LED Street Lighting – Seattle

I’ve read about the development of LED street lighting by Cree and a number of other manufactures and was curious just how well it actually worked.

Recently, I had the opportunity to see it in person. In Seattle on 10th Ave E between Harvard and Roy there is a section of street lighted by LED lights. It is both whiter and considerably brighter than the high-pressure sodium vapor lamps used elsewhere. I would have taken pictures but couldn’t find any place to park.

However, suffice it to say that LED’s are definitely up to the task. I worry a bit about the relatively broad spectrum and bright light, while visually better, might create worse light pollution and interfere with night sky viewing to a greater degree.

2 thoughts on “LED Street Lighting – Seattle

  1. Concern re LED street lights and the dark skies iniative is not founded on fact. LED street lights, in our experience as a major povider, have the opposite result as unlike high pressure sodium lights the LED light is focused on the ground through a specially designed lens system.Light pollution is therefore minimal.

    Graham Slane
    Visual Network Solutions Ltd (UK)

  2. Time will tell as more of these are installed. The high pressure sodium vapor lamps here are also fitted with a lens system that directs light downward.

    We wouldn’t be able to see anything if those surfaces weren’t reflective.

    Because the bulk of sodium vapors light output is in a very few narrow spectral lines, there are filters available for telescopes that greatly reduce their effect.

    But the spectrum of the LED lamps is much more broadband. That makes them visually much more pleasant but I do worry about the light being reflected back into the sky.

    I wonder why nobody has considered street lights with motion sensors so they come on when there is a car or pedestrian but shut off when there is no movement.

    That would seem to address light pollution issues as well as save energy and extend the life of the LEDs.

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