# 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..

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

### 15. The “crack-the-whip” effect for doubles and triples is:

Explanation
Double and triple trailer combinations are more likely to be overturned due to the "crack-the-whip" effect than are other vehicles. Drivers must steer gently when pulling trailers.

### 16. A distracted driver:

Explanation
Distracted drivers perceive hazards on the road more slowly than drivers who are focused, or they do not perceive hazards at all.

### 17. When braking with ABS, you should:

Explanation
When braking a vehicle equipped with an Anti-Lock Braking System (ABS), you should not brake any differently than you would if driving a vehicle with a different braking system.

### 18. A thin layer of ice that forms on road surfaces is called:

Explanation
Black ice is a thin layer of ice that is clear enough for the road surface to be seen through it. A road covered in black ice may look like it is merely wet. You should be very careful when temperatures are below freezing and the road looks wet.

### 19. A cargo van is:

Explanation
The added weight of a heavy load will make a vehicle sit lower than usual. A vehicle will often be taller when carrying a light load than when carrying a heavy load. If your vehicle fits under an overpass while carrying a full load, it is not guaranteed that it will fit under the same overpass if it is empty.

### 20. Radial and bias-ply tires:

Explanation
Radial and bias-ply tires should not be used together. All wheels on a vehicle should be the same style and equally-sized.