Which color arrow indicates that a driver must actively prepare for a change in direction rights?

The yellow arrow is used to signal that a driver must actively prepare for a change in direction, indicating caution and the potential for both a change in traffic conditions and signal status. When a yellow arrow is displayed, it warns drivers that the light is about to change to red, meaning they should be prepared to stop or adjust their driving accordingly. This signal helps maintain safe traffic flow by ensuring that drivers are aware of the upcoming need to yield, stop, or proceed with heightened awareness.

The other colors serve different purposes; for instance, a red arrow means the driver must stop and not proceed in the direction indicated, while a green arrow indicates that the driver can proceed safely in the direction shown. A blue arrow is not typically used in traffic signal systems to indicate changes in direction. Thus, the yellow arrow's role is crucial for alerting drivers to prepare for changes, making it the most appropriate answer.