At what pressure does the low air pressure warning light activate?

The low air pressure warning light typically activates at around 60 psi. This is a critical safety feature designed to alert the driver that the air brake system is not operating at an adequate pressure level, which could compromise the effectiveness of the brakes. When the air pressure drops to this level, it indicates that the air supply may be insufficient to maintain proper braking force, thereby creating a potential safety hazard.

Understanding this activation point is vital for school bus drivers, as it helps them recognize when they need to take immediate action to address air pressure issues, such as safely pulling over and inspecting the system before continuing to drive. The other pressures listed are not the standard activation point for the warning light and would either be too low, meaning safety is not adequately ensured, or too high, which wouldn't serve the purpose of alerting the driver in a timely manner.