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 Oklahoma 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. Doubles combinations:

Explanation
Because doubles and triples are more vulnerable than singles to jackknifing and rolling over, drivers should look far ahead of their vehicles so they can react to hazards well in advance and slow down or change lanes gradually.

2. Using a helper when backing up a large vehicle is:

Explanation
Backing a CMV is always dangerous due to limited visibility, so using a helper to monitor your blind spots is encouraged whenever possible.

3. If using spring brakes when hauling a heavy load, a complete stop will:

Explanation
Spring brakes do not work on all axles. If your vehicle's spring brakes activate due to low pressure in an air brake system, your vehicle will need a longer distance to stop than usual, especially if you are carrying a heavy load.

4. If you doubt that you have enough space to safely drive under a bridge or sign, you should:

Explanation
If you are not certain that your vehicle will fit under overhead objects, you should slow down and take a different route, if possible.

5. What can happen if the exhaust system is not working properly?

Explanation
Leaks in an exhaust system are extremely dangerous because they may allow toxic fumes into the cab or sleeper berth, endangering drivers and passengers.

6. During a trip, landing gear should be:

Explanation
Landing gear, or trailer supports, should always be completely raised before a vehicle is driven. Landing gear that is not entirely raised could catch on railroad tracks or other hazards on the roadway.

7. Anti-Lock Braking Systems (ABS):

Explanation
An Anti-Lock Braking System (ABS) helps prevent wheels from locking up during a hard application of brakes.
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