What indicates it is safe to move back into the right lane after passing a vehicle?

The correct answer is indicated by the ability to see the front of the vehicle or its headlights in your rearview mirror. This perspective confirms that you have successfully passed the vehicle and that it is at a safe distance behind you. Being able to see the front of the vehicle means you can assess its position relative to your own vehicle, ensuring there is enough space for you to safely move back into the right lane without risking any collision.

This is particularly important for maintaining safety on the road, as returning to your lane too early can lead to dangerous situations, such as cutting off another driver or causing them to brake suddenly. The act of verifying that you can see the vehicle in your rearview mirror is a critical step in safe driving practices during overtaking maneuvers.