In article , Jimmie D wrote:

"Mark Lloyd" wrote in message
.. .
On Thu, 13 Mar 2008 02:36:47 +0000 (UTC), (Don
Klipstein) wrote:

Keep in mind the life expectancy of traffic signal incandescents in
traffic signal use.

- Don Klipstein )

I notice that all (or almost al) traffic signals around here use LED
arrays.

Same here, and most of them have a lot of burned out and flickering LEDs.
I thought they would last longer han this.

Philadelphia converted nearly all of their red traffic signals to LED
sometime in the late 1990's, at a time when red LED traffic signals had
GaAlAsP LEDs instead of InGaAlN ones. (The older chemistry glowed a
deeper shade of red, and was less efficient - red traffic signals of that
type consumed something like 30 watts, and the newer LED chemistry got
that down to something like 11-15 watts.)

A few percent, maybe several percent of Philadelphia's red traffic
signals have some LEDs out, but they are still largely working after
something like a decade.

Many of Upper Darby's red and green traffic signals were converted to
LED a few years ago. A couple of the green ones have a few LEDs out.

I seem to think that the LED ones are greatly outlasting incandescent
ones.

- Don Klipstein )