The sign you are referring to is known as a "Dead End" sign (in German, "Sackgasse"). This sign indicates that the road is a dead-end and does not continue beyond a certain point. When you see this sign, it means that you will need to turn around and find another route, as there is no through traffic.

Drivers should exercise caution when approaching a dead-end, especially if they are unfamiliar with the area. It’s important to check for any pedestrians or cyclists and be prepared to navigate within the limited space available to turn around safely.

If you have any other questions about driving rules or need further clarification, feel free to ask!