What is the proper way to release the parking brake on an air-braked vehicle?

Answer: C — Fully depress the brake pedal while pulling the release knob

The proper way to release the parking brake on an air-braked vehicle involves fully depressing the brake pedal while pulling the release knob. This method ensures that the braking system is effectively managed and minimizes the risk of the vehicle rolling unexpectedly when the parking brake is disengaged. By pressing the brake pedal first, you are activating the service brakes, which helps prevent any movement of the vehicle while the parking brake is being released. This is particularly important in ensuring safety on inclines or when parked on any slope, as it provides immediate control over the vehicle’s movement. When releasing the parking brake, this process also ensures that air pressure is appropriately managed in the braking system. If done correctly, it can help in maintaining system integrity and performance, allowing for a smoother transition from a parked state to a ready-to-drive state without incident.