Practice question

For the Washington CDL Air Brakes knowledge test, what is the typical pressure range at which the tractor protection valve closes during a major loss of air?

  1. Between 20 and 45 psi
  2. Between 100 and 125 psi
  3. Below 5 psi
  4. Above 150 psi

Answer: A — Between 20 and 45 psi

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