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 possible answer choices. Test questions come from the Idaho Commercial Driver’s License Manual. Questions come from chapters covering: Driving Safely, Transporting Cargo 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
Passing Score

1. Alcohol evaporators are:

Explanation
Some air brake systems include an alcohol evaporator. The evaporator introduces alcohol into the braking system to prevent the formation of ice, which can cause damage.

2. Rust around wheel nuts may mean:

Explanation
It is important to inspect your tires before every drive. Rust around wheel nuts may indicate that they are loose.

3. If the emergency air line loses pressure:

Explanation
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.

4. If a vehicle's Anti-Lock Braking System (ABS) is malfunctioning:

Explanation
An Anti-Lock Braking System (ABS) intervenes to reduce brake pressure if there is a risk of wheel lockup. If the ABS isn't working, the vehicle's basic braking functions are not affected. A driver should continue to drive and brake in a normal manner.

5. If there is ice on the front of your side mirror:

Explanation
If your mirrors or wiper blades become icy while you are driving, you can expect the road surface to be icy as well.

6. Alcohol can be removed from your system:

Explanation
The liver removes alcohol from the body at a fixed rate, so the only way to sober up after consuming alcohol is to allow your body time to remove the alcohol on its own.

7. If a trailer begins to skid, it is best for the driver to:

Explanation
If your trailer begins to skid, you should release the brakes to regain traction. The trailer will begin to straighten out once the wheels begin to grip the road again.
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