Instructions

Air Brakes

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.. Read More

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 or four answer choices. To pass, the applicant must answer at least 20 questions correctly. Test questions come from the Connecticut 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.

Number of Question 25

Passing Score 20

7. Before driving a vehicle with air brakes, you should ensure that the spring brakes come on automatically when:

Air pressure falls below 45 psi.

Air pressure falls below 20 psi.

Driving downhill.

Driving uphill.

Before driving a vehicle with air brakes, you should ensure that the spring brakes come on automatically when air tank pressure falls to a level between 20 and 45 psi. You can do this by chocking the wheels and releasing air from the braking system by stepping on and off the brake pedal. Once the pressure drops to an unsafe level, the parking brake valve should pop out and spring brakes should come on.

8. What must be on an air tank in an air-braked vehicle?

A check valve

A lock

A trap door

An oxidizer

All air tanks on air-braked vehicles must have one-way check valves located between the air compressor and the first reservoir. This prevents air from flowing out in the event of a leak.

9. If braking at a speed of 55 mph while driving on dry pavement, the brake lag can add ____ to your vehicle's total stopping distance.

32 feet

15 feet

50 feet

10 feet

The total stopping distance for vehicles equipped with air brakes is made up of four factors: perception distance, reaction distance, brake lag distance, and braking distance. When braking at a speed of 55 mph while driving on dry pavement, the brake lag can add around 32 feet to a vehicle's total stopping distance.

10. An Anti-Lock Braking System (ABS):

Is not available for vehicles with air brakes.

Is not helpful in most driving situations.

Can help you maintain control when braking.

Anti-Lock Braking Systems (ABS) are compatible with air brakes and help a driver maintain control of their vehicle by preventing wheel lockup.

11. When leaving your vehicle unattended:

The parking brake must be always be used.

The parking brake should never be used.

Windows in the cab should be lowered.

Always apply the parking brake when leaving your vehicle unattended.

12. If the low pressure warning light comes on while you are driving:

Braking will only be possible if there is still enough air in the tanks.

You can apply the brakes 14 times before the air in the system runs out.

You should continue to drive normally and check the brake system when it is convenient.

You should stay at least 100 feet away from other vehicles.

When driving a vehicle with air brakes, if the low air pressure warning light comes on, it is important for you to stop and safely park your vehicle as soon as possible. There may be a leak in the system. Controlled braking will remain possible only as long as there is enough air left in the tanks.

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