Practice question

For a North Carolina CDL combination vehicle, when should you use the trailer hand valve (trolley valve)?

  1. As your primary stopping control while driving
  2. Only to test the trailer brakes; not for normal stopping
  3. To park the trailer overnight
  4. On every downhill grade

Answer: B — Only to test the trailer brakes; not for normal stopping

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Practice more: NC CDL Combination Vehicles Practice Questions - North Carolina CDL Combination Vehicles Test Exam →