Air Brake Practice Test

Air brake equipped vehicles must have:

1. A backup hydraulic system

2. A supply pressure gauge

3. At least two brake heaters

4. An air use gauge

The correct answer is: A supply pressure gauge

Vehicles equipped with air brakes are required to have a supply pressure gauge to provide the driver with important information about the air system. This gauge indicates the amount of air pressure available in the air storage tanks, which is crucial for ensuring that the brakes can operate safely and effectively. Proper air pressure is essential, as inadequate pressure can lead to brake failure or diminished braking power, potentially resulting in accidents. Maintaining an optimal level of pressure not only supports operational effectiveness but also helps the driver monitor the system for any potential issues. This gauge serves as a critical feedback mechanism, allowing operators to assess whether the air brakes are functioning within safe parameters and to take corrective action if needed. While other components, like hydraulic systems or gauges for specific functions such as air use, may be found on some vehicles, they are not mandated in all air brake systems. The supply pressure gauge, however, is a fundamental requirement for ensuring safety in air brake operation.