Wisconsin CDL — Air Brakes Practice Test

The Wisconsin CDL — Air Brakes knowledge test has ~25 questions; you need ~20 correct (80%) to pass.

Or take one of 10 full-length practice tests

25 questions · pass with 20 correct. You get instant feedback and an explanation after every answer.

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The full-length test, with feedback and an explanation after every answer.

Wisconsin CDL — Air Brakes practice tests

10 full-length practice tests, each with 25 questions and a pass mark of 20, like the real test. You see the answers and explanations after you grade.

Test 1
25 questions · pass with 20
When may you fully apply the brakes during an emergency stop?
Test 2
25 questions · pass with 20
During the inspection you find that the low air pressure warning signal never comes on. Why does the manual treat that as a serious hazard?
Test 3
25 questions · pass with 20
What is the purpose of a modulating control valve for the spring brakes?
Test 4
25 questions · pass with 20
Using the proper braking technique on a downgrade, when do you release the brakes?
Test 5
25 questions · pass with 20
On a vehicle equipped with one, needing more and more application pressure to hold a steady speed points to what?
Test 6
25 questions · pass with 20
If you keep driving after the low air warning comes on, what limits your braking?
Test 7
25 questions · pass with 20
In stab braking, why must you wait for the wheels to start rolling before reapplying the brakes?
Test 8
25 questions · pass with 20
With the foot brake fully applied and held for one minute on a single vehicle, how much air loss is too much?
Test 9
25 questions · pass with 20
When you road-test the service brakes at about 5 mph, what should you be watching for?
Test 10
25 questions · pass with 20
What is a 'wig wag' low-pressure warning device?