BC Air Brake Test 4

Do you want to drive a truck in British Columbia? To be a commercial driver in this province, you need a licence that is specific to the type of truck you want to drive. As a truck driver, you are a critical part of the transportation industry. The power and size of large trucks are awe-inspiring. Even while you’re driving safely, the smallest mistake can cause serious damage. Before you can get your commercial driver’s licence, you must pass both a written and practical test. The written test (also known as the British Columbia commercial driver’s licence knowledge exam) has several multiple-choice questions. You must get at least an 80% to pass the knowledge examination. This 50-question practice test will help you to prepare for the British Columbia (BC) Air Brake written test required to get your commercial driver’s licence. As you answer the questions on this test, we recommend checking each question’s explanation to gain further insight into the rule behind it. All questions on this test are based on the 2025 BC commercial driver’s guide. Good luck and drive safely!

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BC Driver and Vehicle Services

Official British Columbia driver's manual (2025)

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Written by Andrei Zakhareuski Updated over a week ago

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List of questions (classic view)

How often should the air tanks be drained?
On a tractor-trailer, if the supply and service lines to the trailer are cross-connected, what may happen?
How do you release DD3 safety actuator brakes?
When you're going to tow a trailer, how can you tell if the trailer's antilock braking system (ABS) is working?
Wedge brakes are
The purpose of the tractor protection valve is
To test the tractor protection valve, disconnect both trailer air lines and
In a tractor-trailer, the connections between the tractor and the trailer include which of the following components?
The hand valve control ("spike") applies
Which brakes are more powerful, the spring brakes or the service brakes?
Which of the following is NOT a part of a truck's braking system?
A tractor-trailer's braking system supplies compressed air to which trailer brakes FIRST?
An S-cam is found in
When coupling a tractor to a trailer, how many air lines do you have to connect?
If there is a loss of air to the service brakes in a trailer with a spring brake priority system, how can you brake the trailer to a stop?
In a trailer with a spring brake priority system, compressed air is supplied to which brakes FIRST?
How many air lines must be connected to a DD3 safety actuator brake chamber?
The tractor protection valve closes to stop the flow of compressed air to
To uncouple your tractor from the trailer, how should you set the trailer air supply valve?
Which of the following is not a component of a wedge brake?
How often should you check brake chamber pushrod travel?
Which of the following is a part of a disc brake?
In an air braking system, which of the following is not commonly part of a disc brake?
Which of the following are helpful in reducing heat in the air brake system?
Which of the following can affect pushrod stroke?
What is the purpose of a relay valve?
The quick release feature of a relay valve allows for
To “tug test” the trailer service brakes after you couple your tractor to the trailer, you should apply
To obtain an air brake endorsement in British Columbia, you must do which of the following?
When are water-cooled brakes used?
What are the main components of a simple, basic air brake system?
What is an advantage of automatic slack adjusters?
Which of the following are advantages of a dual air brake system?
What is your stopping distance?
You may be fined as much as _______ for driving a vehicle whose brakes are out of adjustment.
You're driving a vehicle equipped with air brakes. If the low air pressure warning signal comes on, what should you do?
If an air line ruptures between the compressor and the supply reservoir, what will prevent loss of air pressure in the service brake system?
What is the air brake endorsement for industrial roads called?
If the safety valve opens, which of the following is the most likely cause?
You're driving a tractor-trailer. If you're applying a pressure of 30 psi to the trailer brakes with the foot valve, you can apply a greater pressure at the same time by also using
Cut-in pressure must never be lower than
What colour is the parking brake control button?
In an air brake system, spring brakes are intended for
The pushrod stroke occurs when compressed air enters the
In an air brake system, what does a governor do?
Which of the following is the best way to inspect an air compressor?
When can you adjust automatic slack adjusters?
If the outer layer of an air line is damaged, but the inner tube is still OK, what should you do?
To make sure the air tanks are securely attached to your vehicle, you should
Before inspecting your air brakes, you should