Tag Archives: traffic lights

traffic lights for everyone

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.

colour blind to traffic lights

Colour blindness afflicts about 1 in 12 men in the world. Women are far less affected because they have two X chromosomes. Men only have one X chromosome and therefore there is no backup if the gene for good colour vision is damaged or changed. Of course, colour blindness is a misnomer. Very few people indeed are really colour blind and the term colour defective is scientifically more correct. So-called colour blind people have trouble discriminating between colours that the rest of us see as different. Most commonly the difficult is in telling reds and greens apart which is where the term red-green colour blind derives from. Though people need to be able to pass colour-vision test before they can be employed in certain professions (such as being an aeroplane pilot) where colour decisions are critical, everyone is allowed to drive a car. Even though traffic lights are red and green!!

The argument for allowing colour blind people to drive has always been, I think, that drivers quickly learn the positions of lights. Red, is on top, amber in the middle and green on the bottom. However, is that red-amber-green order used everywhere in the world. It is used in the UK where I live. But elsewhere?

Whether to do with the order of the lights or not, several studies have shown that colour blindness is a risk factor in driving. Hence the development of the UniSignal (Universal Signal Light). Developed in South Korea the UniSignal uses different shapes for different colours so that drivers can recognise which light is on whatever the order in the particular city in which they find themselves.

Kandinsky would approve!