The Daring Dufas wrote:
Pete C. wrote:
The Daring Dufas wrote:
Pete C. wrote:
The Daring Dufas wrote:
Pete C. wrote:
The Daring Dufas wrote:
HeyBub wrote:
When used in traffic signals, the lights don't get warm enough
to melt snow.
The snow obscures the signal and people die.

"Cities around the country that have installed energy-efficient
traffic
lights are discovering a hazardous downside: The bulbs don't
burn hot enough
to melt snow and can become crusted over in a storm - a problem
blamed for
dozens of accidents and at least one death."

http://news.yahoo.com/s/ap/20091216/...red_stoplights


Some cities are considering hiring midgets to sit atop the
signals with
hair-dryers and long extension cords to keep the traffic signals
clear.
(Some species of monkeys could be trained to do the job, but the
training
time would take too long to be effective this season.)


I can see a couple of ways to prevent the problem and one is to use
the type of heater that is used in outdoor CCTV cameras. Another
way would be a simple snap on clear plastic cover that would prevent
snow from getting into the hooded area. Oh yea, teeny little
windshield
wipers.

TDD
I would expect it wouldn't be that difficult to install an optical
sensor at the end of the hood looking back at the light and use
that to
switch on a heater if it did not detect sufficient brightness when
the
signal light was on. No extra energy use unless there actually was
snow
obscuring the signal. Probably around $20 manufacturing cost, so sell
for $200, a fairly insignificant cost given what the signals
themselves
cost. Also only needed in climates that have blowing sticking snow.
Using the same material as used in the manufacture of self regulating
heat tape, an inexpensive add on heater that worked automatically
could
be produced.

TDD
No point in heating all the time, or even just when it's cold. Much
better to heat only when it's cold and something (snow) is obscuring
the
light. The minimal cost of the extra control components will be far
outweighed by the lifetime power savings of only having the heater
active during sticking snow events.
Birds have actually built nests in the lights so turning on a heater
every time a bird lights in the light (pun) you would turn on heat.

TDD

Yes, but that's an entirely different problem, and one that would
afflict both LED and incandescent signals.

If it's a Hippie bird, it would build its nest in a flashing light
because it's psychedelic. *snicker*

I think a Hippie bird would choose the red lights with the flashing
white strobe light in it. Cool man. That's cool.