Iowa CDL Class A, B or C DMV Practice Tests & Cheat Sheets

CDL Class A, B or C. Complete CDL driver training course. All the questions in this test are from the official DMV written exam. You can use our free online tests to evaluate how likely you are to pass the official DMV test. Or you can just cut to the chase and increase your chances of passing by upgrading to Premium Membership and unlock official DMV tests. In addition, you will also receive a master cheat sheet which contains all your state’s DMV questions and answers. Premium membership also unlocks a smart tracker which keeps an inventory of all incorrectly answered questions for easy, fast and effective revision. Practice with our free tests or hit Upgrade button below for premium access and increase your chances of passing your DMV written exam.

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Quick Facts:

Number of Questions – 20

Passing Percentage – 80%

Test Type – Free Test

Prevent wheel lockup
Prevent the air compressor from overheating
Prevent the front brakes from being used on ice
Prevent the brakes from being used if downshifting would be more effective

Only at the front wheels.
Only at the rear wheels.
Only at the driver’s side wheels.
At each wheel.

10 psi
25 psi
50 psi
100 psi

Iowa DMV CDL Air Brakes Quick Practice Test

Iowa DMV CDL Air Brakes Quick Practice Test For 2024

99.5% Pass Rate

It stops the compressor from pumping air.
It turns on the air compressor.
It stores the compressed air.

Compressed air
Liquid air
Nitrogen

In cold weather.
In hot weather.
In dry weather.

Because the air gets old and needs to be replaced
Because compressed air contains some water and the water collects in the tanks
To allow for a change in pressure