What should a driver do when the air pressure warning light comes on?

When the air pressure warning light comes on, it is crucial for the driver to respond appropriately to ensure safety. The correct action is to use the service brakes to stop the vehicle immediately.

This response is essential because the air pressure warning light indicates that the air pressure in the brakes may be insufficient for safe operation. A drop in air pressure can lead to brake failure, making immediate action necessary. Using the service brakes allows the driver to bring the bus to a controlled and safe stop before the brake system loses all functionality.

Opting for alternative methods, such as using the emergency brake system or the parking brake, may not provide the necessary stopping power in an emergency situation, and relying on low gears to pump the brakes could compromise the vehicle's control on the road. Therefore, stopping immediately using the service brakes ensures that the driver can maintain safety for themselves and the passengers.