What does the term "deadheading" refer to in bus operation?

The term "deadheading" specifically refers to the situation when a bus operator drives a bus without passengers to reposition it for service. This situation often occurs when a bus needs to travel from one location to another, such as from a maintenance facility back to its designated route or to pick up a scheduled service after completing one route. During deadheading, the bus is not in service, meaning it isn't picking up passengers, but it is essential for maintaining the bus schedule and operational efficiency.

The other options, such as driving with passengers or making unnecessary stops, do not embody the concept of deadheading, as they involve active service with passengers or impacts on the service schedule. Similarly, leaving the terminal without adhering to the planned route schedule does not align with the definition of deadheading, which is focused on the position and readiness of the bus rather than its operational compliance.