Lighting one side of a dual carriageway

[A303Chris]

Also been done on the A329 Berkshire Way in Bracknell.

Although from personal experience the columns are not tall enough and lane one westbound hardly gets any light.

That's a pure cost cutting exercise, reusing old columns and cutting down the other side. I'd love to see a lighting analysis diagram for that.

You are probably correct, Bracknell Forest BC, are known for there accounting. They have just started charging parents £5 for an hours use of a play park within a country park!

[Chris5156]

Not a dual carriageway but a before and after in Sheffield one this really wide road always struck me as odd when they replaced the lighting and only installed one side. Those columns don't look at all tall enough to throw light on the other side.

No, that counts, it definitely IS a dual carriageway!

[ManomayLR]

Not a dual carriageway but a before and after in Sheffield one this really wide road always struck me as odd when they replaced the lighting and only installed one side. Those columns don't look at all tall enough to throw light on the other side.

No, that counts, it definitely IS a dual carriageway!

One of those elusive D1s, however short it might be.

This is like the new smart motorways single span gantries. Like these. They have full lane control signals but are only anchored on one side.

[Scratchwood]

Recently I've come across several locations where the full width of a dual carriageway is lit by one row of very powerful streetlights at one side of the road - nothing in the central reserve, nothing on the opposite verge. I guess this saves installation and maintenance costs, and possibly power consumption too.

There's two on the A1 that I passed last night - one between Tempsford and Sandy (too recent to appear on Streetview) and another here near Hendon. These are managed by the HA and TfL respectively, so it's clearly not one highway authority's trick. The Hendon one is particularly noteworthy as the lights also supposedly light the parallel service roads - a total of four carriageways - but don't seem to do a very good job of lighting much beyond the northbound carriageway in reality.

Is this a new recession-friendly technique for lighting dual carriageways? Are there more examples?

On that London example on the A1 near Hendon, it's interesting that the section in question has a crash barrier separating the London bound A1 from a service road and only then a pavement, whereas as soon as the service road and crash barrier ends and there is a conventional pavement, both sides are lit. I assume it would be considered too dangerous for pedestrians to have a weakly lit pavement with no protection.

[Chris5156]

Another for this occasional series: the A515 in the city on the Foyle.

[Bryn666]

Another for this occasional series: the A515 in the city on the Foyle.

I think this one may be related to the pylons; it's easier to not have hinged columns and to keep lighting away from cables altogether.

[RJDG14]

This thread got me wondering what the point of streetlights you see in some countries like Russia that look like this is (these are some quick diagrams I drew):

WeirdLights.png

(10.55 KiB) Not downloaded yet

You virtually never see lights like this in the UK, with 2 lanterns on a single column on one side of the road. I think there may have been a small number a bit like the right example on the M6 around Preston/Warrington a few years ago if I recall correctly (and may still be), and I never understood the point of having 2 lanterns so close together.

[Chris5156]

This thread got me wondering what the point of streetlights you see in some countries like Russia that look like this is (these are some quick diagrams I drew):

WeirdLights.png

I remember asking about these when I was on holiday in Bulgaria as a child. (Of course I was the sort of child who would ask a tour guide about streetlights.) Their explanation was to do with the Soviet-era power supply being fairly weak, and because of that the maximum wattage of lightbulbs in Soviet bloc countries was very low. As a result, if you needed a particularly bright light, you quickly reached a point where the brightest available lamps were not bright enough. The only thing you could do to make it brighter was to add a second lamp.

Russia and similar countries have probably got a lot of legacy installations that continue to operate this way, but they may also see advantages to continuing with this even now that any power supply or hardware limitations are gone. For example, if a lamp fails, that streetlight would still operate at 50%, so there is a resilience aspect to having two lights on the same post.

[RJDG14]

This thread got me wondering what the point of streetlights you see in some countries like Russia that look like this is (these are some quick diagrams I drew):

WeirdLights.png

I remember asking about these when I was on holiday in Bulgaria as a child. (Of course I was the sort of child who would ask a tour guide about streetlights.) Their explanation was to do with the Soviet-era power supply being fairly weak, and because of that the maximum wattage of lightbulbs in Soviet bloc countries was very low. As a result, if you needed a particularly bright light, you quickly reached a point where the brightest available lamps were not bright enough. The only thing you could do to make it brighter was to add a second lamp.

Russia and similar countries have probably got a lot of legacy installations that continue to operate this way, but they may also see advantages to continuing with this even now that any power supply or hardware limitations are gone. For example, if a lamp fails, that streetlight would still operate at 50%, so there is a resilience aspect to having two lights on the same post.

I'd have thought that the modern day Russian power supply (even with the current Ukraine related sanctions) would be pretty much identical to that in the rest of Europe. I don't think these double lights were common in East Germany, and from old photos I've seen, East German lights were as bright to those in West Germany. West/East Germany did use different lantern models and bulbs though. I think most streetlights in West Berlin were a mixture of flourescent and mercury while most in East Berlin were sodium, although ironically I'd have assumed the opposite from the lantern designs.

The US uses only 120V (compared with ~230V in most of Europe and Asia) yet doesn't generally use double lights, and most American lights from what I've seen are as bright as those in Europe. Modern day Russia (and I assume the former USSR) uses the same ~230V (220-240) voltage to western Europe. It's possible that Soviet bulbs simply weren't very good.

Some of these single side double-lights definitely in ex-Soviet countries look less than 30 years old - the current Moscow Ring Road I think has quite a lot of them despite having been extensively upgraded during approximately the late 1990s.

May I ask if Bulgaria was still under communism at the time you visited, or was this in the years following the collapse of communism?

In my opinion I think a lot of the 1970s communist streetlight designs have aged better than most installations in the UK from the same era - many have a similar lantern aesthetic to a lot of the low pressure sodium installations from the 1990s and 2000s, and lanterns like this were pretty rare in the UK prior to the 1990s.


One thing that the UK has been pretty unique on seems to have been the cropping of streetlight brackets as part of LED installations - many areas of the UK have lost nearly all of their former streetlight brackets as part of LED upgrades in recent years, and most new streetlight columns in the UK have lacked brackets since the 2000s, whereas most other countries including the Republic of Ireland have installed LED upgrades without significantly modifying the appearance of the columns. From what I can tell most of the LED lanterns in use across the UK can be installed without the need of significant cropping. I've wondered why this seems to be a UK thing. Some of the UK's earliest LED retrofits from 10-15 years ago did not seem to involve bracket cropping (beyond what was needed for the installation) unlike most of the newer ones.

On average I'd say LED upgrades have reduced light pollution in many areas compared with the former sodium lights, however an increasing number of homes seem to have LED lights on at night, either at all times or via oversensitive motion triggers. There's one home near mine that installed this very bright LED floodlight on its driveway (which can be seen from my back garden) about a year ago which seems to be on at all times (either that or it triggers for 10 minutes or so every time someone walks along the footpath) and it's definitely worsened the light pollution in my back garden as a result, even though the LED lights installed in my close about 3 years ago are better in this regard than their predecessors. I'd be tempted to say that their driveway light is actually brighter than the LED streetlights in my close, which the council tends to dim during the early hours of the morning. Automatic lights on driveways or front doors should only trigger when someone gets within a metre or two of the sensor, but they more commonly seem oversensitive and trigger even if someone walks along the verge side of the footpath on the other side of the road (this is something that gets on my nerves) about 10 metres away.

[Vierwielen]

This thread got me wondering what the point of streetlights you see in some countries like Russia that look like this is (these are some quick diagrams I drew):

WeirdLights.png

I remember asking about these when I was on holiday in Bulgaria as a child. (Of course I was the sort of child who would ask a tour guide about streetlights.) Their explanation was to do with the Soviet-era power supply being fairly weak, and because of that the maximum wattage of lightbulbs in Soviet bloc countries was very low. As a result, if you needed a particularly bright light, you quickly reached a point where the brightest available lamps were not bright enough. The only thing you could do to make it brighter was to add a second lamp.

Russia and similar countries have probably got a lot of legacy installations that continue to operate this way, but they may also see advantages to continuing with this even now that any power supply or hardware limitations are gone. For example, if a lamp fails, that streetlight would still operate at 50%, so there is a resilience aspect to having two lights on the same post.

DId he mean that the power supply was "weakly" (ie poorly) regulated - prone to having voltage spikes which would cause light bulbs to blow, or did he mean that the available current was low?

[wallmeerkat]

Another for this occasional series: the A515 in the city on the Foyle.

On a tangent - further on down that road they're painting zigzags for a pedestrian crossing, have the regulations changed such that a dual carraigeway the central line is also zigzagged? https://www.google.com/maps/@55.0367904 ... ?entry=ttu

[Chris5156]

I think most streetlights in West Berlin were a mixture of flourescent and mercury while most in East Berlin were sodium, although ironically I'd have assumed the opposite from the lantern designs.

East Germany wasn’t quite so advanced - the districts of Berlin that were in the east still have significant stocks of gas street lighting, which looks like any other mid-20th century sodium streetlight but which all burn natural gas.

May I ask if Bulgaria was still under communism at the time you visited, or was this in the years following the collapse of communism?

It was 1991, so it was so soon after the fall of communism that everything you saw and touched was from the soviet era. The streetlights were mostly mercury and all incredibly dim.

he mean that the power supply was "weakly" (ie poorly) regulated - prone to having voltage spikes which would cause light bulbs to blow, or did he mean that the available current was low?

I was ten years old and didn’t ask! I think the meaning was that there was greater demand for power than could be supplied, so the state regulated demand by restricting the wattage of lightbulbs and other appliances in order to reduce the load. The fact that another arm of the state might routinely try to circumvent that by putting up twice as many lamps fits nicely with everything else I’ve read about the dysfunctional nature of many eastern bloc states!