Modern air brake systems combine three different systems. They are the service brake, parking brakes, and the?

Modern air brake systems combine three different systems. They are the service brake, parking brakes, and the?

• A. Anti-lock brakes
• B. Emergency brakes
• C. Hydraulic brakes
• D. Vacuum brakes

Answer: (B)

In modern air brake systems, three braking subsystems work together: the service brakes for normal stopping controll by the driver, the parking brakes to hold the vehicle when it’s parked, and the emergency brakes as a safety backup that can stop the vehicle if the air supply fails. The emergency brakes kick in automatically when air pressure drops to a low level or if there’s a significant system failure, providing a fail-safe stop so you can still bring the vehicle to a halt. Other options don’t fit this trio. Anti-lock brakes are about preventing wheel lock during braking, not a separate system in the air brake setup. Hydraulic brakes rely on fluid pressure, and vacuum brakes are an older, non-air system—neither aligns with the three-part air brake configuration.

In modern air brake systems, three braking subsystems work together: the service brakes for normal stopping controll by the driver, the parking brakes to hold the vehicle when it’s parked, and the emergency brakes as a safety backup that can stop the vehicle if the air supply fails. The emergency brakes kick in automatically when air pressure drops to a low level or if there’s a significant system failure, providing a fail-safe stop so you can still bring the vehicle to a halt.

Other options don’t fit this trio. Anti-lock brakes are about preventing wheel lock during braking, not a separate system in the air brake setup. Hydraulic brakes rely on fluid pressure, and vacuum brakes are an older, non-air system—neither aligns with the three-part air brake configuration.