What is this obsession with LED?...only white LEDs are economical to use, all the other colours remove the efficiency advantages, and none of them are fully monochromatic either.
I apologise if the topic has slid away from North West Discussion, therefore I'll keep it brief.
Although LEDs have proved to be useful lightsources (at least in the short term anyway), the assumption that white LEDs are more economical over other colours, is probably based more on what the general public has been programmed to perceive as best, compared to "those dim, orange streetlights".
When low pressure sodium was introduced from the 30s, the key attraction was the excellent efficacy over gas and GLS lamps. The fact that colour rendition was not seen as important, must have carried huge sway when you consider how much of the UK was ultimately lit by it, especially from the 1960s onwards.
In this age of constant surveillance due to cctv as well as social media uploads, monochromatic lighting at night is now no longer seen as desirable / fashionable. With the increased incidence of civil disturbance, it comes as no surprise that LED's white light is seen by many as the only tool for fighting those crimes of the darkness.
The problem though, is that whilst LED has brought numerous benefits to our towns and cities, such as lower running costs etc, there is one aspect which has not materialised - the equality of LED light.
The equality of LED light? It could be an alien concept, so here is my theory.
LED streetlights have been heavily promoted as offering "more for less for longer" ie more lumens for less Watts for a long time.
Ok, fair enough and I will concede that there have been some awful installations of SOX and SON, which have been remarkably improved with LED, so in that respect I have no problems.
My observation though is where the proud, civic centres are lit with copious quantities of LEDs, providing almost television studio quality lighting (and probably producing more CO2 than the old scheme), whilst those roads and streets on the outskirts have to fumble along through the night with more measly pickings (assuming they stay on that long).
The downward adjustment in BS5489 to make white light more viable, means that whilst it may look better than SOX or SON, the amount of it is probably less and this would be more notable in residential areas. There have been plenty of reports in the papers about hostility to LED, regardless of their eco prowess.
Additionally, LED lanterns will only provide a cut off distribution. Whilst good for energy bills, directing the publicly funded light to just where it is needed means the surrounding streetscene is left in the dark. Add a good line of trees or poor spacings into the equation and the result is very gloomy indeed.
Surely, the advantages of good LED (including its design and installation) should be spread a little wider, beyond those areas that bring in the money!