No Amber LEDs for the UK?

[halowraith1]

What is it with the UK gov's insistence to use bright-white LED street lights? Amber LEDs are available, in fact I hear that they'll be getting trialled in some parts of New Zealand sometime. So what's stopping them from being used here? The current LEDs are WAY to intense, and not particularly kind to the eyes.

[Glen]

Why do you want orange streetlighting that only illuminates some colours, when white lighting is available?

[avtur]

The question is did we have amber/orange street lamps because we wanted them or were they a function of the lamp technology previously available?

There is clearly a difference between old tech street lamps and new LED's, personally I'm not sure that is a problem, it is certainly a change and we humans don't like change, but I'm not sure LED's are any less able to do the job than previous era orange street lamps. In fact they are far more efficient in their use of power and heavily tinted orange was not the best for seeing all colours.

[Mark Hewitt]

What is it with the UK gov's insistence to use bright-white LED street lights? Amber LEDs are available, in fact I hear that they'll be getting trialled in some parts of New Zealand sometime. So what's stopping them from being used here? The current LEDs are WAY to intense, and not particularly kind to the eyes.

Because the old orange street lighting totally sucked. The new white light is way better in every way.

[Chris Bertram]

The question is did we have amber/orange street lamps because we wanted them or were they a function of the lamp technology previously available?

There is clearly a difference between old tech street lamps and new LED's, personally I'm sure that is a problem, it is certainly a change and we humans don't like change, but I'm not sure LED's are any less able to do the job than previous era orange street lamps. In fact they are far more efficient in their use of power and heavily tinted orange was not the best for seeing all colours.

The French used to insist on car headlamps being tinted yellow, for a reason - at night, the human eye is supposed to be more sensitive to light in that part of the spectrum, and they felt it aided clarity of vision. They were, of course, in a minority, and eventually joined the rest of the world in having white headlamps. Sodium lighting is also quite amber/yellow in colour, and yes, that is a function of the chemical composition of the bulbs, as anyone who remembers sodium being set alight in school chemistry lessons can tell. But perhaps that was one of the reasons for the choice of sodium as the predominant street light technology over trying to develop the blue/white mercury lighting into more powerful units. I'm not entirely convinced by the rush to pure white LED lighting - but we'll see from road safety stats over the coming years whether I'm right or wrong.

[Nwallace]

Living in an area that's now lit with various white options; visibility and colour distinction are considerably better under a white light than the old yellow.

[halowraith1]

Why do you want orange streetlighting that only illuminates some colours, when white lighting is available?

because they give me a headache, that's why. the glare is horrible and having one outside your bedroom window isn't particularly fun. if someone's more interested in colour rendering than looking where they're going, then they shouldn't be driving.

there's a reason why so many people don't like them.

[avtur]

.... if someone's more interested in colour rendering than looking where they're going, then they shouldn't be driving ....

People are interested to see what's around them precisely because they are driving, if that is helped by white LED's then so much the better. I have an LED street lamp directly across the road from my bedroom window, I really don't see the problem.

[Pendlemac]

Why do you want orange streetlighting that only illuminates some colours, when white lighting is available?

because they give me a headache, that's why. the glare is horrible and having one outside your bedroom window isn't particularly fun. if someone's more interested in colour rendering than looking where they're going, then they shouldn't be driving.

there's a reason why so many people don't like them.

Sounds like there is a problem with the beam cutoff. Correctly set up the beam should go more or less straight down with very little overspill.

I help out at an astronomy centre and they have just replaced some of the local streetlights with LEDs. There is now zero illumination of the hill behind them while the road is better lit. ( The reason for being happy that the hill is unlit is that the reflected light from it would give a glow effect at the bottom of images taken with a long exposure. )

[Johnathan404]

I move between orange sodium and white LED regions and much prefer the white LED, as do "so many people". The only complaint I had when the council changed the lighting outside my house is that I no longer had my garden path lit up for free, although I appreciate the reduced overspill was one of the main points.

So the far the vague concerns raised read like a meme involving a Simpsons character and a cloud.

[Fenlander]

The only complaint I had when the council changed the lighting outside my house is that I no longer had my garden path lit up for free, although I appreciate the reduced overspill was one of the main points.

The one outside ours casts a shadow via it's own pole on our driveway but at the same time the sideways scatter shines straight in out bedroom window.
The motley old collection of mixed lights that are on the street to the rear of us light our rear garden but they're on that great council energy efficiency wheeze - they get turned off when it's dark (ie midnight).

[Northern Lights]

What is it with the UK gov's insistence to use bright-white LED street lights? Amber LEDs are available, in fact I hear that they'll be getting trialled in some parts of New Zealand sometime. So what's stopping them from being used here? The current LEDs are WAY to intense, and not particularly kind to the eyes.

We don't need "amber".....way too "warm".

What the main ruckus is about:- that we need nothing higher than 3000K colour temp in most residential & quiet side roads for street lights....

However most councils are fitting 4000K & 6000K LED street lights as when you go higher in colour temp (K) you get slightly better efficiency...

Again these calculations tend to bias towards the fact that as you go higher in the colour temp of a light you are forcing the human eye to use more of the "daylight" part of the eye sensors.....& as the human eye "perceives" blue rich light (& therefore higher colour temps) as "daylight" & "brighter"...thus enabling the specifiers to use a dimmer & lower powered version..& thus more "eco"...

Practical example:- get a row of LED bulbs the same power, spec etc..one of 2000K, 3000K, 4000K, 6000K...….as you look along the row from the lowest K to the highest K, the higher K ones will look brighter...but its the same lm & power as the 2000K which will look way dimmer....all due to colour temp..

The other problem is that the higher the colour temp the more the difference between the lit & unlit areas on a street...& again due to the human eyes sensors we cannot see from the lit area into the unlit areas as easily as before under the old SON/SOX as under those lights we used more dark adapted sensors...

I like LED & have 2700K around the house & am getting some more....& I have LED DRLs on the car....just that there is a huge amount of badly designed & badly implemented stuff out there & the councils appear to follow the "save more cash" mantra at the expense of everything else....

PS several years ago a town on the Scottish borders fitted LED streetlights...all no more than 3000K...to meet the Dark Sky standards...

PPS I hate the LED stuff the council installed where I am..4000K & rubbish...even with huge blanking (total blank) plates facing my house the blue rich light which bounces of the building & road opposite causes more glare & lights up my bedroom more than the old HPS light did. In fact they used the same fitting & same blanking plates so I have NO light pool my side. Just they totally do not understand that blue wavelength light scatters more & bounces around off surfaces more than any other colour light wave...& these LEDs that they used are high blue as blue LED with a yellow phosphor coating...

[JohnnyMo]

The question is did we have amber/orange street lamps because we wanted them or were they a function of the lamp technology previously available?

Low pressure sodium produced more illumination per unit of electricity than any other technology at time time. Unfortunately the light was orange not white. Bright orange or dim white ?

[sotonsteve]

The debate, as others have pointed out, should be more towards the colour temperature. 3000k is a warm white that is pleasant and acceptable to most. 4000k and greater is considered to be harsh and cold to many, and has been the focus of much criticism.

Councils seem keen to use higher colour temperatures as they are fractionally more efficient, and fractionally is apparently enough justification to overrule other factors like creating a pleasant street scene. We all know the perils of councils, designers and computer design packages. That's how before the recession we ended up with lighting schemes having increasingly more columns, taller columns and higher wattage lanterns, because it's "what the computer says" or "what the standards say", and common sense went out the window. The recession put common sense back into street lighting, such as in the Hampshire PFI where they decided "you know what, let's not increase the number of columns on residential streets, and lets keep the wattages low, because even though we won't meet the British Standards it will still be an improvement over what is existing". That's my point, the idea of using high colour temperature LED is a clinical decision, just as in years gone by lighting designers were obsessed by Lumens and the more the better. Speaking of which, not all areas got the memo that you can tone down the brightness of lighting if you use a white light source. On the motorways near me the new LED lighting is perceivably much brighter than the existing SON lighting. You may say that's not a bad thing, but the existing lighting wasn't poor. It would be an improvement if it was white and as perceivably as bright before. It is overkill for it to be perceivably brighter. Yes, LED saves energy compared with SON, but it could save even more energy if it wasn't cranked up to extreme brightness levels. And whilst on the subject of motorways down my way, the LED lighting switches on well in excess of half an hour before any of the local authority sodium and fluorescent lighting. They must be using 100Lux switching (suitable for high wattage SOX) compared with the typical 20-35Lux that local authorities use now.

Other countries are quite wary of the colour temperature debate. I've seen suggestion that in Dutch speaking Belgium, the specification is for cool white on motorways and major highways and warm white everywhere else. That seems like a sensible way of doing things.

[scynthius726]

I find the old sodium lights spread the light a bit better. When sodium lights are replaced like-for-like with LEDs you tend to end up with alternate bright and dark patches.

[Northern Lights]

I find the old sodium lights spread the light a bit better. When sodium lights are replaced like-for-like with LEDs you tend to end up with alternate bright and dark patches.

& this statement is where you get into trouble as what you are seeing is actually different to the on paper specs..& thus as usual the general public get confused...

yes there is a chance that the LED housing will have better & sharper cut off compared to the sodium...

BUT...all things equal it is again the higher colour temp of the LED which causes our eyes to see "perceive" a greater contrast between the lit & unlit areas...thus less "bleed" of the light into the unlit areas...so as you say..more defined "pools" of light now under LED ..& you struggle to see beyond the pool of light, where as under the sodium you can see beyond the pool of light easier as the human eye is using more "dark adapted" sensors due to the lower colour temp...

[Jonathan24]

I find the old sodium lights spread the light a bit better. When sodium lights are replaced like-for-like with LEDs you tend to end up with alternate bright and dark patches.

& this statement is where you get into trouble as what you are seeing is actually different to the on paper specs..& thus as usual the general public get confused...

yes there is a chance that the LED housing will have better & sharper cut off compared to the sodium...

BUT...all things equal it is again the higher colour temp of the LED which causes our eyes to see "perceive" a greater contrast between the lit & unlit areas...thus less "bleed" of the light into the unlit areas...so as you say..more defined "pools" of light now under LED ..& you struggle to see beyond the pool of light, where as under the sodium you can see beyond the pool of light easier as the human eye is using more "dark adapted" sensors due to the lower colour temp...

That is exactly the same criticism I have of LED retrofit lighting, or at least the way it is being installed i.e. there are a lot more dark patches when SON is replaced with LED on the same columns. Having said that, what you say makes sense, but councils should not be rushing to replace all SON/SOX with LED, without considering this consequence and dealing with it adequately (even though LED does make a lot of sense financially and asethically in other ways).

[Reading]

I find the old sodium lights spread the light a bit better. When sodium lights are replaced like-for-like with LEDs you tend to end up with alternate bright and dark patches.

& this statement is where you get into trouble as what you are seeing is actually different to the on paper specs..& thus as usual the general public get confused...

yes there is a chance that the LED housing will have better & sharper cut off compared to the sodium...

BUT...all things equal it is again the higher colour temp of the LED which causes our eyes to see "perceive" a greater contrast between the lit & unlit areas...thus less "bleed" of the light into the unlit areas...so as you say..more defined "pools" of light now under LED ..& you struggle to see beyond the pool of light, where as under the sodium you can see beyond the pool of light easier as the human eye is using more "dark adapted" sensors due to the lower colour temp...

That is exactly the same criticism I have of LED retrofit lighting, or at least the way it is being installed i.e. there are a lot more dark patches when SON is replaced with LED on the same columns. Having said that, what you say makes sense, but councils should not be rushing to replace all SON/SOX with LED, without considering this consequence and dealing with it adequately (even though LED does make a lot of sense financially and asethically in other ways).

I absolutely agree with this - some residential roads are like driving through strobe lighting now - also the LED is less diffuse than the older lighting and so is more likely to cause dazzle/glare when it hits small scratches on a motorcycle visor

[Patrick Harper]

Living in an area that's now lit with various white options; visibility and colour distinction are considerably better under a white light than the old yellow.

SOX wattages were never decided on for given applications based on the normalised efficiency of lumens per watt and the light source's scotopic content, they were always specified based on lumens per watt alone. Seeing as the human eye is rather terrible at perceiving yellow night under scotopic conditions, SOX installations tended to be nowhere near powerful enough for the job (e.g: we should have been using 90W lamps in residential settings, not 35/55W). Whether white light is safer than yellow light based on colour alone is a topic I've never found a source substantial enough to prove either way.

With newer knowledge and technologies it should be possible to test yellow light, with the appropriate compensation for lower perceived scotopic content, against white LEDs and put the subject to bed.

[sotonsteve]

[SOX installations tended to be nowhere near powerful enough for the job (e.g: we should have been using 90W lamps in residential settings, not 35/55W).

That is your opinion, but I think the vast majority of people would disagree with you. 35W SOX was perfectly bright enough for residential settings. The fact that in a lot of areas we now have stuff like 16W LED with reduced luminous output compared with 35W SOX is testament to this.