Energy saving street lamps?

[Belrmar]

https://youtu.be/mi8eE_NEfHM


This video shows some radar mounted street lamps that dimm when no cars are going trough. The idea seems pretty good but are the numbers reliable or is just a gimmic?

[SparkyFX]

Interesting of course, it does however contain some conflicting assumptions:

• headlights in cars are mandatory
• if the road is rarely used (incl. pedestrians), whats the point in having it illuminated at all to then save the cost for lighting, or having it lit for animals crossing the road
• can not be retrofitted to discharge type lamps (they need a couple of minutes warm up before full brightness), therefore includes installation cost for new lamp type
• radar performance during rain/fog/snow (aka "when you need street lamps") might vary, depending on type
• the higher efficiency means less heat to e.g. thaw ice or demist the housing, icicles falling on pedestrians heads might be a bad idea after all

[glarsson]

Up here in the northern part of Europe we have long periods of darkness during half of the year. We therefore have roads that are heavily used during the afternoon and evening but rarely used during the night. Saving energy on lighting during the night would save energy.

Retrofitting lamps has already started. It all started a couple of years ago due to the ban on mercury-based lamps. We replaced all of our street lamps (mercury based) with LEDs years ago. Why replace with terrible yellow sodium-based lamps or metal halogen lamps. They will probably also be banned due to poor efficiency.

When planning the LED retrofit we discussed lighting with the city light people and they revealed that when the LED retrofit is complete the next phase will be intelligent networked street lights allowing activation of lamps ahead of an approaching vehicle and other smart functions.

[Gregg]

I would think passive IR activation added to smart street lamps would be very beneficial.  If the lights could show up animals crossing the road ahead of the nominal headlight beam illumination, it could save a lot of crashes especially on slick roads.  Even hitting a rabbit on an icy road can cause a crash or an even worse crash trying to avoid it at the last minute.

[Someone]

Why replace with terrible yellow sodium-based lamps or metal halogen lamps. They will probably also be banned due to poor efficiency.

The current top end LEDs only just surpass sodium or metal halide lamps in efficiency:
https://en.wikipedia.org/wiki/Luminous_efficacy
They're unlikely to be banned for inefficiency when they remain some of the most efficient bright light sources available.

[glarsson]

When we had to replace our 125W mercury streetlights we had the options to install 125W sodium, 125W metal halide or 25W LED. The 25W LED is way brighter (on the ground where it matters) than the old mercury.

[coppice]

Why replace with terrible yellow sodium-based lamps or metal halogen lamps. They will probably also be banned due to poor efficiency.

The current top end LEDs only just surpass sodium or metal halide lamps in efficiency:
https://en.wikipedia.org/wiki/Luminous_efficacy
They're unlikely to be banned for inefficiency when they remain some of the most efficient bright light sources available.

Not only are sodium lamps efficient, but they also work well in fog. If you travel around areas of the UK where some streets have white lights and some have sodium, the streets lit by sodium are far easier to navigate in fog. I don't know the reason. Perhaps its something about the sensitivity of the eye at orange wavelengths.

[stj]

very true, but the bolshevik spy's dont like them because they arent "camera friendly"
they would rather film accidents than prevent them.

[Kleinstein]

...
Not only are sodium lamps efficient, but they also work well in fog. If you travel around areas of the UK where some streets have white lights and some have sodium, the streets lit by sodium are far easier to navigate in fog. I don't know the reason. Perhaps its something about the sensitivity of the eye at orange wavelengths.

In fog and mist the blue light is scattered more than other colors - this is why the sky overhead is blue and the sun going down is red. Yellow is a kind of medium to  long wavelenght and thus scattered less. It more an effect of having less blue than yellow being special. Red light also work well in the fog. If you have residual fog in the morning with already enough light, it helps to use sunglasses, as they reduce the blue light and this way visually reduce the fog.

For a similar reason the head light at cars in France have a yellow tint, reducing the blue and thus scattering in fog an with scratches on the windshield.

There is another effect in the eyes making it easier to adapt to low light if less blue light is present.

[floobydust]

It seems like a good idea, but some math says "not really".

Assume it's dark on average 1/2 the time gives 4,380hrs darkness/year.
Dimming to 1/5 power, 75% of the time, for 60% electricity savings.
At $0.10/kWhr 100W fixture, resulting electricity savings over 10 years $263.

But changing to new LED fixture costs $100, and $75 labour to install it.

So $88/10 years saved does not seem so great. With 50% dimming you break even after 10 years.

Interesting to look at more of the picture: GE Review of HPS, Induction and LED Street Lights, a bit old 2011. {URL contains brackets and BB code did not like, cut paste}
"https://www.ewh.ieee.org/r2/delaware_bay/0311/Street Lighting Comparrison IND HPS LED 2152011 [Compatibility Mode].pdf"


The ballast efficiency, optical efficiency, lumen depreciation due to aging need to be considered if comparing HPS to LED. It's not as good as it seems, from the armchair.

[nctnico]

Up here in the northern part of Europe we have long periods of darkness during half of the year. We therefore have roads that are heavily used during the afternoon and evening but rarely used during the night. Saving energy on lighting during the night would save energy.

They tried that over here but the lights are back on. Some sources say it was more expensive to turn the lights on/off when needed.

[cdev]

They could dim them a bit and save energy but not reduce their life.. coverage would still be the same.

[stj]

it's probably a slow slip into the world of total survailance eastern-block style.

https://intellistreets.com/Intellistreets%20Catalog.pdf


http://hub-group.com/products/smart-node/

[Red Squirrel]

This has crossed my mind too, that street lights should dim or shut off based on activity.  It could even be an averaging thing, it would detect activity via various sensors and if there is no activity for a set time they would dim.  If they start to detect activity they would ramp up.   You don't want them just going on and off constantly because of 1 car passing by as it would be quite annoying for home owners that live near them.   This of course would mean that sometimes you'd be driving in the dark, but it's not any different than driving on a highway.  Have to drive more carefully to avoid moose etc. 

Took my drone up at night for fun and you can see all the streets lit up with no cars.  Kind of a waste of energy.   The LEDs are much more efficient though.   




But then if you had them turn off, and an incident happens, then they'll try to sue the city...  so can't really win.

[Cyberdragon]

https://www.sepco-solarlighting.com/solar-street-lighting

Problem solved...

[SparkyFX]

Thats right, even under rough conditions modern xenon systems operate quite reliably and fast.

I never heard of a xenon lamp blowing up in normal operation (at least in vehicles). They rather leak gas and start shining violet or otherwise change colour. The "discharge" is meant as "high intensity discharge" type lamp vs. filament/incandescent/LED/....

The theory of operation is usually not compatible with many starts, electronic starters changed that a bit, yet the glass tube is only sealed so good and will probably have a limited amount of temperature cycles. Yet, Wikipedia states 30000 hours lifetime for various types used in street lamps.

Most people probably would describe white light as brighter, although there are some effects that are beneficial to night vision in the conventional street light.

[ciccio]

In a town near mine they installed solar powered street lamps (not inexpensive). After some times  someone stole all the solar panels and battery boxes..

[tszaboo]

We have these smart lights near where I work. Here is my experience.
They turn on way too late. Basically I'm driving 50 in a city, it turns on for me for a second or two, before passing the light. The morons also installed this near a pedestrian crossing, so it is in the dark, when cars approach it.
So you need to use high beams (also illegal in a city, but whatever, at least nobody dies) to check if there is someone on the walkway approaching the crossing.
Also, a bunch of time it just doesn't work. You can install these with software bugged all over the place. Nobody cares, because it is not mandatory for a city to have working lighting for the streets. And in reality, people could die because a null pointer exception made by an underplayed grad student untested code installed by a wannabe green city.

And they spend way to much money to save very little. It doesnt pay the installation cost over it's lifetime.
Producing the "smartness" has probably higher environmental impact, than producing the energy.
They dont do proper design for the LEDs, so it is too glaring, temporarily blinding you if you look at it, causing accidents.

It is a stupid idea.

By the way, future historians will describe the late 20, early 21 century like this: "They already had air conditioning, but nobody ever used it properly"

[mikeselectricstuff]

can not be retrofitted to discharge type lamps (they need a couple of minutes warm up before full brightness), therefore includes installation cost for new lamp type

Xenon lamps can ramp up very quickly, though being explosive and expensive. However, hybrid lamps (xenon+halide) also have pretty high initial intensity percentage but with much longer lifetime, though still have a good dangerous gas pressure even when cold.

On many discharge type lamps, lifetime is significantly related to the number of starts, so you don't want to be turning them on & off often. This is a big advantage of LEDs for "intelligent" streetlighting.

[nctnico]

This has crossed my mind too, that street lights should dim or shut off based on activity.  It could even be an averaging thing, it would detect activity via various sensors and if there is no activity for a set time they would dim.  If they start to detect activity they would ramp up.   You don't want them just going on and off constantly because of 1 car passing by as it would be quite annoying for home owners that live near them.   This of course would mean that sometimes you'd be driving in the dark, but it's not any different than driving on a highway.  Have to drive more carefully to avoid moose etc. 

Took my drone up at night for fun and you can see all the streets lit up with no cars.  Kind of a waste of energy.   The LEDs are much more efficient though.   

There is also a safety aspect. Lights make it less appealing for attackers and rapists.

[schmitt trigger]

Also, a bunch of time it just doesn't work. You can install these with software bugged all over the place. Nobody cares, because it is not mandatory for a city to have working lighting for the streets. And in reality, people could die because a null pointer exception made by an underplayed grad student untested code installed by a wannabe green city.

An acquaintance of mine has this saying: "There are no stupid ideas. Only poor software implementations". 

[floobydust]

Saves energy but ends up costing more due to costs upgrading the light fixture 
Then the next generation will have solar panels on top. Toss them, and repeat.
Then the next generation will have superior LEDS. Toss them, and repeat...

[stj]

and after you save energy using auto-dimming led's,
you can waste even more on the hidden camera, mic, wireless mesh network, 3g / bluetooth sniffer etc.

because if you dont, the terrorists will win!
(atleast that's the type of bullshit that eminates from the u.n. "strong cities" program!!)

[vk6zgo]

Why replace with terrible yellow sodium-based lamps or metal halogen lamps. They will probably also be banned due to poor efficiency.

The current top end LEDs only just surpass sodium or metal halide lamps in efficiency:
https://en.wikipedia.org/wiki/Luminous_efficacy
They're unlikely to be banned for inefficiency when they remain some of the most efficient bright light sources available.

Not only are sodium lamps efficient, but they also work well in fog. If you travel around areas of the UK where some streets have white lights and some have sodium, the streets lit by sodium are far easier to navigate in fog. I P


on't know the reason. Perhaps its something about the sensitivity of the eye at orange wavelengths.

And any object which has no yellow in its colour, just looks black.

I nearly got run over by a dark  blue taxi in Southampton years ago.
I barely saw him, & he obviously didn't see me on a zebra crossing.
Of course, that was just after they changed the rules so that you had to drive with dipped beams instead of parking lights.
It took a couple of years for British drivers to catch on!

On another occasion, I lost my pInk hired Cortina.
I found a yellow one, though-----just as well they wrote the rego number on the key tag, or I'd still we wandering the streets of Southampton!

[coppice]

Not only are sodium lamps efficient, but they also work well in fog. If you travel around areas of the UK where some streets have white lights and some have sodium, the streets lit by sodium are far easier to navigate in fog. I don't know the reason. Perhaps its something about the sensitivity of the eye at orange wavelengths.

And any object which has no yellow in its colour, just looks black.

With dark car colours, including black, being currently the most popular on British roads, half the cars look black under white street lights.

[james_s]

LED efficiency was not impressive at all when streetlights first started using them but it has improved quite a lot and continues to improve. While being a lighting guy I hate to see the demise of discharge lighting and a great many unique light sources that have been developed over the years but whatever my opinions, LED is the future of lighting. At a lighting industry trade show last year literally *everything* being shown was LED. Other sources that had been popular, HID, fluorescent, induction, it was like they didn't exist at all. Low pressure sodium lamps are in the process of being phased out, I believe only one company still manufactures the lamps and production is likely to stop within a decade. Metal halide was promising, particularly the high color rendering ceramic types but development has pinnacled and essentially frozen as LED has surpassed the efficiency, lifespan and color quality. MH and HPS(SON) lamps are still made in large numbers as replacement lamps in existing luminaires but that will rapidly decrease. All new street lights that have been installed in my area within the last 5 years or so have been 100% LED, and very soon that is going to be all the major manufactures offer.

With LEDs being capable of instant-on, dimming, long life sealed luminaires that don't need relamping it's easy to see why they are taking over for roadway lighting. I think the sensor activated streetlights have merit if done properly, they could easily dim to say 10% power until movement is detected nearby. At 10% power a light will still appear much more than 10% of full brightness.

It's entirely possible to make LEDs that emit a nearly monochromatic yellow that mimics the color of low pressure sodium if the market desires. I've always thought LPS lamps looked cool but they never caught on in the US, I've only ever seen a very small handful of them in the wild.

[SparkyFX]

With dark car colours, including black, being currently the most popular on British roads, half the cars look black under white street lights.

Which means you can not correctly identify the colour of the vehicle that mowed you down while doing so (maybe because the driver didn´t see you?!). Well, if vehicles run over pedestrians at night because they can´t see them, i consider that a possible street lamp fail. :-)

Modern headlights are quite good anyway, the street lamps still serve the purpose of seeing pedestrians crossing a bit earlier and lighting places. No idea if making them intelligent is really necessary. If you want some place to be lighted at night for looking like a less scary place, then it needs to be lit in all areas, not switched off or only lit where there is movement. I guess that would be rather a psychological effect and i don´t see which niche this should fill. There needs to be some problem solved without creating too many new at the same time after all.

E.g. more parts usually scale to more causes of failure. If road maintenance needs to service this style of lamp more often for defects or false reports of being broken it might generate a loss over conventional lamps.

[james_s]

With LED you don't have to turn the lights completely off, you can dim them down to use considerably less power while still having enough light that the area doesn't look dark and scary. Generally I find that streetlights are much brighter than necessary, and ironically the dark sky regulations requiring full cutoff luminaires results in still higher light levels being needed along with more lamps placed closer together. Otherwise you end up with small pools of light spaced out along a dark road. IMO even light is far more useful than bright light. You don't need a lot of it, you just need the light spread out so it illuminates the shadows.

[stj]

maybe a radical re-think is needed.

how about ditching the streetlamps and using illuminated bollards along the edge of the road at shorter intervals?
that would light the pavement and buildings, making people visible and able to get about.
but it would reduce power use and equipment costs - maintenance wouldnt require a lift either.

i know the bollard lights work well, because i'v seen it used at a couple of buildings with large outdoor area's.

[SparkyFX]

Thats right, just tried to point out that not all problems can be solved by technology or would be contradicted by applying too much.
E.g. motorists usually try to get the whole road lighted up to see as much as possible and as much as is allowable (or even ignore that part) and then complain about all the bedazzlement by everyone else.

[coppice]

maybe a radical re-think is needed.

how about ditching the streetlamps and using illuminated bollards along the edge of the road at shorter intervals?
that would light the pavement and buildings, making people visible and able to get about.
but it would reduce power use and equipment costs - maintenance wouldnt require a lift either.

i know the bollard lights work well, because i'v seen it used at a couple of buildings with large outdoor area's.

There are streets in the heart of HK which have no street lights, and you hardly ever notice. There is so much light from the advertising that you just don't need street lights.

[schmitt trigger]

Otherwise you end up with small pools of light spaced out along a dark road. ...

Exactly!

That is what happens when existing light poles designed for HID lamps are retrofitted with LEDs

[james_s]

Otherwise you end up with small pools of light spaced out along a dark road. ...

Exactly!

That is what happens when existing light poles designed for HID lamps are retrofitted with LEDs

That's not the fault of LEDs as a technology though, it's a fault of requirements in many areas for luminaires to be FCO, ie no light emitted above 90 degrees. It's perfectly possible to make LED sources with the same optical characteristics as the HID lamps they replace. We had the same problem here with HID lamps, older semi-cutoff luminaires replaced with full-cutoff types resulting in uneven lighting. To get the light even you need a lot more sources so it does little to combat the problem of light pollution. A better approach would be to use *less* light overall, and focus on even illumination. You don't need roadways lit brightly enough to comfortably read a book. Unfortunately in the real world you end up with legal guidelines that dictate the light levels required in various situations.

[grumpydoc]

For a similar reason the head light at cars in France have a yellow tint, reducing the blue and thus scattering in fog an with scratches on the windshield.

Not since the early 1990's

[stj]

Is street lighting THAT important? I mean, I've driven on a lot of highways without street lights, and people drive at 80mph+ with no other sources of light besides headlight, and I don't see a big problem here.

I feel much relaxed and comfortable driving in the dark where all I can see is the road in front of me. Driving in the day or under a well lit road distracts me and makes me tired.

get out and walk a few miles.
then come back and edit your post.

i'v been on country roads at night and you cant see *anything* without a full moon or a flashlight in your hand!

[stj]

no, you implied that street lighting is not required because you have headlights on your car.

street lighting is not there for you, it's there for people who dont have lights.
walkers, cyclists etc.

[coppice]

no, you implied that street lighting is not required because you have headlights on your car.

street lighting is not there for you, it's there for people who dont have lights.
walkers, cyclists etc.

Street lights are there for the drivers too. The accident rate on unlit roads, especially motorways, is far higher than lit ones.

[soubitos]

Saving energy is never a bad idea... or is it?
Electrical power is produced 24/7/365 and the bulk comes from coal/nuclear/gas/hydro.
During the night, there is no peak demand but power is still being produced, simply because it cannot be otherwise.
So, the street lights are not causing any problem to the grid, they are scheduled loads during off-peak hours and they even help stabilize the grid.
The only use for tampering with the way street lights work until today could be to replace them all with LED lights, power them with PV WITH storage batteries so then yes, it is obvious conserving stored energy is useful... since there is no replacement for "basis" power plants though, i dont see why one should invest so much in conserving energy that would almost 100% be produced and go to waste anyway!

[glarsson]

During the night, there is no peak demand but power is still being produced, simply because it cannot be otherwise.
So, the street lights are not causing any problem to the grid, they are scheduled loads during off-peak hours and they even help stabilize the grid.
The only use for tampering with the way street lights work until today could be to replace them all with LED lights, power them with PV WITH storage batteries so then yes, it is obvious conserving stored energy is useful... since there is no replacement for "basis" power plants though, i dont see why one should invest so much in conserving energy that would almost 100% be produced and go to waste anyway!

In places further away from the equator than Greece the dark part of the day definitely overlays the peak hours. Northern Sweden, as an example, has 24 hours of no sun at all during mid-winter but the need for street lights varies over those 24 hours.

[james_s]

Saving energy is never a bad idea... or is it?
Electrical power is produced 24/7/365 and the bulk comes from coal/nuclear/gas/hydro.
During the night, there is no peak demand but power is still being produced, simply because it cannot be otherwise.
So, the street lights are not causing any problem to the grid, they are scheduled loads during off-peak hours and they even help stabilize the grid.
The only use for tampering with the way street lights work until today could be to replace them all with LED lights, power them with PV WITH storage batteries so then yes, it is obvious conserving stored energy is useful... since there is no replacement for "basis" power plants though, i dont see why one should invest so much in conserving energy that would almost 100% be produced and go to waste anyway!

This is a great argument toward adding more electric vehicles to the system to augment traditional fuel powered vehicles. These cars can be charged at night when overall demand is lower and that helps to mitigate one of the primary arguments from naysayers which is that grid capacity is insufficient to account for them.

[soubitos]

So.. i use my electric car at day... and charge at night... what if i run out of juice say at 13:00? I wait? I pull the portable PV from the back and wait more? I go to the nearest "power" station and hook to the grid? I start the gas power generator i keep in the back? LOL..... I am not a naysayer but.... its one think to WISH something works and a totally different to actually work.... learned that the hard way

[glarsson]

So.. i use my electric car at day... and charge at night... what if i run out of juice say at 13:00? I wait? I pull the portable PV from the back and wait more? I go to the nearest "power" station and hook to the grid? I start the gas power generator i keep in the back? LOL..... I am not a naysayer but.... its one think to WISH something works and a totally different to actually work.... learned that the hard way

What if you run out of petrol or (even worse) diseasel at 13:00? That is a failure in you, not in the "fuel".

[soubitos]

Quote from: glarsson on Today at 09:48:49 PM

>Quote from: soubitos on Today at 09:04:39 PM

So.. i use my electric car at day... and charge at night... what if i run out of juice say at 13:00? I wait? I pull the portable PV from the back and wait more? I go to the nearest "power" station and hook to the grid? I start the gas power generator i keep in the back? LOL..... I am not a naysayer but.... its one think to WISH something works and a totally different to actually work.... learned that the hard way

What if you run out of petrol or (even worse) diseasel at 13:00? That is a failure in you, not in the "fuel".

If i run out of gas ANY time of the day, i most likely am 5 min away from the nearest gas station!!!
If i am supposed to only charge at night so as not to overload the grid and to help balance the night shift, then any time of the day i run out of juice, thats that.....

[floobydust]

You can augment LED street lights with solar or wind gen, and batteries.
It's just a matter of pounding through the numbers to see if it's worth it, or if just a SJW fantasy that it's green and surely better for the world.

I don't think Panasonic's LED streetlight “Kaze-Kamome” (Wind Seagull) did really well, with it's Savonius rotor wind generator. Looked neat though.

[james_s]

So.. i use my electric car at day... and charge at night... what if i run out of juice say at 13:00? I wait? I pull the portable PV from the back and wait more? I go to the nearest "power" station and hook to the grid? I start the gas power generator i keep in the back? LOL..... I am not a naysayer but.... its one think to WISH something works and a totally different to actually work.... learned that the hard way

Well, the 5 friends and family members I personally know who have electric cars have never had that problem. If they did I guess they would do the same thing most people would do if they broke down and call for a tow? Like millions of others who live in the suburbs they drive only 15-30 miles a day commuting to work and running errands so with a 50-80 mile range they get out of the car, running out of juice is not something that has ever happened.

I don't have to wish for it to work, I can see it work any time I want, I can call up one of these people and ask for a ride, I've driven several of the cars myself out of curiosity. But what about longer trips you'll ask? Well all the EV owners I know live in multi-car households so they have another vehicle should that be necessary. Will this work for everyone? No, but it doesn't have to either, hence my comment that EVs can augment traditional fuel powered cars. We don't need or even want everyone to have them because that probably would drive up the cost of electricity and then the powers that be would find a way to make up for the massive gas tax revenue no longer coming in, but we could certainly have more than we do now. If I didn't love my particular car so much I'd be tempted to get an EV. At least 95% of my driving is the 16 mile round trip to and from the office, I could do 95% of my driving in a car that had a paltry 20 mile range if I could plug it in to charge at night. Not saying I'd be comfortable cutting it that close but certainly the ~60 mile range of my friend's Leaf would be more than adequate. For those 5% of trips that need more range I could borrow my partner's gas powered car.

I've never been able to figure out why some people get so hung up on the "but what if someone needs x, y or z? Then what??!?" Well, then an EV may not be the right choice for them, but that doesn't mean there aren't many millions of people that it will work for. Heck it's getting more and more common for city dwellers to not own any car at all, they use mass transit and various taxi services. The data is readily available though clearly showing that vast numbers of people drive well under 50 miles a day and/or live in multiple car households and/or have access to other forms of transportation. Oh and just because you ideally should charge at night when demand is lowest (and rates can be lower to encourage this) doesn't mean you can't charge at any other time should it become necessary. Maybe you pay a bit more so you generally try to avoid it, but that doesn't mean it's not an option.

[IanMacdonald]

I can see this being a big problem for residents, with lights flashing all the time.

Besides, you will probably find that the costs far outweigh any energy savings.  As for banning mercury lights, that is crazy. The mercury poses no environmental threat unless it is disposed of carelessly. Maybe they should ban wind turbines in that case, after all they too contain substances which would be toxic if spilled.

https://enkonn-solar.com/ -I find hard to believe would work satisfactorily. Do the math on energy in, energy out before you believe ads like this.

[cdev]

In rural areas and between towns, one could argue for motion-sensing on LED highway lighting at night. That it doesn't make sense to have lights on when there is no traffic on the highway. The lights can switch off when there has not been any traffic in a while and switch back on when a car is approaching.

[f4eru]

Blinkenlights are probably much more disturbing for animals, humans included, than a constant light source in the dark.

[NiHaoMike]

What about fade the lights over a period of several seconds when brightening and a minute or two when dimming?

[jmelson]

I can see this being a big problem for residents, with lights flashing all the time.

They could make this less objectionable by having the lamps ramp up and down instead of just going from full off to full on and vice-versa.  Of course, when turning on, they need to come up fairly fast as traffic approaches.  If you wanted to get real fancy, you could interconnect the lamps with some mid-range RF network, so lamps 1/4 mile away could get advance notice of approaching traffic.

Jon

[james_s]

I think if they ramped up to full brightness over a period of say half a second it would be fast enough yet still not so fast that it felt jarring. I know from experimenting with dimmable consumer LED bulbs that running at 10% of full rated power consumption results in considerably more than 10% apparent light output. Partly due to non-linearity of the eye, but LED efficiency also rises pretty dramatically as current drops.

[f4eru]

What about fade the lights over a period of several seconds when brightening and a minute or two when dimming?

Brightening a light gradually is what signals animals, including human mammiferes that the sun is rising.
It will mess up the sleep.

[james_s]

Brightening a light gradually is what signals animals, including human mammiferes that the sun is rising.
It will mess up the sleep.

But brightening up over a period of a second or two? I hardly think that will trigger it. Certainly for me I find it much less jarring to ramp up the bedside lamp slowly if I need to turn it on for some reason than to just flip on a light without a dimmer. We're not talking ramping up the light over a half hour period or something.

[SiliconWizard]

Saves energy but ends up costing more due to costs upgrading the light fixture 
Then the next generation will have solar panels on top. Toss them, and repeat.
Then the next generation will have superior LEDS. Toss them, and repeat...

Absolutely! Where I live they even have changed fixtures twice since they switched to LED-based lights! Besides, those lights sold for public markets are extremely expensive. Total rip-off.

Additionally, whereas they draw much less power, they have much more brightness, partly due to their specific spectrum but probably partly for marketing reasons. Some streets at night are so bright that it's almost like dim sunlight... crazy. This night light pollution is a real problem and has increased significantly with LED-based lighting.

https://news.nationalgeographic.com/2017/11/light-pollution-energy-LED-bulbs-spd/

[stj]

Additionally, whereas they draw much less power, they have much more brightness, partly due to their specific spectrum but probably partly for marketing reasons. Some streets at night are so bright that it's almost like dim sunlight..

that's the idea,
the government officials are all suffering from SODS (survailance obsession disorder) and need the light for all the camera's.
it's even in the marketing crap from the manufacturers.

[james_s]

Additionally, whereas they draw much less power, they have much more brightness, partly due to their specific spectrum but probably partly for marketing reasons. Some streets at night are so bright that it's almost like dim sunlight..

that's the idea,
the government officials are all suffering from SODS (survailance obsession disorder) and need the light for all the camera's.
it's even in the marketing crap from the manufacturers.

That seems to be a primarily British thing. There are some CCTV cameras here in the US but the vast majority are privately owned and not centrally monitored by big brother.

[SiliconWizard]

Not just british. It's becoming pervasive in most of Europe.

I believe there are also many in California.

[stj]

and people are sick of it.
https://camover.noblogs.org/
just one example.

[Eka]

• can not be retrofitted to discharge type lamps (they need a couple of minutes warm up before full brightness), therefore includes installation cost for new lamp type

Non issue. The economics of retrofitting a fixture fail big time. Much cheaper to just replace fixture and all. The LED street lights have so much less service calls for bulb replacements during their life they easily pay for them selves multiple times. In the US and Europe it costs a few hundred dollars to replace a HID street light bulb when you factor in the costs of the equipment and operator to do it. Don't need to do that service call once or twice and you pay for the new LED fixture. The savings will be more like 5 to 10 less service calls over the life of the LED bulb. I would be surprised if it was less than $1000 saved in service calls per year per mile of lit road for LEDs versus sodium vapor bulbs. That pays for lots of additional retrofits. Energy savings are not the reason to swap. HID bulbs are very efficient.

Bulb replacement costs in office buildings is driving retrofits and initial installs to LEDs. A T5 fluorescent has similar efficiencies, but needs replacement 5 to 10 times as often. You have to pay somebody to replace that bulb. It adds up.

[stj]

so what is the service life of an led lamp-head?
because a low-pressure sodium lamp lasts atleast 10 years.

[coppice]

so what is the service life of an led lamp-head?
because a low-pressure sodium lamp lasts atleast 10 years.

The quoted lifetime of LED lamp heads is usually very long - up to 50 years for some. However, design quality is highly variable, so what happens in the real world will only be found over the next 20 or 30 years.

[stj]

50years my ass, that's a fraud claim right there.
so unless the invertor/buck convertor has no electrolytics and the leds arent phosphor coated there is no way it will hit a decade IMO.
i know some types have already been replaced after only a couple of years.

[theoldwizard1]

The City of Detroit converted all of their street lamps to LED a few years ago.  Or I should say after almost 100 years, the City of Detroit gave up on trying to generate and distribute their own electrical power and handed it over to the local utility, Detroit Edison.  Most of the street lamps had not been operating for as long as 20+ years !  Some areas of the city actually had their street lamps wired in series !  Detroit Edison completed the conversion a few years back

One thing about the new LED street lamps is that the reflector creates a much smaller "pool" of light.  People in the neighborhoods noticed this, but nothing is likely to be done about it in the near future.

[james_s]

As I mentioned earlier, the small pool of light is due to dark sky regulations that mandate no light emitted above 90 degrees. In practice this means the luminaires mounted at typical heights produce a small pool of light. The older sag lens types spread the light much more evenly but also spray some small amount upward. This issue is not limited to LED sources.

[stj]

it's not just that, the reflectors are designed to be used at a specific height and spacing between lamps to avoid uneven spots or black spaces.
this probably gets ignored by the people buying and using them.

[james_s]

In many installations they reuse the existing poles for obvious reasons, poles that were designed for sag lens semi-cutoff luminaires. New installations often look cluttered with so many poles that it looks a bit silly.

[coppice]

50years my ass, that's a fraud claim right there.
so unless the invertor/buck convertor has no electrolytics and the leds arent phosphor coated there is no way it will hit a decade IMO.
i know some types have already been replaced after only a couple of years.

You know, we do build some electronics for a 50 year life, and actually achieve it with only a modest number of early failures. Life time is largely a cost/performance tradeoff choice. The issue will be whether people are prepared to pay what it costs to achieve a 50 year life.

I would have thought 10 years would be a more reasonable target life for most street lighting, to keep the initial cost down. Use solid caps and the right plastics, and that shouldn't be hard to achieve.

[james_s]

I have numerous electronic devices that are 50+ years old and still work, although most are not in continuous service and some have had capacitors replaced at one point or another. I do agree that 10-20 years is more reasonable for a streetlight though. By 10 years the optics will be filthy.

I have seen old mercury streetlights that had been running the same lamp for 30+ years though. Around the early 70s the lamp technology had been refined to the point that some of them actually lasted too long to be economical for the manufacture. There was an electrode composition for a while that made white inst as of black deposits in the arc tube and they stopped using it because the lamps were lasting too long. GE called them "Bonus Line" and Westinghouse used a similar design in their Lifeguard lamps for a few years.

[stj]

electronics can be made to last, but phosphor coatings still have a limited life.
if you want to use the old RGB method of white led light generation then maybe you can get a long life,
but using blue or UV with phosphor coatings - not happening - not yet atleast.

[SiliconWizard]

50years my ass, that's a fraud claim right there.
so unless the invertor/buck convertor has no electrolytics and the leds arent phosphor coated there is no way it will hit a decade IMO.
i know some types have already been replaced after only a couple of years.

Yeah, I don't buy it one second. I believe the power LEDs themselves are only rated up to a few thousand hours of operating time. Let's assume an average of 10 hours per day of lighting. You're going to reach EOL within a few years. Not to mention that they are subject to relatively high temperatures during daytime in sunny areas, which will likely shorten their lifetime further even if they are not powered at those temps. 10 years *max* is probably what you're gonna get with top-notch LEDs and designs.

As we said above, it doesn't even matter unfortunately (which is why those claims can be made without harming the companies that make them). It's close to 100% certain that those fixtures will be replaced every few years anyway for a number of other reasons (mass surveillance being one of them - and technology is bound to progress fast in this area in the coming years/decades).

[coppice]

electronics can be made to last, but phosphor coatings still have a limited life.

Do you have any information about that? I looked recently, and couldn't find anything. Flourescent tube bombard the phosphor quit e hard with heavy ions, and the best lifetimes are something like 10k hours. Electron devices bombarding with electrons get a lot more life, but eventually fade. What sort of life do you get just bombarding with not too extreme photons?

[james_s]

Well we already know that 10 years is achievable, the first LED streetlights I saw started going in around then and at least some of those are still in service. I think a 10 year lifespan is a pretty reasonable goal. When you figure most HID sources are relamped about once per 3 years and labor is the largest part of that cost, a 10 year LED luminaire is looking pretty reasonable. Claims much longer than that, well it may be doable but I wouldn't bank on it. There's s good chance whatever company sold them won't be around by then anyway.

[james_s]

electronics can be made to last, but phosphor coatings still have a limited life.

Do you have any information about that? I looked recently, and couldn't find anything. Flourescent tube bombard the phosphor quit e hard with heavy ions, and the best lifetimes are something like 10k hours. Electron devices bombarding with electrons get a lot more life, but eventually fade. What sort of life do you get just bombarding with not too extreme photons?

That's not an easy question to answer. "Lifespan" is normally defined as time before L70, i.e. lumen output 70% of initial. The decay is roughly a halflife and depends heavily on how hard the phosphor is driven, chemical composition, quality, etc. If you use a good phosphor and don't pump it too hard, it can last a very long time. Use a cheap phosphor like low cost 5mm white LEDs and it will fade in just a few months.

[stj]

the phosphor gets damaged by heat from the dye more than anything.

[SiliconWizard]

Speaking of surveillance cameras coupled to bright streetlights:

https://qz.com/1458475/the-dea-and-ice-are-hiding-surveillance-cameras-in-streetlights/

[Audioguru]

In my city, we save energy on the new LED streetlights because some of them do not work (Chinese ones?).
The streets are still dark all night because most lights are shaded by trees.

Why do cars have headlights? Duh, to see the road at night? The streetlights are to light the road for little old lady drivers who do not know how to turn on the headlights and the car maker saved a few cents by not making headlights automatic.

[stj]

no, streetlamps are for people on foot. (and government camera's)
though obviously they let you see more road than your car will illuminate.

[coppice]

Why do cars have headlights? Duh, to see the road at night? The streetlights are to light the road for little old lady drivers who do not know how to turn on the headlights and the car maker saved a few cents by not making headlights automatic.

Most of the UK's motorways were built without street lights. The high death rate resulted in all the junctions being retrofitted with lights. The still not very good death rate resulting in the eventual lighting of the entire motorway network. Its not just about providing light for pedestrians. Before the motorways were lit they were OK to drive on in the middle on the night, when they were fairly quiet. In the winter rush hours they could be pretty scary.

[stj]

i mostly used them in the night,
so just following the "cats eyes" like a 70's video game! 

[grumpydoc]

The still not very good death rate resulting in the eventual lighting of the entire motorway network.

The whole of the UK motorway network is not lit, I don't even think all the junctions are, maybe all of the motorway-motorway intersections but certainly not all the junctions.

[coppice]

The still not very good death rate resulting in the eventual lighting of the entire motorway network.

The whole of the UK motorway network is not lit, I don't even think all the junctions are, maybe all of the motorway-motorway intersections but certainly not all the junctions.

Perhaps. There is certainly a lot more lighting than there used to be. Even the M25, running through suburban London, was mostly unlit for years.

[grumpydoc]

There is certainly a lot more lighting than there used to be.

M25, perhaps.

They've actually reduced lighting on the M5 Strensham to Birmingham stretch.

[james_s]

You would need extremely bright headlamps to not be over-driving your lights at highway speed. Street lighting allows you to see further up ahead than you otherwise could, and also lets you see anything off to the side that could potentially become an obstacle, such as wild animals. Accident rates on unlit roads are much higher than lit roads, all else being equal. Street lighting done properly improves situational awareness.