What should the driver do during the performance stop in the stall?

During the performance stop in the stall, applying the service brake as soon as the bus moves is the correct action. This step is crucial in ensuring that the vehicle is safely brought to a halt, demonstrating effective control of the bus. Engaging the service brake allows the driver to assess the braking system's response and functionality, which is essential for safety during operation.

Using the service brake in this scenario helps to confirm that it engages properly and that the bus can stop effectively. It's a critical safety check that ensures the braking system is working as intended before proceeding with driving or any other maneuvers.

In contrast, engaging the parking brake isn't suitable during movement since it is designed for securing the vehicle when it is stationary, rather than during operation. Shifting to reverse can pose safety risks and distract from the necessary performance check. Similarly, accelerating quickly would compromise control and contradict the objective of assessing the vehicle's braking system.