When driving on the taxiway, vehicles must operate to the right of what?

When driving on a taxiway, vehicles must operate to the right of the taxiway centerline. The taxiway centerline is a critical marker that helps maintain safe distances between aircraft movements and ground vehicles. It is designed to ensure that vehicles do not encroach into the path of taxiing aircraft, which is essential for safe airport operations. Following this guideline helps maintain order on the taxiway and minimizes the risk of collisions between vehicles and aircraft.

The other markers and boundaries mentioned in the options have different purposes; for example, pavement edge markings typically define the limits of the taxiway surface, while pavement stress markings may indicate areas where pavement strength is a concern. Aircraft boundaries are essential for identifying areas designated for aircraft parking and operations, but they do not dictate how vehicles should navigate on the taxiway itself. Thus, understanding the requirement to keep to the right of the taxiway centerline is fundamental for anyone operating a vehicle on the taxiway.