What is the purpose of the air pressure gauge in a school bus?

The purpose of the air pressure gauge in a school bus is to monitor air pressure levels in the vehicle's air brake system. This gauge provides crucial information about the functioning of the brakes, which rely on compressed air for operation. Maintaining the correct air pressure is essential for ensuring that the brakes work effectively, allowing the driver to stop safely and efficiently. If the air pressure is too low, it can compromise the braking system, leading to potential safety hazards.

In contrast, the other options do not pertain to the air pressure gauge. Fuel level indicators measure the amount of fuel in the tank, while an engine temperature gauge displays the temperature of the engine to prevent overheating. A speedometer shows how fast the bus is traveling, which is also important, but it does not relate to air pressure monitoring. The significance of the air pressure gauge underscores the importance of regular checks to ensure safe operation, especially in a school bus where the safety of children is paramount.