Instructions

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 four possible answer choices. Test questions come from the Colorado 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 20

Passing Score 16

1. Trailers manufactured after ____ must be equipped with Anti-Lock Braking Systems (ABS).

1943

1998

2009

2015

Trailers and converter dollies manufactured on or after March 1, 1998 are required to have Anti-Lock Braking Systems (ABS).

2. If the brakes “pull” to one side or the other when you use them, it's a sign that:

The brakes are working properly.

The brakes need to be checked.

The brakes are new.

The brakes have too much stopping power.

If your vehicle "pulls" to one side when braking, you may have brake trouble. If there is an issue with your brakes, you should fix the issue before driving. Operating an unsafe vehicle is against federal and state laws.

3. The ____ tells a driver how much pressure is in the air tanks.

Application pressure gauge

Air compressor governor

Supply pressure gauge

Drum brake

A vehicle that is equipped with air brakes must also be equipped with a supply pressure gauge. This gauge tells the driver how much air pressure is in each of the vehicle's air tanks.

4. Which of the following is not a part of an air brake system?

A service brake system

A parking brake system

An emergency brake system

An axle brake system

Air brakes consists of three separate braking systems: the service brake system, the parking brake system, and the emergency brake system.

5. If braking at a speed of 55 mph while driving on dry pavement, the brake lag can add ____ to your vehicle's total stopping distance.

32 feet

15 feet

50 feet

10 feet

The total stopping distance for vehicles equipped with air brakes is made up of four factors: perception distance, reaction distance, brake lag distance, and braking distance. When braking at a speed of 55 mph while driving on dry pavement, the brake lag can add around 32 feet to a vehicle's total stopping distance.

6. When a vehicle is started, warning lights and buzzers:

Should stay on for several minutes.

Should turn off within a few seconds.

Should stay on until manually turned off.

Should not come on.

After an engine is started, the warning lights and buzzers for oil, coolant, charging circuits, and the Anti-Lock Braking System (ABS) should go out right away.

7. When driving a double or triple, it is important to remember that:

The vehicle requires more space than most other vehicles.

Other drivers will likely get out of your way when necessary.

The vehicle likely weighs the same as other vehicles.

The vehicle can easily fit into small spaces.

Doubles and triples need more space than other vehicles, both because they are longer than other vehicles and because their size and weight prevent them from turning or stopping suddenly. When driving a double or triple, always make sure you have enough space before entering traffic, crossing traffic, or changing lanes.

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