Stopping, making U-turns, and backing up on autobahns are indeed prohibited, making the statement true. Autobahns are high-speed highways in Germany designed for efficient and safe long-distance travel. To maintain the flow of traffic and ensure safety, any actions that could disrupt this flow, such as stopping on the roadway, executing U-turns, or reversing, are not allowed.
Stopping is particularly dangerous because it can lead to accidents given the high speeds at which vehicles travel on these roads. Similarly, making U-turns or backing up could result in severe traffic disruptions and poses a significant safety risk. Therefore, strict regulations are in place to prevent these actions and to ensure that the autobahn remains safe and efficient for all users.