When is it safe to return to your lane after passing another vehicle?

Returning to your lane after passing another vehicle requires ensuring that it is safe to do so. The best practice is to wait until you can see the other vehicle's headlights in your rearview mirror. This indicates that there is enough distance between your vehicle and the one you just passed, ensuring that you won't cut off the other driver and that it's safe for you to return to your lane.

The other options do not adequately ensure safety. Returning immediately after passing does not allow for a safe following distance to be established. Waiting for the other vehicle to signal could be misleading or not applicable in cases where the vehicle does not use their signals. Lastly, just reaching a certain speed does not guarantee that it is safe to merge back into your lane, as the other vehicle may still be too close. Therefore, confirming visibility of the other vehicle's headlights in your rearview mirror is the most reliable method to assess when it's safe to return to your lane after passing.