What does this traffic sign indicate?

This traffic sign is a warning sign indicating that you are approaching traffic lights ahead. In Germany, this triangular sign with a red border and a depiction of traffic lights inside alerts drivers to be prepared to stop or adjust their speed according to the upcoming traffic signal.

It is important because it helps prevent accidents by giving drivers advance notice to expect a stop or change in traffic flow. The sign does not mean the light is currently red or yellow but simply warns that a traffic light-controlled intersection is approaching.

Remember, when you see this sign, start paying close attention to the traffic light and be ready to stop if necessary. This improves safety at intersections where traffic flow is regulated by lights.