When checking the air brake system, the low air pressure warning light should activate before the pressure drops below what level?

The low air pressure warning light in a school bus is a crucial safety feature that alerts the driver when the air pressure in the braking system is falling to potentially unsafe levels. In North Carolina, the regulations dictate that this warning light must activate before the air pressure drops below 60 psi. This threshold is established to ensure that drivers are alerted well in advance of the air pressure reaching a dangerously low level, where braking effectiveness could be compromised.

Maintaining air pressure above this level is essential for the safe operation of the vehicle, as the air brake system relies on sufficient pressure to function correctly. If the pressure were to drop too low, it could lead to brake failure, resulting in an inability to stop the bus safely. Therefore, the 60 psi activation point serves as a critical safety measure that helps prevent accidents and ensures the driver has adequate time to respond appropriately when the warning light activates.