What does a supply pressure gauge indicate?

Answer: C — How much pressure is in the air tanks

The supply pressure gauge is a critical instrument in the air brake system of a commercial vehicle, particularly those equipped with air brakes. It specifically indicates the amount of pressure in the air tanks, which is essential for the proper functioning of the braking system. Understanding the pressure level helps the driver ensure that there is adequate air supply for safe braking performance. If the pressure falls below a certain level, it can signal that there may be an issue with the air brake system, necessitating immediate attention to avoid potential safety hazards. This gauge is vital for maintaining the integrity and efficiency of the air brake system, contributing significantly to overall vehicle safety.