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.