🚛CDL Doubles/Triples — Question 20 of 20
With the hand valve on, you should test the trailer brakes by opening the service line valve at the rear of the trailer. When you do this, you should hear:
Answer: A
Air escape from the open valve.
You should hear air venting to the atmosphere when the hand valve is on and the service line valve is opened at the rear of the trailer. This lets you know that the trailer brakes are getting air when the service line is then closed.
All choices
- AAir escape from the open valve.
- BThe emergency line valve open and release air.
- CThe service brakes slowly move to the fully applied position.
CDL Doubles/Triples Test Info
Questions on Exam
20
Passing Score
80%
Time Limit
Typically 30 minutes; varies by testing location
The Doubles/Triples test content is federally standardized, so this question applies in every state. Age limits, fees, and testing procedures do vary — check your state's CDL requirements.
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More CDL Doubles/Triples Practice Questions
- Converter dollies:
- The converter dolly air tank drain valve on coupled double/triple trailers should be:
- Crack-the-whip effect occurs when:
- Which of these statements about the handling of doubles and triples is true?
- Which trailer is most affected by the crack-the-whip, resulting in a rollover?