What is the purpose of air brakes in heavy vehicles?

The purpose of air brakes in heavy vehicles is primarily to provide effective braking control through the use of compressed air. This system is especially crucial for large vehicles, such as trucks and buses, as they require a more robust braking solution than traditional hydraulic systems can provide.

Air brakes utilize compressed air to activate brake pads, delivering a high level of stopping power that is essential for the weight and momentum of heavy vehicles. The system is designed to respond quickly and reliably under varying conditions, which is critical for safety, especially when transporting large loads. Additionally, because air brakes can be adjusted for differing loads, they maintain effectiveness regardless of how heavy or light the vehicle is loaded at any given time.

The other options do not accurately represent the purpose of air brakes. Increasing speed, enhancing engine performance, and reducing fuel consumption are not functions related to the braking system. Instead, they focus more on vehicle efficiency and performance rather than safety and control during braking.