Practice question

Why should a commercial driver never use the trailer hand valve (trolley brake) to correct a jackknife in progress on a slippery road?

Applying the trailer brakes when trailer wheels are already sliding locks the trailer tires completely and worsens the jackknife skid
It causes the tractor engine to stall immediately
It detaches the trailer kingpin automatically
It drains the fuel tank into the air lines

Answer: A — Applying the trailer brakes when trailer wheels are already sliding locks the trailer tires completely and worsens the jackknife skid

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