Air Brakes Endorsement Test | Alabama 2026 #2

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 2026, 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

1 . In a dual air brake system:

Each system has separate air tanks, hoses, and lines.

The systems share air tanks, but each has its own separate hoses and lines.

Each system uses the same lines and hoses.

One system is the main braking system and a second system is ready to be used if the first one fails.

A dual air brake system is made up of two separate air brake systems. The systems share a single set of brake controls, but each has its own air tanks, hoses, and lines.

2 . During a static leakage test, the maximum leakage rate for a triple combination vehicle with air brakes is ____ in a minute.

3 psi

5 psi

7 psi

9 psi

When performing a static leakage test on a triple combination vehicle with air brakes, the leakage rate should be no more than 5 psi in one minute. If air leaks from the air brake system at a quicker rate, the vehicle should not be driven because something likely needs to be repaired.

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

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

Immediately stop driving.

Drive with the hazard lights activated.

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.

4 . What do anti-lock brakes do?

Help a driver avoid wheel lockup

Lock up the front wheels

Prevent a vehicle from accelerating while traveling uphill

Prevent a vehicle from accelerating while traveling downhill

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

5 . The air compressor governor controls:

When the air compressor pumps air into the air storage tanks.

How fast air is pumped into the air storage tanks.

The temperature of air pumped into the air storage tanks.

The speed of the vehicle.

In an air brake system, the air compressor governor controls when the air compressor pumps air into the air storage tanks.

6 . Brakes can get out of adjustment quickly, especially:

If they are hot.

In the winter time.

If they are used frequently.

Brakes are particularly prone to getting out of adjustment if they are hot. Be sure to routinely check the adjustment of your brakes. For a vehicle to be safely controlled, all brakes must be properly functioning and adjusted.

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2026 Alabama | Frequently Asked Questions

To secure a CDL Doubles/Triples endorsement in Alabama, you must already possess a valid commercial driver's license (CDL). You'll then need to pass the Doubles and Triples Endorsement Knowledge Test. This test covers topics such as coupling and uncoupling, inspecting doubles and triples, and the proper procedures for towing double/triple trailers.

To obtain a CDL Doubles/Triples license, you must first have a valid commercial driver's license (CDL). Next, you'll need to pass the Doubles/Triples Endorsement Knowledge Test. This test covers areas such as coupling and uncoupling, inspecting doubles and triples, and correct towing procedures. Finally, pay the necessary fees to add the endorsement to your CDL.

While Alabama doesn't mandate specialized training for a CDL Doubles/Triples endorsement, it's recommended to study the Doubles/Triples section in the CDL manual thoroughly. This will prepare you for the written knowledge test at your local DMV. Practical experience driving such vehicles can also be beneficial, but it's not a legal requirement.

Yes, to obtain a CDL Doubles/Triples endorsement, you must pass the Doubles/Triples Endorsement Knowledge Test. This written test covers specific areas related to driving double and triple trailers, such as coupling and uncoupling, inspecting doubles and triples, and the correct procedures for towing these types of trailers.

The CDL Doubles/Triples endorsement test is a written knowledge test, not a skills test. It covers topics like coupling and uncoupling, inspecting doubles and triples, and correct towing procedures. However, practical skills like maneuvering such vehicles safely are important to learn during training, even though they are not directly tested during the endorsement exam.

No, it's not permissible to operate double/triple trailers without a valid CDL Doubles/Triples endorsement in Alabama. This endorsement is required by law to ensure that drivers have the necessary knowledge and skills to operate these types of vehicles safely. Operating without the proper endorsement can result in fines and penalties.

You can add the CDL Doubles/Triples endorsement to your existing Commercial Driver's License. You don't need to initiate a completely new application. However, you will need to pass the Doubles/Triples Endorsement Knowledge Test and pay any associated fees to obtain this endorsement. Always check with your local DMV for specific procedures and requirements.

Yes, there are limitations for drivers with a CDL Doubles/Triples endorsement. These drivers can only operate vehicles that are specifically designed for double or triple trailers. They can't exceed the weight limits set by federal and state laws, and they must comply with hours of service regulations to prevent fatigue-related accidents. Additionally, specific routes may be restricted for these vehicles.

In Alabama, the maximum legal weight for a double or triple trailer setup is 80,000 pounds, depending on the trailer's axle configuration. The maximum length for any one trailer is 53 feet, but the combined length of all trailers can't exceed 65 feet. Violating these restrictions may result in penalties or fines.

Yes, drivers with a CDL Doubles/Triples endorsement must follow specific safety guidelines. These include conducting pre-trip inspections, understanding how to couple and uncouple correctly, and knowing how to handle the high rollover risk associated with these trailers. They must also ensure proper weight distribution in trailers and follow the rules for maintaining safe following distances. Compliance with all federal and state regulations is mandatory.