About 8% of men are colour blind. In the past I have written about how designers may not adequately take this into account effectively ignoring 4% of the population. I also wrote about how in Korea the problem of traffic lights for colour blind people was being addressed by using different shapes for the different colours.

Now I am interested to hear about a development from Japan – Professor Ochiai at Kyushu Sangyo University has developed a clever modification that is not noticed by people with normal colour vision but helps those who are colour blind. Before the introduction of LED lights people often could tell red from green by the difference in brightness. But LED lights are so bright that they look rather similar in brightness, and for someone with red-green colour blindness they may look identical. Professor Ochiai has added a blue cross to the red light which is very visible to colour-blind observers but can hardly be noticed by the rest of us. Very clever!!

The new lights are being tested in Fukuoka and are due to go on test in Tokyo soon.