> FWIW, I was passed by a trucker last night with apparent LED tail lights on
> his trailer.  It had multiple LEDs it appeared.

I should hope so!  They've made great strides in producing "super-bright"
red LEDs, but I don't think that a single of even the best ones now made
would be sufficient.

Someone mentioned that they'd only seen LEDs used in red traffic signals,
but not the other colors.  There's one intersection in Sunnyvale, CA at
which I've seen LEDs used in the green signal.  I suspect that they are
doing a trial, as I haven't yet seen them elsewhere.