Free District of Columbia CDL Air Brakes Practice Test 2022

Do you need an Air Brakes endorsement or an L endorsement for your commercial driving license? The District of Columbia CDL Air Brake has some differences from other endorsements because your license will receive a mark of restriction if you fail the test. So having good preparation before exam day is very necessary. To ensure that our DC CDL practice test questions are relevant, all of them are based on the DC CDL Manual. Each question has a detailed explanation for you to thoroughly learn the format and the topic. Don't be afraid of having a restriction on your license. Let’s try with our CDL practice test to get ready to pass the District of Columbia CDL Air Brake Test now. 

Our CDL practice tests:
Based on 2022 DC commercial driver's license manual
Full answers + detailed explanations
Perfect for first-time, renewal applicants
DC CDL Air Brakes Test format:
25 questions
20 correct answers to pass
80% passing score
List of questions
1.
The most common type of foundation brakes are:
2.
The stop light switch:
3.
A low pressure warning signal could be __________.
4.
Your truck or bus has a dual air brake system. If a low air pressure warning comes on for only one system, what should you do?
5.
The proper use of the brakes when going down a long steep grade after selecting a proper gear is to brake until your speed is about ____ below the posted speed and release your brake.
6.
The supply pressure gauge shows how much pressure:
7.
Your brakes are fading when:
8.
While applying the brakes, what tells the driver how much air pressure is being used?
9.
When using a vehicle with air brakes, the parking needs to be used _______.
10.
If the low air warning comes on while you are driving, you should:
11.
To check the free play of manual slack adjusters of S-cam brakes, you should park on:
12.
All of the following are factors in total stopping distance except:
13.
Total stopping distance with air brakes is Perception distance + Braking Distance + Brake Lag Distance +:
14.
Under normal braking conditions, the vehicle:
15.
Brake drums (or discs) must not have cracks longer than ____ the width of the friction area.
16.
The most common problem found in roadside inspections is:
17.
The brake pedal in an air brake system _______.
18.
Why does a heavily loaded vehicle need a longer distance to stop?
19.
How are brakes designed?
20.
If your vehicle has an alcohol evaporator, the evaporator's purpose is to _____.
21.
Initial air leakage rate for combination vehicles should be:
22.
A warning to drivers behind you that the air brakes have been applied is the:
23.
Vehicles with ABS have malfunction lamps that are what color?
24.
Water and oil _______.
25.
What is the function of a safety valve?