What is the function of the air brake system in commercial vehicles?

The air brake system in commercial vehicles primarily functions to slow down or stop the vehicle using compressed air. This system is essential for larger vehicles, such as trucks and buses, which require a more robust braking system due to their weight and the forces involved in stopping.

In an air brake system, air is compressed and stored in tanks. When the driver applies the brake, this compressed air is released into the brake chambers, which activates the braking mechanisms on the wheels. This allows for a powerful braking force that can safely bring heavy vehicles to a stop, even in emergencies.

The other options provide misleading or irrelevant functions related to braking systems. Enhancing fuel efficiency relates to engine and aerodynamics, while boosting vehicle speed refers to acceleration, and assisting in turning corners does not pertain to the primary purpose of braking systems. Therefore, the identified function of using compressed air to control the vehicle’s speed directly addresses the critical safety and performance requirements for commercial vehicles.