During which step in the pre-trip inspection of a school bus do you check the back emergency door?

The correct step for checking the back emergency door during a pre-trip inspection of a school bus is during the interior check. This step focuses on the inside of the bus, where safety features, including emergency exits like the back door, are evaluated. It's imperative to ensure that the emergency doors are not only functional but also free from obstructions. Ensuring that these exits work correctly is vital for ensuring the safety of passengers in case of emergencies.

The exterior check primarily addresses the bus's exterior components, while fluid checks concentrate on the engine and other vital systems to prevent breakdowns. The lights check focuses on the bus's lighting systems, ensuring visibility and compliance with safety regulations. Thus, the interior check is the appropriate context for examining emergency doors and other interior safety features.