What safety feature is activated if the parking brake is disengaged during pump operation?

The safety feature that is activated when the parking brake is disengaged during pump operation involves the safety interlocks that prevent throttle control from operating. This system is designed to enhance safety by ensuring that the vehicle remains stable and does not move unexpectedly while operating the pump. When the parking brake is disengaged, the throttle control being disabled helps to prevent accidents that could occur if the vehicle were to roll or shift during pump operations.

By incorporating this feature, fire apparatus manufacturers aim to make the operation of fire pumps safer for firefighters and minimize the risk of injury or equipment damage. It reflects the importance of maintaining vehicle stability during critical operations like firefighting where the safety of the crew is paramount. In contrast, other options either do not directly relate to the disengagement of the parking brake or do not accurately describe the mechanism of action or purpose within this context.