At what air pressure range do the emergency brakes automatically engage?

The emergency brakes on a bus engage automatically when the air pressure drops to a range of 20 to 45 psi. This is a critical safety feature designed to prevent accidents that could occur if the air pressure in the braking system falls below a certain level. The system is engineered to activate the emergency brakes as a precautionary measure to ensure that the vehicle can come to a stop in case of a failure in the primary braking system.

Maintaining proper air pressure is essential for brake functionality. When air pressure is above 45 psi, the brakes function normally. However, once the pressure drops to 20 psi, the system recognizes that the air supply is insufficient for safe operation and automatically engages the emergency brakes, thereby allowing the bus to stop safely and reducing the risk of uncontrolled movement. Understanding this range is vital for drivers to ensure safety protocols are followed and to maintain the bus in good working order.