Driving Colorblind? See This New LED Traffic Signal!

Red light, green light, what light? That's the question a growing number of colorblind people are asking when confronted by new LED traffic signal lights. Since up to 10 percent of the population suffers from red-green colorblindness, an answer is needed pronto... and Professor Taro Ochiai of Japan's Kyushu Sangyo University thinks he's got one: a redesigned LED traffic light easily visible by everyone.

Red-green colorblindness is the most common type of colorblindness, affecting 7 to 10 percent of the world's population. Though those afflicted generally find difficulty in distinguishing red and green colors, other visual clues such as brightness make it possible to lead relatively normal lives and lifestyles, including walking city streets, riding bicycles and driving motor vehicles.

Not any more, it seems. A rising number of complaints by red-green colorblindness sufferers revealed a problem with the new LED traffic signals that have slowly been phased in at Japanese road intersections. Reports indicate the new lamps are much harder to distinguish using only brightness as a visual cue. 

Kyushu Sangyo University professor Taro Ochiai has been working on a practical solution since 2003, the year that LED signals began to be installed. Unlike other modifications to traffic signals, some of which involve framing the individual lights in differently shaped cowlings, Ochiai suggests certain changes to the LEDs inside the lamps. This is a simple fix, as LED traffic signals are made up of many single LEDs.

To someone with red-green colorblindness, a traffic signal's lights will appear “yellow-yellow-gray” instead of “red-yellow-green”. Ochiai asked lighting manufacturer Koito Electric Industries, Ltd., to incorporate quadruple-strength blue LEDs positioned in an X pattern within the red lamp.

Ordinary observers will see a non-distracting pink X when close to the traffic signal and usually won't see the X at all from afar. Red-green colorblind observers, however, can easily distinguish the contrasting blue X against the “yellow” background, even from large distances.

Professor Ochiai's so-called “Traffic Signal for Road [Universal-Design LED Traffic Signal Light for Color Deficient Drivers]” won the 2011 Good Design Award in the Public Facilities and Equipment category.

Japan's municipalities are taking notice as well: one of Ochiai's modified traffic signals is already in operation as a test in the southern city of Fukuoka with a second signal due to be installed shortly in Tokyo's downtown Minato ward. (via Mainichi Daily News)

Mar 3, 2012
by Anonymous

Bad design

Bad design. The Manual for Uniform Traffic Control Devices requires the red to be on the left in horizontal signals, and the green to be on the right.

The signals are already designed so the red has some orange in it, and the green has some blue in it, so all major color blindness types see three different colors. The new LED signals now have the colors they tried to use with incandescent bulbs and failed to get.