Practice question

For an NJ commercial vehicle equipped with air brakes, what happens if the emergency (supply) air line to the trailer is broken or disconnected during driving?

  1. The trailer keeps rolling freely
  2. The trailer's emergency brakes (spring brakes) apply automatically because supply line pressure drops
  3. The tractor brakes lock up
  4. The engine stops

Answer: B — The trailer's emergency brakes (spring brakes) apply automatically because supply line pressure drops

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Practice more: NJ CDL Air Brakes Test Practice Questions - New Jersey Commercial Driver License (CDL) Air Brakes Knowledge Test Exam →