At 05:13 PM 7/27/99 , you wrote:

>
>To facilitate things, I heard that they will implement a fourth color
>lamp (blue) by this way the code list could be expanded.
>
>:)

They already have blue lights- if you ever get the chance to see a regular
incandescent stop-light lens- the green lens is actually blue.   I guess it
is because of the yellow tinge that most incandescents have.  (The blue
lens thing is really the truth... Before he retired, my father worked for
the US Dept. of Transportation, Federal Highway Administration, and for a
while he was head of the division that was working on uniform signs and
signals.  This was before the advent of LED stoplights, however.)

Matt Bennett