What is the purpose of air brakes in commercial vehicles?

The purpose of air brakes in commercial vehicles is primarily to reduce speed and stop the vehicle using compressed air. Unlike hydraulic brake systems that rely on fluid pressure, air brakes function by using air pressure to engage the brake pads against the brake drums or discs. This system is especially important for large vehicles like trucks and buses, as they require significant stopping power to manage their weight and size safely.

Utilizing compressed air has several advantages. For instance, air brakes can release more easily and provide quicker engagement than other types, which is critical for controlling large vehicles. The air brake system includes important components such as the brake chamber and relay valves, which work together to create an effective and responsive braking action.

Other options, while related to vehicle operation, do not accurately describe the main function of air brakes. Enhancing fuel efficiency or increasing driver comfort addresses entirely different aspects of vehicle performance and operation, not the braking system itself. Similarly, while traction on wet roads is relevant to vehicle handling, it is not the role of air brakes. Thus, the primary and defining role of air brakes is indeed to slow down and stop the vehicle through the use of compressed air.