Instructions

Double

This endorsement is required if the driver will pull two or three trailers. To receive this endorsement, applicants must pass a test. The test consists of 20 multiple choice.. Read More

This endorsement is required if the driver will pull two or three trailers. To receive this endorsement, applicants must pass a test. The test consists of 20 multiple choice questions. To pass, the applicant must answer at least 16 questions correctly. Each question has three or four possible answer choices. Test questions come from the North Carolina Commercial Driver License Manual. Questions come from chapters covering: Driving Safely, Air Brakes (if applicable), Combination Vehicles and Doubles and Triples. The Double/Triple endorsement can be used with the Class A CDL.

Number of Question 20

Passing Score 16

1. Belts in the engine compartment should be:

Frayed.

Tight.

Greasy.

Easy to slide off.

When inspecting your vehicle's engine, check the belts for tightness and excessive wear. The amount of "give" that is safe for each belt in a given engine will vary, so learn what is appropriate for your vehicle.

2. Fully-loaded rigs:

Are less likely to roll over than empty rigs.

Are more likely to roll over than empty rigs.

Are just as likely to roll over as empty rigs.

Should not be driven.

Because the weight of cargo gives them a higher center of gravity, fully-loaded rigs are 10 times more likely to roll over in a crash than empty rigs.

3. When you leave your vehicle, you should:

Apply the parking brake.

Apply the air brake.

Not apply any brake.

Leave the door open.

Always apply the parking brake when leaving your vehicle.

4. When using a fire extinguisher on a fire, you should:

Get as close to the fire as possible.

Stand as far away from the fire as possible.

Aim the extinguisher at the top of the fire.

When using a fire extinguisher, you should stand as far away from the fire as possible. Aim the extinguisher at the base of the fire, not at the flames. If you are not sure which kind of extinguisher should be used on a fire, particularly a hazardous materials fire, you should wait for the firefighters to arrive and allow them to extinguish it.

5. The air compressor is connected to the:

Transmission.

Engine.

Radiator.

The air compressor of an air brake system is connected to the engine through gears or a v-belt. The compressor may be air-cooled or cooled by the engine cooling system.

6. If the emergency air line loses pressure:

The service brakes will activate.

The tractor protection valve will close.

The rear trailer will detach from the combination.

The tractor protection valve keeps air in the trailer's braking system should the trailer break away or develop a leak. A loss of air pressure in the emergency line will cause the tractor protection valve to open and the emergency trailer brakes to activate.

7. If the brakes “pull” to one side or the other when you use them, it's a sign that:

The brakes are working properly.

The brakes need to be checked.

The brakes are new.

The brakes have too much stopping power.

If your vehicle "pulls" to one side when braking, you may have brake trouble. If there is an issue with your brakes, you should fix the issue before driving. Operating an unsafe vehicle is against federal and state laws.

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