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
The most common type of foundation brakes are:
The air compressor stops pumping air at what psi?
The reduced stopping power caused by overuse of the service brakes and excessive heat is called:
An application pressure gauge shows how much air you are applying to the brakes. Increased application pressure to maintain the same speed indicates that __________.
Parking or emergency brakes of trucks and buses can be legally held on by ____ pressure.
The most important thing to do when a low air pressure warning comes on is:
To test the vehicle's service brakes, move the vehicle:
The brake system that applies and releases the brakes when the driver uses the brake pedal is the ________ brake system.
The type of brakes that clamp the rotor between the brake shoes is:
When performing the controlled braking method for an emergency stop, you are _________.
Another name for the brake pedal is the "foot valve", or:
What type of brakes pushes a wedge between the ends of two brake shoes to stop the vehicle?
When your brake's main air pressure is lost ________.
When brakes are applied, the brake shoes will press against the:
Total stopping distance with air brakes is Perception distance + Braking Distance + Brake Lag Distance +:
In case of emergency stops, drivers should:
To test the parking brake, stop the vehicle, put the parking brake on, and:
The brake pedal in an air brake system _______.
If you need to make an emergency stop, you should brake so that you can ________.
How should the air leakage rate be tested?
The air compressor is connected to the engine through ______.
Some vehicles are equipped with a separate air tank used specifically to release the spring brakes in an emergency, called a:
What is the purpose of an air storage tank?
Vehicles with air brakes have pressure gauges connected to the _______.
To test the parking brake you should _______.