Initially, Japan’s traffic lights were green as international traffic law decrees. Despite this, the country’s official traffic documents referred to green traffic lights as “ao” (blue) rather than “midori” (green). “Midori” is a rather new word to describe color, so it was never used in official documents before. Japanese linguists demanded that the mistake be corrected, and the government found a compromise.

They mandated the use of the bluest shade of green possible for traffic lights, satisfying international regulations while still allowing the continued use of the term “ao.” So, despite appearances, Japan’s traffic lights are technically blue-green. It’s a bureaucratic solution that worked.