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. Test questions come from the Michigan 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

8. You can confirm that a tractor protection valve is working properly by:

Explanation
You should test the tractor protection valve by allowing the air supply to properly charge, turning off the engine, then releasing air from the system by pressing the brake pedal several times. The tractor protection valve should move into its emergency position when psi drops to an unsafe level.

9. Truck tractors with air brakes built on or after March 1, 1997 must have:

Explanation
Truck tractors with air brakes built on or after March 1, 1997, and other vehicles with air brakes built on or after March 1, 1998, must be equipped with anti-lock brakes.

10. You should check and adjust your mirrors:

Explanation
Be sure to check your mirrors before beginning a drive. Your posture may change day to day and your mirrors may need to be adjusted.

11. To stay alert while driving, you should:

Explanation
Splitting driving responsibilities with a second driver lowers the chance that either of you will drive while fatigued. You can also reduce the risk of fatigue by avoiding heavy foods and keeping the interior of the cab cool.

12. To prevent your vehicle from rolling backward when beginning to move, you can:

Explanation
To ensure that your vehicle does not roll backward when beginning to move after a stop, you should partly engage the clutch before removing your right foot from the brake pedal.

13. If the low air pressure warning signal comes on, you should:

Explanation
If the low air pressure warning signal comes on while you are driving a vehicle with air brakes, you should immediately bring the vehicle to a safe stop while you are still able to control the brakes. Inspect and repair the brakes as soon as possible.

14. When making a left turn, you should start the turn:

Explanation
When making a left turn, you should wait until you reach the center of the intersection before actually beginning to turn. Due to off-tracking, the left side of your vehicle could hit another driver if you begin turning too early.
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