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Safely pulling double and triple trailers requires knowledge and skill. If you want to pull double or triple trailers, you must add the Doubles/Triples (T) endorsement to your Class A CDL. The Oklahoma doubles triples test consists of 20 questions. To pass, you must correctly answer at least 16 questions (80%). The OK CDL doubles triples test covers the following sections of the Oklahoma CDL Manual: Driving Safely, Air Brakes (if you plan to operate vehicles equipped with air brakes), Combination Vehicles, Doubles and Triples. Take this OK CDL practice test now to prepare for the actual test! Important: Triple trailers are not legal in Oklahoma.
1. Before driving a vehicle with a dual brake brake system, the driver should:
pump the brake pedal 10 times to build pressure.
wait at least 10 minutes before driving.
allow time for the air compressor to build up a minimum of 100 psi pressure in both the primary and secondary systems.
2. Blocking and bracing are:
coupling devices used to connect the service air lines from the truck or tractor to the trailer.
used to keep cargo from sliding and to prevent movement of cargo.
driving techniques used to regain control when your drive wheels start to skid.
3. Which of the the following statements about fatigue is true?
Fatigue impairs your vision and judgment.
Fatigued driving is one of the leading causes of accidents.
All of the above.
4. The parking brake:
should be used whenever you park.
should be used when you need to apply the brakes firmly.
should be used when driving in bad weather.
5. Emergency brakes are:
not required on buses.
required on all vehicles.
not required on doubles.
6. The heavier the vehicle:
the less work the brakes must do to stop it.
the higher the center of gravity will be.
the more work the brakes must do to stop it.
7. Do NOT use the parking brakes:
when you leave your vehicle.
if the brakes are very hot.
when you park for less than two hours.
8. To start moving without rolling back, you should:
partly engage the clutch before you take your right foot off the brake.
put on the parking brake whenever necessary.
All of the above.
9. _________ rigs are much more likely to roll over in an accident than _________ rigs.
Fully loaded ; empty
Fully loaded ; overloaded
Empty ; fully loaded
10. Air brakes:
should be used only when driving on wet roads.
are prohibited on larger vehicles.
are an effective way to stop large and heavy vehicles.
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OK CDL Doubles Test

Number of questions: 20
Correct answers to pass:16
Passing score:80%
Number of questions: 20
Correct answers to pass:16
Passing score:80%
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