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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 New Mexico doubles triples test consists of 20 questions. To pass, you must correctly answer at least 16 questions (80%). The NM CDL doubles triples test covers the following sections of the New Mexico CDL Manual: Driving Safely, Air Brakes (if you plan to operate vehicles equipped with air brakes), Combination Vehicles, Doubles and Triples. Take this NM CDL practice test now to prepare for the actual test!
1. Emergency brakes are:
required on all vehicles.
not required on doubles.
not required on buses.
2. If you hear a loud loud "bang" and the steering feels "heavy", you should:
hold the steering wheel firmly and stay off the brake.
pump the brakes until the vehicle has slowed down.
brake hard and pull off the road.
3. On front tires, tread should be at least:
4/16 inch
4/32 inch
2/32 inch
4. To know how much space you should keep in front of you:
estimate how many seconds it would take you to reach the vehicle ahead.
wait until the vehicle ahead of you passes a clear landmark, then count off the seconds until you reach the same spot.
estimate how many vehicle lengths there are between you and the vehicle ahead.
5. In your mirror, you see a car approaching from the rear. The next time you check your mirror, you don't see the car. If you wish to change lanes, you should:
ease into the other lane slowly so the other car can get out of the way.
assume the car left the roadway and change lanes as normal.
wait until you are sure the car isn't in your blind spot.
6. If your vehicle has air brakes, to check that air flows to all trailers:
go to the rear of the second trailer and open the emergency line shut-off.
pull gently on the trailer with the tractor.
watch each trailer’s air gauge for a drop of 25 psi.
7. To prevent rollover, you should:
put the lightest parts of the cargo under the heaviest parts.
keep the cargo as close to the ground as possible.
place the cargo near the rear of the trailer.
8. Weight that is loaded so there is a high center of gravity:
reduces the chance that the load will shift to the side or fall off.
makes a vehicle easier to handle.
causes greater chance of rollover.
9. You can release dolly brakes:
by closing the emergency line valve.
by opening the service line valve.
by opening the air tank petcock.
10. When driving in extremely hot weather, if the air pressure in the tires is too high, you should:
let air out of the tires to decrease pressure.
continue driving.
stop and remain stopped until the tires cool off.
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NM CDL Doubles Triples Test

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