Fluorescent street lighting

[MadMan]

Chicago has been a high pressure sodium city for pretty much ever. Just recently moving over to LEDs. However, my shop is in Evanston, and the street lights there are pretty new (~5 years) and I always thought they were some kind of HID, metal halide or whatever. A couple weeks ago, I looked up close while one was lighting, and to my surprise I found it was actually an induction fluorescent! The bulb is a rectangular loop. I honestly didn't know there were any street lamps like that.

But otherwise no. lol

[MIPS]

Originally Posted by MadMan

Chicago has been a high pressure sodium city for pretty much ever.

State Street for a while ran a few blocks of fluorescent. According to the internet it was all radio controlled.



Looks ridiculous if you ask me. That is four lamps per pole.

[Eric H]

This brought back something I haven't thought of in years, if ever.

I can't remember fluorescent street lamps but I'm almost sure they were used at Grocery and Department Stores in the parking lots.

[Telecolor 3007]

In Bucharest (trolleybuses still run there; that portion of boulevard is called nowday Regina Elizebata and on the uphill side it's going to that avenue with variation of lighting): http://2.bp.blogspot.com/_yBuaXM1mcZ...iu-Dej1975.jpg Picture is from around 1966-1967. By 1971, those lamps where gone.
Here is an colour picture: http://i.imgur.com/PcGAdxvl.jpg Same avenue, but uphill. The downhill is a river valley, dug by Dâmobviţa (Dâmbovitza) River, the main river of Bucharest.

[old_tv_nut]

Originally Posted by MIPS

State Street for a while ran a few blocks of fluorescent. According to the internet it was all radio controlled.



Looks ridiculous if you ask me. That is four lamps per pole.

Fluorescents are generally sub-optimum for operation in cold climates. Fixtures have to be specially designed to prevent low output and random flickering.

If you're a Chicagoan of my age you can recall those State Street fluorescent lamps being brighter than other streets. Then along came much brighter mercury vapor lamps, bright enough on the main streets that people would forget to turn on their headlights when leaving a gas station. Those were replaced by even brighter high pressure sodium, used for a long time until LEDs started to become available. There is currently some not-completely verified research that the bright bluish white LEDs could disturb sleep rythms or have other effects, and the suggestion is to use "warm white" LEDs instead. Similar negative claims were made about mercury vapor, but apparently never got any traction.

There is experimental evidence that the color temperature that appears most neutral depends on the lighting level, and esthetically, artifical light should be "warmer" (lower color temperature) at low levels like street lighting, and daylight (higher) color temperature only in applications where the light levels are quite high, like a glassed-in atrium. I experienced this personally in the high definition TV trials in the 1990s, where the test viewing room was lit with D65 fluorescents lamps as a low level background to the TV pictures, which are much brighter but standardized at D65 white. On entering the room, I could not convince myself that the light was actually neutral. The human visual system's "color constancy" can simultaneously identify white objects in that light as white (not blue) while seeing that the overall light is bluish.

So, whether or not the "bright white" LED street lights have any health effects at all, most people dislike them, and changing to "soft white" color temperature will fix that.