Hacker News Reader

Comment by labster | Hacker News Reader

If you're driving in Japan, you're likely to be eaten by a grue light. That said, we actually mix some blue into modern green lights, so that colorblind people can distinguish the two colors.

In official CalTrans terminology, the yellow lights are called "amber lights" -- so we have our own weirdness in the U.S.

View on HN

The colour-blindness explanation is a bit of a red herring in places outwith Japan.

One can be totally red-green colour blind and still have no problem with traffic lights in the U.K., for example. The stop lights are the ones at the top and the go lights are the ones at the bottom. Colour blindness, after all, does not prevent one from detecting which light is lit.

In countries where there might be both horizontal and vertical arrangements, this would not apply. But the U.K. only permits a single, vertical, layout for traffic lights with stop lights above go ones.

If it's dark you can't see which light is at the top or bottom. You see a lit light, but can't see the unlit lights.

The black boards with white borders are a relatively recent addition to traffic lights, and they're not fitted to all UK lights, which is why our green has a bit of blue added.

No. The official position (as quoted by someone who actually asked the Highways Agency) is that the ability to actually tell red from green is not necessary for traffic lights. The sequence of lights and the positions of the lights is adequate.

* http://andrewhenley.co.uk/2012/02/colour-blindness-and-red-t...

The statutory instrument that governs traffic lights does not actually state anything more specific than "green", so claims that "our green has a bit of blue added" are not borne out by the regulations that actually apply, which do not mandate any such thing. (The regulations are specific about sizes in mm and timings in s, with allowed margins of variability, so the lack of specifics as to colour is not simply because the regulations are generally vague.) Since it isn't a mandate in the first place, explanations that this is mandated for the benefit of the colour blind are ill-founded.

* http://legislation.gov.uk/uksi/2016/362/schedule/14/part/2/m...

The idea that colour changes are done to help the colour blind ironically comes to newspapers and Internet discussions from outwith the U.K., from research and proposals in countries where there are multiple allowed arrangements and position alone is not an unambiguous determiner.

An easier explanation for more blue in traffic lights as they switch to LEDs is that blue LEDs are just boringly cheaper.

What? Blue LEDs used to be the most expensive. Say $1 per in bulk vs 2 cents for red or green. Has that gone full circle?

That is my understanding. Blue LEDs were last to be developed so they carried their R&D costs until more recently, but between efficiency breakthroughs and mass production improvements have passed through to being the cheapest to buy, especially in terms of lumens per dollar in places where you really need brightness such as traffic lights or overhead LED lighting in homes.

There is less blue in trafic lights as they switch to LEDs because green LEDs are i) dirt cheap and ii) don't require the coloured filter that the older halogen heads did.

Except SIRA make the filters added to halogen traffic lights, and they made the green filters a green blue specifically to help people with colourblindness see the difference.

This is specified in BS EN 12368.

All your government link says is "we don't want to admit there's a problem because then we'd have to pay for it".

Please note that I didn't claim "traffic light manufacturers are forced by UK law to add blue".

Amber, the color of traffic lights, waves of grain and... pretty much nothing else.

Reminds me of (grammatical) petrels:

https://www.kith.org/words/lists/petrels-list/

It's as if when modifiers and nouns sense they are dying in a language, they clutch on to one another for support, and eventually become like a single unit.

I think there's also a naturally-occurring substance that's amber-colored, but I can't remember what it's called.

I've never heard "amber" used as a modifier for "amber."

"Quick, bring me the amber amber, Amber!"

I didn't write the comment very clearly, but the petrels were a hint I was talking about language and usage, not simply objects in that part of the spectrum.

Ale is a notable omission, but the candidates dwindle.

Medications are usually dispensed in amber-colored vials and bottles (my Dad used to work for a company that manufactured them).

Also, amber used to be a common color (though maybe not as common as green, from my experience) for monochrome terminals and computer screens.

I still see the word used often enough that I don't think it should be declared dead quite yet...

That's because they're a mix of yellow and orange. They're called amber across Europe too, officially anyway. :)

Red, amber, green in the UK. Always amber and never yellow.

Conversely, UK railway signals are always yellow and never amber.

Not where I'm from, it's simply yellow.

Reply on news.ycombinator.com