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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 Montana doubles triples test consists of 20 questions. To pass, you must correctly answer at least 16 questions (80%). The MT CDL doubles triples test covers the following sections of the Montana CDL Manual: Driving Safely, Air Brakes (if you plan to operate vehicles equipped with air brakes), Combination Vehicles, Doubles and Triples. Take this MT CDL practice test now to prepare for the actual test! Important: Triple trailers are not legal in Montana.
1. When checking the lights before driving:
you should check them from inside the vehicle.
the engine must be running.
you should turn off the engine.
make sure the parking brake is not set.
2. To use the controlled braking method in an emergency, you should:
pump the brake pedal 3 times.
apply the brakes as hard as you can without locking the wheels.
apply your brakes all the way, and release the brakes when the wheels lock up.
apply the brakes when the wheels lock up.
3. Which of the following is NOT a reason for hydraulic brake failure?
Stab braking
Loss of hydraulic pressure
Brake fade on long hills
All of the above.
4. To reduce the chance of rollover, you should:
distributed the cargo as low as possible inside the trailer.
place the cargo as high as possible inside the trailer.
put the lightest parts of the cargo under the heaviest parts.
None of the above.
5. After the pre-trip inspection, drivers should inspect their cargo and its securing devices again within ________ after beginning the trip.
50 miles
20 miles
25 miles
two hours
6. You are driving a double. Before entering traffic, you should:
always come to a complete stop.
turn on your headlights.
make sure you have a large enough gap before entering or crossing traffic.
assume there is enough room to merge into traffic.
7. If the safety relief valve in the air brake system releases air:
this will supply more power to the brakes.
this will supply more power to the drive wheels.
the valve is fully operational.
something is wrong.
8. Before connecting the converter dolly to the rear trailer, make sure that:
the kingpin rests on the fifth-wheel.
the locking jaws rest on the kingpin.
the shut-off valves at the rear of the first trailer are open.
the trailer height is slightly lower than the center of the fifth-wheel.
9. In a combination vehicle, ________ is most likely to turn over.
the last trailer
the trailer behind the tractor
the tractor
All of the above.
10. Excessive use of the service brakes results in overheating. Too much heat can:
cause the brakes to grab.
cause the brakes apply unevenly.
make the brakes stop working.
cause the brakes to squeak.
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MT CDL Doubles Triples Test

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