If a typical fully-charged air system flows out at 125 psi, what are the maximum leakage rates per minute of single and combination vehicles after the initial drop?
A. 1 psi for single vehicles, 2 psi for combination vehicles
B. 2 psi for single vehicles, 3 psi for combination vehicles
C. 3 psi for single vehicles, 4 psi for combination vehicles
D. 4 psi for single vehicles, 5 psi for combination vehicles

The Federal Motor Carrier Safety Regulations set the maximum air loss rate for single vehicles at 1 psi per minute and for combination vehicles at 2 psi per minute, after an initial drop when the system is fully charged at 125 psi. The correct answer is A. 1 psi for single vehicles, 2 psi for combination vehicles.

Explanation:

The maximum leakage rates for air brake systems in commercial vehicles such as single and combination vehicles are specified by the Federal Motor Carrier Safety Regulations. For a typical fully-charged air system that flows out at 125 psi, the maximum air loss per minute after the initial pressure drop is:

1 psi for single vehicles
2 psi for combination vehicles

These values are set to ensure the safety and reliability of the air brake system during operation. If the air loss exceeds these limits, it may be indicative of a leak in the system which would require immediate attention and repair to maintain vehicle safety and performance. The correct option in this case is: A. 1 psi for single vehicles, 2 psi for combination vehicles.