Street lights shine all night whether or not anyone is there. This is a waste of electricity and causes light pollution. If street lights were set off by something indicating the presence of a human being, such as body temperature, sound, carbon dioxide or something similar, to which they were also fairly sensitive, they would be on around someone alone at night but otherwise off. This would also be safer, as the presence of possible attackers would be signalled by the lights around them being on. In busier areas the lights would be on most of the time, in quiet areas they would signal the presence of a possible threat.

The problem is finding something specific enough to people that can't be disguised.

I feel there is some basic flaw with this idea that i'm missing. Someone please enlighten me.
-- nineteenthly, Jan 20 2005

Dark Campus Policy http://www.darksky....infoshts/is054.html
Keeping things dark at school. [oneoffdave, Jan 20 2005]

HB archives: "streetlight motion detector" streetlight_20motion_20detector
Circa early 2002 from [egnor]. Lacking the mysterious human-detection feature, of course. [bristolz, Jan 20 2005]

The flaw is that it's baked. With photocells, motion sensors, etc. And some have found that going dark is best. For instance, "Vandalism and graffiti have been successfully reduced in many American schools with the Dark Campus Policy... Vandalism and graffiti-and the associated cost of repairs-dropped immediately when "security" lights were removed or turned off."
-- ldischler, Jan 20 2005


Excellent. Not baked over an entire city though. I'm glad there's evidence in favour of it working.
-- nineteenthly, Jan 20 2005


For some reason I feel that this wouldn't be economical due to filament strain . . . the cost of the shortened life span of the bulbs, and man-hours and materials costs to save a few cents worth of electricity.

I would draw a parallel to street lanterns . . . having someone at each lamp to put it out and reignite it every time someone came along, to save gas.

*shrug*

That, and it's baked. :-)
-- contracts, Jan 20 2005


Two of the streetlights on my street do this, except in reverse. They turn *off* when someone approaches (walking, car, whatever).
-- tekym, Jan 20 2005


Sodium lamps do not have filaments, but i think you could be right about the inefficiency, because i think streetlights might use a lot of energy when they're first turned on, [contracts]. However, would it make any difference if the lamp dimmed rather than went out completely, or if an LED-type system were used instead? They needn't be very bright. Also, economics is not the only issue.

I looked for a similar idea, but didn't find it. Sorry.
-- nineteenthly, Jan 20 2005


Sodium lamps do not have filaments, but i think you could be right about the inefficiency, because i think streetlights might use a lot of energy when they're first turned on, [contracts]. However, would it make any difference if the lamp dimmed rather than went out completely, or if an LED-type system were used instead? They needn't be very bright. Also, economics is not the only issue.

I looked for a similar idea, but didn't find it. Sorry. Was there no "street lighting" category then?
-- nineteenthly, Jan 20 2005


I had an old idea like this that involved sensitive magnetic slide chargers and LEDs, but I guess I deleted it
-- schematics, Jan 22 2005


oh no ! these stray dogs & cats exhale CO2 & keep the lamps glowing most of the time.
-- vedarshi, Jan 22 2005



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