Q
Before driving a vehicle with air brakes, you should ensure that the spring brakes come on automatically when:
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AAir pressure falls below 45 psi
BThe vehicle reaches 20 mph
CBrakes are applied
Detailed Explanation
The correct answer is "Air pressure falls below 45 psi". This is based on federal CDL regulations and safety standards.
Correct Answer: Air pressure falls below 45 psi
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