"charles" wrote in message
...
In article ,
Nightjar wrote:
On 15/03/2013 01:41, Arfa Daily wrote:
...
A very interesting reference document. It is now in my favourites. As
to
driving in the dark, I think a lot depends on your age. I don't know if
it is a general physical degradation in your night time vision, or just
a perceived thing. What I do know is that I am a lot less comfortable
now driving in the dark, than I was 20 years ago....

It is age related. I read somewhere that, by the time you are 80, you
have night vision equivalent to a 20 year old wearing dark sunglasses.

and another problem is that cataracts tend to cause flare from bright
lights.

--
From KT24

Using a RISC OS computer running v5.18



Again, something that many of us will suffer without it impacting on our
general life, and without it being a big issue - at least in the earlier
stages - as long as stuff is well and properly lit at night. At the moment,
I still have a LPS light standard right outside my house. I would guess that
it is about 4 metres tall. It has a 35 watt lamp fitted. With the 'turn-off'
regime that we have suffered in the street, it is the only light for some
distance in both directions. However, looking out of the window last night,
everything was clearly illuminated in both directions up and down the
street, including all of the gardens across the street, which I think is an
important security 'feature'. At the other end of the street, where the
light standards have been replaced, these are now some 2 metres taller, so
immediately change the whole character of the street. They just look 'wrong'
in an urban street of houses type setting. Height wise, they would be ok on
a main road.

The light from them does not light the street in the same 'pleasant' way -
even setting aside the monochromatic and poor CRI nature of sodium - as the
existing lights. The light is concentrated to the point where there is none
in gardens. I guess that this is because the optics have been designed to
squeeze as much light out of the mono-planar LEDs as possible, to justify
the efficiency claims that are made for them ...

Arfa