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CDL Practice Test: Doubles And Triples

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CDL Practice Test: Doubles And Triples

Doubles And Triples Questions

Click On The Picture To Begin

Good Luck!

Which of these steps for uncoupling the converter dolly is correct?
  • Release converter gear spring brakes
  • Disconnect safety chains
  • Quickly pull clear of the dolly
  • Lock the pintle hook on first semitrailer
This is a question from page 57 - click here to look up the answer

Quote From Page 81 Of The Illinois CDL Manual:

Uncouple converter dolly:

  • Lower dolly landing gear
  • Disconnect safety chains.
  • Apply converter gear spring brakes or chock wheels.
  • Release pintle hook on first semitrailer.
  • Slowly pull clear of dolly.
Next
The following are proper steps to connecting the converter dolly to the front trailer, except:
  • Hook dolly to front trailer
  • Lock pintle hook
  • Back first semi-trailer into position in front of dolly tongue
  • Secure converter gear support in the lowered position
This is a question from page 56 - click here to look up the answer

Quote From Page 81 Of The Illinois CDL Manual:

Connect converter dolly to front trailer:

  • Back first semi-trailer into position in front of dolly tongue.
  • Hook dolly to front trailer.
  • Lock pintle hook.
  • Secure converter gear support in raised position
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Next
Why do you need to manage your space better while pulling doubles/triples?
  • Doubles / triples take up more space in turns
  • All of these answers are correct
  • Doubles / triples tend to be blown around more during windy conditions
  • Doubles / triples require more stopping distance to avoid a jackknife
This is a question from page 55 - click here to look up the answer

Quote From Page 80 Of The Illinois CDL Manual:

Doubles and triples take up more space than other commercial vehicles. They are not only longer, but also need more space because they cannot be turned or stopped suddenly. Allow more following distance. Make sure you have large enough gaps before entering or crossing traffic. Be sure you are clear at the sides before changing lanes.

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Next
Should you unlock the pintle hook with the dolly still under the rear trailer?
  • Unlocking the pintle while under the rear trailer is a matter of personal choice
  • Yes, the pintle hook should always be unlocked while still under the rear trailer
  • None of these answers are correct
  • No, the dolly tow bar may fly up, possibly causing injury and making it very difficult to re-couple
This is a question from page 57 - click here to look up the answer

Quote From Page 81 Of The Illinois CDL Manual:

Caution: Never unlock the pintle hook with the dolly still under the rear trailer. The dolly tow bar may fly up, possibly causing injury and making it very difficult to re-couple.

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Next
How do you check to make sure the trailer height is correct before coupling?
  • The trailer should be a minimum of 1ft higher than the fifth wheel, so the trailer king pin will not strike the fifth wheel plate and cause damage
  • The trailer should be slightly higher than the center of the fifth wheel, so the trailer doesn't have to raise up when the dolly is pushed under
  • The trailer must be slightly lower than the center of the fifth wheel, so the trailer is raised slightly when dolly is pushed under.
  • The trailer landing gear should be lowered completely so that you can push the dolly under the trailer and be ready to drive once attached
This is a question from page 56 - click here to look up the answer

Quote From Page 81 Of The Illinois CDL Manual:

Connect converter dolly to rear trailer:

  • Make sure trailer brakes are locked and/or wheels chocked.
  • Make sure trailer height is correct. (It must be slightly lower than the center of the fifth wheel, so trailer is raised slightly when dolly is pushed under.)
  • Back converter dolly under rear trailer.
  • Raise landing gear slightly off ground to prevent damage if trailer moves.
  • Test coupling by pulling against pin of number two semi-trailer.
  • Make visual check of coupling. (No space between upper and lower fifth wheel. Locking jaws closed on kingpin.)
  • Connect safety chains, air hoses and light cords.
  • Close converter dolly air tank petcock and shut-off valves at rear of second trailer (service and emergency shut-offs).
  • Open shut-off valves at rear of first trailer (and on dolly if so equipped).
  • Raise landing gear completely.
  • Charge trailers (push "air supply" knob in) and check for air at rear of second trailer by opening the emergency line shut-off. If air pressure is not there, something is wrong and the brakes will not work.
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Next
Which of the following is NOT one of the steps involved in checking airflow to all trailers?
  • If you do NOT hear air escaping from both lines, check that the shut-off valves on the trailer(s) and dolly are in the OPEN position
  • Use the tractor parking brake and or chock the wheels to hold the vehicle
  • Wait for air pressure to reach normal, then push in the yellow "tractor air supply" knob
  • Open the emergency line shut-off valve at the rear of the last trailer. You should hear air escaping, showing the entire system is charged
This is a question from page 59 - click here to look up the answer

Quote From Page 82 Of The Illinois CDL Manual:

Check air flow to all trailers: Use the tractor parking brake and or chock the wheels to hold the vehicle. Wait for air pressure to reach normal, then push in the red "trailer air supply" knob. This will supply air to the emergency (supply) lines. Use the trailer handbrake to provide air to the service line. Go to the rear of the rig. Open the emergency line shut-off valve at the rear of the last trailer. You should hear air escaping, showing the entire system is charged. Close the emergency line valve. Open the service line valve to check that service pressure goes through all the trailers (this test assumes that the trailer handbrake or the service brake pedal is on), then close the valve. If you do NOT hear air escaping from both lines, check that the shut-off valves on the trailer(s) and dolly (5) are in the OPEN position. You MUST have air all the way to the back for all the brakes to work.

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Next
How can you reduce your chances of a rollover accident when pulling two or three trailers?
  • Always put extra pressure on the service brake so that the rear trailer remains directly behind the first trailer
  • When going around corners, you should make quick movements to swing the rear trailer around directly behind the tractor
  • Be mindful that a safe speed on a curve for a straight truck or a single trailer combination vehicle may be too fast for a set of doubles or triples.
  • While taking a tight turn, be sure to brake during the entire turn
This is a question from page 55 - click here to look up the answer

Quote From Page 80 Of The Illinois CDL Manual:

Prevent Trailers From Rolling Over - To prevent trailers from rolling over, you must steer gently and go slowly around corners, on ramps, off ramps and curves. A safe speed on a curve for a straight truck or a single trailer combination vehicle may be too fast for a set of doubles or triples.

TruckingTruth's Advice:

When it comes to driving doubles or triples, everything you do should be slower and smoother than driving a vehicle with only one trailer.

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Next
When pulling 3 trailers, the lightest trailer should:
  • Be the last trailer
  • Be the middle trailer
  • The placement of the lightest trailer doesn't matter
  • Be the first trailer
This is a question from page 56 - click here to look up the answer

Quote From Page 80 Of The Illinois CDL Manual:

For the safest handling on the road, the more heavily loaded semi-trailer should be in first position behind the tractor. The lighter trailer should be in the rear.

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