Do new streetlamps in LED Angeles increase LP ?

[skysurfer]

Not according to the city council (they even cite the Dark Sky Association)

http://bsl.lacity.org/led.html

but according to this article it does.

http://www.flagstaffdarkskies.org/da...n-the-problem/

I think, when properly installed (fully shielded and no more lumens light output) it won't give more skyglow, even with full-spectrum 4000K LEDs.
But, indeed, yellow leds (which are often used in lights on towing vehicles or display on buses) are even better for street lighting and I really don't understand why these are not used.

This technology allows much better control (including dimming leds more in the wee hours and / or with few traffic).

http://money.cnn.com/2015/04/10/tech...hts/index.html

[chappo001 (Mike)]

I think something in this story has gone awry. Whilst I don't know the specific situation in Los Angeles, the situation in Davis, California was that the street lights have been retrofitted to a CCT of 1800K, there is approximately 2.5% blue in the spectrum, at 4000K there would be in well in excess of 10% and if the lights are described as white then there will be much more blue.

The blue spectrum cannot be filtered out. The concept (or practice) of full spectrum lighting has pretty much had its day, the future of lighting lies in spiky spectrums using lasers and narrow band LEDs.

The objective of managers of dark sky parks in Europe and North America tends to be installing 1800K, amber or pc-amber. I'd totally agree that the "warmer" light at lower CCT is much better for vision, that's not how everyone sees it. I am colour blind though. The existing research shows that the blue light component of many current white LEDs is offensive and annoying to people.

[chappo001 (Mike)]

Here's an example of the lights being installed in Davis, California.https://www.pinterest.com/pin/573364596290324798/

And that image showing the freeway in Los Angeles, it's over lit and definitely light pollution, white light onto white concrete - what where they thinking. They should know better. Even when the lighting is done well it can be a fail. The Corso strip in Manly is one of the brightest objects from the ISS around Sydney - you wouldn't think so from the ground.