Ontario MTO Truck Knowledge Test 2025 – 400 Free Practice Questions to Pass the Exam

The primary function of the air brake system in a truck is to regulate the braking force applied to the wheels. This is crucial for ensuring safe and effective stopping, especially given the weight and size of trucks. The air brake system uses compressed air to activate the brakes, providing substantial braking power that is essential for larger vehicles.

When the driver applies the brakes, the system distributes air pressure to the brake components on each wheel. This allows for a controlled and proportional braking force, enabling the driver to quickly decelerate or stop the vehicle while maintaining stability. The reliable operation of air brakes is vital for safety, particularly when navigating descents or tight turns.

Other options, such as enhancing engine performance, cooling the braking system, or maintaining tire pressure, do not pertain to the core function of the air brake system. Instead, these options either relate to different vehicle systems or are not relevant in the context of braking performance.