Arizona Air Brakes CDL Practice Test

A fully charged air system typically has ____ psi.

1. 100

2. 125

3. 150

4. 175

The correct answer is: 125

A fully charged air system in commercial vehicles, especially those equipped with air brakes, typically maintains a pressure of about 125 psi. This standard is important because it ensures that there is enough air pressure available to operate the air brakes effectively. Maintaining this pressure is crucial for safety and performance; it affects the braking response and the overall function of the air brake system. If the air pressure falls below this level, the brakes may not engage properly, potentially compromising the driver's ability to stop the vehicle in a timely manner. Additionally, the 125 psi mark serves as a reference point for drivers to monitor their air brake systems. It's important for drivers to regularly check their gauges and ensure the system is operating within the correct parameters to prevent brake system failures that could occur with insufficient air pressure.