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Comment by acadapter | Hacker News Reader

Color blindness compatible design is, IMO, a very neglected part of the equality debate, in many other fields. This disability has a very skewed gender ratio due to how it works genetically.

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Most green lights in the US have a blue tint so that color blind people can see the blue. Most but not all, which is really frustrating as a colorblind person. More than once I've been sitting at a light until my wife told me it was green as there is one light near me without that blue tint. (we are making a left turn so light has both the round red stop light and the green left turn arrow on at the same time)

There is no clicking/hum that distinguishes those 2 states? If that's the case, you should probably check with council to have those nearby lights changed into disability-friendly setup. You may be surprised how effective it may be, maybe council has some part of the budget allocated to this so they will give it higher priority (or not, but at least try, you can help other people too)

Crosswalk lights in the US may have audio but usually not the roadway lights, and depending on the jurisdiction the crosswalk may not always get the light at the same time as the roadway, not to mention that you may not hear it if you are at the centermost lane of a road four or five lanes wide in each direction.

There is for pedestrians, but when I'm in my car with the windows closed I can't hear them.

I'm pretty sure the international agreement on road signaling completely forbids any stop and go light from being on the same place, so that you can distinguish them without depending on any color.

But well, the US never follows any agreement it signs, so yeah, that happens.

Sure, but green is so washed out for me that the green position may not be there at all for all the good it goes. If you tell me the green is lit I'll look close and see it is on, but I will not notice without being told to look.

I learned this lesson in my first ever public lecture. Approximately 10% of my audience had some form of colour blindness, rendering the majority of my figures incapable of communicating their intent.

Since then I have rendered all figures for public consumption in black and white, and lines instead of surfaces where possible.

Depending on what exactly your figures were/are, you might benefit from the viridis colour map, available in matplotlib and R (and probably in many other places). It's colourful, so those without colour blindness get a richer display than if you used greyscale, and the colours chosen aren't too affected by most common forms of colour blindness. But for those that really can't see the colours, even if you literally just convert to monochrome, it still works. It also looks nice :-)

Here's a talk by the creators: https://www.youtube.com/watch?v=xAoljeRJ3lU

Here's a little article about it (with some R specifics): https://cran.r-project.org/web/packages/viridis/vignettes/in...

Am I wrong that in that article magma appears to do better? Particularly in the last two (red-blind and grayscale), it seems like viridis looks the same for large parts of the scale, while magma retains its distinction.

I think it just won the poll [1] because it subjectively looks nicer. NJS, in that video, said something like: I don't care which wins, they're all so much better than the current situation. But magma is a good choice too and it's also available in matplotlib.

[1] http://bids.github.io/colormap/

Android has a colorblind developer option in the settings you can use to quickly check how it might look for others.

I just turn that on, open the camera and look at my color pallete through the camera.

I have the relatively typical male, minor colorblindness. Using color as an signal is fine, but just make sure there's something else that's independently conveying the info.

Also, another way to find out how common colorblindness is among your male friends: go rock climbing in a gym. Color is used on the holds to signify the route, and colorblind people who quickly start asking about color as they're climbing.

Traffic lights are still fine for colour-blind people aren't they? The order of the lights doesn't change.

Night time?

Also lights with more than three bulbs, some indicating left or right turns, of which will take on two or more colours themselves. Some lights have a bulb above red for cyclists and transit. Some lights called beacons are a single bulb that take on several colours.

https://www.ontario.ca/document/official-mto-drivers-handboo...

Yes. They can still drive fine, but don't get the benefits of color coding, like being able to infer whether red or green is lit from the light reflected off of other objects. That becomes somewhat important in low visibility situations where the position is hard to determine.

It seems the harder difficulty is red and yellow, see the comments in this article, but led lights have improved the situation for some:

https://www.color-blindness.com/2007/02/06/colorblind-at-the...

There are a few different types of colorblindness, so I wouldn't extrapolate that.

For me personally, the green light looks much closer to a white than to, say, the green of a grass.

I just happen to have a friend with red-green blindness, who was my reference point in answering. It's good to point out there are different types with different impacts, though.

Funny thing, I'm NOT colorblind and apparently I only rely on the color. I've been driving for over 10 years now, mostly in the capital that has traffic lights everywhere, and sitting at my desk now not looking at a traffic light, I wouldn't want to bet money on the order.

I always assumed red was at the top as it's the most important. It's the first one to peak out behind tall trucks.

Some places have the lights sideways, and usually red is on the left, but it's not always consistent.

If I were designing them I'd always have the red be noticeably larger.

It depends on their kind of colorblindness.

I see green lights as white, which is fine most of the time because of the order.

The exception is when there's a lot of glare from the sun setting behind me, and I sometimes can't tell if it's green, or just the sun reflecting at the right angle. It also washes out the red and yellow, making it harder to see if they're lit.

I am the same--green traffic lights are nearly white. Normally, it's enough to know it's not the red or yellow light. Sometimes at night--face with an array of white lights in the distance--it can be an issue.

At my last eye test at the RMV, the clerk tried to tell me I wasn't color blind. I mean, sure, I've been able to drive with it for 40 years, but I know damn well I'm color blind.

Horizontal lights are not consistent across countries. The linked article has an image of a Japanese horizontal traffic light with red on the right, whereas an American traffic light would have red on the left.

And some countries don't have horizontal lights at all.

https://youtu.be/sXbHdKJ1D78

I don't think I've ever seen horizontal lights in Europe at all. Fairly common in Japan though.

Which is even worse. I grew up in an area with only vertical lights. After several years of driving I ended up in an area with a horizontal light, one end was white and I had no clue if that meant stop or go. (I'm colorblind so I normally think top=stop, bottom=go)

Most color blind have issue to see shades and subtle differences. They see red and green just fine.

The people who do not see red at all however, see red as black. So, they do not see red traffic light at all.

> The order of the lights doesn't change.

For 3 lights streetlights no. For 2 lights streetlights it depends. They can be (in DE) either red and yellow or yellow or green.

AFAIK yellow + green is only ever used for turning traffic and is always installed together with a regular 3-bulb traffic light for the other directions. Stand-alone two-bulb traffic lights are always red + yellow, with red on top, just as usual.

With the switch from incandescent bulbs to LED traffic lights it would be very easy to change the shape of the lights: e.g. octagonal for stop, triangular for caution, and circular for go. Keep the colors, but add shape as well. Seems like an obvious and useful change to me.

That might fall apart for people with poor visual acuity.

If they're roughly the same size and in the same order as the round lights today, people with poor visual acuity would still see more or less what they see currently.

If you can tell neither the color of the light, nor its shape...

Should you be driving?

Almost fifty years ago, I worked with a guy who was color-blind. This was in Colorado, where at the time some of the little towns in the mountains still had traffic lights arranged horizontally rather than vertically. He must have known the order at one time--I think I learned it for my license test--but of course with little chance for reinforcement tended to forget. I suppose that such lights are all gone now.

They're common in at least four states still: https://www.youtube.com/watch?v=sXbHdKJ1D78

> The order of the lights doesn't change.

That argument has two issues: First, not all US traffic lights have order, as single-light ones replace stop signs in some (mostly suburban/rural) areas. Second, light position is still hard to discern at night.

My personal take: the red and yellow hues in traffic lights are often indistinguishable for those of us with red-green colorblindness.

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