Free District of Columbia CDL Air Brakes Test 2024

The knowledge you have gained from studying air brakes will be tested so that you can become a safer driver today.

We have included 30 multiple-choice questions, carefully based on the District of Columbia Commercial Driver License Manual and the actual types of questions you will find on the DMV exam. A hint and an explanation have been provided for each question. Please read each explanation to gain further insight as you prepare for the questions on the actual DMV exam. Good luck on your exam, and drive safely!

Perfect for first-time and renewal CDL/CLP applicants, and those adding endorsements
Triple-checked for accuracy

What you need to know

9 min to complete

Available in EN and ES

Verified by Steven Litvintchouk, M.S., Chief Educational Researcher, Member of ACES. See our detailed commitment to accuracy and quality in our practice tests.

What to expect on the actual DC DMV exam

questions

correct answers to pass

80%

passing score

Helpful links

DC DMV website

List of questions (classic view)

How would you check your truck's slack adjusters?
Which of the following is NOT part of the drum brake?
Which of the following is NOT part of the braking process when driving a tractor-trailer combination vehicle with an anti-lock braking system (ABS)?
Which of the following should you do before leaving your vehicle unattended?
When should you use the parking brake?
Which of the following will be true about your brake function if your anti-lock braking system (ABS) fails?
An anti-lock braking system (ABS)
When should you drain your air tanks?
What is the best way to test your vehicle's low air pressure warning signal?
At what measurement is the safety valve USUALLY set to open?
How can you tell if your vehicle is equipped with an anti-lock braking system (ABS)?
Which of the following are true about a dual air brake system?
Which vehicles must have low air pressure warning signals?
The purpose of a supply pressure gauge is
If the air tanks are not drained,
Which of the following is NOT part of the air brake system?
Spring brakes are
The tractor protection valve
Why must you study air brakes in the District of Columbia?
Under which conditions are front wheel brakes good?
How do brakes work on a long, steep downgrade?
Slack adjusters are
What is the best way to test if your vehicle's spring brakes come on automatically?
Which of the following can cause brakes to fail or fade?
After the initial drop, the maximum acceptable leakage rates per minute are
The low air pressure warning signal will come on before the pressure in the air tanks falls below
A low pressure warning signal is required on
All vehicles equipped with air brakes have
With air brake-equipped vehicles, the parking brakes should be used
The use of air brakes on a downgrade is only a supplement to the

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