Practice question

What is the tested combination-vehicle principle for trailer skids?

  1. Correct a jackknife by pulling the fifth-wheel release
  2. A trailer jackknife usually starts when trailer wheels lock and slide sideways.
  3. Apply more trailer-only braking to a trailer skid
  4. Keep the wheels locked until the vehicle stops

Answer: B — A trailer jackknife usually starts when trailer wheels lock and slide sideways.

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