Final answer:
A traffic signal always signals lane changes as vehicles adjust their position to stop at the signal.
Step-by-step explanation:
The question is asking whether a traffic signal always, sometimes or never signals lane changes. In social studies, we study transportation and traffic rules as part of our study on societies and their organization. In this case, a traffic signal always signals lane changes. When a driver approaches a traffic signal and it turns red, they are required to stop and wait for it to turn green before continuing. This means that they must change lanes to the lane that allows them to stop at the signal. So, a traffic signal always signals a lane change as vehicles adjust their position to stop at the signal.