A driver is assembling a triple-trailer combination. After coupling the second trailer, when should the third trailer's brakes be released for the first time during assembly?

A driver is assembling a triple-trailer

Multiple choice — select the best answer

AImmediately after the dolly pintle hook is connected to the second trailer's rear coupler
BOnly after all air lines are connected, the trailer glad hands are charged, and the combination has been test-pulled forward to check coupling
CBefore connecting air lines, so the driver can freely position the third trailer
DAfter moving the combination forward 10 feet to verify the kingpin has seated

✓ Correct answer: B. Only after all air lines are connected, the trailer glad hands are charged, and the combination has been test-pulled forward to check coupling Per the CDL manual coupling procedure, air lines must be connected and the system charged before brakes are released; and coupling should be verified with a test pull before the trailer's parking brakes are released for road movement.

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A driver is assembling a triple-trailer combination. After coupling the second trailer, when should the third trailer's brakes be released for the first time during assembly?

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