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  • Perfect for first-time and renewal commercial applicants, and those adding endorsements
  • Based on 2024 ON commercial driver's licence manual
  • Updated for May 2024
Verified by Steven Litvintchouk, M.S., Chief Educational Researcher, Member of ACES. See our detailed commitment to accuracy and quality in our practice tests.

About this test

A commercial truck driver’s licence is required to drive any commercial vehicle in Ontario. There are two types of driving jobs available: owner-operator and employee. If you plan on running your own business or becoming a driver-for-hire, you will need a truck driver’s licence. To receive a trucking licence, you will have to pass two exams: a commercial knowledge exam with multiple-choice questions and a road test, which will test your general driving skills. To help you study for the knowledge test, we have prepared this second practice exam with 50 questions to test your knowledge of driving large vehicles in Ontario. We encourage you to read the hints and explanations provided and check out our sources. You will notice that the questions are slightly more difficult. This is because they start to examine some of the more technical definitions and concepts found in the official 2024 ON commercial driver’s manual. Once you have studied these questions, giving another truck driver practice test a try may be a good idea. Good luck!

What to expect on the actual ON exam

25

questions

20

correct answers to pass

80

passing score

List of questions (classic view)

  1. The hand valve of a tractor-trailer
  2. In a vehicle equipped with air brakes, what does the governor control?
  3. Polarized gladhands on a tractor
  4. ln vehicles with three dash-mounted push-pull valve knobs, how are the valve knobs usually coloured?
  5. If there is a loss of pressure in the trailer supply line, you would expect the trailer brakes to be applied and
  6. If the air pressure reaches 150 psi, the safety valve will open. Where is the safety valve located?
  7. The low air warning device must activate by the time that tank air pressure falls to
  8. Under Ontario law, tank air pressure must not drop below _______ while the vehicle is in operation.
  9. Minimum governor cut-out pressure is
  10. When you test the system air-loss rate of a bus or straight truck, the maximum acceptable leakage rate is 3 psi within
  11. Maximum governor cut-out pressure is
  12. When you test the system air-loss rate, the maximum acceptable leakage rates per minute for a straight truck, a tractor pulling one trailer, and a tractor pulling two trailers are
  13. With the engine idling at _________, air pressure must rise from 85 to 100 psi within two minutes.
  14. Minimum governor cut-in pressure is
  15. The governor cut-in pressure is normally _________ below the cut-out pressure.
  16. Air pressure must rise _____________ with the engine idling at 600–900 rpm within 2 minutes.
  17. Before starting the air brake practical test, make sure that air pressure is at least
  18. The spring brakes will start to apply when the air pressure falls below
  19. A tractor-trailer with one trailer will fail the air-loss rate test if the loss rate exceeds
  20. The trailer air supply valve will close automatically if air pressure in the trailer supply line drops to
  21. A tractor-trailer with two trailers will fail the air-loss rate test if the loss rate exceeds
  22. Before testing the low air pressure warning device, make sure that air pressure is at least
  23. The air-loss rate test can be performed only when
  24. Air compressors can either be driven by the engine belt and pulleys or
  25. The spring brake test is passed if the vehicle
  26. Different sizes of brake chamber on the same axle can cause
  27. To test the air brakes, the vehicle should be parked
  28. In a drum brake, the brake linings are attached to
  29. Where is the air dryer located?
  30. Which of the following are major components of the air supply circuit?
  31. When draining the air tanks, you observe excessive oil coming out of the supply tank. Which of the following is most likely to be faulty?
  32. You can usually make a normal stop by applying no more than
  33. The coil spring in most spring parking brake chambers can exert a force of
  34. The spring brake in a certain Type 30/30 brake chamber can exert a force of 2,200 pounds. Which of these choices is the least air pressure needed to release the spring brake?
  35. In the air service circuit, there is a double (two-way) check valve connected to the primary and secondary service tanks. What does this valve do?
  36. In which of the following situations should a spring parking brake chamber be caged?
  37. Wedge brakes are designed to be
  38. Where are the air brake chambers located?
  39. What does an ABS system do?
  40. When you are going at twice the speed, your service brakes will need to work _________ to stop your vehicle.
  41. What is the most frequent reason for placing a commercial vehicle out of service?
  42. How can you check whether the trailer spring brakes have activated?
  43. Which of these vehicles is most likely to be equipped with air brakes?
  44. Where is the air pressure gauge for the service tanks?
  45. Which colour is the trailer supply line?
  46. What can cause the air pressure in the air brake system to drop?
  47. How do you apply the parking brakes?
  48. Your vehicle's air compressor is belt driven. How do you check for correct belt tension?
  49. Which of these is not a part of a drum brake?
  50. When brakes become overheated, they also become