When passing a vehicle, how should you check if it's safe to return to your lane?

When passing a vehicle, it is essential to ensure that it is safe to return to your lane. Checking your rearview mirror for the vehicle's headlights provides a clear indication of the distance and position of the vehicle you just passed. If you can see the headlights of the vehicle behind you in your rearview mirror, it suggests that there is enough space for you to maneuver back into your lane safely. This method relies on visual confirmation of the vehicle's position in relation to yours.

Using other methods such as judging the passing vehicle's speed or listening for engine sounds may not provide reliable information about the proximity of the vehicle. Additionally, checking the rearview mirror of the vehicle you are passing does not give you an accurate assessment of your own safety for returning to your lane. Therefore, visually confirming the presence of the headlights in your rearview mirror is the most effective way to ensure that it is safe to return to your lane after passing.