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. Rims with welding repairs:

Explanation
Wheels or rims that have had welding repairs should never be used.

2. Having anti-lock brakes on only one axle:

Explanation
If a vehicle has anti-lock brakes on just one axle, the driver will still have more control during braking than they would without any anti-lock brakes.

3. If you realize you may be running late to your destination, you should:

Explanation
To reduce the risk of developing aggressive driving behavior, you should take measures to manage your stress. One strategy to do this is to simply take a deep breath and accept your circumstances if you realize you will be late to your destination.

4. Texting while driving is especially dangerous because:

Explanation
Texting while driving is particularly dangerous because it is both a mental and physical distraction to the driver. In addition to diverting a driver's mental attention away from the road, texting requires a person to remove at least one hand from the vehicle's controls.

5. After a tire has been changed, the driver should stop after a short distance to:

Explanation
After changing a tire, you should stop a short distance later to recheck the tightness of the tire's lug nuts.

6. If you cannot reverse your trailer in a straight path, you should:

Explanation
If you need to back your trailer but cannot back up in a straight path, you should back on a curved path toward the driver's side of the vehicle. This will allow you the best possible visibility while backing.

7. Rust around wheel nuts may mean:

Explanation
Rust around wheel nuts may mean that they are loose. Check the tightness of the nuts if you see any rust in the area.
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