Ace Your DMV Written Test with our Guaranteed Cheat Sheet.
Cheat Sheet

Iowa CDL Permit Test - Air Brakes

(From the 2020 Iowa CDL driver handbook)
Number of questions: 25
Passing score: 20
Directions: This endorsement is required for driving a vehicle with air brakes. To receive this endorsement, applicants must pass a written test. The test consists of 25 multiple choice questions. Each question has three answer choices. To pass, the applicant must answer at least 20 questions correctly. Test questions come from the Iowa Commercial Driver License Manual. Questions come from the chapter covering: Air Brakes. The Air Brakes endorsement may be used with the Class A, B or C CDL.
You have made error so far
Passing grade —
5 or fewer errors
advertising
1.
When leaving a vehicle unattended, a driver should:
Always set the parking brake.
Only set the parking brake if the vehicle is parked on a slope.
Deflate the tires by 10 percent.
2.
If the spring brakes are on, you should:
Not use the brake pedal.
Press the accelerator.
Move the steering wheel.
3.
Why do large vehicles use air brakes?
Other brake systems squeak too loudly.
Air brakes are very effective systems.
Other braking systems are hard to come by.
4.
Brake fade is a result of:
Brakes being exposed to sunlight.
Brakes being exposed to moisture.
Excessive use of the brakes.
5.
If using spring brakes when hauling a heavy load, a complete stop will:
Be impossible.
Take a long time.
Take a short amount of time.
6.
In a vehicle with dual parking control valves, a separate air tank can be used:
To make the air brakes work more effectively.
To temporarily release the spring brakes.
To charge the brakes on the rear trailer.
Ace Your DMV Written Test
Get your Cheat Sheet Now!

Wait, before you go

Ace your DMV Written Test with our Guaranteed Cheat Sheet.

  • Cheat Sheets Save Time
  • Cheat Sheets pass on your first try