and those adding endorsements

What you need to know

4.78 out of 5 • 9 votes
Verified by Steven Litvintchouk, M.S., Chief Educational Researcher, Member of ACES. See our detailed commitment to accuracy and quality in our practice tests.
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List of questions (classic view)
  1. In determining how well your air brake system works, which is NOT a significant factor?
  2. Which colour is the trailer supply line?
  3. When is a pre-trip inspection required?
  4. What gauges should you check after starting your vehicle?
  5. Why are there two service tanks in a modern air brake system?
  6. What is the purpose of the National Safety Code?
  7. What does this sign mean?
  8. In Canada, how many classes of dangerous goods are there?
  9. What must you do at a stop sign with a painted stop line?
  10. When brakes become overheated, they also become
  11. What does this sign mean?
  12. Your vehicle is equipped with an air brake system, including a belt-driven air compressor. How do you check for correct belt tension?
  13. What does this sign mean?
  14. Before driving down a grade (hill), you should
  15. What does this sign mean?
  16. Your vehicle has tandem drive axles and is equipped with an inter-axle differential. You should NOT use it if
  17. What does this sign mean?
  18. What is a commercial vehicle's danger zone?
  19. This sign indicates that you may park for one hour
  20. What is the first step of the pre-trip inspection?
  21. In a vehicle equipped with air brakes, the pushrod stroke occurs when compressed air enters the
  22. What is the Gross Vehicle Weight Rating (GVWR)?
  23. Driving a commercial vehicle on the road is
  24. In an air brake system, what does a governor do?
  25. Where are the air brake chambers located?
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