Arizona Air Brakes CDL Practice Test

With dual air systems, the air pressure should build...

1. From 85 to 100 psi in 45 seconds

2. From 70 to 100 psi in 60 seconds

3. From 85 to 150 psi in 45 seconds

4. From 70 to 150 psi in 60 seconds

The correct answer is: From 85 to 100 psi in 45 seconds

The correct answer highlights the expected performance of a dual air brake system. Specifically, in a well-functioning dual air brake system, the air pressure should build from 85 to 100 psi in a span of 45 seconds. This rate of pressure build-up is crucial as it demonstrates the efficiency and operational readiness of the air brake system. Dual air systems consist of two separate air systems to ensure that, in the event of failure in one system, the other can still provide adequate braking power. The specified pressure range—between 85 psi and 100 psi—demonstrates that the system is capable of achieving a safe operational level quickly. If the pressure does not rise to the specified levels within the designated time, it indicates a potential issue in the system that could compromise safety while driving. In contrast, the other options reflect different pressure levels or time frames which do not align with the standard expectations for dual air brake systems. Understanding these specifications is critical for ensuring optimal safety and functionality in commercial vehicles equipped with air brakes.