The function of an Anti-Lock Braking System (ABS) is to prevent the vehicle's wheels from locking up from hard brake application.

Help a driver avoid wheel lockup

Prevent a vehicle from accelerating while traveling uphill

Prevent a vehicle from accelerating while traveling downhill

If the low air pressure warning signal comes on while you are operating a vehicle with air brakes, you should stop and safely park the vehicle as soon as possible. It is essential that you are able to stop safely while you still have some braking power remaining.

Test the brakes while driving, but continue driving if nothing seems wrong.

Drive with the hazard lights activated.

If equipped, ABS is in addition to a vehicle's normal braking system and does not increase or decrease the braking power of any other system. ABS only activates when a vehicle's wheels are about to lock.

Are in addition to other braking systems and do not reduce a vehicle's braking power.

Reduce a vehicle's normal braking capacity.

Are in addition to other braking systems and do not reduce a vehicle's braking power.

Are not effective on larger vehicles.

Before driving a vehicle with a dual air system, allow time for the air compressor to build up a minimum pressure of 100 psi in both the primary and secondary systems.

Wait to begin driving until the air compressor builds up a minimum pressure of 100 psi in both the primary and secondary systems.

Let the vehicle warm up before driving to ensure that fuel reaches the engine.

Wait to begin driving until the air compressor builds up a minimum pressure of 100 psi in both the primary and secondary systems.

Begin driving just after the vehicle starts.

Pump the pedal about 20 times to build pressure, then begin driving.

Some air brake systems include an evaporator that introduces alcohol into the system. The alcohol can help prevent ice from forming within the system.

Prevents ice from forming in the braking system.

Makes the brakes work without squeaking.

Prevents ice from forming in the braking system.

Lubricates parts of the braking system.

Air Brakes Endorsement Test | Alabama 2025 #1 Page 3 of 4

Train for FREE online with our Alabama CDL air brake test. The official exam test consists of several obligatory parts, with all of them checking your knowledge of different blocks of road rules. If you need to obtain a AL Class A/Class B driver license in 2025, practice as much as possible. Free sample tests published on our website will help you check and improve your knowledge and boost your grades. Please bear in mind that the requirements for CDL may vary from state to state.

Number of Question 25

Passing Score 20

Number of Tests 20

Air Brakes Endorsement Test | Alabama 2025 #1 Page 3 of 4

13 . What do anti-lock brakes do?

14 . To stop in a vehicle that uses air brakes, the driver should:

15 . If the low air pressure warning signal comes on in a vehicle with air brakes, the driver should:

16 . Anti-Lock Braking Systems (ABS):

17 . When operating a vehicle with a dual brake system, a driver should:

18 . An alcohol evaporator in an air brake system:

See the exact questions that will be on the 2025 DMV exam.

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