| |
Main
Date: 20 Sep 2006 05:52:42
From: Buck
Subject: Passing thoughts
|
I have been considering the results of the recently posted brief on Ian
Walker's study of motorists passing cyclists
(http://www.drianwalker.com/overtaking/). I have come to realize that
there is some legitimacy to his work. Although, I think he missed an
important point.
When I move further left in my lane, passing behavior changes. Yes, the
relative position between me and the passing vehicle may be closer.
However, I find that people are more reluctant to pass me illegally.
The two most common illegal passes I encounter are passing in a
no-passing zone, and not moving completely into the other lane when
passing (lane sharing). It is the latter behaviour that my lane
position seems to affect most.
Pulling my kids' trailer around also seems to inspire the same results.
An added benefit of the trailer is the speed at which people pass.
Whether they are slowing to observe this unusual contraption on the
road or they have genuine concern about what may be inside, I don't
know. But I have fewer vehicles zooming past when the trailer is on
board. The added benefit is a place to hang my clothes for work!
I would like to see him revisit the video data he collected and make
the comparison in passing technique. I've emailed him with this
suggestion.
-Buck
|
|
| |
Date: 23 Sep 2006 08:05:01
From: Tom Keats
Subject: Re: Passing thoughts
|
In article <1158756761.995570.11880@h48g2000cwc.googlegroups.com >,
"Buck" <bicyclebuck@gmail.com > writes:
> When I move further left in my lane, passing behavior changes. Yes, the
> relative position between me and the passing vehicle may be closer.
> However, I find that people are more reluctant to pass me illegally.
> The two most common illegal passes I encounter are passing in a
> no-passing zone, and not moving completely into the other lane when
> passing (lane sharing). It is the latter behaviour that my lane
> position seems to affect most.
The latter maneouver is a pretty good compromise, when it's
executed well, under safe conditions. The rider gets a comfort
gin of passing distance, and the driver isn't very inconvenienced.
I don't care how far over the line they go, as long as they
don't buzz me.
cheers,
Tom
--
-- Nothing is safe from me.
Above address is just a spam midden.
I'm really at: tkeats [curlicue] vcn [point] bc [point] ca
|
| |
Date: 22 Sep 2006 19:18:33
From: Chris Y.F.N.W.
Subject: Re: Passing thoughts
|
I agree with what Buck says. I've never mounted video cameras or
proximity sensors on my bike, however, so these comments are based on
nothing more than my thirty three years of experience commuting, club
riding, tours and endurance events. so take them for what you deem them
worth. But from commuting in Los Angeles during rush hour to pleasent
rides in the Carolina countryside, I have noticed a common phenomenon.
When I hug the curve, drivers are more likely to pass in more
unfavorable conditions, and do so closer. Whereas if I ride out about a
third of the way into the lane this is not the case. Even when I move
over as they approach, they will swing quite wide to go around me (into
the next lane here in the Carolinas), or wait patiently behind me until
they can see far enough down the road so to be sure they can safely do
so.
IOW, they treat me as if I were a slow moving car. As so they should.
- -
Comments and opinions compliments of,
"Your Friendly Neighborhood Wheelman"
My web Site:
http://geocities.com/czcorner
To E-mail me:
ChrisZCorner "at" webtv "dot" net
|
| | |
Date: 23 Sep 2006 00:57:08
From: Wayne Pein
Subject: Re: Passing thoughts
|
Chris Y.F.N.W. wrote:
I've never mounted video cameras or
> proximity sensors on my bike, however, so these comments are based on
> nothing more than my thirty three years of experience commuting, club
> riding, tours and endurance events. so take them for what you deem them
> worth. But from commuting in Los Angeles during rush hour to pleasent
> rides in the Carolina countryside, I have noticed a common phenomenon.
>
> When I hug the curve, drivers are more likely to pass in more
> unfavorable conditions, and do so closer. Whereas if I ride out about a
> third of the way into the lane this is not the case. Even when I move
> over as they approach, they will swing quite wide to go around me (into
> the next lane here in the Carolinas), or wait patiently behind me until
> they can see far enough down the road so to be sure they can safely do
> so.
>
> IOW, they treat me as if I were a slow moving car. As so they should.
>
This is my experience also.
Wayne
|
| |
Date: 22 Sep 2006 14:32:00
From: peter
Subject: Re: Passing thoughts
|
Wayne Pein wrote:
> I had a few email exchanges with the author several days ago.
>
> Here's one:
>
> Me: Since you were struck twice in a short period, what is your
> explanation? What were the road, traffic, driver, and your conditions?
> What did the drivers say if anything?
>
> Response: I was struck by a bus and a truck - both got too close
> passing. In normal circumstances I would have been able to move away
> when I felt them getting close, but the study being what it was, I
> couldn't move every time I felt a vehicle getting close as not only
> would I lose those data, they were the most interesting data!
>
>
> He knows I've written a bunch of papers at www.humantransport.org,
> including collision studies. I think his answer to my question was a
> dodge. However, if he thinks he could have moved away, they must have
> been very very slow. I think it's possible he was passing on the right,
> or he's making it up entirely.
His explanation sounds reasonable to me. When riding in city traffic
it's not uncommon for a car or truck to partially pass me and then
start drifting to the right before the pass has been completed. This
normally doesn't lead to a collision since it's easily noticed by the
cyclist but would result in a glancing impact if the cyclist strictly
held his line instead of moving to the right.
|
| |
Date: 22 Sep 2006 14:27:26
From:
Subject: Re: Passing thoughts
|
Buck wrote:
> Wayne Pein wrote:
> > I had a few email exchanges with the author several days ago.
> >
> > Here's one:
> >
> > Me: Since you were struck twice in a short period, what is your
> > explanation? What were the road, traffic, driver, and your conditions?
> > What did the drivers say if anything?
> >
> > Response: I was struck by a bus and a truck - both got too close
> > passing. In normal circumstances I would have been able to move away
> > when I felt them getting close, but the study being what it was, I
> > couldn't move every time I felt a vehicle getting close as not only
> > would I lose those data, they were the most interesting data!
> >
> >
> > He knows I've written a bunch of papers at www.humantransport.org,
> > including collision studies. I think his answer to my question was a
> > dodge. However, if he thinks he could have moved away, they must have
> > been very very slow. I think it's possible he was passing on the right,
> > or he's making it up entirely. Definitely aggrandizing.
>
> No, it was part of the study design. He used another device to help him
> maintain his lane position. I think he is being reasonable in his
> explanation. If he had moved to accomodate the other vehicle, the data
> for that pass would have been thrown out of the study. I imagine that
> both passing drivers felt that he would adjust his lane position to
> accomodate them.
I agree with Buck. HIs explanation sounds reasonable to me. The
general idea is to hold extraneous variables constant, and measure the
item of interest. He was holding his position constant. If he dodged,
we'd miss the important point that at least two drivers gave him
_negative_ passing clearance.
When the full paper appears in print, we'll get more details, but I
seriously doubt he was passing on the right. That makes no sense in an
experiment designed to measure how people pass him!
Let's see what the full paper says.
- Frank Krygowski
|
| | |
Date: 22 Sep 2006 23:57:54
From: Bill Sornson
Subject: Re: Passing thoughts
|
frkrygow@gmail.com wrote:
> Buck wrote:
>> Wayne Pein wrote:
>>> I had a few email exchanges with the author several days ago.
>>>
>>> Here's one:
>>>
>>> Me: Since you were struck twice in a short period, what is your
>>> explanation? What were the road, traffic, driver, and your
>>> conditions? What did the drivers say if anything?
>>>
>>> Response: I was struck by a bus and a truck - both got too close
>>> passing. In normal circumstances I would have been able to move away
>>> when I felt them getting close, but the study being what it was, I
>>> couldn't move every time I felt a vehicle getting close as not only
>>> would I lose those data, they were the most interesting data!
>>>
>>>
>>> He knows I've written a bunch of papers at www.humantransport.org,
>>> including collision studies. I think his answer to my question was a
>>> dodge. However, if he thinks he could have moved away, they must
>>> have been very very slow. I think it's possible he was passing on
>>> the right, or he's making it up entirely. Definitely aggrandizing.
>>
>> No, it was part of the study design. He used another device to help
>> him maintain his lane position. I think he is being reasonable in his
>> explanation. If he had moved to accomodate the other vehicle, the
>> data for that pass would have been thrown out of the study. I
>> imagine that both passing drivers felt that he would adjust his lane
>> position to accomodate them.
>
> I agree with Buck. HIs explanation sounds reasonable to me. The
> general idea is to hold extraneous variables constant, and measure the
> item of interest. He was holding his position constant. If he
> dodged, we'd miss the important point that at least two drivers gave
> him _negative_ passing clearance.
>
> When the full paper appears in print, we'll get more details, but I
> seriously doubt he was passing on the right. That makes no sense in
> an experiment designed to measure how people pass him!
>
> Let's see what the full paper says.
Frank, who argues endlessly about how safe cycling is and how "exceedingly
rare" bike falls/crashes/accidents are, now supports a whack-job who says he
got hit three times in only 2500 car-passes.
You couldn't make up this stuff...
BS (well, yeah)
|
| |
Date: 22 Sep 2006 14:18:41
From: Buck
Subject: Re: Passing thoughts
|
Wayne Pein wrote:
> I had a few email exchanges with the author several days ago.
>
> Here's one:
>
> Me: Since you were struck twice in a short period, what is your
> explanation? What were the road, traffic, driver, and your conditions?
> What did the drivers say if anything?
>
> Response: I was struck by a bus and a truck - both got too close
> passing. In normal circumstances I would have been able to move away
> when I felt them getting close, but the study being what it was, I
> couldn't move every time I felt a vehicle getting close as not only
> would I lose those data, they were the most interesting data!
>
>
> He knows I've written a bunch of papers at www.humantransport.org,
> including collision studies. I think his answer to my question was a
> dodge. However, if he thinks he could have moved away, they must have
> been very very slow. I think it's possible he was passing on the right,
> or he's making it up entirely. Definitely aggrandizing.
No, it was part of the study design. He used another device to help him
maintain his lane position. I think he is being reasonable in his
explanation. If he had moved to accomodate the other vehicle, the data
for that pass would have been thrown out of the study. I imagine that
both passing drivers felt that he would adjust his lane position to
accomodate them.
-Buck
|
| | |
Date: 22 Sep 2006 22:23:24
From: Wayne Pein
Subject: Re: Passing thoughts
|
Buck wrote:
> Wayne Pein wrote:
>
>>I had a few email exchanges with the author several days ago.
>>
>>Here's one:
>>
>>Me: Since you were struck twice in a short period, what is your
>>explanation? What were the road, traffic, driver, and your conditions?
>>What did the drivers say if anything?
>>
>>Response: I was struck by a bus and a truck - both got too close
>>passing. In normal circumstances I would have been able to move away
>>when I felt them getting close, but the study being what it was, I
>>couldn't move every time I felt a vehicle getting close as not only
>>would I lose those data, they were the most interesting data!
>>
>>
>>He knows I've written a bunch of papers at www.humantransport.org,
>>including collision studies. I think his answer to my question was a
>>dodge. However, if he thinks he could have moved away, they must have
>>been very very slow. I think it's possible he was passing on the right,
>>or he's making it up entirely. Definitely aggrandizing.
>
>
> No, it was part of the study design. He used another device to help him
> maintain his lane position. I think he is being reasonable in his
> explanation. If he had moved to accomodate the other vehicle, the data
> for that pass would have been thrown out of the study. I imagine that
> both passing drivers felt that he would adjust his lane position to
> accomodate them.
>
> -Buck
>
Buck,
I know how he conducted his data collection. He told me in detail as you
describe.
It's funny how I've never adjusted my lane position to accommodate
passing. Never. I hold a steady line and ride. If a motorist honks for
me to get out of the way or let me know he is there, I either wave him
by, give the finger, or move even further into the lane depending on the
situation. I do not move over for motorists. Ever. And I've never been
hit in many years of everyday riding on mostly narrow roads.
I think you can see that he didn't answer anything in my questions. He
was more than willing to go into detail and provide relatively lengthy
discussion on other topics, but he dodged on discussion of his hits.
You could be correct in your assessment of how he got hit, but I believe
that however he got hit he is aggrandizing the event. I think they were
very slow speed brushes at worst.
Wayne
|
| |
Date: 22 Sep 2006 14:08:20
From: Buck
Subject: Re: Passing thoughts
|
Mike Jacoubowsky wrote:
> > What you are suggesting is that the experiment is impossible to conduct
> > because every cyclist will be "reactive" to some extent. I'd rather see
> > some data from a single cyclist than a gaggle of cyclists because it is
> > easier to control all of the potential variables.
>
> Guess it depends upon what you want to study. We know very well how things
> affect this one particular cyclist. We know little, if anything, about how
> things affect your or I. As has been pointed out many, many times, this
> particular cyclist is a statistical anomaly. Getting hit twice in such a
> short period of time, and both times apparently while wearing a helmet...
I agree that these two events are an anomaly, even moreso after
visiting his website and seeing some information about his experience
as a cyclist. Should these anomalies affect the validity of the other
2,300 measurements? I won't know until I know more about the accidents.
> > One thing that would be interesting to know is whether he actually looked at
> his data more-or-less in real time, or checked everything only after the
> experiment was concluded. That could be a *huge* factor.
In what way are you suggesting this could be a factor? From personal
correspondence, I know that his lane position was held more-or-less
constant by his method of determining lane position. This may have been
a contributing factor in the accidents as it required some of his
attention. His analytical method prevented him from checking his data
in real time.
Even if he were able to check it in real time, just how would this
affect the outcome? In my experience, passing vehicles do so in a
matter of a second or two at most. There is little time to react.
Perhaps if he were watching them approach with a mirror and making lane
position adjustments based on what he saw the results would would be
affected. But his method was to hold his lane position regardles of
vehicle type approaching from the rear.
> In any event, we might agree that a better study would involve many cyclists
> involved in many passing situations each. And in no event should the
> participants be aware of the measurements at any time during the study.
Perhaps this would be possible with strategically-placed video cameras.
But the logistics and expense would be prohibitive. It would also only
be valid for the exact lane configuration and speed being observed. It
would have to be replicated many times to answer the more general
questions.
If you design the experiment so the cyclist is unaware, your measures
could be confounded by the reactions of the cyclists to passing
vehicles. In this case, the cyclist was holding lane position despite
the passing distance of overtaking vehicles.
-Buck
|
| |
Date: 22 Sep 2006 10:30:34
From: Buck
Subject: Re: Passing thoughts
|
r15757@aol.com wrote:
> frkrygow@gmail.com wrote:
> ...
> > As http://www.zzapp.org/rileygea/itsa/helmet2.htm points out,
> > information on something as simple as "Was the cyclist wearing a
> > helmet" is _massively_ unreliable on a national scale. We have no
> > hopes of sifting existing information to learn even that, let alone
> > anything more.
>
>
> I agree completely. The data isn't there.
>
> Frank, how will you claim that this guy's ridiculous
> 'study' has merit without also coming to the conclusion
> that cycling is ungodly dangerous?
>
> At his rate of collision, I would have been struck by
> vehicles over 2,500 times so far.
Everyone is focused on the collisions when they should be focused on
the study. I actually bothered to do some digging and discovered that
he has a great deal of cycling experience. Here's what he posted on his
website: http://www.drianwalker.com/cycling.html
Now, how many of the pundits around here have cycled solo across
Europe?
I do wonder what happened in those incidents. But I won't assume that
both of these events were his fault or that he could have done
something to prevent either one. They are probably just a run of bad
luck. Strange things happen in quick succession sometimes.
Most research comes from a passion about a subject. Dr. Walker appears
to be someone with a passion for cycling. He designed an experiment
which had enough scientific rigor to warrant funding. The work was
placed under scientific review and passed for publication. He had a
couple of incidents while conducting the experiments. He had the
fortitude to report those incidents as he should.
When it is published, if Frank and Jobst and whomever else around here
with a background in scientific research start poking holes in the
methodology, then I'll consider there may be a problem with the study
design.
-Buck
|
| | |
Date: 22 Sep 2006 22:57:25
From: Mike Jacoubowsky
Subject: Re: Passing thoughts
|
> I do wonder what happened in those incidents. But I won't assume that
> both of these events were his fault or that he could have done
> something to prevent either one. They are probably just a run of bad
> luck. Strange things happen in quick succession sometimes.
Should "bad luck" be a valid statistical factor in a study like this? For
anyone to invoke the "bad luck" clause in an experiment is a flag that the
sample size is too small.
--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA
"Buck" <bicyclebuck@gmail.com > wrote in message
news:1158946233.766225.83820@k70g2000cwa.googlegroups.com...
> r15757@aol.com wrote:
>> frkrygow@gmail.com wrote:
>> ...
>> > As http://www.zzapp.org/rileygea/itsa/helmet2.htm points out,
>> > information on something as simple as "Was the cyclist wearing a
>> > helmet" is _massively_ unreliable on a national scale. We have no
>> > hopes of sifting existing information to learn even that, let alone
>> > anything more.
>>
>>
>> I agree completely. The data isn't there.
>>
>> Frank, how will you claim that this guy's ridiculous
>> 'study' has merit without also coming to the conclusion
>> that cycling is ungodly dangerous?
>>
>> At his rate of collision, I would have been struck by
>> vehicles over 2,500 times so far.
>
> Everyone is focused on the collisions when they should be focused on
> the study. I actually bothered to do some digging and discovered that
> he has a great deal of cycling experience. Here's what he posted on his
> website: http://www.drianwalker.com/cycling.html
> Now, how many of the pundits around here have cycled solo across
> Europe?
>
> I do wonder what happened in those incidents. But I won't assume that
> both of these events were his fault or that he could have done
> something to prevent either one. They are probably just a run of bad
> luck. Strange things happen in quick succession sometimes.
>
> Most research comes from a passion about a subject. Dr. Walker appears
> to be someone with a passion for cycling. He designed an experiment
> which had enough scientific rigor to warrant funding. The work was
> placed under scientific review and passed for publication. He had a
> couple of incidents while conducting the experiments. He had the
> fortitude to report those incidents as he should.
>
> When it is published, if Frank and Jobst and whomever else around here
> with a background in scientific research start poking holes in the
> methodology, then I'll consider there may be a problem with the study
> design.
>
> -Buck
>
|
| |
Date: 22 Sep 2006 09:55:24
From: Buck
Subject: Re: Passing thoughts
|
Mike Kruger wrote:
> "Buck" <bicyclebuck@gmail.com> wrote in message
> news:1158854834.114001.275140@i3g2000cwc.googlegroups.com...
> > No. We have data regarding 2,300 vehicles passing a control. The
> > passing vehicles were the experiment, the cyclist was the control. The
> > control conditions were changed to see what the experiment participants
> > (although they didn't know they were participating) would do.
> >
>
> Your argument would be valid if the "control" was nonreactive -- e.g. a
> lamp-post that would always be a lamp-post regardless of the hypothesis,
> regardless of skill, and even with a wig would still be a lamp-post.
>
> That doesn't apply in this case because the experimenter is potentially
> reactive.
I suppose by "reactive" you mean that the cyclist would be adjusting
his lane position based on the passing distance of the vehicles.
I see several problems with this logic. First, any immediate reaction
would likely occur after the vehicle has already passed, thus negating
the effects of the reaction on the distance measurement. Second, you
assume that the cyclist does not have a standard method for measuring
distance to road edge and maintaining proper lane position. Third, the
assumption of long-term conditioning would suggest that there would be
no cyclists on the road as we would all eventually be bullied off the
road by passing motorists.
What you are suggesting is that the experiment is impossible to conduct
because every cyclist will be "reactive" to some extent. I'd rather see
some data from a single cyclist than a gaggle of cyclists because it is
easier to control all of the potential variables.
-Buck
|
| | |
Date: 23 Sep 2006 03:44:48
From: Mike Kruger
Subject: Re: Passing thoughts
|
"Buck" <bicyclebuck@gmail.com > wrote in message
news:1158944124.406258.11310@d34g2000cwd.googlegroups.com...
>
> What you are suggesting is that the experiment is impossible to conduct
> because every cyclist will be "reactive" to some extent. I'd rather see
> some data from a single cyclist than a gaggle of cyclists because it is
> easier to control all of the potential variables.
>
No, I didn't suggest that at all. I suggested that it is utterly
inappropriate for Walker to have used himself as the sole subject in this
experiment -- since he was aware of his own hypothesis, and aware of his own
need to produce "good" results to get published --
I suspect Walker intended his study as a pilot study and intended to
replicate it correctly, like he must have learned in grad school if he took
even an introductory social research methods course.
There's nothing wrong with using yourself to shake down the equipment and
the procedure and develop preliminary hypotheses. In fact, it's a darn good
idea. But then you go and do the real study using accepted methods.
But somewhere along the line it got out of hand and he published this piece
of junk science. Perhaps he is under pressure to publish soon to keep his
job.
You are making an important point, though. You are quite correct that the
total number of cyclists involved would probably have to be fairly small,
because you would have to train the cyclists to ride properly (e.g. the
appropriate speed to control, the appropriate width from the curve, how to
read the instrument that tells you how far away you are, etc.). Control of
the measurement is important.
|
| | | |
Date: 23 Sep 2006 13:23:57
From:
Subject: Re: Passing thoughts
|
On Sat, 23 Sep 2006 03:44:48 GMT, "Mike Kruger"
<MikeKr@mouse-potato.com > wrote:
>
>But somewhere along the line it got out of hand and he published this piece
>of junk science.
Um, are you not aware that the author is not the publisher?
|
| | |
Date: 22 Sep 2006 17:36:21
From: Mike Jacoubowsky
Subject: Re: Passing thoughts
|
> What you are suggesting is that the experiment is impossible to conduct
> because every cyclist will be "reactive" to some extent. I'd rather see
> some data from a single cyclist than a gaggle of cyclists because it is
> easier to control all of the potential variables.
Guess it depends upon what you want to study. We know very well how things
affect this one particular cyclist. We know little, if anything, about how
things affect your or I. As has been pointed out many, many times, this
particular cyclist is a statistical anomaly. Getting hit twice in such a
short period of time, and both times apparently while wearing a helmet...
One thing that would be interesting to know is whether he actually looked at
his data more-or-less in real time, or checked everything only after the
experiment was concluded. That could be a *huge* factor.
In any event, we might agree that a better study would involve many cyclists
involved in many passing situations each. And in no event should the
participants be aware of the measurements at any time during the study.
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
"Buck" <bicyclebuck@gmail.com > wrote in message
news:1158944124.406258.11310@d34g2000cwd.googlegroups.com...
> Mike Kruger wrote:
>> "Buck" <bicyclebuck@gmail.com> wrote in message
>> news:1158854834.114001.275140@i3g2000cwc.googlegroups.com...
>> > No. We have data regarding 2,300 vehicles passing a control. The
>> > passing vehicles were the experiment, the cyclist was the control. The
>> > control conditions were changed to see what the experiment participants
>> > (although they didn't know they were participating) would do.
>> >
>>
>> Your argument would be valid if the "control" was nonreactive -- e.g. a
>> lamp-post that would always be a lamp-post regardless of the hypothesis,
>> regardless of skill, and even with a wig would still be a lamp-post.
>>
>> That doesn't apply in this case because the experimenter is potentially
>> reactive.
>
> I suppose by "reactive" you mean that the cyclist would be adjusting
> his lane position based on the passing distance of the vehicles.
>
> I see several problems with this logic. First, any immediate reaction
> would likely occur after the vehicle has already passed, thus negating
> the effects of the reaction on the distance measurement. Second, you
> assume that the cyclist does not have a standard method for measuring
> distance to road edge and maintaining proper lane position. Third, the
> assumption of long-term conditioning would suggest that there would be
> no cyclists on the road as we would all eventually be bullied off the
> road by passing motorists.
>
> What you are suggesting is that the experiment is impossible to conduct
> because every cyclist will be "reactive" to some extent. I'd rather see
> some data from a single cyclist than a gaggle of cyclists because it is
> easier to control all of the potential variables.
>
> -Buck
>
|
| | | |
Date: 22 Sep 2006 20:43:33
From: Wayne Pein
Subject: Re: Passing thoughts
|
I had a few email exchanges with the author several days ago.
Here's one:
Me: Since you were struck twice in a short period, what is your
explanation? What were the road, traffic, driver, and your conditions?
What did the drivers say if anything?
Response: I was struck by a bus and a truck - both got too close
passing. In normal circumstances I would have been able to move away
when I felt them getting close, but the study being what it was, I
couldn't move every time I felt a vehicle getting close as not only
would I lose those data, they were the most interesting data!
He knows I've written a bunch of papers at www.humantransport.org,
including collision studies. I think his answer to my question was a
dodge. However, if he thinks he could have moved away, they must have
been very very slow. I think it's possible he was passing on the right,
or he's making it up entirely. Definitely aggrandizing.
Wayne
|
| | | | |
Date: 23 Sep 2006 13:22:10
From:
Subject: Re: Passing thoughts
|
On Fri, 22 Sep 2006 20:43:33 GMT, Wayne Pein <wpein@nc.rr.com > wrote:
>I had a few email exchanges with the author several days ago.
>
>Here's one:
>
>Me: Since you were struck twice in a short period, what is your
>explanation? What were the road, traffic, driver, and your conditions?
>What did the drivers say if anything?
>
>Response: I was struck by a bus and a truck - both got too close
>passing. In normal circumstances I would have been able to move away
>when I felt them getting close, but the study being what it was, I
>couldn't move every time I felt a vehicle getting close as not only
>would I lose those data, they were the most interesting data!
>
>
>He knows I've written a bunch of papers at www.humantransport.org,
>including collision studies. I think his answer to my question was a
>dodge. However, if he thinks he could have moved away, they must have
>been very very slow. I think it's possible he was passing on the right,
>or he's making it up entirely. Definitely aggrandizing.
>
I expect you'll be writing to the Journal which has accepted his
article for publication, telling them of your concerns, and asking to
be invited to be on their editorial board.
|
| |
Date: 22 Sep 2006 09:17:11
From:
Subject: Re: Passing thoughts
|
frkrygow@gmail.com wrote:
...
> As http://www.zzapp.org/rileygea/itsa/helmet2.htm points out,
> information on something as simple as "Was the cyclist wearing a
> helmet" is _massively_ unreliable on a national scale. We have no
> hopes of sifting existing information to learn even that, let alone
> anything more.
I agree completely. The data isn't there.
Frank, how will you claim that this guy's ridiculous
'study' has merit without also coming to the conclusion
that cycling is ungodly dangerous?
At his rate of collision, I would have been struck by
vehicles over 2,500 times so far.
Robert
|
| |
Date: 22 Sep 2006 09:10:49
From:
Subject: Re: Passing thoughts
|
Mike Jacoubowsky wrote in part:
> The tough part is identifying different types of behaviour (through
> observation) and then use post-accident analysis to determine if those
> behaviors were involved. ...
I'll save you the time and trouble.
You're barking up the wrong tree. It's not about
behavior. It's about mind-set. It's about awareness,
vigilance, and presence in the moment, regardless of
behavior. Veteran bike messengers have proven
it beyond a shadow of a doubt over the past
several decades. (Are we to conclude from the
very low accident rates of veteran messengers
that red light running is the safest behavior?)
And if that's not enough for you, note
that in the majority of car-bike collisions
involving experienced adult cyclists, the rider
was riding lawfully at the time of the wreck.
That is to say that there was nothing unusual
or crazy or overtly incorrect about the _behavior_
of these riders at the time of their accidents.
Robert
|
| |
Date: 22 Sep 2006 07:44:56
From:
Subject: Re: Passing thoughts
|
Mike Jacoubowsky wrote:
>
> The tough part is identifying different types of behaviour (through
> observation) and then use post-accident analysis to determine if those
> behaviors were involved. Could be that the data is already there, gathered
> individually for each accident, but nobody's pulled it all together in one
> place. Or could be that we don't know what we're looking for.
I'm sure the data's _not_ already there. Have you ever seen an
accident report for a car-bike accident?
The local one I've seen (a mild sideswipe accident involving a friend
who was passed too closely) was on a form intended, not surprisingly,
to record car vs. car accidents. The officer described the damage to
the bike and cyclist by referring to an outline of a _car_ on the form.
(The cyclist's injured elbow was represented by the car's left side
mirror).
One of the few bike-specific areas on the form was a subset of "Safety
Equipment." Under "Non-motorist" the choices were "None used," "Helmet
used," "Protective pads," "Reflective clothing," "Lighting," "Other,"
and "Unknown." This field was left blank. (The cyclist in question
was, in fact, wearing a helmet... but no 'protective pads,' whatever
that means!)
Also, under "Injuries," the two entries were "Unknown" (for the driver)
and "No injury" for the cyclist with a badly bruised elbow.
As http://www.zzapp.org/rileygea/itsa/helmet2.htm points out,
information on something as simple as "Was the cyclist wearing a
helmet" is _massively_ unreliable on a national scale. We have no
hopes of sifting existing information to learn even that, let alone
anything more.
- Frank Krygowski
|
| | |
Date: 22 Sep 2006 15:32:21
From: Mike Jacoubowsky
Subject: Re: Passing thoughts
|
> I'm sure the data's _not_ already there. Have you ever seen an
> accident report for a car-bike accident?
And a strong disincentive to collection of such information is that it tends
to make the cyclist look guilty.
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
<frkrygow@gmail.com > wrote in message
news:1158936296.060457.227920@i3g2000cwc.googlegroups.com...
>
> Mike Jacoubowsky wrote:
>>
>> The tough part is identifying different types of behaviour (through
>> observation) and then use post-accident analysis to determine if those
>> behaviors were involved. Could be that the data is already there,
>> gathered
>> individually for each accident, but nobody's pulled it all together in
>> one
>> place. Or could be that we don't know what we're looking for.
>
> I'm sure the data's _not_ already there. Have you ever seen an
> accident report for a car-bike accident?
>
> The local one I've seen (a mild sideswipe accident involving a friend
> who was passed too closely) was on a form intended, not surprisingly,
> to record car vs. car accidents. The officer described the damage to
> the bike and cyclist by referring to an outline of a _car_ on the form.
> (The cyclist's injured elbow was represented by the car's left side
> mirror).
>
> One of the few bike-specific areas on the form was a subset of "Safety
> Equipment." Under "Non-motorist" the choices were "None used," "Helmet
> used," "Protective pads," "Reflective clothing," "Lighting," "Other,"
> and "Unknown." This field was left blank. (The cyclist in question
> was, in fact, wearing a helmet... but no 'protective pads,' whatever
> that means!)
>
> Also, under "Injuries," the two entries were "Unknown" (for the driver)
> and "No injury" for the cyclist with a badly bruised elbow.
>
> As http://www.zzapp.org/rileygea/itsa/helmet2.htm points out,
> information on something as simple as "Was the cyclist wearing a
> helmet" is _massively_ unreliable on a national scale. We have no
> hopes of sifting existing information to learn even that, let alone
> anything more.
>
> - Frank Krygowski
>
|
| |
Date: 21 Sep 2006 15:32:32
From: Buck
Subject: Re: Passing thoughts
|
Mike Jacoubowsky wrote:
> But... the study that's needed is a bit more broad-based than whether
> wearing a helmet makes a difference or not. What's needed is a study that
> simply asks (and answers) the question- "What are the behaviours while
> riding a bike that influence your safety vs cars?"
The type of study you suggest would be very difficult to design.
Correlations between parameters would confound the analysis. In the
work presented, three things were varied: helmet use, lane position,
and wig use (as a proxy for being "female"). We don't know if he used a
wig with a helmet or not. Held constant was the bicycle. Ignored (and
probably varied) was the clothing he wore. I do not know if he used the
same route. He did vary the time of day, but we don't know if the
values reported are averaged with each of the above conditions.
Just using the three priy variables we know of, helmet/no helmet,
lane position (with five distances), and wig/no wig, we have 20
different combinations to be tested. Throw in bicycle type,
with/without panniers, "racer" clothes / "normal" clothes, blinking
lights/no lights/reflectors/no visual devices, fenders/no fenders,
number of lanes, passing/no passing zones, one-way streets, rider age,
rider experience, and the list goes on.... It should be clear that the
task becomes infinitely complex when we ask such general questions.
I really look forward to the complete paper. I also look forward to
replication in a variety of riding conditions here in the U.S.
-Buck
|
| | |
Date: 22 Sep 2006 03:56:02
From: Mike Jacoubowsky
Subject: Re: Passing thoughts
|
>> wearing a helmet makes a difference or not. What's needed is a study that
>> simply asks (and answers) the question- "What are the behaviours while
>> riding a bike that influence your safety vs cars?"
>
> The type of study you suggest would be very difficult to design.
> Correlations between parameters would confound the analysis. In the
> work presented, three things were varied: helmet use, lane position,
> and wig use (as a proxy for being "female"). We don't know if he used a
> wig with a helmet or not. Held constant was the bicycle. Ignored (and
> probably varied) was the clothing he wore. I do not know if he used the
> same route. He did vary the time of day, but we don't know if the
> values reported are averaged with each of the above conditions.
The tough part is identifying different types of behaviour (through
observation) and then use post-accident analysis to determine if those
behaviors were involved. Could be that the data is already there, gathered
individually for each accident, but nobody's pulled it all together in one
place. Or could be that we don't know what we're looking for.
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
"Buck" <bicyclebuck@gmail.com > wrote in message
news:1158877952.131428.189520@k70g2000cwa.googlegroups.com...
> Mike Jacoubowsky wrote:
>> But... the study that's needed is a bit more broad-based than whether
>> wearing a helmet makes a difference or not. What's needed is a study that
>> simply asks (and answers) the question- "What are the behaviours while
>> riding a bike that influence your safety vs cars?"
>
> The type of study you suggest would be very difficult to design.
> Correlations between parameters would confound the analysis. In the
> work presented, three things were varied: helmet use, lane position,
> and wig use (as a proxy for being "female"). We don't know if he used a
> wig with a helmet or not. Held constant was the bicycle. Ignored (and
> probably varied) was the clothing he wore. I do not know if he used the
> same route. He did vary the time of day, but we don't know if the
> values reported are averaged with each of the above conditions.
>
> Just using the three priy variables we know of, helmet/no helmet,
> lane position (with five distances), and wig/no wig, we have 20
> different combinations to be tested. Throw in bicycle type,
> with/without panniers, "racer" clothes / "normal" clothes, blinking
> lights/no lights/reflectors/no visual devices, fenders/no fenders,
> number of lanes, passing/no passing zones, one-way streets, rider age,
> rider experience, and the list goes on.... It should be clear that the
> task becomes infinitely complex when we ask such general questions.
>
> I really look forward to the complete paper. I also look forward to
> replication in a variety of riding conditions here in the U.S.
>
> -Buck
>
|
| |
Date: 21 Sep 2006 14:58:08
From:
Subject: Re: Passing thoughts
|
Mike Jacoubowsky wrote:
>
>
> But... the study that's needed is a bit more broad-based than whether
> wearing a helmet makes a difference or not. What's needed is a study that
> simply asks (and answers) the question- "What are the behaviours while
> riding a bike that influence your safety vs cars?"
I'm not sure what you have in mind there.
Yes, I think there is value in having Walker's passing distance study
repeated using more riders. But it's not surprising that he did it the
way he did, with just himself as a subject. Getting funding to study
such a thing is probably not easy; so rather than hire a small army of
college students to do the riding, he did it himself.
FWIW, I suspect there will be follow up studies trying to verify his
results. And I suspect a very well-funded study by the Harborview
Institute will claim to disprove it entirely, no matter what everyone
else finds! ;-)
But your more general question, "What are the behaviors while riding a
bike that influence your safety vs. cars?" - how exactly would you
propose to study this?
ISTM that you can't send out a gaggle of cyclists and ask them to all
ride differently. You'll get a multivariate mess of folks riding slow,
fast, close to the curb, away from the curb, straight and steady,
weaving, legally, illegally, etc. etc. If you can somehow measure
results, you'll have a hellacious statistical problem trying to
separate out the influences.
ISTM that it's more efficient to examine one variable at a time, which
is what Walker did. And it makes some sense to examine the factor that
is touted most loudly as a safety tool. I look forward to the
follow-up studies.
- Frank Krygowski
|
| | |
Date: 23 Sep 2006 20:00:02
From: Matt O'Toole
Subject: Re: Passing thoughts
|
On Thu, 21 Sep 2006 14:58:08 -0700, frkrygow wrote:
> Mike Jacoubowsky wrote:
>>
>>
>> But... the study that's needed is a bit more broad-based than whether
>> wearing a helmet makes a difference or not. What's needed is a study
>> that simply asks (and answers) the question- "What are the behaviours
>> while riding a bike that influence your safety vs cars?"
>
> I'm not sure what you have in mind there.
>
> Yes, I think there is value in having Walker's passing distance study
> repeated using more riders. But it's not surprising that he did it the
> way he did, with just himself as a subject. Getting funding to study
> such a thing is probably not easy; so rather than hire a small army of
> college students to do the riding, he did it himself.
>
> FWIW, I suspect there will be follow up studies trying to verify his
> results. And I suspect a very well-funded study by the Harborview
> Institute will claim to disprove it entirely, no matter what everyone
> else finds! ;-)
>
> But your more general question, "What are the behaviors while riding a
> bike that influence your safety vs. cars?" - how exactly would you
> propose to study this?
>
> ISTM that you can't send out a gaggle of cyclists and ask them to all
> ride differently. You'll get a multivariate mess of folks riding slow,
> fast, close to the curb, away from the curb, straight and steady,
> weaving, legally, illegally, etc. etc. If you can somehow measure
> results, you'll have a hellacious statistical problem trying to separate
> out the influences.
In this particular case you're probably right. But wouldn't it be great
to have bike accidents reported and investigated with at least as much
rigor as is applied to motor vehicle accidents? Most of us with plenty of
riding and advocacy experience know which behaviors cause accidents, but
better data to back this up would go a long way toward building consensus
for better rider and driver education, road design, etc.
Matt O.
|
| |
Date: 21 Sep 2006 09:07:14
From: Buck
Subject: Re: Passing thoughts
|
Chris Neary wrote:
> Wow, so we have really great data applicable to ONE person.
>
> The problem isn't that ONE person collected the data - the problem is that
> ONE person was the experiment from which the data was collected.
No. We have data regarding 2,300 vehicles passing a control. The
passing vehicles were the experiment, the cyclist was the control. The
control conditions were changed to see what the experiment participants
(although they didn't know they were participating) would do.
-Buck
|
| | |
Date: 24 Sep 2006 19:32:23
From: Chris Neary
Subject: Re: Passing thoughts
|
>No. We have data regarding 2,300 vehicles passing a control. The
>passing vehicles were the experiment, the cyclist was the control. The
>control conditions were changed to see what the experiment participants
>(although they didn't know they were participating) would do.
I have serious doubts about the ability of others to reproduce Mr. Walker's
results. Until they do, I am reserving judgement on their validity.
Chris Neary
diabloridr@tcsn.net
"Cycle tracks will abound in Utopia" - H.G. Wells
|
| | |
Date: 22 Sep 2006 01:33:54
From: Mike Kruger
Subject: Re: Passing thoughts
|
"Buck" <bicyclebuck@gmail.com > wrote in message
news:1158854834.114001.275140@i3g2000cwc.googlegroups.com...
> Chris Neary wrote:
>
>> Wow, so we have really great data applicable to ONE person.
>>
>> The problem isn't that ONE person collected the data - the problem is
>> that
>> ONE person was the experiment from which the data was collected.
>
> No. We have data regarding 2,300 vehicles passing a control. The
> passing vehicles were the experiment, the cyclist was the control. The
> control conditions were changed to see what the experiment participants
> (although they didn't know they were participating) would do.
>
Your argument would be valid if the "control" was nonreactive -- e.g. a
lamp-post that would always be a lamp-post regardless of the hypothesis,
regardless of skill, and even with a wig would still be a lamp-post.
That doesn't apply in this case because the experimenter is potentially
reactive.
--
"President Washington, President Lincoln, President Wilson, President
Roosevelt have all authorized electronic surveillance on a far broader
scale." --Attorney General Alberto Gonzalez
|
| | | |
Date: 22 Sep 2006 03:58:33
From: Mike Jacoubowsky
Subject: Re: Passing thoughts
|
> Your argument would be valid if the "control" was nonreactive -- e.g. a
> lamp-post that would always be a lamp-post regardless of the hypothesis,
> regardless of skill, and even with a wig would still be a lamp-post.
>
> That doesn't apply in this case because the experimenter is potentially
> reactive.
And probably increasingly paranoid as the experiment went on! I'd put a
smiley there, but it's really a pretty sad thing. This guy is now making the
assumption that, if you ride a bike on the road, you're going to get hit by
a car.
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
"Mike Kruger" <MikeKr@mouse-potato.com > wrote in message
news:64HQg.3382$GR.1497@newssvr29.news.prodigy.net...
> "Buck" <bicyclebuck@gmail.com> wrote in message
> news:1158854834.114001.275140@i3g2000cwc.googlegroups.com...
>> Chris Neary wrote:
>>
>>> Wow, so we have really great data applicable to ONE person.
>>>
>>> The problem isn't that ONE person collected the data - the problem is
>>> that
>>> ONE person was the experiment from which the data was collected.
>>
>> No. We have data regarding 2,300 vehicles passing a control. The
>> passing vehicles were the experiment, the cyclist was the control. The
>> control conditions were changed to see what the experiment participants
>> (although they didn't know they were participating) would do.
>>
>
> Your argument would be valid if the "control" was nonreactive -- e.g. a
> lamp-post that would always be a lamp-post regardless of the hypothesis,
> regardless of skill, and even with a wig would still be a lamp-post.
>
> That doesn't apply in this case because the experimenter is potentially
> reactive.
>
> --
> "President Washington, President Lincoln, President Wilson, President
> Roosevelt have all authorized electronic surveillance on a far broader
> scale." --Attorney General Alberto Gonzalez
>
|
| |
Date: 21 Sep 2006 08:54:18
From: Buck
Subject: Re: Passing thoughts
|
Mike Jacoubowsky wrote:
> One of the most-basic requirements for such studies is being able to
> duplicate the conditions and verify the results. Most technicians &
> researchers would be careful to use tools & situations that would minimize
> variability in results if someone else were to conduct the experiment. When
> such variability cannot be helped, the solution is to have a cross-section
> of people or whatever involved, so that the bias or technique of an
> individual does not unduly shape the results of the study.
One of the sticking points in my mind was the method used to verify
lane position. I contacted Dr. Walker and asked him a few questions
about his methodology. To control his lane position, he mounted a laser
pointer on his bike and set the angle to achieve the distances noted in
the already-published charts. While he did say that it was surprisingly
easy to maintain lane position with this method, I would not want to
follow the same methodology as it would take my focus away from the
traffic. I did not ask about his accidents.
> So I agree, we shouldn't be tossing out all research done by just one
> person. But we have to look at the FACTS presented in this case, few as they
> may be. And the FACTS are that this guy had two collisions with cars,
> apparently during the 1250 times he was passed by a car while wearing a
> helmet.
>
> I would have been dead long ago if those were the odds I faced each time I
> got out on a bike. As would most people in this newsgroup.
At this point, I think that many of the questions brought about by the
brief will be answered when the full paper is publsihed. As to the
accidents, perhaps his methodology contributed to them, perhpas they
did not. I know that when bad things happen to me, they tend to happen
in quick succession.
> Rarely do I feel so strongly about an issue that it agitates me this much.
> But bad science applied to cycling, whether it be something like this (which
> affects how people view their safety on the road) or scaring people
> literally off their seats by claiming they'll become impotent... yes, it
> really bugs me that stories like those get media attention.
What really bothers me about this story is that it was released to the
media BEFORE the full paper was published. Sensationalism rarely does
anyone any good. I will withhold my judgement on the quality of the
science until the full paper is published. However, I do believe the
reporters responsible for those stories should be forced to ride a few
hundred miles in downtown NY traffic without a helmet.
-Buck
|
| |
Date: 20 Sep 2006 15:30:18
From: Buck
Subject: Re: Passing thoughts
|
Mike Jacoubowsky wrote:
> > (http://www.drianwalker.com/overtaking/). I have come to realize that
> > there is some legitimacy to his work. Although, I think he missed an
> > important point.
>
> There may be legitimacy to the concept, but there is *no* legitimacy to the
> manner in which he performed his "study."
>
> As I pointed out in an earlier thread-
>
> "A sample size of ONE rider. That's right, ONE rider, who emulated
> male & female by using a wig or not. This is not good science. It's not even
> a good story.
I disagree with you on this. When more than one person collects data,
additional variation is introduced into the data collection process.
Using a single person to collect data is a way to eliminate the
variation caused by slight changes in measurement technique.
This is easily observable in any high school chemistry class. Ask a
group of students to read the volume in a graduated cylinder. You will
get a variety of answers because they all read the meniscus slightly
differently. This is despite clear instructions on the proper
methodology for reading the meniscus.
You may argue that the example is for students in a learning
environment. But scientists in the medical field use the same
reasoning. When I was involved in medical research, we assigned
specific technicians to specific tasks throughout the life of each
study we conducted. This was to prevent any variation in techniques. It
is easier to deal with a consistent error than a random error.
If we were to toss out all research in which one technician or one
researcher were responsible for all data collection, we would toss out
a great deal of research.
-Buck
|
| | |
Date: 21 Sep 2006 13:13:16
From:
Subject: Re: Passing thoughts
|
On 20 Sep 2006 15:30:18 -0700, "Buck" <bicyclebuck@gmail.com > wrote:
>
>If we were to toss out all research in which one technician or one
>researcher were responsible for all data collection, we would toss out
>a great deal of research.
Research should be evaluated on its own merits. You'll find that it
is people with an agenda who will sieze upon a single element of some
study, and generalize it to all the studies with whose results they
disagree, and so "toss out" all they find opposing them.
If they truly suspected there was an effect from a single evaluator,
rather than strut out an opinion, they (and we) would be better served
if they repeated the experiment, changing only the number of
evaluators. This of course would be work, and blather is much the
simpler course.
|
| | | |
Date: 21 Sep 2006 19:27:53
From: Mike Jacoubowsky
Subject: Re: Passing thoughts
|
> Research should be evaluated on its own merits. You'll find that it
> is people with an agenda who will sieze upon a single element of some
> study, and generalize it to all the studies with whose results they
> disagree, and so "toss out" all they find opposing them.
>
> If they truly suspected there was an effect from a single evaluator,
> rather than strut out an opinion, they (and we) would be better served
> if they repeated the experiment, changing only the number of
> evaluators. This of course would be work, and blather is much the
> simpler course.
Absolutely agree 100%.
But... the study that's needed is a bit more broad-based than whether
wearing a helmet makes a difference or not. What's needed is a study that
simply asks (and answers) the question- "What are the behaviours while
riding a bike that influence your safety vs cars?"
--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA
<jtaylor@NOSPAM.hfx.andara.com > wrote in message
news:dh35h2t54v17i9igtvfeus6vpv8uqt5cl8@4ax.com...
> On 20 Sep 2006 15:30:18 -0700, "Buck" <bicyclebuck@gmail.com> wrote:
>
>
>>
>>If we were to toss out all research in which one technician or one
>>researcher were responsible for all data collection, we would toss out
>>a great deal of research.
>
> Research should be evaluated on its own merits. You'll find that it
> is people with an agenda who will sieze upon a single element of some
> study, and generalize it to all the studies with whose results they
> disagree, and so "toss out" all they find opposing them.
>
> If they truly suspected there was an effect from a single evaluator,
> rather than strut out an opinion, they (and we) would be better served
> if they repeated the experiment, changing only the number of
> evaluators. This of course would be work, and blather is much the
> simpler course.
>
|
| | |
Date: 21 Sep 2006 04:12:44
From: Mike Kruger
Subject: Re: Passing thoughts
|
"Buck" <bicyclebuck@gmail.com > wrote in message
news:1158791418.793296.72370@m73g2000cwd.googlegroups.com...
> Mike Jacoubowsky wrote:
>>
>> "A sample size of ONE rider. That's right, ONE rider, who emulated
>> male & female by using a wig or not. This is not good science. It's not
>> even
>> a good story.
>
> I disagree with you on this. When more than one person collects data,
> additional variation is introduced into the data collection process.
> Using a single person to collect data is a way to eliminate the
> variation caused by slight changes in measurement technique.
>
> This is easily observable in any high school chemistry class. Ask a
> group of students to read the volume in a graduated cylinder. You will
> get a variety of answers because they all read the meniscus slightly
> differently. This is despite clear instructions on the proper
> methodology for reading the meniscus.
>
Yes, there is variance added when more than one person collects data. The
proper statististical techniques can separate out this variance.
But the important thing is that this variance per person is very necessary
in a study like this. We don't know what cues the experimenter -- who knows
what he expects to find -- might have been giving off. There's no control on
this. You mentioned chemistry, so you are surely aware that medical studies
of new drugs are, ideally, done double-blind to avoid this type of problem.
One thing that we do know is that he got hit twice in 200 miles of riding
during this study. Does that sound typical of anybody?
This seems like a nice pilot study, just to shake down the methodology and
see if there might be something there. But it should have been followed up
by an adequately controlled study that might have actually told us
something.
Mike Kruger
--
"President Washington, President Lincoln, President Wilson, President
Roosevelt have all authorized electronic surveillance on a far broader
scale." --Attorney General Alberto Gonzalez
|
| | |
Date: 20 Sep 2006 20:04:01
From: Chris Neary
Subject: Re: Passing thoughts
|
>> "A sample size of ONE rider. That's right, ONE rider, who emulated
>> male & female by using a wig or not. This is not good science. It's not even
>> a good story.
>
>I disagree with you on this. When more than one person collects data,
>additional variation is introduced into the data collection process.
>Using a single person to collect data is a way to eliminate the
>variation caused by slight changes in measurement technique.
Wow, so we have really great data applicable to ONE person.
The problem isn't that ONE person collected the data - the problem is that
ONE person was the experiment from which the data was collected.
Chris Neary
diabloridr@tcsn.net
"Prize the doubt, low kinds exist without"
- Inscription at Ramsmeyer Hall, Ohio State University
|
| | |
Date: 21 Sep 2006 00:20:59
From: Mike Jacoubowsky
Subject: Re: Passing thoughts
|
> If we were to toss out all research in which one technician or one
> researcher were responsible for all data collection, we would toss out
> a great deal of research.
We're talking about two entirely different things here. I hope.
One of the most-basic requirements for such studies is being able to
duplicate the conditions and verify the results. Most technicians &
researchers would be careful to use tools & situations that would minimize
variability in results if someone else were to conduct the experiment. When
such variability cannot be helped, the solution is to have a cross-section
of people or whatever involved, so that the bias or technique of an
individual does not unduly shape the results of the study.
So I agree, we shouldn't be tossing out all research done by just one
person. But we have to look at the FACTS presented in this case, few as they
may be. And the FACTS are that this guy had two collisions with cars,
apparently during the 1250 times he was passed by a car while wearing a
helmet.
I would have been dead long ago if those were the odds I faced each time I
got out on a bike. As would most people in this newsgroup.
Rarely do I feel so strongly about an issue that it agitates me this much.
But bad science applied to cycling, whether it be something like this (which
affects how people view their safety on the road) or scaring people
literally off their seats by claiming they'll become impotent... yes, it
really bugs me that stories like those get media attention.
--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA
"Buck" <bicyclebuck@gmail.com > wrote in message
news:1158791418.793296.72370@m73g2000cwd.googlegroups.com...
> Mike Jacoubowsky wrote:
>> > (http://www.drianwalker.com/overtaking/). I have come to realize that
>> > there is some legitimacy to his work. Although, I think he missed an
>> > important point.
>>
>> There may be legitimacy to the concept, but there is *no* legitimacy to
>> the
>> manner in which he performed his "study."
>>
>> As I pointed out in an earlier thread-
>>
>> "A sample size of ONE rider. That's right, ONE rider, who emulated
>> male & female by using a wig or not. This is not good science. It's not
>> even
>> a good story.
>
> I disagree with you on this. When more than one person collects data,
> additional variation is introduced into the data collection process.
> Using a single person to collect data is a way to eliminate the
> variation caused by slight changes in measurement technique.
>
> This is easily observable in any high school chemistry class. Ask a
> group of students to read the volume in a graduated cylinder. You will
> get a variety of answers because they all read the meniscus slightly
> differently. This is despite clear instructions on the proper
> methodology for reading the meniscus.
>
> You may argue that the example is for students in a learning
> environment. But scientists in the medical field use the same
> reasoning. When I was involved in medical research, we assigned
> specific technicians to specific tasks throughout the life of each
> study we conducted. This was to prevent any variation in techniques. It
> is easier to deal with a consistent error than a random error.
>
> If we were to toss out all research in which one technician or one
> researcher were responsible for all data collection, we would toss out
> a great deal of research.
>
> -Buck
>
|
| |
Date: 20 Sep 2006 17:16:08
From: Mike Jacoubowsky
Subject: Re: Passing thoughts
|
> (http://www.drianwalker.com/overtaking/). I have come to realize that
> there is some legitimacy to his work. Although, I think he missed an
> important point.
There may be legitimacy to the concept, but there is *no* legitimacy to the
manner in which he performed his "study."
As I pointed out in an earlier thread-
"A sample size of ONE rider. That's right, ONE rider, who emulated
male & female by using a wig or not. This is not good science. It's not even
a good story.
It makes the case of over 1000 cars, which is fine, reasonable sample size.
But it draws conclusions based upon an unobserved single participant (who
just happens to be the author of the study, and who just happens to have
been hit TWICE during the study after having been passed by 2500 motorists.
Think about what that's saying. Let's assume he wore the helmet half the
time, and both times he was hit he was wearing the helmet. If that's the
case, then his rate of being physically hit by a passing car is ONCE EVERY
625 CARS!!! If this were typical, most of us wouldn't live long enough to
figure out the next version of Windows, Linux, or Apple OS-X.
Complete & total nonsense. It could be that the premise actually is true...
that cars may in fact actually pass closer to a helmeted cyclist than a
non-helmeted cyclist... but there is nothing in that experiment to support
that, due to the absurd flaws in how it was run. Other than to suggest that
the author is a terribly unskilled cyclist, that is. That conclusion is
inescapable."
> When I move further left in my lane, passing behavior changes. Yes, the
> relative position between me and the passing vehicle may be closer.
> However, I find that people are more reluctant to pass me illegally.
> The two most common illegal passes I encounter are passing in a
> no-passing zone, and not moving completely into the other lane when
> passing (lane sharing). It is the latter behaviour that my lane
> position seems to affect most.
As you act more like a car, the cars will treat you more as they would treat
a car. Which is generally a good thing. I'm not a John Forrester type; I
don't believe that all cyclists are best-served by acting like a car. But it
is an advantage for the stronger riders, who can more easily take the lane
when required, with a minimal effect on the flow of traffic.
> Pulling my kids' trailer around also seems to inspire the same results.
> An added benefit of the trailer is the speed at which people pass.
> Whether they are slowing to observe this unusual contraption on the
> road or they have genuine concern about what may be inside, I don't
> know. But I have fewer vehicles zooming past when the trailer is on
> board. The added benefit is a place to hang my clothes for work!
Agree 100%. People are often terrified of pulling their kids in a trailer,
believing they're going to get run over. My experience hauling my kids
around was the opposite; people gave me a very comfortable amount of space,
much more than when I rode without the trailer. Yes, it shows that people
drive differently depending upon what they see on the road in front of them,
but it doesn't add validity to the experiment, because it has nothing to do
with *you* riding differently, which I suspect was the case with the
cyclist/author in the experiment (when helmeted vs non-helmeted).
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
"Buck" <bicyclebuck@gmail.com > wrote in message
news:1158756761.995570.11880@h48g2000cwc.googlegroups.com...
>I have been considering the results of the recently posted brief on Ian
> Walker's study of motorists passing cyclists
> (http://www.drianwalker.com/overtaking/). I have come to realize that
> there is some legitimacy to his work. Although, I think he missed an
> important point.
>
> When I move further left in my lane, passing behavior changes. Yes, the
> relative position between me and the passing vehicle may be closer.
> However, I find that people are more reluctant to pass me illegally.
> The two most common illegal passes I encounter are passing in a
> no-passing zone, and not moving completely into the other lane when
> passing (lane sharing). It is the latter behaviour that my lane
> position seems to affect most.
>
> Pulling my kids' trailer around also seems to inspire the same results.
> An added benefit of the trailer is the speed at which people pass.
> Whether they are slowing to observe this unusual contraption on the
> road or they have genuine concern about what may be inside, I don't
> know. But I have fewer vehicles zooming past when the trailer is on
> board. The added benefit is a place to hang my clothes for work!
>
> I would like to see him revisit the video data he collected and make
> the comparison in passing technique. I've emailed him with this
> suggestion.
>
> -Buck
>
|
| |
Date: 20 Sep 2006 06:47:20
From:
Subject: Re: Passing thoughts
|
Buck wrote:
> I have been considering the results of the recently posted brief on Ian
> Walker's study of motorists passing cyclists
> (http://www.drianwalker.com/overtaking/). I have come to realize that
> there is some legitimacy to his work. Although, I think he missed an
> important point.
>
Now that I've read not only other people posting on this, but the press
release and the managerial version of the publication (the full
publication is not yet out yet), I think this is junk science.
It's amusing to discuss, and the findings might even be right, but
there's no validity to the study itself.
I've outlined this in more detail here:
<http://journals.aol.com/mikekr/ZbicyclistsZlog/entries/2006/09/16/want-to-get-hit-by-a-car-wear-a-helmet/798 >
|
| | |
Date: 20 Sep 2006 15:12:08
From:
Subject: Re: Passing thoughts
|
On 20 Sep 2006 06:47:20 -0700, zbicyclist@yahoo.com wrote:
>Buck wrote:
>> I have been considering the results of the recently posted brief on Ian
>> Walker's study of motorists passing cyclists
>> (http://www.drianwalker.com/overtaking/). I have come to realize that
>> there is some legitimacy to his work. Although, I think he missed an
>> important point.
>>
>Now that I've read not only other people posting on this, but the press
>release and the managerial version of the publication (the full
>publication is not yet out yet), I think this is junk science.
>
Perhaps you will apply to be on the editorial board.
|
|
