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.
Air brakes consist of ________.
2.
Your truck or bus has a dual air brake system. If a low-pressure warning comes on for only one system, what should you do?
3.
What can legally hold a parking or emergency brake in position for a truck, truck tractor, or bus?
4.
When is it OK to leave your truck unattended without applying the parking brakes and choking the wheels?
5.
Excessive heat caused by using your brakes too often can also cause:
6.
If your vehicle has an alcohol evaporator, it is there to:
7.
The main factor in causing brake fade is:
8.
What negatively affects the braking power of a spring brake?
9.
To make sure that the spring brakes come on automatically, do all of the following except:
10.
When testing air leakage rates for single vehicles, initial loss rate should be less than:
11.
Some vehicles are equipped with a control allowing you to apply the spring brakes gradually, called a:
12.
What must the air pressure be, at minimum, in both parts of a dual air brake system?
13.
If air pressure is not built up within the correct amount of time, then:
14.
Pressing and releasing the brake pedal unnecessarily:
15.
The S-cam:
16.
Automatic air tanks _______.
17.
In dual air systems, how long should it take air pressure to build 85 to 100 psi?
18.
In tractors and straight trucks spring brakes will come on fully when the air pressure drops to what range?
19.
The air tanks must be drained because:
20.
How does the antilock brake system benefit the driver?
21.
Why should air tanks be drained completely?
22.
The safety valve in the air compressor tank is set to open at _____.
23.
On large buses low pressure warning devices usually signal at ______.
24.
Vehicles with air brakes _________.
25.
What is a wig wag ?