# Cree $99 LED streetlight could come to a city near you



## glock_nor_cal (Aug 8, 2013)

http://m.cnet.com/news/cree-$99-led-streetlight-could-come-to-a-city-near-you/57597262?ds=1


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## sgt253 (Aug 8, 2013)

Have some around my area. Can definitely see the road much more clearly. Nice to see efficiency and productivity are not diametrically opposed to being "greener". Here comes the future...


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## EZO (Aug 8, 2013)

This product could be a game changer. They claim it will pay for itself within one year. Where I live many towns have had lengthy ongoing debates about whether it is worthwhile to invest in energy efficient street light upgrades. Some smaller towns have shut off street lights in less frequented parts of town to save money. With this technology, the upgrades become a no brainer, assuming they have reliability and durability.







P.S. I wonder how long it will take for this thread to get moved over to "fixed lighting" where it likely belongs? :tsk:


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## tobrien (Aug 8, 2013)

EZO said:


> This product could be a game changer. They claim it will pay for itself within one year. Where I live many towns have had lengthy ongoing debates about whether it is worthwhile to invest in energy efficient street light upgrades. Some smaller towns have shut off street lights in less frequented parts of town to save money. With this technology, the upgrades become a no brainer, assuming they have reliability and durability.
> 
> 
> 
> ...



what's the D-ring for that's just barely visible in the pic? hanging city/municipal banners?


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## EZO (Aug 8, 2013)

tobrien said:


> what's the D-ring for that's just barely visible in the pic? hanging city/municipal banners?



Good question! I don't know for sure, but it looks like it might be for easy panel access to the innards of the device. Grab the ring, twist counterclockwise half a turn and pull? I guess you could hang something from it depending on how hot it gets in that spot.


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## GordoJones88 (Aug 8, 2013)

I have local city parks that upgraded the parking lots to LEDs. But the park sidewalks are still the old orange dim incans. You can see the parking lot lights a mile away they are so stupid bright, like football field bright.


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## GunnarGG (Aug 9, 2013)

In my town they have changed out some of the lights to LED.
A couple of years ago there was a poll about what type of light people preferred.
Along the beachwalk there was about 8 different types of lights, I think 2 or 3 of them was LED.
I didn't vote myself and I can't recall ever seeing any result from the poll.
I do remember that when I walked there I actually thought the LED lights gave more glare than the others when you aproached them.
That could probably be improved by some type of diffuser or shade.


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## markr6 (Aug 9, 2013)

Hopefully they use a nice warm tint. We don't want every lit area in the city looking like a gas station or operating room!


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## GordoJones88 (Aug 10, 2013)

markr6 said:


> Hopefully they use a nice warm tint. We don't want every lit area in the city looking like a gas station or operating room!



The warmer tint LED lights have reduced output efficiency so will likely not be the top choice.


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## RedForest UK (Aug 10, 2013)

There will be two versions, one will be 4000k.


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## EZO (Aug 10, 2013)

RedForest UK said:


> There will be two versions, one will be 4000k.



Yes, they are available with 4000K or 5700K modules and will come in three housing styles with seven different variations, a selection of optics types with optional backlight shields and three mounting options.


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## offthetrail (Aug 10, 2013)

I just upgraded all of our exterior lighting at work to LED. I went with Beacon products, http://www.beaconproducts.com/. 77 lights in total, replacing high pressure sodium and metal halide. The payback (ROI) was 3.7 years, which is not too shabby at all.
I went with 5000k. The color is so much better than before, and it is much brighter. That, along with the $19K per year electrical savings, I was super excited. Cities could save tons of money if they switched.


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## fnj (Aug 10, 2013)

Mods, why is this thread in the LED Flashlights section??


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## PhotonWrangler (Aug 10, 2013)

I would like to see some pictures of these Crees in use.


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## EZO (Aug 10, 2013)

PhotonWrangler said:


> I would like to see some pictures of these Crees in use.



This is an XSP streetlight installation in Hollywood, California. The photo is from CREE's website.

Looks pretty good if the photo is accurate.


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## PhotonWrangler (Aug 10, 2013)

That does look pretty good, particularly the color quality, although one wonders why they had to resort to a time exposure for the photo.


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## Norm (Aug 10, 2013)

fnj said:


> Mods, why is this thread in the LED Flashlights section??



Because that is where it was posted, it has been moved now.

In future if you want to bring something to the attention of staff please report the post and request it be moved, don't rely on a staff member seeing your post.

Norm


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## EZO (Aug 11, 2013)

PhotonWrangler said:


> That does look pretty good, particularly the color quality, although one wonders why they had to resort to a time exposure for the photo.



I think you bring up a good point PW. A time exposure might look good but it doesn't (or at least _may_ not) give an accurate representation of what the street really looks like under these lights.


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## tobrien (Aug 11, 2013)

EZO said:


> I think you bring up a good point PW. A time exposure might look good but it doesn't (or at least _may_ not) give an accurate representation of what the street really looks like under these lights.



i agree with you


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## SemiMan (Aug 11, 2013)

So what would be a suitable exposure? 1/100? 1/1000? You need exposure time to reduce noise and get depth of field. The HPS section looks fairly even too.


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## PhotonWrangler (Aug 11, 2013)

I agree, they do have to compensate for the noise floor of the camera's sensor. Having said that, the sodium lights in the background look ever so slightly overexposed to my eyes, so the Crees might be a bit dimmer than they appear in this photo. Although the vastly improved CRI of the LEDs over sodium lamps might make up for this somewhat.

Does anyone live near this area who can give us their own impressions of the comparative brightness?


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## EZO (Aug 11, 2013)

SemiMan said:


> So what would be a suitable exposure? 1/100? 1/1000? You need exposure time to reduce noise and get depth of field. The HPS section looks fairly even too.



One can't arbitrarily assign a shutter speed without knowing other factors such as the ISO setting, the speed and focal length of the lens and the aperture you've chosen. Increasing exposure times will increase noise levels rather than reduce them regardless of which sensor one is using or its particular noise characteristics. Depth of field, of course, would be a factor of focal length and aperture but depth of field is only a minor issue in a wide street scene image like this if the purpose is to show the ambient lighting produced by the product.


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## SemiMan (Aug 11, 2013)

Long exposure would result in lower ISO which in a night scene almost always means less noise. 

The foreground is very close in the picture so depth of field comes into play for focus. Depth of field means higher f-stop requiring longer exposure for less noise as opposed to higher ISO.

Poor focus does not cut it for marketing shots.

Sent from my Nexus 4 using Tapatalk 4


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## EZO (Aug 11, 2013)

Hey, I found a better version of the CREE photo.


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## PhotonWrangler (Aug 11, 2013)

Well they've wiped the EXIF data from the image. All we know is that it was passed through Adobe Photoshop CS5 on a MAC, so we only have the relative brightness of the individual light sources in the picture to go on.

**Edit** Just saw Ezo's larger version of the picture - thanks! This one has no EXIF data at all, so I'm thinking this was the source photo that was later resized in Photoshop for their website.

Looking at the list of case studies on their website, none of them are within driving distance for me. Dang.


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## EZO (Aug 11, 2013)

SemiMan said:


> Long exposure would result in lower ISO which in a night scene almost always means less noise.
> 
> The foreground is very close in the picture so depth of field comes into play for focus. Depth of field means higher f-stop requiring longer exposure for less noise as opposed to higher ISO.
> 
> ...




Don't want to get into a snit about how digital photography works but long exposures don't "result" in different ISO numbers. Longer exposure increases noise, regardless of ISO selection, period! Using a higher ISO would not be an issue in this instance with a modern professional level camera. The focal length and speed of the chosen lens would likely be more important in making an image like this one. Depth of field in a photo like this hardly equates with "poor focus" or effectiveness for marketing.


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## EZO (Aug 11, 2013)

PhotonWrangler said:


> Looking at the list of case studies on their website, none of them are within driving distance for me. Dang.



I looked at those too, but FWIW none of these case studies are for this new $99 streetlight we are discussing. I don't know much about CREE's other streetlight offerings but I guess they've been around long enough to actually do case studies.


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## PhotonWrangler (Aug 11, 2013)

Regardless of the length of exposure, all we really have to go on is the relative brightness of the individual light sources in the photo. Looking at the amount of blooming in the green traffic lights, the sodium lamps and the Shell logo on the gas station sign, then comparing that to the markedly reduced blooming on the LEDs which are closer to the camera, I'm left to guess that the shot was overexposed a tiny bit to bring up the brightness on the LEDs.


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## EZO (Aug 11, 2013)

PhotonWrangler said:


> Regardless of the length of exposure, all we really have to go on is the relative brightness of the individual light sources in the photo. Looking at the amount of blooming in the green traffic lights, the sodium lamps and the Shell logo on the gas station sign, then comparing that to the markedly reduced blooming on the LEDs which are closer to the camera, I'm left to guess that the shot was overexposed a tiny bit to bring up the brightness on the LEDs.



I think your observations are probably on the money. On the other hand, it is possible that the LED streetlights have the optionally available backlight shields installed so they may not "bloom" so much because of that and the more directional nature of LEDs. We are left only to make our best guess.


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## SemiMan (Aug 11, 2013)

EZO said:


> Don't want to get into a snit about how digital photography works but long exposures don't "result" in different ISO numbers. Longer exposure increases noise, regardless of ISO selection, period! Using a higher ISO would not be an issue in this instance with a modern professional level camera. The focal length and speed of the chosen lens would likely be more important in making an image like this one. Depth of field in a photo like this hardly equates with "poor focus" or effectiveness for marketing.



Actually you started the snit with a not so accurate post so let's get into it ....

1) Increasing ISO always increases noise. Increasing ISO pure and simple increases analog gain which always results in noise.

2) Increasing exposure ONLY increases the number of photons that hit the sensor and hence the number of electrons generated. As a primary source of noise in digital imaging is Shot noise and is a factor of the square root of the electrons generated, then increasing exposure (to the limit of the full well capacity of the sensor) will Decrease noise. This must be balanced with dark current that generates dark noise. Shot noise is a pure physical process and cannot be avoided. Dark current is a factor of sensor design and newer sensors are better at controlling this. 

3) If you will look at the picture, everything is crisp and in focus, both near field and far field. This tells me it was not shot with a feal low F-Stop. Given that the lens was stopped down, then either ISO needed to be increased and/or exposure (and likely both).

4) Streets are only illuminated to approximately 10lux. Even with modern SLRs, that is dark enough that noise is an issue when you are stopped down enough to get good depth of field for focus for the whole scene.

5) Given that the photo was stopped down, ISO not super high to keep noise under control, and a scene of perhaps 10 lux, then you will need a reasonable length of exposure for the image to use the full range of the sensor again to keep noise low.


Oh, and for the record again longer exposure does not automatically result in more noise. Most of the time it will result in less because the alternative is higher ISO which does Always result in more noise.

Semiman


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## PhotonWrangler (Aug 11, 2013)

Mmmkay, going out on a limb here...

Looking at the headlight streaks for the cards facing the camera, I'm guessing each streak to be about 50 feet long. If we assume the speed limit to be 25mph 'cause it's a business district, and given that 25mph = 36.7 feet per second, I'm guessing a little under 2 seconds exposure time.

I'm also guessing that I might be over-analyzing this picture a bit. :tinfoil:


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## EZO (Aug 11, 2013)

SemiMan said:


> Actually you started the snit with a not so accurate post so let's get into it ....
> 
> 1) Increasing ISO always increases noise. Increasing ISO pure and simple increases analog gain which always results in noise.
> 
> ...



I refuse to go down this path with you Semiman, for several reasons, not the least of which is that I don't wish to get this otherwise interesting and friendly thread closed. Using phrases like, _"Actually you started the snit with a not so accurate post so let's get into it ...."_ is provocative and poor form my friend. You seem like a guy who may have a lot of facts but not so much knowledge so I won't bite because I've seen too many of these sort of arguments on these boards. They never end well. Let's go back to talking about the CREE streetlight........like adults, shall we?


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## EZO (Aug 11, 2013)

PhotonWrangler said:


> Mmmkay, going out on a limb here...
> 
> Looking at the headlight streaks for the cards facing the camera, I'm guessing each streak to be about 50 feet long. If we assume the speed limit to be 25mph 'cause it's a business district, and given that 25mph = 36.7 feet per second, I'm guessing a little under 2 seconds exposure time.



I noticed that too and was thinking the same thing about the approximate exposure. All in all, I feel like the photo conveys a "normal" looking street scene at night when comparing all the different light sources but there's no way we can really know for sure.


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## PhotonWrangler (Aug 11, 2013)

EZO said:


> I noticed that too and was thinking the same thing about the approximate exposure. All in all, I feel like the photo conveys a "normal" looking street scene at night when comparing all the different light sources but there's no way we can really know for sure.



I agree completely. I really want to see these in person. I've been a fan of Cree products for a long time and I want to see this technology succeed in this application, especially from the standpoint of color rendering. I hate sodium lamps and their weird color spectrum. I understand that HPS is very efficient but they render a lot of things as black, including roadside vegetation.

I once worked with a guy who spent some time on the Lucalox(tm) development team. Apologies to him, but I'm hoping that HPS days are numbered for street lighting.


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## SemiMan (Aug 11, 2013)

EZO said:


> I refuse to go down this path with you Semiman, for several reasons, not the least of which is that I don't wish to get this otherwise interesting and friendly thread closed. Using phrases like, _"Actually you started the snit with a not so accurate post so let's get into it ...."_ is provocative and poor form my friend. You seem like a guy who may have a lot of facts but not so much knowledge so I won't bite because I've seen too many of these sort of arguments on these boards. They never end well. Let's go back to talking about the CREE streetlight........like adults, shall we?



I will state again that you started down the path with the "I don't want to get into a snit ... and proceeding to get into a snit". Your post was inaccurate. Increasing exposure time does not inherently increase noise and within the limits of the amount of light available for the scene and the required F-Stop to get the depth of field desired (as opposed to reducing light --- important during the day, not at night), increasing exposure is the only way to decrease noise as increasing exposure has far less impact on noise than increasing ISO.

In terms of knowledge, unless you have designed cameras, I am guessing my knowledge in the area is equal or better than yours.

And yes I do have an issue with people on boards spreading erroneous information.


In terms of time exposure, it does not degrade the image and was pretty much required to get a "nice" image. No perfect shutter speed or exposure really exists to simulate human vision since our vision dynamically adapts to the scene. Generally of most importance for comparison pictures is consistency in the before and after or right and left.

Semiman


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## PhotonWrangler (Aug 11, 2013)

Perhaps there should be a separate thread for camera image sensors. Can we move on and get back to the topic of Crees please?


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## SemiMan (Aug 11, 2013)

One thing to note in this picture which is a common feature (most see it that way) of LED lighting is the tighter optical control and limited back light. If you look at the HPS section, the vertical surfaces of the building are well lit. In the LED sections, the building face is dark. Given the width of the sidewalks, the amount of back-light may even be a little low as some sidewalks pieces in the LED section look fairly dark.

Semiman


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## PhotonWrangler (Aug 11, 2013)

SemiMan said:


> One thing to note in this picture which is a common feature (most see it that way) of LED lighting is the tighter optical control and limited back light. If you look at the HPS section, the vertical surfaces of the building are well lit. In the LED sections, the building face is dark. Given the width of the sidewalks, the amount of back-light may even be a little low as some sidewalks pieces in the LED section look fairly dark.
> 
> Semiman



Good catch, Semiman. Ezo mentioned this also in relation to the blooming (or lack thereof) on the LED fixtures. This suggests that the LED fixtures have less "excess light" (for lack of a better term) and all of it needs to be tightly focused downwards to achieve the goals. Look at the little puddles of white light on the street surface, more noticeable on the right side. This also suggests some sort of focusing mechanism.

One side benefit of this approach is less light pollution for observatories. I've noticed that large cities always have an orange cloud hanging over them at night - sodium orange. It's so bad that I was actually able to use this orange cloud to navigate when I got lost in the open countryside one night. I just followed the orange cloud back to the city.


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## jtr1962 (Aug 11, 2013)

An easy way to end the debate about the picture being overexposed to make the LED streetlights seem brighter is to look at the part of the street lit by the sodium lamps. If anything, it looks _darker_ than the street lit by the LEDs. If the photo was overexposed to make the LED lighting appear brighter (presumably because it wasn't as bright as the sodium lighting), the relative light levels would still be the same, and the sodium lighting would appear brighter. Because the sodium lighting isn't brighter, I'm left to conclude that the LED street lighting provides similar or better lighting levels. Moreover, the light quality is much better. The part of the street lit by sodium lighting looks ugly, uninviting, and muddy. You can't even really distinguish yellow street markings from white ones. The part lit by LED looks much more natural. The lighting is also more even.


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## Norm (Aug 11, 2013)

My warning has been deleted, both parties concerned are aware that they need to improve how they communicate. Let's play nicely. 

Norm


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## jtr1962 (Aug 11, 2013)

markr6 said:


> Hopefully they use a nice warm tint. We don't want every lit area in the city looking like a gas station or operating room!


It depends upon how warm. 4000K is OK. Anything much warmer starts to get into the realm where depth perception and peripheral vision suffer, not to mention colors start to look distorted. One of points of LED streetlighting over the alternatives is that it's much more aesthetically pleasing. If you make it too warm, you loose that advantage. You also lose some efficiency advantages also.


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## PhotonWrangler (Aug 11, 2013)

There is a gas station in my area that converted their canopy lighting to LEDs. I have no idea who the manufacturer is, and the color temperature looks to be around 5000k. The light is at least as bright as their former mercury vapor lighting if not a little brighter and much whiter. There is also a college campus in my area that's using LED post lights in the pedestrian areas around the campus. They're not quite as bright as HID lamps but they're much closer to the ground so the brightness at ground level is adequate.


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## SemiMan (Aug 11, 2013)

PhotonWrangler said:


> Good catch, Semiman. Ezo mentioned this also in relation to the blooming (or lack thereof) on the LED fixtures. This suggests that the LED fixtures have less "excess light" (for lack of a better term) and all of it needs to be tightly focused downwards to achieve the goals. Look at the little puddles of white light on the street surface, more noticeable on the right side. This also suggests some sort of focusing mechanism.
> 
> One side benefit of this approach is less light pollution for observatories. I've noticed that large cities always have an orange cloud hanging over them at night - sodium orange.




As a WAG, I would guess the picture was taken from the boom truck being used to install the lights and it looks like from about the height of one of the street lights.

Most modern fixtures would be full cutoff and Dark-Sky compliant. They will have very little light above 80% from vertical hence why no blooming. The HPS lights would be the older style sag-glass lenses and will have significant light output still at high angles. There are HPS lights that are full cutoff/Dark Sky as well and similarly would not bloom.

JTR, I found the HPS section in the picture to look as bright. I would not be surprised at all by that as often the HPS section is overlit due to poor lighting control but also when the bulbs are new due to the built in factor for their depreciation.

Semiman


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## SemiMan (Aug 11, 2013)

jtr1962 said:


> It depends upon how warm. 4000K is OK. Anything much warmer starts to get into the realm where depth perception and peripheral vision suffer, not to mention colors start to look distorted. One of points of LED streetlighting over the alternatives is that it's much more aesthetically pleasing. If you make it too warm, you loose that advantage. You also lose some efficiency advantages also.



I am not completely bought into 4K and up for exterior, especially for certain urban street scenes. There is a lot of conjecture about higher CCTs being better, but actually little scientific study or evidence to back it up in terms of increased safety once you are beyond mesopic levels which most street scenes are lit at. JTR, I know you have special concerns being a cyclist commuter and there could be validity when looking at potholes and the like where shadowing could create lesser than mesopic lighting levels. We do need to consider the glare of higher CCT (blue at least) and environmental impacts. It is not a simple one dimensional argument.

Semiman


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## jtr1962 (Aug 11, 2013)

SemiMan said:


> I am not completely bought into 4K and up for exterior, especially for certain urban street scenes. There is a lot of conjecture about higher CCTs being better, but actually little scientific study or evidence to back it up in terms of increased safety once you are beyond mesopic levels which most street scenes are lit at. JTR, I know you have special concerns being a cyclist commuter and there could be validity when looking at potholes and the like where shadowing could create lesser than mesopic lighting levels. We do need to consider the glare of higher CCT (blue at least) and environmental impacts. It is not a simple one dimensional argument.


Glare is one side of the argument but that could mostly be alleviated with streetlight designs which only project light down, perhaps by stringing linear arrays between lamp posts instead of just having a discrete fixtures (and the linear array deals with heat much better as a bonus).

The other side is low CCT kills peripheral vision. Peripheral vision is important at the urban driving speeds of 15 to 30 mph. There's also the aesthetic argument. Low CCT just makes things look muddy, dingy, old, and ugly. 3000K may be better than sodium lighting, but it's just a lesser degree of the same set of problems. It's only once you get to 4000K and beyond at streetlighting levels that white starts to look white. Remember it's important to be able to tell yellow lines from white lines when driving, and you really can't easily do that until CCT reaches about 4000K.

On another note, higher CCTs would make even more sense if we increased street lighting levels. Yes, for now power usage is a constraint, but I'm envisioning some future where we have cheap electricity from, say, fusion. In such a future, especially with ultra efficient LEDs, there's no reason we can't light streets to photopic levels, perhaps even to light levels similar to a cloudy day (>1000 lux).


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## PhotonWrangler (Aug 11, 2013)

I like the idea of stringing linear arrays. I remember seeing some old fluorescent streetlights where the lamp extended from the curb into the street area; if we turned those fixtures 90 degrees we'd have something approaching this idea. They would probably have to remain as solid, fixed strings as any swaying in the wind would create confusing moving shadows at night.


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## SemiMan (Aug 11, 2013)

PhotonWrangler said:


> I like the idea of stringing linear arrays. I remember seeing some old fluorescent streetlights where the lam,p extended from the curb into the street area; if we turned those fixtures 90 degrees we'd have something approaching this idea. They would probably have to remain as solid, fixed strings as any swaying in the wind would create confusing moving shadows at night.




Linear lights are a nice idea, but the mounting to ensure alignment could be difficult and it means many more points of failure and likely would end up being more costly.

Anything beyond 4000K starts to look blueish, anything below red/yellowing. 3500K would still be predominantly white especially at night.

In terms of peripheral vision there is validity to this, but a little bit of blue enhancement, and 3500K may be enough with a standard blackbody curve to accomplish this.

I for one, and I expect I am part of a significant majority, hope that we never ever light the exterior to 1000lux. That would destroy circadian rhythms for all things non-human, destroy any concept of dark skies, etc. and it would not matter what angle of light was used.

Semiman


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## jtr1962 (Aug 11, 2013)

SemiMan said:


> I for one, and I expect I am part of a significant majority, hope that we never ever light the exterior to 1000lux. That would destroy circadian rhythms for all things non-human, destroy any concept of dark skies, etc. and it would not matter what angle of light was used.


I'm thinking mainly of using those light levels in cities where there's not much in the way of non-humans to worry about. Then again, taking an opposite approach, if Google's idea of self-driving cars works and nobody is allowed to drive any more, we don't need to light the streets at all, just the sidewalks, crosswalks, and bike paths. The latter three can be lit to much lower levels because the eye will remain dark adjusted without bright ambient streetlight. Oh, and cars won't need lights either, the theory being they can "see" pedestrians/cyclists via IR/radar, and pedestrians/cyclists don't need to see cars because the cars will always defer to them.


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## SemiMan (Aug 11, 2013)

jtr1962 said:


> I'm thinking mainly of using those light levels in cities where there's not much in the way of non-humans to worry about. Then again, taking an opposite approach, if Google's idea of self-driving cars works and nobody is allowed to drive any more, we don't need to light the streets at all, just the sidewalks, crosswalks, and bike paths. The latter three can be lit to much lower levels because the eye will remain dark adjusted without bright ambient streetlight. Oh, and cars won't need lights either, the theory being they can "see" pedestrians/cyclists via IR/radar, and pedestrians/cyclists don't need to see cars because the cars will always defer to them.




I see us moving more towards the latter, not the formal. I can see us having less light, not more. People like the dark ... to a point.

Semiman


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## idleprocess (Aug 11, 2013)

jtr1962 said:


> Then again, taking an opposite approach, if Google's idea of self-driving cars works and nobody is allowed to drive any more, we don't need to light the streets at all, just the sidewalks, crosswalks, and bike paths.



With all the vulnerabilities that automakers refuse to engineer out of CAN bus implementations, I doubt we need to worry about self-driving cars being deployed en masse anytime soon.


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## degarb (Aug 12, 2013)

GordoJones88 said:


> The warmer tint LED lights have reduced output efficiency so will likely not be the top choice.




I would buy one for work, if it were 10k lumens (double that output/efficiency would be ideal) and $99. 

If Philips truly gets low cost 200 lpw lamps to replace office tube cfls, by next year. It would be logical that they could use the technology in streetlighting. Win, win, even if you early adopt.


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## Swireless2013 (Aug 13, 2013)

I wonder how many cities are planning to implement these in the near future. I would live to see these bring down energy consumption in my city. We have wasted enough money on other things. These could go a long way if implemented across the entire town.


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## degarb (Aug 14, 2013)

PhotonWrangler said:


> One side benefit of this approach is less light pollution for observatories. I've noticed that large cities always have an orange cloud hanging over them at night - sodium orange. It's so bad that I was actually able to use this orange cloud to navigate when I got lost in the open countryside one night. I just followed the orange cloud back to the city.



Remarkable stuff in this thread: S. advocating 3500 (not sold on 4000k?), and Cree Streetlighting being responsible for those over age 30-statistically incapable of simultaneously driving and using their gps- being stranded en masse on the outskirts of town.. Damn that Cree!! 

My world is upsidedown. Now, to slow down and get out of this CPF forum app, and figure out if the phone has a GPS, or I am screwed tonight in Amish Country. Wait! My cell signal dropping out, no offline navigation with Google Maps. Well, at least, they still have payphones in the country. Right?


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## ronan_zj (Aug 22, 2013)

No LED upgrades in San Francisco and bay area, and I wish they will do it coz it really dark here at night


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