Arizona Air Brakes CDL Practice Test

What is the primary function of the service brake system?

1. It is an official vehicle inspection

2. Applies and releases the brakes by using the brake pedal under normal driving

3. They keep the air tank pressure serviced

4. It is only on vehicles with hydraulic brakes

The correct answer is: Applies and releases the brakes by using the brake pedal under normal driving

The primary function of the service brake system is to apply and release the brakes using the brake pedal during normal driving conditions. This system is crucial for controlling the speed of the vehicle and enabling the driver to stop safely. When the driver presses the brake pedal, it activates the service brakes, which engage the braking mechanism, providing the necessary friction to slow down or halt the vehicle. The other options do not accurately describe the function of the service brake system. For instance, an official vehicle inspection refers to the process of checking a vehicle's compliance with safety standards and regulations and does not pertain to the operational aspect of braking. Keeping the air tank pressure serviced relates to maintaining a specific pressure level in the air brake system but does not encompass the actual function of applying the brakes. Lastly, stating that the service brake system is only present on vehicles with hydraulic brakes overlooks the fact that air brake systems also utilize service brakes to manage stopping power effectively. Thus, the correct understanding emphasizes that the service brake system's main role is to facilitate safe and effective braking during normal vehicle operation.