A problem with LEDs

This hit sci.engr.lighting today also, but the discussion was less silly there.

For one thing, there was even mention of statistics for number of crashes and body count to be attributable to snow-obscured LED traffic signals, and that was in combination with drivers being incompetent at driving through intersections controlled by snow-disabled LED traffic signals.

It appears to me so far from what was posted in S.E.L. that the crash count tallied so far is around 40 and the body count tallied so far is 1 nationwide through USA throughout its entire history so far with LED traffic signals. Most that I see were in existence for at least a few years already.

- Don Klipstein ( snipped-for-privacy@misty.com)

Reply to
Don Klipstein
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As it turns out, I have yet to see even one LED traffic signal effectively obscured by snow or any other form of water in Philadelphia and that city's suburbs. It does snow there, with only one of the past

135 winters there officially having only a trace of snowfall, an average one having about 21-22 inches of snow, and the worst one of the past 135 (1995-1996) having 66-67 or so inches of snow, including over 30 inches in a record-breaking storm. And by-and-large, northwestern parts of the city that I grew up in and most of the city's northern and western suburbs that most of my family has lived in since 1991 and that I know well usually get substantially more due to higher elevation.

And quite the share at least of the snow there is the wet sticky kind blamed for obscuring LED traffic signals. And most of it falls with wind in the range of "moderate breeze", "fresh breeze" or "strong breeze".

- Don Klipstein ( snipped-for-privacy@misty.com)

Reply to
Don Klipstein

Although I don't doubt that birds have built nests in traffic signals, I have yet to see this even once so far atage in late 40's and living and working entirely in urban and inner-ring-suburb locations. And I have roughly 50,000 miles experience driving cars almost entirely in such areas, along with a goodly 300,000 miles driving bicycles on streets in such areas, and walking on streets in such areas likely having lifetime mileage for me to be an additional 30,000 miles.

Perchance Philadelphia's birds are not as birdbrained as their politicians and Philadelphians electing/re-electing them to office are?

- Don Klipstein ( snipped-for-privacy@misty.com)

Reply to
Don Klipstein

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Oh no! Are we going to see cute young girls dancing around proclaiming "I'm an insulation girl!" Well, it gets the attention of the guys.

TDD

Reply to
The Daring Dufas

Should that one be the one to be the cream that rises to the top, I propose that it be an incandescent lightbulb designed to last 100,000 or 200,000 hours, or for that matter a 230V lightbulb with life expectancy at 120V of a couple million hours, even around a million at 130V.

A 100W 230V 1000-hour (or is it 1500?) Europe-typical big-brand (Philips or Osram) incandescent typically achieves IIRC around 1300 lumens at 230V.

At 120V, that one produces around 100 or mid-upper-90's lumens, and consumes 37 maybe 38 watts. I would take 2.5 lumens/watt (before losses from colored lenses) over zero when power consumption has to incur a large uptick and there is need for more light.

- Don Klipstein ( snipped-for-privacy@misty.com)

Reply to
Don Klipstein

I can't speak for Philly, but in Black, AL there has only been one signal light (period). Years ago (70/80s) "The boys" shot the lamps out of the blinker light (red/amber). Martins (birdies) made a nest in the signal. Eventually, a new highway was built around Black, Al and the signal was still the only one ever placed at the only intersection

- if you visit Black, AL.

Reply to
Oren

I think Walnut Grove, AL may have had two blinking lights. Funny thing about Black, AL, there are few Black folks residing there.

TDD

Reply to
The Daring Dufas

Oh my God! This is funny, I tripped over this link:

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TDD

Reply to
The Daring Dufas

All midgets outsourced to India, and China.

Reply to
Stormin Mormon

Look, if the federal government can settle a "little people" lawsuit over discrimination in public housing by building an entire apartment house in Chicago and letting about a thousand midgets, dwarfs, leprechauns, elves, and pygmies live there at no cost, they ought to be able to recruit enough workers for a few crucial intersections.

I've seen the apartment house. It's called the "Chicago Stay Free Mini-Pads."

Reply to
HeyBub

I believe some of Thomas Edison's light bulbs are still working. They are on DC and I'm sure the voltage is low. I don't think they ever turn them off or if they do it's slowly decreasing the voltage and the opposite for on.

Reply to
Tony

And we all complained about the heaters to keep refrigerators from getting condensation.

(Not aimed at anyone, just at the whole thread.)

Reply to
Tony

Seems to me that if you come to an intersection with a light and the snow is obscuring a smart person would want to stop. So maybe this is just another darwin example.

Reply to
jamesgangnc

I'd forgotten about that. You're totally correct.

Reply to
Stormin Mormon

BOO!!! HISS!!!

Reply to
Stormin Mormon

I used to live in Bolingbrook, IL, a southwestern suburb of Chicago. All the traffic light are LED. I have seen them obscured when there is a wind blown wet snow. But, it usually doesn't last long, so I don't know how much an issue it really is. BTW, they also had UPSs on every traffic light, so power failures didn't affect the lights. I don't know how many hours the lights would keep working.

Reply to
Art Todesco

Y'know, I think most of ours in town here in northern MN are incandescent still, but I've still seen them full of snow. I think all it takes is for there to be a little space open above the snow pile; the cold air gets in behind the pile and makes the heating effect from the bulbs irrelevant.

What they perhaps need are separate heaters at the bottom of the shrouds, but I'm not sure how that could be (reliably and relatively maintainance-free) switched so that the heaters only ran when they needed to. Perhaps there's some way of detecting how much light from the bulb is being reflected back (due to snow build-up) and tripping the heater that way.

cheers

Jules

Reply to
Jules

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