Isn't it true that there are blue traffic lights in Japan?

If we translate the title of a traffic light go signal from Japanese into English, we’ll get a phrase “blue signal”. But you won’t see blue traffic lights anywhere in the streets of Japanese cities. Their colors are absolutely standard, that is, red, yellow and green. 

So what is the cause of this mess? 

We should look for it in history. On 8 November 1968 most countries of the world accepted Vienna Convention on Road Signs and Signals which led them to the international standardization of sings and signals. 

Nevertheless, Japan decided to take its own path and chose a blue light as a go signal instead of green one. But in five years the authorities of Japan changed its mind and set a green light as a go one. This step was justified by the poor visibility of a blue signal over long distances, because the electromagnetic waves of a blue light dissipate in the atmosphere. 

However the Japanese continued to call a green traffic light “ao singu” which means “a blue signal”. One of the particularities of Japanese culture played its part in it. The point is, a green color has long been considered as one of the shades of a blue color. 

The hieroglyph pronounced “ao” means a benchmark blue color, but its shades (light blue, dark blue and the shades which are close to green) are also designated by the same hieroglyph in a certain context. 

Thus, a green-blue traffic light signal became one of the symbols of complexity and entanglement of Japanese language and culture.