terry wrote:
Often wondered why street lights on all night. Wasted energy etc. Also
unnecessary pollution where electrcity is generated by coal or other
fossil fuel. Could save some small municipalities some cost?


For the same reason that street lights are (usually) not on during the
daytime. Street lights are on at night so people (mostly) and animals can
see.

They also act as a deterrent - roaches don't like light.

I live across the street from an apartment house. There is a largish street
light in front of my house that illuminates the street (of course) and the
parking lot of the apartment complex. Every time the light goes out (the
last time because some fool hit it while doing about 100mph) the goblins at
the apartment house come out to play. For all I can tell, they are dancing
around semi-naked while chanting unintelligible incantations to something
that cannot even charitably be called music. It's spooky and the only thing
I can do is maintain a well-armed vigilance lest their witch-doctor lose
control or they run out of virgins.