Free Iowa CDL Air Brakes Practice Test 2023

Do you need an Iowa Air Brakes endorsement or an L endorsement for your commercial driving license? The Iowa CDL Air Brake test 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 questions are relevant, all of our CDL practice test packs are based on the Iowa 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 our Iowa CDL Practice Test to get ready to pass the Iowa CDL Air Brake Test now. 

Our CDL practice tests:
Based on 2021 IA commercial driver's license manual
Full answers + detailed explanations
Perfect for first-time, renewal applicants
IA CDL Air Brakes Test format:
25 questions
20 correct answers to pass
80% passing score
List of questions
When inspecting air brakes:
In case of emergency when driving a vehicle equipped with dual parking control valves, you should:
The air loss rate for a straight truck or bus with the engine off and the brakes on should not be more than:
A low pressure warning signal could be __________.
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.
The main factor in causing brake fade is:
To make sure that the spring brakes come on automatically, do all of the following except:
When you need to apply more pressure to help your brakes work normally effectively, this means that your brakes are fading. Which of the following can cause fading brakes?
When the safety valve releases air this indicates ___________.
When does the air compressor governor allow air to start pumping?
Air braking takes more time than hydraulic braking because:
The air compressor governor controls:
Automatic air tanks _______.
Why does a heavily loaded vehicle need a longer distance to stop?
In dual air systems, how long should it take air pressure to build 85 to 100 psi?
How are brakes designed?
When driving an older vehicle that has a manual front brake limiting valve, drivers should:
On newer vehicles, the parking brake control knob is typically yellow, but on older vehicles, the parking brake might be what color?
What does the air compressor governor control?
What is proper braking technique for drivers travelling down a hill or any other downgrade?
Spring brakes are applied:
The spring brakes of a tractor will come on when the air pressure falls within _______.
Typically, at what psi does the air compressor governor stop the compressor from pumping air?
The governor stops the compressor from pumping air at:
If your brakes are wet, what should you do to dry them quicker?