[Darksky][DSLF] Digest Number 414 (fwd)

[Jan Hollan]

see mainly the continuing discussion on CO/FCO (message 3), but also the
traffic signs (1). j.

---------- Forwarded message ----------
Date: 26 Aug 2001 09:09:58 -0000
From: DarkSky-listAyahoogroups...
To: DarkSky-listAyahoogroups...
Subject: [DSLF]  Digest Number 414

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There are 3 messages in this issue.

Topics in this digest:

      1. RE: Caltrans sign lighting updates
           From: Dave DeSantis <desantisAsasquatch...>
      2. AASHTO
           From: Gary Citro <callistoAoptonline...>
      3. FCO vr SCO
           From: "Fabio Falchi" <fabio.falchiAlibero...>


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Message: 1
   Date: Sat, 25 Aug 2001 13:14:06 -0700
   From: Dave DeSantis <desantisAsasquatch...>
Subject: RE: Caltrans sign lighting updates

Actually, Caltrans is gradually starting to switch to new reflective
signage, which is now a federal MUTCD requirement. And I was told by a
friend that Caltrans is also considering removing some of the sign lights
on those that already have reflective signage where the headlights are
considered to be sufficent. It is Caltrans' policy that all old button
copy signs with non reflective backgrounds are to remain lit, and that the
new reflective signage can still have lighting where visibility may be a
problem, such as around curves on the freeways, etc. Also, some of the
imported cars from Europe have cut off headlights that permits lighting
only on the pavement. This greatly reduces glare but poses a problem when
it comes to sign visibility where no sign lighting is used. But still, you
are right, reflective signs really do not need any lighting because when
you add lighting, they make the signs brighter than necessary; making them
even harder to read...thats definitely a waste of energy:(

Hope this helps.

Dave



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Message: 2
   Date: Sat, 25 Aug 2001 14:26:05 -0400
   From: Gary Citro <callistoAoptonline...>
Subject: AASHTO

As a recent message points out, at the end of the
day, we're still stuck w/ current AASHTO standards, as far as highway
lighting is concerned.
FWIW, As part of the NY effort, Gail Clyma has found out that AASHTO
anticipates having an updated guide out around May-June of next year.

Gary Citro




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Message: 3
   Date: Sun, 26 Aug 2001 09:20:13 +0200
   From: "Fabio Falchi" <fabio.falchiAlibero...>
Subject: FCO vr SCO

Hi Cliff,

why do you use a percentage when the simplest thing is to use the light
intensity in candles/klumens? The intensity at various angles is plotted or
tabulated on the fixtures tech data sheet of the manufactures, so that we
know how the product behaves.
The fact that CIE has not a definition of FCO yet should push us to make
pressure on CIE to adopt no limitations between 0° and 89.999°...If this
definition is adopted the pole spacing can be the same or even larger (if we
consider the glare factor that decrease the need of high luminance) than
SCO: David, could you explain where are physical law violated? There is no
reason that a limitation in the light above the horizon give us a shorter
pole spacing.
IES should consequently adhere to the Commission Internationale de
l'Eclairage. In the law and regulation we push to be approved we should
include not the FCO term (ambiguos and which definition we have no control
on), but the 0 cd/klm on and above the horizon.

Clear skies,
Fabio

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FABIO FALCHI
Istituto di Scienza e Tecnologia dell'Inquinamento Luminoso - ISTIL
Light Pollution Science and Technology Institute
e-mail:  falchiAlightpollution...
web:     http://www.lightpollution.it/dmsp/
            http://www.istil.it
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