What is the primary purpose of air brakes in a commercial vehicle?

The primary purpose of air brakes in a commercial vehicle is to provide effective stopping power for heavy loads. Air brakes are specifically designed to handle the unique challenges associated with stopping larger, heavier vehicles, such as trucks and buses. Unlike standard hydraulic brakes, air brakes use compressed air to operate the braking system, which allows for more powerful and consistent braking force.

This system is especially crucial for commercial vehicles that often carry substantial loads, making safe stopping not just important but essential for the safety of all road users. When the driver applies the brakes, air is released from the reservoirs into the brake chambers, which then activates the brake shoes against the brake drums, creating the necessary friction to slow down or stop the vehicle.

The other options center around benefits that, while important, do not reflect the primary function of air brakes. Fuel efficiency and driving comfort might be considerations in the overall design and operation of a vehicle, but they do not serve as the main purpose of the air brake system. Increasing vehicle speed is also contrary to the primary design objective; air brakes aim to enhance safety by ensuring reliable braking, especially under heavy loads, rather than promoting speed.