Heart of darkness

[Dr Lobster*]

just wondering how your local authority is saving money by turning out street lighting?

here in west norfolk much of the a10 is out (only a few years ago they resurfaced the road and installed 'state of the art' lighting. some of minor back roads to the smaller villages are also no longer lit, especially out along the a47.

some of the housing estates around the town have every other light out or big sections out with a few lights on here and there. it's not that bad but in places it's pretty dark.

some of the roads around here have a lot of tree coverage and are very difficult to drive along at night - especially with some of the newer cars / boy racers have very bright lights which almost wash your vision.

so, hows your local council saving a few pennies? and are the rural areas fare worse?

[marksi]

I (just) remember that in the 1970s the streetlights used to go off at midnight in the town centre.

That seems unacceptable now, but I'm sure you could reduce the level of lighting on motorways and A roads where there are only cars, not people. After all, people aren't all equipped with lights, whereas vehicles are.

Some fascinating facts from the Institute of Lighting Engineers:

Streetlights are generally operated throughout the hours of darkness as a service to the residents and road users of the area. There is very little difference in the cost of operating a streetlight all night as against part of the night and it is generally considered that the additional cost is more than offset by the added benefit of greater security to people and property, the potential reduction in traffic accidents and the assistance provided to the emergency services by the all night operation of streetlights. In residential areas there is very strong evidence that providing light significantly reduces crime.

The average cost of operating a streetlight inclusive of energy costs, lamp replacement and maintenance is calculated as between £50 and £70 per annum – approximately £1 per week.

It is generally assumed that the average wattage of a streetlight is about 90 watts. Assuming an average number of hours that the streetlight is on per annum as 4,100 then the amount of energy consumed by an average streetlight over one year will be 369 units of electricity, approximately 8 pence per night or £30 per annum.

The Institution of Lighting Engineers in its leaflet “Protecting a Vital Asset, 2000” determined that there were approximately 6.2 million lighting columns in public ownership.

That suggests that the total cost of the UK's streetlights is around one third of a billion pounds a year.

[Square Eyes]

Maybe they should consider censor activated lighting in streets and motorways that only come on upon approach and with movement, like you get in some offices.

[Neil Jones]

Maybe they should consider censor activated lighting in streets and motorways that only come on upon approach and with movement, like you get in some offices.

You mean "sensor activated lighting", as opposed to "censor" which is to blank it out

The only problem with sensor activated lighting is that it comes on whenever anything crosses its path - be it a car, a person, next door's cat, even bushes blowing in the wind. Therefore if your bedroom and where your head lies happens to be directly in line with the streetlight, it could get kind of annoying at three in the morning to be bathed in street lighting because somebody's crossed the sensor path.

Anybody who has any of these lights (or who has neightbours who set their sensitively and duration of light to some obscenely high level and point the glass straight across) knows that they're kind of sensitive and incredibly irritating sometimes, as they have been known to go off for no apparent reason.

[Square Eyes]

Maybe they should consider censor activated lighting in streets and motorways that only come on upon approach and with movement, like you get in some offices.

You mean "sensor activated lighting", as opposed to "censor" which is to blank it out

I did I feel so foolish

[Dr Lobster*]

i do wonder why they can't use led lighting or something like that though - it gives a very focused light and apparently a single 9v battery can power a single led for several weeks continuously.

surely they could use solar cells and a rechargable battery (like those crappy garden ornaments you get free after spending 30 quid on petrol) and make that into a street lamp?

i know the light isn't no where near as good as a proper sodium vapour light, but it's better than nothing.

[Gavin Scott]

LED lighting isn't quite there yet. The brightest single source on the market is a Luxeon 3w diode. Incredibly efficient, but has to have a heat-sink built around it, so it makes it difficult to cluster them tightly into a fixture.

There are 5w and 10w Luxeon prototypes about to go into production, which are dazzlingly bright to look at, but it would still take a few to compete with the 'throw' of a very tall streetlamp.

The problem with sensor-activated fixtures is that they need to be "instant start", and the exisiting sodium discharge fixtures can't do that.

Its more likely that a form of LED 'guiders' will be placed along street edges, so as to make clear the roadway, rather than illuminating the whole area.

I feel a patent coming on.

[marksi]

There are LED bulbs which fit GU10 holders with about 40 LEDs crammed onto the available space. As yet the maximum brightness they achieve is about 25w compared to 50w for the halogen. That said they only consume about 4w of electricity to achieve the equivalent of 25w.

I'm liking the LED at the edge of the road idea. In the summer you could run that completely off solar power as you have long hours of light and only a few hours of darkness, but it would have to be powered in winter.

[all new Phil]

I've noticed several roadsigns in Sheffield which have appeared recently, which have solar panels on top of them.

Someone mentioned about motorways - I hate driving on motorways at night when there are no lights, it is incredibly difficult to see what's coming up. You can't turn full beam on because of cars on the other side being blinded by it, so I just have to concentrate like ten times more than usual.

[nidave]

Are there not Light pollution laws in place now - I also beleive they have to replace the old orange lights with more directed white light.

Think its: clause (section 102) in the Clean Neighbourhoods & Environment Act 2005

They have replaced all the orange lights with more focused white lamps - the (what only can be described as) orbs have been replaced with downlighters.

[marksi]

I don't think they have to replace the sodium lamps until they'd be replacing them anyway. The white lamps give a much nicer light than the orange ones.