Christoph S November 16, 2023 9:53pm Tech In Plain Sight: What Does A Yellow Light Mean? | Hackaday Fascinating story #history #traffic https://hackaday.com/2023/11/16/tech-in-plain-sight-what-does-a-yellow-light-mean/ Tech In Plain Sight: What Does A Yellow Light Mean? The traffic light is a ubiquitous feature of modern life and is quite old — dating back to 1868 London, although that device was a modified railroad semaphore operated by a policeman, but it …