What does this traffic sign indicate?

The traffic sign you've shown indicates an obligatory diversion for vehicles. In Germany, this sign is employed in situations where there is a road closure or restriction ahead, requiring motorists to take an alternative route.

Understanding this sign is crucial because it ensures that drivers are aware of upcoming changes in the road structure and can adjust their routes accordingly to maintain safety and traffic flow. Following this sign helps prevent accidents and ensures compliance with German traffic laws. Always be alert and ready to follow the indicated detours when you see such signs.