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 Maryland Commercial Driver Guide. 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

13. In a vehicle with dual air brakes, what happens if one system is low on pressure?

The air from the other system will be used to supplement the system with the low pressure.

The front or rear brakes may not work properly.

All brakes will be inoperable.

The low system will use an auxiliary system to fill the tank.

In a dual air brake system, if one of the air systems gets very low on pressure, either the front or rear brakes will not be operating fully. You should bring your vehicle to a safe stop and have the air system repaired.

14. In a dual air brake system, a leak in one system:

Always means there are leaks in both systems.

May not affect the other system.

Is not something to worry about.

Will also affect the other system.

A dual air brake system is made up of two separate air brake systems. If there is an air leak in one system, it may not affect the other.

15. What should happen if the air pressure in the air brake system tanks falls below 60 psi?

A warning light should come on.

Lights should flash on the outside of the vehicle.

A message should appear on the control panel.

The vehicle should stop.

On vehicles with air brakes, a low air pressure warning signal will come on if the pressure in the air tanks falls below 60 psi. On large buses, the signal may activate at 80 to 85 psi.

16. An air brake-equipped vehicle traveling at a speed of 55 mph under ideal driving conditions will need approximately ____ to come to a complete stop.

100 feet

250 feet

300 feet

450 feet

A vehicle's total stopping distance is made up of perception distance, reaction distance, brake lag distance, and braking distance. With all of these factors included, an air brake-equipped vehicle traveling at a speed of 55 mph under ideal driving conditions will need approximately 450 feet to come to a complete stop.

17. If the spring brakes are activated, you should never:

Push down the brake pedal.

Open the hood.

Release air from the air storage tanks.

Open the door to the cab.

Never apply the brake pedal if your spring breaks are activated. Brakes can be damaged if they are subject to both springs and air pressure.

18. When traveling down a steep downgrade:

The air brakes should be used.

Shift into a lower gear, then use brakes to supplement the braking effect of the engine.

The vehicle should be continually downshifted in the place of using the brakes.

The vehicle should be driven on the shoulder.

On a downgrade, the braking effect of the engine should be your primary method of controlling speed. Shift down to a lower gear before starting down the hill and save the brakes for additional slowing or stopping that may be required by road or traffic conditions.

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