Why colour-blind drivers are seeing red on Japan's roads
Japan is road-testing traffic lights that can be seen by people who are colour-blind as well as drivers with perfect vision.
The signals have been developed by Taro Ochiai, a professor at Kyushu Sangyo University, with the first set of lights installed in Fukuoka.
A second month-long test is to be started in Tokyo, before the end of the month.
Prof Ochiai began researching the use of light-emitting diodes (LEDs) in 2003, when they first began to be used in traffic lights.
Drivers with colour-blindness reported that the LED signals were more difficult for them to discern based only on brightness as the visual indicator.
Prof Ochiai incorporated blue LEDs with four times the brightness of the other diodes in the shape of a cross through the red lamp.
Drivers with perfect vision will hardly notice the pink X that is set within the red signal, but red-green colour-blind drivers are easily able to distinguish the contrasting blue X against a background that they perceive as yellow.
The mark is clear even from a distance. Colour-blindness affects around 8pc of men and 0.5pc of women, with most experiencing problems differentiating between red and green. (© Daily Telegraph, London)
- Julian Ryall in Tokyo
Irish Independent
