CDL · Doubles and triples
Which unit is most likely to roll over because of the crack-the-whip effect?
Correct answer: The last trailer in a set of triples.
Answer options
- AThe last trailer in a set of doubles.
- BThe last trailer in a set of triples. Correct
- CA full trailer towed by a straight truck.
Why
The crack-the-whip effect magnifies a quick steering move at each joint, so every trailer swings harder than the one ahead of it. In a triples combination the last trailer swings the most and is the one most prone to rolling over, which is why you must steer gently.
About this question
Topic: Doubles and triples License: CDL
Part of these practice sets:
Where it applies: Asked in every state.
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This question is part of Pulling Doubles and Triples (24 questions). Take the full set and check your score.
Practice Pulling Doubles and TriplesMore questions from Pulling Doubles and Triples
- What kind of parking space is best for a set of doubles or triples?
- Your 100-foot double-trailer rig is traveling 50 mph on a dry road and visibility is good. What is the smallest following gap, in seconds, you should leave behind the vehicle ahead?
- How does the rollover risk of doubles and triples compare with that of single-trailer rigs?
- To begin training as a triple-trailer driver, federal rules say you must first have:
- Pulling a set of doubles, you have to brake hard to keep from hitting something. Which braking method should you use?
- Which of these best describes safe driving with doubles or triples?
- A truck pulling double trailers is 100 feet long and moving at 30 mph. The pavement is dry and you can see well. At minimum, how many seconds of following space should you leave?
- In a set of triples, which position is safest for the lightest trailer?
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