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The University of Aalborg Study on Daytime Flashing Lights forBicycles.



 
 
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  #31  
Old March 21st 17, 04:09 AM posted to rec.bicycles.tech
John B.[_3_]
external usenet poster
 
Posts: 3,554
Default The University of Aalborg Study on Daytime Flashing Lights for Bicycles.

On Mon, 20 Mar 2017 13:54:00 -0400, Frank Krygowski
wrote:

On 3/19/2017 9:08 PM, Jeff Liebermann wrote:
On Sun, 19 Mar 2017 15:24:31 -0700, sms
wrote:

On 3/19/2017 2:02 PM, Jeff Liebermann wrote:

Now I have to go cash my check from Reelight.

Such things are usually done by "loaning" you test samples of the
products, and then "forgetting" to recover them. In theory, you're
expected to declare the value of such samples as income for tax
purposes. Payments of cash or checks are rare unless you are hired as
a consultant.


Yes, but a couple of people in this group insist that the only reason I
favor good lights is because I am getting paid by light companies. The
fact that it isn't true doesn't matter to them. They will come up with
any excuse they can think of to try to ignore the data.


If you arrange with Reelight to send your persecutors some free sample
lights, they might be inclined to reconsider their position.

The problem here is that if you are repeatedly accused of some
dastardly crime against the cycling multitudes, such as accepting
payola from a vendor, the mere repetition of the accusation will
eventually cause it to become a truism. Anyone who searches the web
for bicycle lighting recommendations will eventually blunder across
those accusations. The casual reader is more likely to accept the
accusations at face value than to continue reading the subsequent
discussion material. You might consider writing a explanation, FAQ,
or manifesto on the topic, which you can reference in future
discussions on the topic.


If Mr. Scharf were to do that, honesty would require including quotes of
his original statements saying something like "please start your
purchases from my website" and bragging about his "guerilla marketing to
all aspects of the bicycling community" - or whatever the precise
wording was. (I wish now I'd saved a copy.)


guerilla ~ a member of an irregular armed force that fights by
sabotage and harassment.
--
Cheers,

John B.

Ads
  #33  
Old March 21st 17, 07:06 AM posted to rec.bicycles.tech
Jeff Liebermann
external usenet poster
 
Posts: 2,569
Default The University of Aalborg Study on Daytime Flashing Lights for Bicycles.

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.

Perhaps it would be helpful if I explained how I analyze such studies.
I've done it in this newsgroup at least a dozen times, but have never
really explained how it's done. First, I find the original study.
This is the most difficult part because studies are now hidden behind
pay walls, revised continuously, and "edited for publication" in
different lengths and forms. Once I have the original study, I try to
determine who paid for it. That's because the conclusions and summary
of the study are owned by whomever paid for the study, while the
actual data and calculations are owned by the academics, scientists,
students, and statisticians that ran the study. Often these are
different or even in opposition. I then read the study in as much
detail as I have time available. That's when the differences between
the study and the web page announcing the study become apparent. In
medical studies and surveys, I've seen claims that are quite the
opposite of what the research shows, usually because the claims
support a product or remedy. From this point, my approach varies
depending on what I'm trying to demonstrate, prove, denounce, or
evaluate. Usually, pointing out inconsistencies, gross omissions, and
occasionally math errors is sufficient.

In this case, I have been unable to find the study in either the
original Danish or an English translation. Therefore, I have not read
the original and have had to work with a brief summary from some
unknown report or survey that apparently has been quoted and recycled
extensively. The best I could do is point out that the percentage
cited was meaningless without also disclosing the statistical
population (number of participants in the test). This is hardly "pick
it apart". So, I'll pick at it some more.

One problem with claiming that flashing tail lights reduce accidents
is that there just might not be any correlation between tail lights
and accidents at all. Just because two things correlate (follow the
same trends) does not mean that one causes the other. Some ludicrous
examples:
http://www.tylervigen.com/spurious-correlations
So, how does one prove that flashing tail lights actually cause a
reduction in accidents and that the 30% drop was not a coincidence?
Well, one way is play the record backwards. Instead of giving out
tail lights, find a group that has been using flashing tail lights for
some time and take away their tail lights. If accidents increase,
then there just might be a connection. Perhaps programming the tail
lights so that they flash at different rates under the assumption that
a faster flashing rate is more visible and therefore safer. I could
dream up a few more tests, but basically the idea is to do things that
test for a connection between flashing tail lights and accidents.

The other part of the problem is that it's very easy to demonstrate
that something is unsafe. All that's needed is one accident. However,
it's impossible prove that anything is safe because there will always
be accidents caused by coincidence or disconnected correlations.

Have I "picked apart" your one liner sufficiently?

--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
  #34  
Old March 21st 17, 07:23 AM posted to rec.bicycles.tech
Jeff Liebermann
external usenet poster
 
Posts: 2,569
Default The University of Aalborg Study on Daytime Flashing Lights for Bicycles.

On Mon, 20 Mar 2017 16:13:39 -0400, Frank Krygowski
wrote:

On 3/20/2017 9:59 AM, jbeattie wrote:
Check this out: https://academic.oup.com/eurpub/arti...enting-bicycle
Don't ride in Auckland, even with a blinky.


Interesting study, with weird results. Seemed the group that was just
"occasionally conspicuous" had the lowest crash rate.
(...)


I see one problem with the study. There's little correlation between
accident crash rate and being conspicuous. The problem that drives of
vehicles that hit bicyclists almost always proclaim that they didn't
see the bicyclist. That might be because the bicyclist was not easily
visible, but could also be because the driver wasn't paying attention,
was distracted, in desperate need of corrective vision, or was under
the influence of booze, drugs, or passengers. For these drivers no
amount of conspicuous clothing or flashing lights will improve their
driving.

That begs the question of what is the ratio of attentive drivers to
impaired losers? I don't know. If I arbitrarily assign a 50/50
distribution, then I'll probably find that the overwhelming majority
of bicycle crashes are caused by the impaired losers. That means that
visibility has little effect on the conscientious drivers, who will
probably be paying attention to their driving, and little effect on
the impaired losers, who will probably be immune to any improvements
in visibility.


--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
  #35  
Old March 21st 17, 07:23 AM posted to rec.bicycles.tech
Tosspot[_3_]
external usenet poster
 
Posts: 1,085
Default The University of Aalborg Study on Daytime Flashing Lights forBicycles.

On 20/03/17 16:54, Jeff Liebermann wrote:
On Mon, 20 Mar 2017 06:59:40 -0700 (PDT), jbeattie
wrote:

Check this out: https://academic.oup.com/eurpub/arti...enting-bicycle
Don't ride in Auckland, even with a blinky.
-- Jay Beattie.


187 accidents among 162 participants in 6.4 years? The carnage in the
streets must be awful. I would expect all cyclists to be exterminated
within their expected lifetimes. If I ride for 64 years of my life, I
would expect to get hit about 10 times.

Maybe bicycle fashion is the problem?
https://www.google.com/search?q=dazzle+camouflage+bicycle+jacket&tbm=isch


They won't hold off a New York SUV, but they may stop you getting
torpedoed by a German submarine :-)


https://en.wikipedia.org/wiki/Dazzle...1)_cropped.jpg
  #36  
Old March 21st 17, 07:37 AM posted to rec.bicycles.tech
SMS
external usenet poster
 
Posts: 7,996
Default The University of Aalborg Study on Daytime Flashing Lights forBicycles.

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.

Yet we used to often see studies that were almost completely bogus,
touted as proving something. I recall one study on cycling rates
following the imposition of an MHL where those doing the study decided
that they would simply not count a large group of cyclists that passed
by the counting location because they didn't think that they were normal
cycling traffic. That was a study to "prove" that MHLs caused a decrease
in cycling rates.

Yet the Odense study was actually pretty good as far as these things go,
with two control groups so factors other than the presence or absence of
lights cancelled out. And while it was only a 32% reduction in accident
rates, the fact that 85% cyclists "felt safer" is also a positive
outcome if it leads to higher cycling rates. Part of the reason that
cycling rates trend up following the passing of an MHL is probably the
same reason--"oh, if I wear a helmet then I'll be safe."


  #38  
Old March 21st 17, 03:27 PM posted to rec.bicycles.tech
AMuzi
external usenet poster
 
Posts: 9,026
Default The University of Aalborg Study on Daytime Flashing Lights forBicycles.

On 3/21/2017 1:06 AM, 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.

Perhaps it would be helpful if I explained how I analyze such studies.
I've done it in this newsgroup at least a dozen times, but have never
really explained how it's done. First, I find the original study.
This is the most difficult part because studies are now hidden behind
pay walls, revised continuously, and "edited for publication" in
different lengths and forms. Once I have the original study, I try to
determine who paid for it. That's because the conclusions and summary
of the study are owned by whomever paid for the study, while the
actual data and calculations are owned by the academics, scientists,
students, and statisticians that ran the study. Often these are
different or even in opposition. I then read the study in as much
detail as I have time available. That's when the differences between
the study and the web page announcing the study become apparent. In
medical studies and surveys, I've seen claims that are quite the
opposite of what the research shows, usually because the claims
support a product or remedy. From this point, my approach varies
depending on what I'm trying to demonstrate, prove, denounce, or
evaluate. Usually, pointing out inconsistencies, gross omissions, and
occasionally math errors is sufficient.

In this case, I have been unable to find the study in either the
original Danish or an English translation. Therefore, I have not read
the original and have had to work with a brief summary from some
unknown report or survey that apparently has been quoted and recycled
extensively. The best I could do is point out that the percentage
cited was meaningless without also disclosing the statistical
population (number of participants in the test). This is hardly "pick
it apart". So, I'll pick at it some more.

One problem with claiming that flashing tail lights reduce accidents
is that there just might not be any correlation between tail lights
and accidents at all. Just because two things correlate (follow the
same trends) does not mean that one causes the other. Some ludicrous
examples:
http://www.tylervigen.com/spurious-correlations
So, how does one prove that flashing tail lights actually cause a
reduction in accidents and that the 30% drop was not a coincidence?
Well, one way is play the record backwards. Instead of giving out
tail lights, find a group that has been using flashing tail lights for
some time and take away their tail lights. If accidents increase,
then there just might be a connection. Perhaps programming the tail
lights so that they flash at different rates under the assumption that
a faster flashing rate is more visible and therefore safer. I could
dream up a few more tests, but basically the idea is to do things that
test for a connection between flashing tail lights and accidents.

The other part of the problem is that it's very easy to demonstrate
that something is unsafe. All that's needed is one accident. However,
it's impossible prove that anything is safe because there will always
be accidents caused by coincidence or disconnected correlations.

Have I "picked apart" your one liner sufficiently?


I don't know but significance and meaning may vary.

Just read a newspaper headline about a "new drug found 70%
better than aspirin". Of 3600 people over 5 years there were
2.3% heart attacks in the daily aspirin group and 1.6% heart
attacks in the new new group.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971


  #39  
Old March 21st 17, 03:31 PM posted to rec.bicycles.tech
[email protected]
external usenet poster
 
Posts: 3,346
Default The University of Aalborg Study on Daytime Flashing Lights for Bicycles.

On Monday, March 20, 2017 at 7:42:32 PM UTC-7, John B. wrote:

Unfortunately it does not conceal the fact that what you stated, "a
comparison of bike lights versus no bike lights", was not what the
Odense study tested, nor was it the results of the study.


But John, the whole point is that you have NO IDEA what they accomplished with a study that so obviously had such a small study group that they wouldn't even publish the size of it.

You know that in statistical analysis concerning small percentages of injuries and fatalities as bicycle accidents that the study size has to be gigantic to reveal any pertinent information. So why would you pretend differently?
  #40  
Old March 21st 17, 03:34 PM posted to rec.bicycles.tech
[email protected]
external usenet poster
 
Posts: 3,346
Default The University of Aalborg Study on Daytime Flashing Lights for Bicycles.

On Monday, March 20, 2017 at 8:05:55 PM UTC-7, John B. wrote:
On Mon, 20 Mar 2017 14:01:55 -0400, Frank Krygowski
wrote:

On 3/20/2017 1:08 PM, sms wrote:
On 3/19/2017 11:08 PM, John B. wrote:

snip

We need a double-blind study of accident rates where they use 65,536
different combinations of front and rear lumens, flashing and steady,
battery and dynamo powered, performed in 128 different countries, over
ten years, in a variety of lighting conditions.

Until that study has been completed we can't be absolutely certain
whether or not an increase in conspicuity is beneficial to cyclists, so
it makes no sense for cyclists to make themselves more visible.

Let's get the UN to commission this study.


I'd have thought you'd take on the project as a volunteer.

But you really should include those six foot (two meter) bicycle flags
on vertical poles as part of the study. I still don't understand why
the champion of "If it may possibly help" visibility doesn't use them.

Or even better, sell them via his websites. Your competition is killing
you!
http://www.swagbrokers.com/Fiberglas...Pole-181810804


The various countries I have visited all seem to have rules and
regulations that argue that a orange and white "checkerboard" flag
flown from vehicles operating on airfields is a good thing. I well
remember that when, as a young Airman stationed in Japan, one could
even ride one's personal motorbike on the airfield if flying such a
flag.

If a checkered flag will "fend off" a big Boeing bomber it should
prove equally effective in deterring a California SUV.

I believe that if the State of California should mandate that every
bicycle operated on the highways of the state must be equipped, and
display, a (lets be reasonable here) a 2 foot square (i.e. 4 square
feet) checkered flag it would immediately result in a substantial
decrease in annual bicycle "accidents" and fatalities.

If ridden at night the flag would obviously have to be illuminated in
some manner but that is just details.


John, how old are you? I spent four years in the Air Force in five different states and three different countries and never heard of such a requirement. I then spent three years in commercial aviation and never heard of such a thing either.
 




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