Streetlights are on all night, even in deserted neighborhoods in the wee hours of the morning. This is a waste of electricity and a contributor to light pollution.

Instead, cities should put motion detectors on streetlights. These would be sensitive enough to detect pedestrians and of course cars. A short-range signalling system would be used to turn on lights for a block or so around the motion, so cars will be able to see sufficiently far ahead to drive safely.
-- egnor, Feb 04 2001

The pestilence that walks in the Darkness ... http://www.gizmolog.../super/negotiam.htm
The great H P Lovecraft .... [8th of 7, Oct 05 2004, last modified Oct 21 2004]

No, see, the real problem is not the startup power consumption (which can easily be shown is negligible), but the fact that vapor lamps (Na or Hg) require ~10 minutes to turn on, by which time the car is long past.

But hey, we all know it's high time to replace these lights should be replaced by high-efficiency LEDs, anyway. Besides, if they use LEDs, they can switch the red/green/blue elements independently for holiday-themed street lighting (red and green near Christmas, orange on Halloween, pink on Valentine's Day, etc).
-- egnor, Feb 05 2001


There was a nice idea in New Scientist a few years ago advocating powering street lights near stop signs and roundabouts (and other places where cars have to slow down) from massive inductance coils buried beneath the road. The back emf the motion of the cars would create would slow them down nicely and generate power for the lights.
-- hippo, Feb 05 2001


Natural selection.
-- StarChaser, Feb 05 2001


I tend to wander around in the dark, having extremely good night vision, and having rooms suddenly go "FOOM!" in my face while my eyes are adapted would shortly thereafter result in my having to buy a whole bunch of new lamps...
-- StarChaser, Mar 31 2001


Rather than motion detection, the idea might want to use heat. That way if a car stops or has an accident, the lights stay on.
-- phoenix, Mar 11 2002


A well-designed system would sense your car's position and heading several blocks in advance, so that the lights would light up *before* you got within view of them, not as you got there. That would avoid the "FOOM!" effect -- drivers wouldn't be able to detect any difference from how the lights work now.
-- Jeremi, Mar 11 2002


Would you be able to sleep in a room which keeps being lit up by street lights? I think it would be very anoying...
-- RobertKidney, Mar 12 2002


[dammit, I'm only two years too late, almost. First 'good' idea I get since finding HB too. :o\ ]

...The only down side I can see is that the streetlights would need to be very sensitive so that they remain on if someone is stood still underneath one; else it would greatly improve the dramatics of being mugged (which'd at least give all parties a bigger adrenaline rush!): the mugger stands under a street light and waits until it goes off, then when an innocent passer-by approaches, the mugger is suddenly spotlighted from behind/above as they jump onto their victim acompanied by this trully brilliant stage lighting effect.

People are always after a bigger thrill with life these days anyway, this would meet that new dimension in an ordinary walk at night. (In winter).
-- Elhoy, Dec 09 2002


I once expereinced the opposite of this. As I was walking home, a number of sucessive streetlights went off as I approached and came on again as I walked away. Very Spooky so would be good to reverse the settings for Halloween.
-- oneoffdave, Dec 18 2002


"Negotium perambulans in tenebris" ??
-- 8th of 7, Dec 18 2002


So when the lights go out suddenly like that does it go "MOOF"? Or does "FOOM" still apply?
-- 2 fries shy of a happy meal, Dec 18 2002


How about saving power by keeping just a small fraction of lights on and scanning these over the ground very rapidly like searchlights. If they are swept fast enough then we would have the impression of a well-lit street at only a fraction of the cost.
-- donnythebull, Dec 18 2002


If the street were lit for only half a microsecond instead of a full microsecond, wouldn't we perceive that as being half as well-lit?
-- beland, May 26 2003


Running Lights

follow the vehicles

Flying on a clear night, one is rewarded with stunning views of the lit roads and highways below. Like strings of Christmas lights, the thoroughfares glow in white, amber and green, occasionally punctuated by the headlights of a car or truck that seems to crawl through the darkness. In spite of the radiant beauty, one is struck by the waste of energy caused by illuminating empty stretches.

By utilizing motion sensors and communicating with their neighbors, streetlights need only be turned on for passing traffic. Only the lights by and in front of each moving vehicle need be lit, benefiting taxpayers and astronomers. Of course such lighting must be able to be turned on and off quickly, and the wear and energy required for switching should not cancel out the benefits...and uh...be sure to search before writing the idea.
-- FarmerJohn, Aug 19 2004


"No, see, the real problem is not the startup power consumption (which can easily be shown is negligible), but the fact that vapor lamps (Na or Hg) require ~10 minutes to turn on, by which time the car is long past."

That's true - but those lamps are also designed to last years. For infrequent-use street lamps, why not just use halogen lamps? They also last through several years, and BWM suddenly has a hard-on for lamps of blinding intensity to be used as the standard driving lights. Widen the bowl of the reflector a little, and they'd work fine.

Better than LEDs, too.
-- shapu, Oct 06 2004



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