[Darksky][DSLF] Digest Number 415 (fwd)
Jan Hollan
Tue, 28 Aug 2001 14:37:09 +0200 (CEST)
more on LED signs and FCO...
---------- Forwarded message ----------
Date: 27 Aug 2001 09:08:11 -0000
From: DarkSky-listAyahoogroups...
To: DarkSky-listAyahoogroups...
Subject: [DSLF] Digest Number 415
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There are 6 messages in this issue.
Topics in this digest:
1. Re: FCO vr SCO
From: ctstarwchrAaol...
2. LED Traffic Lights
From: "Mark Klosinski" <klosinskiAntelos...>
3. Re: AASHTO
From: ctstarwchrAaol...
4. Re: LED Traffic Lights
From: ctstarwchrAaol...
5. VDOT has *Smart Roads*
From: ctstarwchrAaol...
6. Re: LED Traffic Lights
From: "Randy John" <skysatAhome...>
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Message: 1
Date: Sun, 26 Aug 2001 08:55:58 -0000
From: ctstarwchrAaol...
Subject: Re: FCO vr SCO
--- In DarkSky-listAy....., "Fabio Falchi" <fabio.falchiAl.....> wrote:
> 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.
>
Hi Fabio:
What you say is absolutely true and I agree completely from a
luminaire design specification standpoint. However, most people not
directly involved in the design process do not understand how to
decipher and evaluate photometric or isofootcandle plots. Stating
the illumination distribution properties in percentages tends to
enhance the level of understanding by the group as a whole. The
Illumination Engineering Society of North America (IESNA) also states
fixture luminance distribution properties in percentages as well.
When presenting this information to legislators they can immediately
visualize what we are saying if speaking in percentage of waste. To
present them with lumens, lux or footcandles of illuminance, and
candela of luminance per square meter at a given angle merely makes
their eyes glaze over with confusion, and rightly so. Most average
people do not know the difference between a lumen and a lemon, mainly
because the terms and concepts of illumination design are not a part
of their daily lives.
When giving presentations, I always strive to use the most effective
means with simple terminology to help others achieve a good level of
understanding. Percentages allow accurate mental images to rapidly
be formed, but 10 candela per 1000 candela of luminance at a given
angle is a very complex issue for most people to rapidly image in
their mind. Hope it helps.
Clear skies,
Cliff
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Message: 2
Date: Sun, 26 Aug 2001 10:02:28 -0400
From: "Mark Klosinski" <klosinskiAntelos...>
Subject: LED Traffic Lights
Hi all:
Has anyone in this group experienced or heard anything about the new "lamps"
for traffic lights? (I assume they are LED Lamps. Maybe about a hundred
little lights.) I first noticed it around Harrisonburg, VA about two months
ago. The lights are brighter than the normal lights. (Does anyone have any
readings?) The lights were not particularly bad in the city. But on my way
home from a star party the other night, I noticed some on a highway outside
the city. Once I went through the light, it was light I was moving into a
vail of darkness. It was kind of frightning. I could not see a thing on
the other side of the traffic light until my eyes readapted.
Any information on these light would be appreciated.
clear skies,
Mark Klosinski
Astro-officers
http://personal.cfw.com/~klosinski/
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Message: 3
Date: Sun, 26 Aug 2001 15:50:18 EDT
From: ctstarwchrAaol...
Subject: Re: AASHTO
In a message dated 8/26/01 12:53:25 AM Eastern Daylight Time,
callistoAoptonline... writes:
> 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:
This might be good news, but it might also tend to bring even more lumens
into our environment depending upon the AASHTO interpretation of what *better
lighting* means. "An Informational Guide for Roadway Lighting" published by
AASHTO was last revised in 1984 before FCO was the preferred method of
roadway lighting.
The facts indicate that traffic fatalities among elderly drivers have risen
dramatically (33%) in the past ten years in spite of the fact that traffic
fatalities have gone down by 9% overall according to October 6, 2000, AASHTO
Journal Volume 100, Number 40. This document states that The Road
Information Program (TRIP), a nonprofit research group, has made the
following recommendations for signage and roadway lighting:
- clearer and less complex signage that is easier to follow (makes sense)
- larger lettering on signs (also makes sense)
- better street lighting, particularly at intersections (please define
*better*)
Recommendations for reducing fatalities at intersections:
- bright, luminous lane markings (facilitated by what means? More lights??)
- overhead indicators for turning lanes (proven to reduce accidents)
- overhead street-signs on both sides (also proven to reduce accidents)
- add or expand left-turn lanes and make sure they are adequate in length
The document also states that federal reports indicate that the aging process
gradually leads to reduced visual acuity, slower reaction times, losses in
information processing ability, and reduced neck and upper body flexibility.
Better lighting to folks like us means a dramatic decrease in visible glare
without loss of illumination of the task area, but what does *better* mean to
TRIP when they make these recommendations to the AASHTO and the Federal
Highway Administration? Has anyone read or have a copy of, "The Older Driver
Highway Design Handbook", published by the Federal Highway Administration?
Although I have not seen the specifications yet, it is very likely that
AASHTO uses standards for roadway lighting based on recommendations of the
Army Corps of Engineers, which still goes by IESNA RP-8-83 recommended
practices. Since the recently published RP-8-00 is ANSI approved it should
be a no-brainer for the ACE to adopt the current IES recommended practices.
Glare reduction with outdoor lighting must be pursued aggressively because
glare is the foremost contributor to reduced visual acuity in the nighttime
environment.
Clear skies,
Cliff Haas
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|| / FCO \
|| / the way \
|| / to go! \
||/ www. \
/| darksky.org \
/||______________\_
Light Pollution Awareness Website
http://members.aol.com/ctstarwchr
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Message: 4
Date: Sun, 26 Aug 2001 16:41:24 -0000
From: ctstarwchrAaol...
Subject: Re: LED Traffic Lights
--- In DarkSky-listAy....., "Mark Klosinski" <klosinskiAn.....> wrote:
>
> Has anyone in this group experienced or heard anything about the
> new "lamps" for traffic lights? (I assume they are LED Lamps.
> Maybe about a hundred little lights.) I first noticed it around
> Harrisonburg, VA about two months ago. The lights are brighter
> than the normal lights. (Does anyone have any readings?)
>
Hi Mark:
What you have experienced sounds very much like the testimony of
others (self included) who have encountered these new LED traffic
signals in high contrast (dark) areas. Here is one clue to help
determine whether a traffic signal is the new LED type.
If you notice a black masque separating each point of illumination in
the signals for red, yellow, and green, it is a pretty good bet you
are behind a new LED retrofit. The matrix appears much like a
ceramic tile floor (tiles represent light source) with the grout
representing the masque. This is not typical of ALL LED traffic
signal designs as you will see at one link provided below, however.
More info about LED traffic signals is available at:
"LED Traffic Signal Lighting" - US Army Forces Command Energy Program
http://www.pnl.gov/forscom/led.html
"LED Traffic Signal Market Transformation: An Update With Boston-Area
Case Studies," published by the American Council for an Energy-
Efficient Economy
http://www.aceee.org/pubs/a011.htm
Product information
http://www.tomar.com/products/sectionj/p084-5.htm
"LED Traffic Signal Program"
http://www.sdge.com/solutions/LEDInfoSheet.html
A search on the web will provide more information...
http://www.google.com/search?q=LED+traffic+signal
Hope it helps!
Cheers,
Cliff Haas
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Message: 5
Date: Sun, 26 Aug 2001 20:44:18 EDT
From: ctstarwchrAaol...
Subject: VDOT has *Smart Roads*
Greetings:
The Virginia Department of Transportation (VDOT)
[http://www.vdot.state.va.us], in cooperation with Virginia Tech's
Transportation Institute (VTTI) [http://www.ctr.vt.edu] and the Federal
Highway Administration (FHWA) [http://www.fhwa.dot.gov], developed a concept
known as the "Smart Road" which allows them to simulate various driving
conditions in an effort to find solutions that improve highway safety.
Included are the ability for VDOT to simulate weather and the system also has
3 different lighting systems to study the effectiveness of reducing
accidents. I'm wondering if they have been experimenting with various
different FCO luminaires. Does anyone know if they have? I tried contacting the two VDOT engineers via email but a few minutes later I received bogus address reports coming back. Maybe the VDOT email server was down for the weekend?
http://www.transportation.org/aashto/success.nsf/SearchSite/057C73A7306518A486256A3200686412?OpenDocument&Highlight=lighting
This link might split into two or three lines. Be sure to cumulatively paste
each line to your browser.
Clear skies and good seeing,
Keep looking up!
Cliff Haas
Chairman of Light Pollution Education
Astronomical Society of Greater Hartford
http://members.aol.com/copernicanview
Light Pollution Awareness Website (LiPAW)
http://members.aol.com/ctstarwchr
Help rid your area of obtrusive outdoor lighting.
Visit http://www.darksky.org Join the IDA today!
[Non-text portions of this message have been removed]
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Message: 6
Date: Mon, 27 Aug 2001 06:13:22 -0000
From: "Randy John" <skysatAhome...>
Subject: Re: LED Traffic Lights
Mark,
Here are some more LED links to add to Cliff's.
Randy
http://www.dialight.com/
http://www.lumileds.com/
http://www.ite.org/
http://www.lrc.rpi.edu/Ltgtrans/LED/
http://www.lrc.rpi.edu/Futures/LF-LEDs/index.html
----- Original Message -----
From: "Mark Klosinski" <klosinskiAntelos...>
To: "DarkSky-list" <DarkSky-listAyahoogroups...>
Sent: Sunday, August 26, 2001 2:02 PM
Subject: [DSLF] LED Traffic Lights
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