If you are driving a combination vehicle, when you use the trailer hand valve, you should:

Never use it for parking.. Section 6.2: Never use the hand valve for parking (it can leak off). Use parking brakes.

If you are driving a combination vehicle, when you use the trailer hand valve, you should:

ANSWER BREAKDOWN
  • A. Incorrect. "Expect the trailer to skid." is not correct. Never use the hand valve for parking (it can leak off). Use parking brakes.
  • B. Correct. Never use the hand valve for parking (it can leak off). Use parking brakes.
  • C. Incorrect. "Use it only for emergencies." is not correct. Never use the hand valve for parking (it can leak off). Use parking brakes.
  • D. Incorrect. "Use it to steer." is not correct. Never use the hand valve for parking (it can leak off). Use parking brakes.