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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 North Carolina doubles triples test consists of 20 questions. To pass, you must correctly answer at least 16 questions (80%). The NC CDL doubles triples test covers the following sections of the North Carolina CDL Manual: Driving Safely, Air Brakes (if you plan to operate vehicles equipped with air brakes), Combination Vehicles, Doubles and Triples. Take this NC CDL practice test now to prepare for the actual test!
1. The best advice for driving in fog is:
use high beams.
use low beams.
don't drive.
drive slowly in the left lane of traffic.
2. Air tank drains:
should not be used in wet weather.
are used to remove water and oil from the air tanks.
protect the tanks and the rest of the system from too much pressure.
are used to move air to the brakes.
3. Emergency brakes must be held on by:
dynamic pressure.
air pressure.
hydraulic pressure.
mechanical force.
4. To know if your vehicle is equipped with ABS, look for:
the ABS shipping paper.
a yellow ABS malfunction lamps on the instrument panel.
an ABS placard.
the ABS logo on the steering wheel.
5. To prevent rollover, you should:
turn the engine off while turning.
drive in the left lane.
drive slowly around corners.
drive on the shoulder of the road when possible.
6. Which of the following is NOT true?
ABS won't compensate for bad brakes.
ABS won't compensate for poor brake maintenance.
ABS only comes into play when a wheel would have locked up because of over braking.
ABS will change the way you normally brake.
7. During a walk around inspection of a combination vehicle, drivers should check that:
the locking jaws are around the shank.
all locking pins are present and locked in place.
the glide plate is securely mounted to the trailer frame.
All of the above.
8. When backing a trailer, you should turn the steering wheel to the right to make the trailer go left (or vice versa). Once the trailer starts to turn, you should:
keep backing up.
turn the wheel the other way to follow the trailer.
turn the wheel moreĀ  in the direction you want to go.
None of the above.
9. Hanging meat in a refrigerated truck can be:
a very unstable load with a high center of gravity.
a very unstable load with a low center of gravity.
a very stable load with a low center of gravity.
a very stable load if properly distributed.
10. On dry pavement, the braking distance when traveling at 55 mph is about:
61 feet.
142 feet.
419 feet.
216 feet.
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NC Doubles Triples Test

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