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 Iowa 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
Passing Score

1. Broken suspension parts:

Explanation
The suspension system holds up a vehicle and its load while keeping the axles in place. Defects in this system are extremely dangerous.

2. When backing, you should:

Explanation
Driving in reverse is always dangerous because you cannot see everything behind your vehicle. Whenever possible, use a helper to monitor your blind spots.

3. Skids caused by over-acceleration can usually be resolved by:

Explanation
A skid caused by over-acceleration can be resolved simply by removing your foot from the accelerator. Skids of this nature happen most frequently on surfaces covered in snow or ice.

4. When traveling on a downgrade, your vehicle will:

Explanation
Gravity causes a vehicle's speed to increase when traveling on a downgrade. Adjust your speed before reaching a downgrade.

5. Driving at night is:

Explanation
Driving at night is more dangerous than driving during the day because hazards become more difficult to see in the dark.

6. When trying to put out an electrical fire, you should:

Explanation
B:C fire extinguishers are designed to work on electrical fires and burning liquids. Don't pour water on an electrical fire.

7. If there is a fire in your vehicle and you are not sure how to extinguish it, you should:

Explanation
If you are not sure which method to use when putting out a fire, do not attempt to extinguish the fire on your own. Instead, wait for firefighters to arrive and let them handle it. This is especially true if you are experiencing a hazardous materials fire.
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