# Free Colorado CDL Air Brakes Practice Test 2023

Our CDL practice tests:
Based on 2021 CO commercial driver's license manual
Perfect for first-time, renewal applicants
CO CDL Air Brakes Test format:
25 questions
80% passing score
List of questions
1.
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?
2.
The reduced stopping power caused by overuse of the service brakes and excessive heat is called:
3.
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?
4.
Under normal conditions, in order to engage the parking brakes the driver should:
5.
Another name for the brake pedal is the "foot valve", or:
6.
When you release the brakes and reduce the air pressure what makes up for that air loss?
7.
What is the purpose of an antilock braking system (ABS)?
8.
When stab braking if you re-apply the brakes before the wheels start rolling, __________.
9.
If you must make an emergency stop, you should brake so you:
10.
The safety valve is set automatically when pressure is:
11.
The parking brake knob is usually:
12.
What must the air pressure be, at minimum, in both parts of a dual air brake system?
13.
Air braking takes more time than hydraulic braking because:
14.
Pressing and releasing the brake pedal unnecessarily _____.
15.
In case of air pressure loss, a mechanical means of preventing the vehicle from moving is called:
16.
With air brake vehicles, the parking brakes should be used:
17.
The brake pedal in an air brake system _______.
18.
Automatic air tanks _______.
19.
If one air system is very low on pressure _______.
20.
Stop light switches are necessary because ________.
21.
During a normal drive, the spring brakes are held back by _____.
22.
You should use the parking brake _____________.
23.
The governor stops the compressor from pumping air at:
24.
Water and oil _______.
25.
Required on all vehicles with air brakes, what tells the driver that air pressure is too low?