Final answer:
When approaching a stopped vehicle with flashing lights on a four-lane highway, you should change to a lane that is not next to the emergency vehicle, if you can do so safely.
Step-by-step explanation:
When approaching a stopped vehicle with flashing lights on a four-lane highway, you should change to a lane that is not next to the emergency vehicle, if you can do so safely. This is known as the 'Move Over' law, which requires drivers to provide a safety buffer for emergency vehicles. By changing lanes, you help ensure the safety of both the emergency personnel and the drivers on the road.