Final answer:
To safely return to the right-hand lane after passing, wait until you see the front of the passed vehicle in your rearview mirror and then carefully change lanes with appropriate signaling.
Step-by-step explanation:
It is safe to return to the right-hand lane after passing another vehicle when you see the passed vehicle in your rearview mirror and it is far enough behind to allow for a safe lane change. Specifically, you should be able to see the front of the passed vehicle in your rearview mirror before you return to the right-hand lane. This ensures that you have enough space to change lanes without cutting off the passed vehicle. Additionally, you should always signal your intention to change lanes to alert other drivers of your actions. Immediate lane changes or relying on the passed vehicle to signal you are not safe practices. Remember, safety is the primary concern when making any maneuvers on the road.