I miss low pressure sodium street lights

[Patrick Harper]

HID is indeed High Intensity Discharge. SON, SOX, Halide and Mercury are all HIDs, though.

I stand corrected, I used 'HID' in the sense of HPD (high pressure discharge).

I have never heard of the latter.
Also, what is this so-called white HPS lamp? Never heard of it before.

It's a SON lamp with a light close in appearance to that of an incandescent lamp, albeit with lesser colour-rendering. Came about in the mid-80s, initially for the Japanese market. So-called 'deluxe' lamps fall somewhere in-between White SON and regular SON. These days low colour temperature garden-variety LED lamps do a similar job.

[Gareth]

This is quite an interesting video on LED streetlighting. In fact, the channel as a whole is worth checking out...

https://youtu.be/wIC-iGDTU40

[traffic-light-man]

HID is indeed High Intensity Discharge. SON, SOX, Halide and Mercury are all HIDs, though.

I stand corrected, I used 'HID' in the sense of HPD (high pressure discharge).

I have never heard of the latter.
Also, what is this so-called white HPS lamp? Never heard of it before.

In work, we generally just refer to lanterns as 'discharge' or 'tungsten' when speaking generally, because there's so many different lamp codes for all the specifically different lamps. Just to add to the confusion, some manufacturers will use different codes to each other for the same lamps, and some lanterns will only use specific lamps from specific manufacturers.

As has been mentioned, White-SON is a specific type of SON lamp where the pressures within the lamp are higher than standard SON, so produces a warm white rather than typically orange. They're quite expensive and have a lower life expectancy than regular SON lamps so never took off as a standard, as far as I'm aware.

This is quite an interesting video on LED streetlighting. In fact, the channel as a whole is worth checking out...

https://youtu.be/wIC-iGDTU40

Great video. After watching that one, I noticed he's also done a video on sodium lighting which is worth a watch, too.

I also particularly like his shelving in the background!

[PhilC]

I was brought up in the West Midlands in the late 1950s/1960s and can remember some SOX street lighting being installed. In those days it was often a straight replacement for existing gas light installations. I can remember walking to school and seeing the lanterns on the back of a lorry and being amazed at the size of them. They were certainly the brightest street lights at the time and I loved the colour of them. Fog has been mentioned upthread, and I can remember one particularly foggy night in about 1958. The fog was so dense I couldn't even see the tops of the lamp posts. All I could see was a warm yellow glow.

Back in those days, as you drove from one authority to another, the street light design would change. Birmingham always used mercury lighting, GEC products IIRC, Solihull always used SOX. Through the Black Country there were upwards of a dozen Urban Districts and County Boroughs, each of which had its own ideas. A trip between Birmingham and Wolverhampton on the A4123 would traverse half a dozen authorities. At night, as you travelled from SOX to mercury and back the quantity and quality of the light varied dramatically. There were two adjacent authorities who used superficially very similar lanterns, but one used mercury and one used SOX. Under the mercury lighting you could hardly see anything compared with SOX.

[Truvelo]

In the 80's the A4123 had these columns fitted with Hyperions and I recall they were the same throughout the Sandwell/Dudley/Wolverhampton sections. I assume this is because it was trunk then so it was under the responsibility of central government. Only in the 90's did the lighting start to change when Sandwell and Dudley went their own ways whilst Wolverhampton kept the existing columns. https://goo.gl/maps/P9hHwVTctjosWGWKA

Of course, I'm too young to remember anything before the early 80's

[ManomayLR]

I was brought up in the West Midlands in the late 1950s/1960s and can remember some SOX street lighting being installed. In those days it was often a straight replacement for existing gas light installations. I can remember walking to school and seeing the lanterns on the back of a lorry and being amazed at the size of them. They were certainly the brightest street lights at the time and I loved the colour of them. Fog has been mentioned upthread, and I can remember one particularly foggy night in about 1958. The fog was so dense I couldn't even see the tops of the lamp posts. All I could see was a warm yellow glow.

Back in those days, as you drove from one authority to another, the street light design would change. Birmingham always used mercury lighting, GEC products IIRC, Solihull always used SOX. Through the Black Country there were upwards of a dozen Urban Districts and County Boroughs, each of which had its own ideas. A trip between Birmingham and Wolverhampton on the A4123 would traverse half a dozen authorities. At night, as you travelled from SOX to mercury and back the quantity and quality of the light varied dramatically. There were two adjacent authorities who used superficially very similar lanterns, but one used mercury and one used SOX. Under the mercury lighting you could hardly see anything compared with SOX.

I've been going down memory lane this week. I'm missing LPS a lot, and I can just about see the lamps on the A1 in the distance from my home. I'm dreading the day we lose the yellow for the last time and LED invades. I spent the day yesterday playing around with Windows XP and Vista virtual machines. I grew up on Windows XP and the nostalgia came flooding in.

[Glenn A]

I can remember it being especially interesting going through Newcastle until the nineties as you had trolley bus pylons converted to street lights on the West Rd, Jesmond Rd and Shields Rd, a mixture of orange sodium lighting dating from the fifties to the seventies on other roads, and concrete columns on the western edge of the city. All culled now and replaced by tedious Biro like black columns with LED lighting.

[ManomayLR]

I can remember it being especially interesting going through Newcastle until the nineties as you had trolley bus pylons converted to street lights on the West Rd, Jesmond Rd and Shields Rd, a mixture of orange sodium lighting dating from the fifties to the seventies on other roads, and concrete columns on the western edge of the city. All culled now and replaced by tedious Biro like black columns with LED lighting.

I don't get why councils are so keen to switch away from low-pressure sodium. I'm tired and bored of HPS, but I'll always have a soft spot for the yellow LPS lights which lit my way during childhood.

[solocle]

LED's can be made in virtually any colour temperature so 1800K is possible which would emulate SOX. There are companies, Philips I believe, producing LED replacement bulbs to fit in a SOX chassis.

That wouldn't work particularly well. One of the distinctive features of SOX is that it's pretty much monochromatic - a thermal spectrum isn't.

[ManomayLR]

LED's can be made in virtually any colour temperature so 1800K is possible which would emulate SOX. There are companies, Philips I believe, producing LED replacement bulbs to fit in a SOX chassis.

That wouldn't work particularly well. One of the distinctive features of SOX is that it's pretty much monochromatic - a thermal spectrum isn't.

Phosphor-converted amber LEDs are almost entirely monochromatic at a similar wavelength too - giving the look of LPS using LED technology. I don't see why they can't put those in instead of white LED, then we'd get an old-school yellow LPS look!

[Patrick Harper]

LED's can be made in virtually any colour temperature so 1800K is possible which would emulate SOX. There are companies, Philips I believe, producing LED replacement bulbs to fit in a SOX chassis.

That wouldn't work particularly well. One of the distinctive features of SOX is that it's pretty much monochromatic - a thermal spectrum isn't.

Phosphor-converted amber LEDs are almost entirely monochromatic at a similar wavelength too - giving the look of LPS using LED technology. I don't see why they can't put those in instead of white LED, then we'd get an old-school yellow LPS look!

Because the British Standards and the equivalents for the EU all require a CRI of 20 and above. Highways authorities match their requirements to those standards so that they won't be held liable for not meeting them should, say an accident occur. LPS doesn't come close to meeting that.

[ManomayLR]

That wouldn't work particularly well. One of the distinctive features of SOX is that it's pretty much monochromatic - a thermal spectrum isn't.

Phosphor-converted amber LEDs are almost entirely monochromatic at a similar wavelength too - giving the look of LPS using LED technology. I don't see why they can't put those in instead of white LED, then we'd get an old-school yellow LPS look!

Because the British Standards and the equivalents for the EU all require a CRI of 20 and above. Highways authorities match their requirements to those standards so that they won't be held liable for not meeting them should, say an accident occur. LPS doesn't come close to meeting that.

What's a CRI? And why, then, do some LPS lights remain on the UK road network?

[Patrick Harper]

Phosphor-converted amber LEDs are almost entirely monochromatic at a similar wavelength too - giving the look of LPS using LED technology. I don't see why they can't put those in instead of white LED, then we'd get an old-school yellow LPS look!

Because the British Standards and the equivalents for the EU all require a CRI of 20 and above. Highways authorities match their requirements to those standards so that they won't be held liable for not meeting them should, say an accident occur. LPS doesn't come close to meeting that.

What's a CRI? And why, then, do some LPS lights remain on the UK road network?

I guess authorities didn't have the finances to replace them all at once?

CRI - colour rendering index. LPS's value is 0/-44 because everything lit by it appears a shade of yellow/amber.

[PhilC]

In the 80's the A4123 had these columns fitted with Hyperions and I recall they were the same throughout the Sandwell/Dudley/Wolverhampton sections. I assume this is because it was trunk then so it was under the responsibility of central government. Only in the 90's did the lighting start to change when Sandwell and Dudley went their own ways whilst Wolverhampton kept the existing columns. https://goo.gl/maps/P9hHwVTctjosWGWKA

Of course, I'm too young to remember anything before the early 80's

From the Hagley Road (A456) junction there were Thorn Alpha 1s on concrete posts for the first section. Later on the were long sections with cut-off lanterns suspended on wires stretched across the whole width of the dual carriageway, one lantern over each carriageway. They would probably have been manufactured by Revo, who were a local company based in Tipton. They produced a couple of similar lanterns, the C13654 for mercury bulbs, and the C13660 for SOX. The last time I remember travelling the whole stretch from Wolverhampton to Birmingham after dark was in June 1967 (I remember the date because I was listening to Radio Luxemburg and The Turtles were at number 1). Of course in later years the lighting was replaced with the Hyperions you remember.

[ManomayLR]

Because the British Standards and the equivalents for the EU all require a CRI of 20 and above. Highways authorities match their requirements to those standards so that they won't be held liable for not meeting them should, say an accident occur. LPS doesn't come close to meeting that.

What's a CRI? And why, then, do some LPS lights remain on the UK road network?

I guess authorities didn't have the finances to replace them all at once?

CRI - colour rendering index. LPS's value is 0/-44 because everything lit by it appears a shade of yellow/amber.

What is HPS and LED’s values?
I personally am an advocate for pure white light LEDs, on the cooler side on major A roads and motorways, and on the slightly warmer side on roads with houses on.

[Chris56000]

Hi!

Not withstanding the awful colour–rendering, it was much easier to cycle at night or in bad weather along a road lit with low–pressure sodium lighting rather than mercury, or high–pressure sodium, because the road was far more evenly illuminated!

Trying to cycle at night on an LED lit road is a lot harder because there's bright pools of light over a relatively small area, and then you're plunged into darkness between them, and even in a car with their much more intense and wider–spread headlamp light than anything that can be fitted to a bicycle, or even a small moped or motorcycle, low–pressure sodium was always easier when finding you way along an unfamiliar road at night!

Chris Williams

[ManomayLR]

Hi!

Not withstanding the awful colour–rendering, it was much easier to cycle at night or in bad weather along a road lit with low–pressure sodium lighting rather than mercury, or high–pressure sodium, because the road was far more evenly illuminated!

Trying to cycle at night on an LED lit road is a lot harder because there's bright pools of light over a relatively small area, and then you're plunged into darkness between them, and even in a car with their much more intense and wider–spread headlamp light than anything that can be fitted to a bicycle, or even a small moped or motorcycle, low–pressure sodium was always easier when finding you way along an unfamiliar road at night!

Chris Williams

This is because the light from an LED lamp, and also most HPS lamps, is directed straight down, while with LPS, the bulbs allow for some sideways (and upward) light distribution.

[traffic-light-man]

Hi!

Not withstanding the awful colour–rendering, it was much easier to cycle at night or in bad weather along a road lit with low–pressure sodium lighting rather than mercury, or high–pressure sodium, because the road was far more evenly illuminated!

Trying to cycle at night on an LED lit road is a lot harder because there's bright pools of light over a relatively small area, and then you're plunged into darkness between them, and even in a car with their much more intense and wider–spread headlamp light than anything that can be fitted to a bicycle, or even a small moped or motorcycle, low–pressure sodium was always easier when finding you way along an unfamiliar road at night!

Chris Williams

This is because the light from an LED lamp, and also most HPS lamps, is directed straight down, while with LPS, the bulbs allow for some sideways (and upward) light distribution.

Well, depending on the lantern design, of course.

SOX and SON lamps (not the lanterns, the actual lamp) produce light with no directionality at all, so all of that work is down to the reflector (where fitted) and bowl design of the lantern.

Typically a modern LED lantern is designed in a way that works hand-in-hand with the fact each LED can be directed using some fairly simple lenses. However, the Hardie lanterns discussed by myself and Gareth further upthread typically mimic the output style of Thorn Beta 5 and Philips MA SOX lanterns, but in 'moon' white, rather than amber. They just use lots of bare SMD LEDs in strips with no real directional control at all.

The pools of light experienced in LED lighting installations is to an extent due to the directionality of the light emitted from the lantern, but ultimately it's the result of either bad lantern design, bad street lighting design or a bit of both. I think there's too many variables to lay the blame wholly on LEDs - if you placed typical sideways-spilling SOX lanterns at (say) half-mile intervals, you would end up with dark spots then, too!

Edited to add clarity.

[Truvelo]

From the Hagley Road (A456) junction there were Thorn Alpha 1s on concrete posts for the first section. Later on the were long sections with cut-off lanterns suspended on wires stretched across the whole width of the dual carriageway, one lantern over each carriageway. They would probably have been manufactured by Revo, who were a local company based in Tipton. They produced a couple of similar lanterns, the C13654 for mercury bulbs, and the C13660 for SOX. The last time I remember travelling the whole stretch from Wolverhampton to Birmingham after dark was in June 1967 (I remember the date because I was listening to Radio Luxemburg and The Turtles were at number 1). Of course in later years the lighting was replaced with the Hyperions you remember.

Wow, Alpha 1s on concrete were only used on the secondary main roads when I grew up. I never knew they were used on the A4123. As for the lanterns on wires I managed to find a photo. This is all exciting stuff.
http://blackcountryhistory.org/collecti ... 45_p_1527/

[PhilC]

From the Hagley Road (A456) junction there were Thorn Alpha 1s on concrete posts for the first section. Later on the were long sections with cut-off lanterns suspended on wires stretched across the whole width of the dual carriageway, one lantern over each carriageway. They would probably have been manufactured by Revo, who were a local company based in Tipton. They produced a couple of similar lanterns, the C13654 for mercury bulbs, and the C13660 for SOX. The last time I remember travelling the whole stretch from Wolverhampton to Birmingham after dark was in June 1967 (I remember the date because I was listening to Radio Luxemburg and The Turtles were at number 1). Of course in later years the lighting was replaced with the Hyperions you remember.

Wow, Alpha 1s on concrete were only used on the secondary main roads when I grew up. I never knew they were used on the A4123. As for the lanterns on wires I managed to find a photo. This is all exciting stuff.
http://blackcountryhistory.org/collecti ... 45_p_1527/

Yes, that's a great photo, exactly as I remember them.

The Alpha 1s at the sides of the carriageway were on quite conventional concrete columns but the ones on the central reservation were of a different design. I have never seen them anywhere else and I can't find a photograph of them. The best way I can describe them are like a Revo Scopas column with a harp bracket, but with only half of the harp bracket present. A single Alpha 1 was then attached to it. They were arranged so that alternate columns faced in opposite directions. As a child the tops of the columns reminded me of the shape of the black tops of the Exide distilled water bottles that garages used to have to top up batteries.