CDL · Doubles and triples
The dolly is now hitched behind the first trailer, and the second trailer sits on the dolly's fifth wheel. What is the proper way to test this coupling?
Correct answer: Pull against the second trailer's kingpin to make sure the jaws are holding it.
Answer options
- ADrive off at normal speed and watch the mirrors to see if the rear trailer follows.
- BPull against the second trailer's kingpin to make sure the jaws are holding it. Correct
- CPull ahead, stop sharply, and see whether the rear trailer bumps into the front one.
Why
Check the second trailer with a pull test against its kingpin, which shows whether the jaws of the dolly's fifth wheel have locked. Then verify by sight that there is no space between the upper and lower fifth wheel and that the jaws are shut around the kingpin.
About this question
Topic: Doubles and triples License: CDL
Part of these practice sets:
Where it applies: Asked in every state.
Practice the whole set
This question is part of Coupling Doubles and Converter Dollies (28 questions). Take the full set and check your score.
Practice Coupling Doubles and Converter DolliesMore questions from Coupling Doubles and Converter Dollies
- Which statement about converter dollies is accurate?
- Uncoupling a set of triples starts with which step?
- What is the reason for moving a dolly clear of the rear trailer before releasing it from the lead trailer?
- Which description fits a converter dolly?
- What should you use to hold the second trailer still before you couple it to the rest of the doubles combination?
- Compared with an A-dolly, what is the main thing a B-dolly or C-dolly adds?
- In the official CDL manual, the section on doubles and triples generally explains coupling and uncoupling for which combinations?
- When you drop the rear trailer from a double combination, what should you do with the air shut-off valve at the back of the front trailer?
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