P3D Re: White LEDs hazardous?

["Gregory J. Wageman" <gjw@xxxxxxxxxx>]

Tom Hubin prognosticates:

>As for the actual spectrum. I have seen 2 versions and I am aware of a
>third. Each manufacturer has different stuff. All proprietary. Lots of
>progress being made. I predict that many common lamps like household
>bulbs and car headlights will soon be replaced with long life and very
>efficient white LED equivalents. You'll see.

Here in Silicon Valley, CalTrans is already replacing the red portion of
traffic signals with LED arrays (that is, arrays of red LEDs).  They are
obvious because they flash momentarily brighter when they first come on.
(Apparently, there is a sensor that regulates their brightness/color to
the precise level required by traffic standards.)  Only the red lights
are being replaced at this time; according to CalTrans, there aren't
sufficiently bright green and amber LEDs being made yet.

I've also seen truck and bus stoplights (red) and turn signals (amber)
that are obviously arrays of LEDs.

So I'd say your prediction is not at all far-fetched.

	-Greg (gjw@xxxxxxxxxx)