What does this traffic sign indicate?

This sign marks the start of an autobahn (German motorway). When you see this sign, special rules apply: there is no general speed limit unless otherwise posted, and certain vehicles like bicycles, mopeds, pedestrians, and trailers are prohibited. It indicates a high-speed road designed for fast and safe travel with multiple lanes separated by a median.

Understanding this sign helps you recognize when you are entering a motorway and need to adjust your driving, such as merging carefully and following specific autobahn regulations.