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The University of Aalborg Study on Daytime Flashing Lights forBicycles.



 
 
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  #51  
Old March 22nd 17, 02:44 AM posted to rec.bicycles.tech
Frank Krygowski[_4_]
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Posts: 5,847
Default The University of Aalborg Study on Daytime Flashing Lights forBicycles.

On 3/21/2017 10:49 AM, wrote:

I was pulled over by a cop and given a mechanical ticket (out of date tag). How did he pick me out of the lot of San Mateo Bridge traffic? I was the only one driving the speed limit and attentive. This says an awful lot about the attentiveness of the average driver.


I don't mean to disagree with the reason the cop paid attention to you.
But I'll raise another possibility.

As I understand it, many (perhaps most?) cop cars these days have
equipment that reads the license plate and tells the cop if there is a
problem associated with it. The problems can be anything from expired
plate to warrant for arrest and beyond. Maybe you were in a database
that the cop's computer accessed.

The scary thing about this relatively new development is that last I
heard, in some states the results of "plate reading" systems are public
record. That means a potential burglar can demand to see every time
your plate has been detected and where; and from that, perhaps learn
when your house is guaranteed to be empty. Or an ex-spouse can track a
former spouse's car and use the data for stalking or other nefarious
purposes. It really does smack of "big brother" or worse.

--
- Frank Krygowski
Ads
  #52  
Old March 22nd 17, 02:54 AM posted to rec.bicycles.tech
Tim McNamara
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Posts: 6,792
Default The University of Aalborg Study on Daytime Flashing Lights forBicycles.

On Sun, 19 Mar 2017 11:53:38 -0700, sms
wrote:
I know how some people dislike any statements that are based on actual
facts, but the data are pretty clear.

See: https://books.google.com.au/books?id=LvthAgAAQBAJ&pg=PA168

It was interesting that in the Odense study, conducted by Reelight,

^^^^^^^^^^^^^^^^^^^^^
Odense Cycle City and the University of Aalborg, accident rates went
down by 32% with the use of daytime lights, but a cyclist's "sense of
security" went up by 85%!


It's funny how often research just happens to find what the person
paying for the research would like it to find (unless you're a
Republican politician paying for climate change research).

That said, I wouldn't be surprised if daytime flashing lights did have a
net positive effect on rider safety. Seems to me the problems with
those are when they are a rider's only light at night.

My car has daytime running lights set to be on by default. Motorcycles
have headlights on when riding during the day or night by law here. The
research on DRLs is not especially consistent but seems net positive,
sometimes barely so and sometimes significantly so:

http://www.dot.state.mn.us/research/...11/TRS1009.pdf

"The most recent large-scale study on this topic conducted in the United
States is a 2008 NHTSA study that found that DRLs had no statistically
significant effects on the types of crashes studied, except for a 5.7
percent reduction in the involvement of light trucks/vans in two-vehicle
crashes. A 2004 NHTSA study that used different analysis methodology
found that DRLs reduced opposite-direction fatal crashes by 5 percent
and opposite-direction/angle non-fatal crashes by 5 percent. That study
also found a 12 percent reduction in crashes involving pedestrians and
bicyclists, and a 23 percent reduction in opposite-direction crashes
involving motorcyclists."

Of at least some interest to us, there may be some evidence that DRLs on
cars might reduce your chances of getting killed in a collision with
one. None of the studies cited seem to have tried DRLs on bicycles.

But the article also points out that methodology has an effect on the
existence, direction and magnitude of any particular outcome. A
seemingly large result with one methodology might not be statistically
significant with another.
  #53  
Old March 22nd 17, 07:34 AM posted to rec.bicycles.tech
John B.[_3_]
external usenet poster
 
Posts: 3,963
Default The University of Aalborg Study on Daytime Flashing Lights for Bicycles.

5On Tue, 21 Mar 2017 21:54:43 -0500, Tim McNamara
wrote:

On Sun, 19 Mar 2017 11:53:38 -0700, sms
wrote:
I know how some people dislike any statements that are based on actual
facts, but the data are pretty clear.

See: https://books.google.com.au/books?id=LvthAgAAQBAJ&pg=PA168

It was interesting that in the Odense study, conducted by Reelight,

^^^^^^^^^^^^^^^^^^^^^
Odense Cycle City and the University of Aalborg, accident rates went
down by 32% with the use of daytime lights, but a cyclist's "sense of
security" went up by 85%!


It's funny how often research just happens to find what the person
paying for the research would like it to find (unless you're a
Republican politician paying for climate change research).

That said, I wouldn't be surprised if daytime flashing lights did have a
net positive effect on rider safety. Seems to me the problems with
those are when they are a rider's only light at night.

My car has daytime running lights set to be on by default. Motorcycles
have headlights on when riding during the day or night by law here. The
research on DRLs is not especially consistent but seems net positive,
sometimes barely so and sometimes significantly so:

http://www.dot.state.mn.us/research/...11/TRS1009.pdf

"The most recent large-scale study on this topic conducted in the United
States is a 2008 NHTSA study that found that DRLs had no statistically
significant effects on the types of crashes studied, except for a 5.7
percent reduction in the involvement of light trucks/vans in two-vehicle
crashes. A 2004 NHTSA study that used different analysis methodology
found that DRLs reduced opposite-direction fatal crashes by 5 percent
and opposite-direction/angle non-fatal crashes by 5 percent. That study
also found a 12 percent reduction in crashes involving pedestrians and
bicyclists, and a 23 percent reduction in opposite-direction crashes
involving motorcyclists."

Of at least some interest to us, there may be some evidence that DRLs on
cars might reduce your chances of getting killed in a collision with
one. None of the studies cited seem to have tried DRLs on bicycles.

But the article also points out that methodology has an effect on the
existence, direction and magnitude of any particular outcome. A
seemingly large result with one methodology might not be statistically
significant with another.


There are innumerable;e studies of the effect of various warning
devices for aircraft viability. highway warning systems, lighting for
ships, and so on that spell such mundane subjects as optimum flash
rate, minimum effective light brightness and so on.

As an example, International Regulations for Preventing Collisions at
Sea 1972 (Colregs), states that a masthead (white) light must be
visible at 6 miles for a vessel of more than 50 meters, from 50 - 12 M
for 3 miles and for a vessel less than 12 M for 2 miles. the red an
green side lights for 3, 2 and 1 miles.

I have never seen such specifications for bicycles. Rather I read
"Ooooo this is a really bright light. It has got to be safe"

I did see, once, a really bright bicycle light. It was about 08:00
(sun up about 05:00) and I was riding on a road with little traffic.
This incredibly bright light came over a hill, perhaps a kilometer
ahead of me. I actually could saw the light before I could see what it
was mounted on. When we finally passed each other I could see that
this guy had a black tube, about a foot and a half long, mounted on
his handle bars. I think he had a six cell mag-light clamped on his
bike, but as I didn't stop to talk with him I can't be sure. But it
sure was bright.

But I don't see six cell mag-lights being suggested for bicycles :-)
--
Cheers,

John B.

  #54  
Old March 22nd 17, 07:56 AM posted to rec.bicycles.tech
John B.[_3_]
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Posts: 3,963
Default The University of Aalborg Study on Daytime Flashing Lights for Bicycles.

On Tue, 21 Mar 2017 18:55:46 -0700, Jeff Liebermann
wrote:

On Mon, 20 Mar 2017 23:37:08 -0700, sms
wrote:

On 3/20/2017 11:06 PM, Jeff Liebermann wrote:
On Mon, 20 Mar 2017 14:26:35 -0700, sms
wrote:

Anytime someone doesn't like the results of a study they try to pick it
apart.

Actually, common practice is to first blame someone and then pick
apart the argument. However, I prefer to undermine the study and let
it collapse under its own weight.

If "pick it apart" is an unacceptable method of debating the merits of
a study, what would you consider to be an acceptable method for this
newsgroup? I could use propaganda, various logical fallacies,
anecdotal evidence, my personal feelings, or perhaps fabricate a
contradictory study. Methinks that "pick it apart" is the same as
breaking down the study into individual claims and seeing how each one
holds together under stress.


There is a tendency to nitpick little things and then to declare the
entire study as worthless, when in fact, other than perhaps in drug
trials, there is just not going to be a "perfect study." Yet the goal of
the study was to determine if flashing lights were effective, and if so,
use the data to remove a ban on flashing lights. The company that was
involved in the study certainly had a vested interest in the outcome,
but they are only one of a multitude of companies that are benefiting
from the outcome.

(...)

You ignored my question. If "pick it apart" is an unacceptable method
of discussing the merits of a study, what is an acceptable method?
Picking at the details while ignoring the main points is common
enough. You are doing it right here in this discussion. My main
point was that there is no proof that a correlation between bicycle
crashes and flashing lights constitutes causation. You ignored that
and went on to deal with the trivia.

Let me propose a method, extracted from my previous rant, which I use:
1. Go to the original source. Avoid summary or survey sources.
2. Find what person or organization is paying for the study. That
often reveals a hidden agenda.
3. Compare the abstract and summery in the report with the actual
data. Often, they're quite different.
4. Look for inconsistencies, dubious sources, "normalization",
pre-selection of participants, and statistical creativity.

All this is certainly "pick it apart" methodology. Oddly, I can't
find a better way to deal with a study or report.

You also seem to ignoring the not so trivial problem that we *ALL* are
discussing the issue without access to the original report and numbers
from the trial. I would like to see the number of accidents with and
without the flashing lights, the methodology, and how the numbers were
produced before blundering further with my guesswork.


There is some information available, although not much. Reelight
apparently donated some 2,000 fore and aft flashing permanently
mounted and, essentially, always on lights for the study. The study
was in Denmark where I would guess that all, or nearly all, bicycles
are equipped with conventional lights as I have read that if one is
caught riding after dark the fine is a rather substantial amount -
perhaps a week's pay if my figures were correct, and in fact in one of
the reports it was stated that the test was between bicycles with a
permanently mounted and always on flashing light and bicycles equipped
with "conventional bicycle lights"

The results of the study was stated to be that the law covering
bicycle lighting was changed to allow flashing lights to be used.

(Hey Mister! Want to participate in this study? Well give you this
thing and all you have to do is fill out this report each week)

As an aside I might also mention that a good friend (now deceased)
owned a company that did financial analysis and the majority of the
studies he did were for companies that were investigating the
possibility of entering a specific market.

Surveys were a major factor in many, maybe most, of his market studies
and I remember him once stating he "could design a survey to prove
anything that the client required".

--
Cheers,

John B.

  #55  
Old March 22nd 17, 12:15 PM posted to rec.bicycles.tech
SMS
external usenet poster
 
Posts: 8,189
Default The University of Aalborg Study on Daytime Flashing Lights forBicycles.

On 3/21/2017 7:54 PM, Tim McNamara wrote:
On Sun, 19 Mar 2017 11:53:38 -0700, sms
wrote:
I know how some people dislike any statements that are based on actual
facts, but the data are pretty clear.

See: https://books.google.com.au/books?id=LvthAgAAQBAJ&pg=PA168

It was interesting that in the Odense study, conducted by Reelight,

^^^^^^^^^^^^^^^^^^^^^
Odense Cycle City and the University of Aalborg, accident rates went
down by 32% with the use of daytime lights, but a cyclist's "sense of
security" went up by 85%!


It's funny how often research just happens to find what the person
paying for the research would like it to find (unless you're a
Republican politician paying for climate change research).


You can understand the frustration of companies designing and producing
a product when there is a really stupid law that prevents them from
selling their product in some countries. It was pretty smart to actually
get with a university to do a well-designed study rather than just
lobbying the government without any data at all.

Reelight may have supplied the 2000 lights used in the study, but the
benefit of the law banning flashing lights being overturned benefits all
cyclists and many companies; Reelight is just a bit player in the
bicycle lighting business.

  #56  
Old March 22nd 17, 12:17 PM posted to rec.bicycles.tech
SMS
external usenet poster
 
Posts: 8,189
Default The University of Aalborg Study on Daytime Flashing Lights forBicycles.

On 3/21/2017 6:55 PM, Jeff Liebermann wrote:
On Mon, 20 Mar 2017 23:37:08 -0700, sms
wrote:

On 3/20/2017 11:06 PM, Jeff Liebermann wrote:
On Mon, 20 Mar 2017 14:26:35 -0700, sms
wrote:

Anytime someone doesn't like the results of a study they try to pick it
apart.

Actually, common practice is to first blame someone and then pick
apart the argument. However, I prefer to undermine the study and let
it collapse under its own weight.

If "pick it apart" is an unacceptable method of debating the merits of
a study, what would you consider to be an acceptable method for this
newsgroup? I could use propaganda, various logical fallacies,
anecdotal evidence, my personal feelings, or perhaps fabricate a
contradictory study. Methinks that "pick it apart" is the same as
breaking down the study into individual claims and seeing how each one
holds together under stress.


There is a tendency to nitpick little things and then to declare the
entire study as worthless, when in fact, other than perhaps in drug
trials, there is just not going to be a "perfect study." Yet the goal of
the study was to determine if flashing lights were effective, and if so,
use the data to remove a ban on flashing lights. The company that was
involved in the study certainly had a vested interest in the outcome,
but they are only one of a multitude of companies that are benefiting
from the outcome.

(...)

You ignored my question. If "pick it apart" is an unacceptable method
of discussing the merits of a study, what is an acceptable method?


1. Attack the statistical sample.
2. Attack the methodology.
3. Attack the premise.

Alas it's not possible to do any of those three with the Odense study. A
huge sample, a sound methodology, and a provable premise.

You can't even claim "risk compensation."
  #57  
Old March 22nd 17, 02:25 PM posted to rec.bicycles.tech
JBeattie
external usenet poster
 
Posts: 3,053
Default The University of Aalborg Study on Daytime Flashing Lights for Bicycles.

On Wednesday, March 22, 2017 at 5:17:44 AM UTC-7, sms wrote:
On 3/21/2017 6:55 PM, Jeff Liebermann wrote:
On Mon, 20 Mar 2017 23:37:08 -0700, sms
wrote:

On 3/20/2017 11:06 PM, Jeff Liebermann wrote:
On Mon, 20 Mar 2017 14:26:35 -0700, sms
wrote:

Anytime someone doesn't like the results of a study they try to pick it
apart.

Actually, common practice is to first blame someone and then pick
apart the argument. However, I prefer to undermine the study and let
it collapse under its own weight.

If "pick it apart" is an unacceptable method of debating the merits of
a study, what would you consider to be an acceptable method for this
newsgroup? I could use propaganda, various logical fallacies,
anecdotal evidence, my personal feelings, or perhaps fabricate a
contradictory study. Methinks that "pick it apart" is the same as
breaking down the study into individual claims and seeing how each one
holds together under stress.


There is a tendency to nitpick little things and then to declare the
entire study as worthless, when in fact, other than perhaps in drug
trials, there is just not going to be a "perfect study." Yet the goal of
the study was to determine if flashing lights were effective, and if so,
use the data to remove a ban on flashing lights. The company that was
involved in the study certainly had a vested interest in the outcome,
but they are only one of a multitude of companies that are benefiting
from the outcome.

(...)

You ignored my question. If "pick it apart" is an unacceptable method
of discussing the merits of a study, what is an acceptable method?


1. Attack the statistical sample.
2. Attack the methodology.
3. Attack the premise.

Alas it's not possible to do any of those three with the Odense study. A
huge sample, a sound methodology, and a provable premise.

You can't even claim "risk compensation."


However, it is amazing to me that a little flea-watt light makes such a dramatic difference. I frequently encounter people with Knog Frogs and various blinkies that I don't notice until long after seeing the rider. Like John B, I've encountered riders with lights so bright that I see them before the rider, but those are rare cases -- as they should be. Riders should not be mistaken for BNSF locomotives. I want to slap those people.

As I understand it, the bicycle mode share in Odense is around 24%. There are lots of cyclists. One wonders why the addition of little flea-watt lights would make the flocks of cyclists more visible during the day. Not saying it ain't so, but it just seems odd. This is a bike commute in Portland: https://farm8.staticflickr.com/7613/...6661f837_z.jpg Gee, I didn't see those ten-thousand riders without lights, officer!

-- Jay Beattie.

  #58  
Old March 22nd 17, 03:51 PM posted to rec.bicycles.tech
Jeff Liebermann
external usenet poster
 
Posts: 2,744
Default The University of Aalborg Study on Daytime Flashing Lights for Bicycles.

On Wed, 22 Mar 2017 14:56:40 +0700, John B.
wrote:

There is some information available, although not much. Reelight
apparently donated some 2,000 fore and aft flashing permanently
mounted and, essentially, always on lights for the study. The study
was in Denmark where I would guess that all, or nearly all, bicycles
are equipped with conventional lights as I have read that if one is
caught riding after dark the fine is a rather substantial amount -
perhaps a week's pay if my figures were correct, and in fact in one of
the reports it was stated that the test was between bicycles with a
permanently mounted and always on flashing light and bicycles equipped
with "conventional bicycle lights"


So, the participants were expected to REMOVE their conventional
lighting system and replace it with a Reelight model? Or did they
leave both of them connected?

The results of the study was stated to be that the law covering
bicycle lighting was changed to allow flashing lights to be used.


That's probably true, as it provides a sales incentive. It also
explains why they ran the test in Denmark, where bicycles are very
common. I doubt that the Danish rule makers would accept a similar
study performed in another country as the basis for changing their
rules.

As an aside I might also mention that a good friend (now deceased)
owned a company that did financial analysis and the majority of the
studies he did were for companies that were investigating the
possibility of entering a specific market.

Surveys were a major factor in many, maybe most, of his market studies
and I remember him once stating he "could design a survey to prove
anything that the client required".


Agreed. I used to work in the advertising and market research sector.
I've also been involved in writing "customer satisfaction" surveys.
Most such surveys have nothing to do with the alleged topic. It's not
unusual to ask questions about unrelated products, buying habits,
driving habits, spending habits, mileage traveled, discretionary cash
available, etc. For example, the survey could be structured asking
indirectly if you bicycle commute, would you consider buying an
ADDITIONAL tail light for your machine(s). Here's one way how it's
done:

[Q] If this daytime flashing light saved your life, would you
consider purchasing one for all your bicycles?

Notice that the question assumes that the flashing light works and
will save lives. That would be followed by a few similar questions,
all assuming that the device works and saves lives. The last question
would be:

[Q] Do you believe the world would be a better place if everyone used
daytime flashing lights on their bicycles?

Most participants will automatically say yes because that's the
expected and "correct" answer. Then, the marketing people can say
"Almost everyone who took the survey would probably purchase a daytime
flashing bicycle light and will recommend it to all their friends".
Never mind that there's a big difference between "used" and "buy" and
that the entire survey assumes that the device works as expected.

Hint: Such survey questions are invariably answered by participants
in top down order. The first few questions involve the greatest
amount of considered thought by the participant. By the time they get
down to the last few questions, they are tired, bored, in a hurry, and
not really thinking clearly. Their resistance to suggestion is then
at its lowest. So, the really important questions are asked last.

--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
  #59  
Old March 22nd 17, 04:11 PM posted to rec.bicycles.tech
Jeff Liebermann
external usenet poster
 
Posts: 2,744
Default The University of Aalborg Study on Daytime Flashing Lights for Bicycles.

On Wed, 22 Mar 2017 05:17:38 -0700, sms
wrote:
You ignored my question. If "pick it apart" is an unacceptable method
of discussing the merits of a study, what is an acceptable method?


1. Attack the statistical sample.
2. Attack the methodology.
3. Attack the premise.


Very good. Please add:
4. Attack the data, if there was any manipulation.
5. Attack the conclusions, if they do not relate to the data.
6. Attack the presentation, if it is structured to confuse.
7. Attack the researchers, if they have an obvious agenda.
8. Attack the publisher, if they edited the report to be "suitable
for publication".
9. Attack the reader, if they are not expected to understand the
report.
10. Attack the author, if present himself as an expert, but without
sufficient qualifications.
11. Attach the sponsor, if there is any potential conflict of
interest.
12. Attack the references, if they are irrelevant, as most are.
13. Attack those not involved in the study, if their involvement would
have improved the accuracy and validity. If that's not available,
accuse the non-involved of sabotaging the study or influencing the
participants.

With these additions, I would suspect that all this constitutes "pick
it apart" and does not constitute an alternative method of argument.
Might as well be blunt... there is no other way to properly debate a
study other than taking it apart, seeing how it ticks, and debunking
everything available, point by point. The other available techniques,
such as propaganda, brainwashing, subliminals, and pontification, are
not really valid methods of debate and discussion.

Alas it's not possible to do any of those three with the Odense study.


Correct. Since the study is not available, YOU cannot claim that it's
valid, authoritative, or even useful from just a summary or extract.
One needs the original study in order to make claims.

A huge sample, a sound methodology, and a provable premise.


Huh? You just declared that it's not possible to analyze the report
and now you repeat your claims. I can do that too. Suppose I write a
report on my study of bicycle sales and declare that at the present
rate of cycling acceptance, everyone on the planet will soon own and
ride a bicycle. I then lock the study behind a pay wall and produce a
summary or abstract that declares that 50% more LBS owners believe
that bicycle production will soon flood the planet. You would have no
clue as to the size of my LBS shop owner sample, how I came to my
conclusion, and what I've done to prove it. Your claims that the
flashing light reduced crashes by 30% is much the same as my claim.

You can't even claim "risk compensation."


Huh? I don't understand.

--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
  #60  
Old March 22nd 17, 04:16 PM posted to rec.bicycles.tech
Frank Krygowski[_4_]
external usenet poster
 
Posts: 5,847
Default The University of Aalborg Study on Daytime Flashing Lights forBicycles.

On 3/22/2017 8:15 AM, sms wrote:


Reelight may have supplied the 2000 lights used in the study, but the
benefit of the law banning flashing lights being overturned benefits all
cyclists ...


IF a significant benefit actually exists. I don't believe that has been
proven.

... and many companies...


Well, of course, any propaganda that leads people to buy products is
good for the companies! (And also for the guerilla marketers!)

--
- Frank Krygowski
 




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