Why have long arms of streetlights usually been shortened when upgraded from sodium to LED?

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M19
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Re: Why have long arms of streetlights usually been shortened when upgraded from sodium to LED?

Post by M19 »

I’d say it’s cost but there is a deep irony in all of this where many authorities had comprehensively replaced all their street lighting with SON only to replace all of the lanterns again but with LED within a couple of years. Doesn’t sound very cost effective to me.

There has been a noticeable trend over the last few decades where we went from obtuse angled brackets to right angled and then to post tops.

My favourite bracket is curved including curved double brackets on dual carriageways - this probably comes from the blue ones that I used to see everywhere when I lived in Abu Dhabi in the 1970s except on the corniche which were different but likeable. (they’re long gone now). These are shots my dad took when we lived there.
https://www.skyscrapercity.com/threads/ ... -146657371

I also like the simple long armed brackets on US highways, but not the trussed ones.
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Re: Why have long arms of streetlights usually been shortened when upgraded from sodium to LED?

Post by AndyB »

That had to be explained to me. Apparently it’s down to the contract - more cost effective to replace with LED lanterns in a very large project early than to keep running more expensive SON lanterns and have a separate contract later.
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Re: Why have long arms of streetlights usually been shortened when upgraded from sodium to LED?

Post by domcoop »

M19 wrote: Wed Apr 06, 2022 21:10 I’d say it’s cost but there is a deep irony in all of this where many authorities had comprehensively replaced all their street lighting with SON only to replace all of the lanterns again but with LED within a couple of years. Doesn’t sound very cost effective to me.

There has been a noticeable trend over the last few decades where we went from obtuse angled brackets to right angled and then to post tops.

My favourite bracket is curved including curved double brackets on dual carriageways - this probably comes from the blue ones that I used to see everywhere when I lived in Abu Dhabi in the 1970s except on the corniche which were different but likeable. (they’re long gone now). These are shots my dad took when we lived there.
https://www.skyscrapercity.com/threads/ ... -146657371

I also like the simple long armed brackets on US highways, but not the trussed ones.
Knowsley council did a streetlighting and roads PFI in 2011 involving removal and replacement of every streetlight, bollard and road sign in the borough, no matter how old (or new).

But what surprised me at the time (LED was obviously the way things were going even in 2011) is that they installed SON!

You can see here an example where Concrete Utilities columns (with two varying slightly curved bracket lengths) with SOX were replaced. If you click the timeline for 2015 you can see the replacement SON, which a couple of years later was replaced by LED as seen in the 2021 image. (It goes without saying the new lanterns were post-top).

Speaking of lanterns on brackets, my favourite is on the A666 in Bolton, and in this view you can see CU with a double curved bracket, a replacement SON with a double straight bracket, and a replacement LED with short stubs on either side!
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Re: Why have long arms of streetlights usually been shortened when upgraded from sodium to LED?

Post by RichardA626 »

I remember noticing these a few years ago, I assumed the newer fittings had a more directional beam to light the road.
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Re: Why have long arms of streetlights usually been shortened when upgraded from sodium to LED?

Post by traffic-light-man »

domcoop wrote: Sat Apr 09, 2022 02:09Knowsley council did a streetlighting and roads PFI in 2011 involving removal and replacement of every streetlight, bollard and road sign in the borough, no matter how old (or new).

But what surprised me at the time (LED was obviously the way things were going even in 2011) is that they installed SON!

You can see here an example where Concrete Utilities columns (with two varying slightly curved bracket lengths) with SOX were replaced. If you click the timeline for 2015 you can see the replacement SON, which a couple of years later was replaced by LED as seen in the 2021 image. (It goes without saying the new lanterns were post-top).
I think LED was still quite expensive and perhaps not considered good enough when the PFI first kicked off, though, hence the roll out of SON at quite a rapid rate, particularly as they removed all the concrete stock. They used white SON and fluorescent quite a bit as well in the earlier stages of the PFI. But yes, some of those Iridiums are going to have had a much shorter service life than the SON and SOX lanterns that they replaced, and perhaps also the LEDs that replace them.

It just shows how fast the LED technology advanced though while the initial replacement phase of the PFI was ongoing. My road just caught the end of the SON installations and is still SON for now, but the adjoining road is LED and has been since the old CU columns were taken out, so they clearly decided to move to LED before they'd had chance to complete the concrete column replacement.

St Helens also went fairly heavy on SON ZX3 (or similar) replacement schemes at one stage and now a lot of those have been replaced with LED after only a short service life as well. The same road I mentioned earlier crosses the border into St Helens, and at that point the ZX3s had about 6 years in service before they bit the dust for LEDs.

The amount of newish SON lanterns that have been sent for recycling across the country is probably already quite mind boggling, really.
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Re: Why have long arms of streetlights usually been shortened when upgraded from sodium to LED?

Post by Chris5156 »

traffic-light-man wrote: Sat Apr 09, 2022 15:47
domcoop wrote: Sat Apr 09, 2022 02:09Knowsley council did a streetlighting and roads PFI in 2011 involving removal and replacement of every streetlight, bollard and road sign in the borough, no matter how old (or new).

But what surprised me at the time (LED was obviously the way things were going even in 2011) is that they installed SON!
I think LED was still quite expensive and perhaps not considered good enough when the PFI first kicked off, though, hence the roll out of SON at quite a rapid rate, particularly as they removed all the concrete stock. They used white SON and fluorescent quite a bit as well in the earlier stages of the PFI.
It's also likely that the decision point was not in 2011, even if that's when the PFI took over. The type of lights that were installed would have been specified in the contract, and the decision about what to put in the contract would have been taken several years earlier, when LED wouldn't have been quite such a safe bet and wouldn't have been as cheap.
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