Evan wrote:


Because traffic signs (and therefore reflectors also) are made out
of aluminum sheet goods cut to whatever size and shape needed
for the specific application required and then a reflectorized
applique sheet which covers the entire surface is applied...

Galvanized steel would not last the years and years required of
a traffic sign... The applique graphics will fade from exposure to
the sun long before anything happens to the aluminum sheet
which would be recycled and made into other things... A sign
panel made of sheet steel would begin to rust even with a
coating on it...


Excellent points. I take it, then, that the guard rails are also made of
Aluminum for exactly the same reasons?