View instructions
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 Colorado doubles triples test consists of 20 questions. To pass, you must correctly answer at least 16 questions (80%). The CO CDL doubles triples test covers the following sections of the Colorado CDL Manual: Driving Safely, Air Brakes (if you plan to operate vehicles equipped with air brakes), Combination Vehicles, Doubles and Triples. Take this CO CDL practice test now to prepare for the actual test! Important: Triple trailers are not legal in Colorado.
1. Which of the the following statements about fatigue is true?
Fatigued driving is one of the leading causes of accidents.
Fatigue may cause you to not see and react to hazards.
Fatigue impairs your vision and judgment.
All of the above.
2. Off-tracking is:
when the tires lose their contact with the road and have little or no traction.
when a vehicle makes a turn and the rear wheels of the trailer end up driving in a different path than the tractor and the front wheels of the trailer.
when a vehicle towing a trailer skids, and the trailer pushes the towing vehicle from behind until it spins the vehicle around.
None of the above.
3. Front-end header boards:
reduce traction.
protect drivers from cargo in case of an accident or emergency stop.
protect drivers from spilled cargo.
should never be used.
4. When driving a truck with more than 1 trailer, drivers should:
allow more following distance.
look far ahead so they can slow down or change lanes when necessary.
be especially careful in adverse conditions.
All of the above.
5. The heavier the vehicle:
the more work the brakes must do to stop it.
the higher the center of gravity will be.
the less work the brakes must do to stop it.
None of the above.
6. When backing, you should:
use a helper if possible.
avoid using the mirrors.
back quickly.
back and turn toward the right side.
7. When the temperature drops:
bridges usually freeze after other parts of the roadway.
bridges will not freeze.
bridges will freeze before the road will.
None of the above.
8. Which of the following statements about doubles/triples is true?
A safe speed on a curve for a single trailer combination vehicle may be too fast for a double/triple.
Doubles/triples may have to go faster around corners than single trailer combination vehicles.
Doubles/triples are more stable than other CMVs.
All of the above.
9. When checking the lights before driving:
the engine must be running.
you should turn off the engine.
you should check them from inside the vehicle.
make sure the parking brake is not set.
10. When parking a trailer without spring brakes, it is very important for safety that you use wheel chocks. Why?
if you don't use wheel chocks, supply air will be sent to the service line instead of going to charge the trailer air tanks.
You may not notice a major leak in the service line until you try to put the brakes on.
The air could leak out of the trailer air tank, releasing its emergency brakes.
None of the above.
Page 1 of 2
Next page

CO CDL Doubles Triples Test

Number of questions: 20
Correct answers to pass:16
Passing score:80%
Share This Online CDL Test
Rate this CDL Doubles Triples Test
4.5 out of 5
based on 225 votes