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Objective measures of overtaking
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James
May 23, 2012, 6:20:41 PM5/23/12
to
http://drianwalker.com/overtaking/overtakingprobrief.pdf
<quote>
Results
Riding position and helmet
Drivers passed closer to the rider the further out into the road he was.
This is contrary to what many experienced bicyclists believed should
happen. Drivers also tended to pass notably closer to the rider when he
wore a helmet (white circles) than when he did not (black squares).
Riding position and helmet wearing accounted for 8% of the variance in
overtaking proximities. The helmet effect was due to shifts in
overtaking distributions rather than qualitative changes. The position
effect operated in a similar way.
</quote>
--
JS.
<quote>
Results
Riding position and helmet
Drivers passed closer to the rider the further out into the road he was.
This is contrary to what many experienced bicyclists believed should
happen. Drivers also tended to pass notably closer to the rider when he
wore a helmet (white circles) than when he did not (black squares).
Riding position and helmet wearing accounted for 8% of the variance in
overtaking proximities. The helmet effect was due to shifts in
overtaking distributions rather than qualitative changes. The position
effect operated in a similar way.
</quote>
--
JS.
Jay Beattie
May 23, 2012, 7:59:40 PM5/23/12
to
http://www.eta.co.uk/2011/04/01/safest-bicycle-helmet-has-built-wig
-- Jay Beattie.
JG
May 24, 2012, 4:05:12 PM5/24/12
to
I have reservations about "notably". While I have only seen his blog
write-ups, not the later, formal article, I don't think he ever
calculated a confidence interval on the data. There must be a
variance in the ultra-sonic distance detection equipment, as well as a
good deal of variance in the physical profiles of overtaking
vehicles. Notably ;-) the briefing does not provide the average
difference which, if I recall correctly, was a few inches and, I
suspect, statistically insignificant.
Of course, none of this addresses whether close overtaking is a
substantial risk factor.
write-ups, not the later, formal article, I don't think he ever
calculated a confidence interval on the data. There must be a
variance in the ultra-sonic distance detection equipment, as well as a
good deal of variance in the physical profiles of overtaking
vehicles. Notably ;-) the briefing does not provide the average
difference which, if I recall correctly, was a few inches and, I
suspect, statistically insignificant.
Of course, none of this addresses whether close overtaking is a
substantial risk factor.
Message has been deleted
JG
May 25, 2012, 12:53:41 PM5/25/12
to
> He was actually hit twice by overtaking vehicles during the experiment
> - both times while wearing the helmet.
Which is an enormously higher rate than a careful cyclist
experiences. Which brings up the other troubling aspect - how much
did his awareness and interest in the experiment affect his riding?
Jay Beattie
May 25, 2012, 1:27:22 PM5/25/12
to
On May 25, 9:12 am, Phil W Lee <p...@lee-family.me.uk> wrote:
> JG <j...@cox.net> considered Thu, 24 May 2012 13:05:12 -0700 (PDT) the
> I've actually had the opportunity to discuss the study with him face
> to face.
>
> BTW, the wig he used was brunette, not blonde.
>
> The variation in the distance he rode from the kerb was small, so
> cannot be usefully interpreted in terms of the relative safety of
> primary position (taking the lane) versus gutter hugging.
This kind of study is beyond useless -- or as scientists put it "not
even wrong." The study had zero controls; the motorists were not
questioned, polled or even categorized (experienced, non-
experienced). There is no telling whether the rider(s)were sending
other signals to drivers, whether they were riding a straight line,
etc., etc. You would have to install a track or a wire guide for the
cyclists to ensure repeatability.
Really, 8.5 cm closer with a helmet? That's less than 3.5 inches. I
meander more than that just picking up a butt cheek to adjust my
shorts. Moroever, according to the chart, the non-helmeted rider got
passed more closely than the helmeted rider when riding about .80
meters from the curb -- what accounts for that? It's obviously not
helmet related.
I have been riding the same commute routes for almost 30 years (28 to
be exact), and have been passed closely with or without a helmet, with
or without my wife, on sunny days, on rainy days, in a box, with a
fox, etc., etc. The only conistent fact is that big vehicles do pass
more closely, and if I take the lane, cars still pass -- and usually
very closely if there is no on-coming traffic.
I've got 200,000-300,000 lifetime miles on a bike, and I've been hit
by an over-taking vehicle exactly once, and it was a bus, and it was
because (according to the driver), the bus was forced over by a car
(hey, hit the cyclist and avoid denting a fender). If your friend and
test subject got hit twice, he is either an idiot or riding in the
world's most dangerous spot for cyclists. And if the latter, he
really, really needs a helmet -- if only to prevent the inevitable
scalp laceration.
-- Jay Beattie.
> JG <j...@cox.net> considered Thu, 24 May 2012 13:05:12 -0700 (PDT) the
> to face.
>
> He was actually hit twice by overtaking vehicles during the experiment
> - both times while wearing the helmet.
>
> That's a substantial enough risk factor for me.
> He was actually hit twice by overtaking vehicles during the experiment
> - both times while wearing the helmet.
>
>
> BTW, the wig he used was brunette, not blonde.
>
> The variation in the distance he rode from the kerb was small, so
> cannot be usefully interpreted in terms of the relative safety of
> primary position (taking the lane) versus gutter hugging.
This kind of study is beyond useless -- or as scientists put it "not
even wrong." The study had zero controls; the motorists were not
questioned, polled or even categorized (experienced, non-
experienced). There is no telling whether the rider(s)were sending
other signals to drivers, whether they were riding a straight line,
etc., etc. You would have to install a track or a wire guide for the
cyclists to ensure repeatability.
Really, 8.5 cm closer with a helmet? That's less than 3.5 inches. I
meander more than that just picking up a butt cheek to adjust my
shorts. Moroever, according to the chart, the non-helmeted rider got
passed more closely than the helmeted rider when riding about .80
meters from the curb -- what accounts for that? It's obviously not
helmet related.
I have been riding the same commute routes for almost 30 years (28 to
be exact), and have been passed closely with or without a helmet, with
or without my wife, on sunny days, on rainy days, in a box, with a
fox, etc., etc. The only conistent fact is that big vehicles do pass
more closely, and if I take the lane, cars still pass -- and usually
very closely if there is no on-coming traffic.
I've got 200,000-300,000 lifetime miles on a bike, and I've been hit
by an over-taking vehicle exactly once, and it was a bus, and it was
because (according to the driver), the bus was forced over by a car
(hey, hit the cyclist and avoid denting a fender). If your friend and
test subject got hit twice, he is either an idiot or riding in the
world's most dangerous spot for cyclists. And if the latter, he
really, really needs a helmet -- if only to prevent the inevitable
scalp laceration.
-- Jay Beattie.
AMuzi
May 25, 2012, 3:26:43 PM5/25/12
to
http://online.wsj.com/article/SB10001424052702303610504577418553690077864.html?mod=googlenews_wsj
Their paper:
http://ajph.aphapublications.org/doi/abs/10.2105/AJPH.2012.300711
--
Andrew Muzi
<www.yellowjersey.org/>
Open every day since 1 April, 1971
Message has been deleted
DirtRoadie
May 25, 2012, 3:35:22 PM5/25/12
to
On May 25, 10:12 am, Phil W Lee <p...@lee-family.me.uk> wrote:
> He was actually hit twice by overtaking vehicles during the experiment
> - both times while wearing the helmet.
>
> That's a substantial enough risk factor for me.
And the reason you know these were the RESULT of wearing a helmet
> He was actually hit twice by overtaking vehicles during the experiment
> - both times while wearing the helmet.
>
> That's a substantial enough risk factor for me.
is.....?
I have been hit twice while wearing white socks. I'll never do THAT
again - way too risky!
DR
Jay Beattie
May 25, 2012, 3:45:57 PM5/25/12
to
>
> Their paper:
>
> http://ajph.aphapublications.org/doi/abs/10.2105/AJPH.2012.300711
Dude, helmets make you go faster! Also, what the f*** is risky about
going 11.9 mph (assuming you don't have a serious heart condition)?
What this tells us is that the males felt "racier" wearing helmets --
or felt that they had to be racey. It's like getting new tires or bar
tape or wearing lycra shorts. They should run the experiment with
yellow TdF jerseys and see what happens. Leader jerseys cause risk
compensation! Or, lightweight, aerodynamic bikes cause risk
compensation!
So, if I do well in a TT, am I risk compensating?
-- Jay Beattie.
JG
May 25, 2012, 4:28:24 PM5/25/12
to
> Helmet use was recorded in 99, or 3.8%, of 2,621 movements made by 587 cyclists captured on camera.
Well, I should probably read the paper first, but this is hilarious!
The helmets were given away for free - and perhaps no more than 23 (of
the 587) actually wore them!-)
Well, I should probably read the paper first, but this is hilarious!
The helmets were given away for free - and perhaps no more than 23 (of
the 587) actually wore them!-)
AMuzi
May 25, 2012, 4:53:49 PM5/25/12
to
dangerous an intersection as ever there was.
datakoll
May 25, 2012, 9:39:43 PM5/25/12
to
why ona bike path with the senile, a move to the other behind side not the passinf behind position then DING DING PASSING ON THE LEFT while aurally behind on the left.
have you tried a mask for Sunday morning's ?
have you tried a mask for Sunday morning's ?
datakoll
May 25, 2012, 9:57:05 PM5/25/12
to
On Friday, May 25, 2012 7:39:43 PM UTC-6, datakoll wrote:
> why ona bike path with the senile, a move to the other behind side not the passinf behind position then DING DING PASSING ON THE LEFT while aurally behind on the left.
>
> have you tried a mask for Sunday morning's ?
DING DING PASSING ON THE RIGHT
> why ona bike path with the senile, a move to the other behind side not the passinf behind position then DING DING PASSING ON THE LEFT while aurally behind on the left.
>
> have you tried a mask for Sunday morning's ?
shit..
datakoll
May 25, 2012, 11:12:29 PM5/25/12
to
the Messiah is filling in time....
everyone does this across the plastic sheet...
and a reason for doing it. UNIFORMS !
PROPHYLACTICS ! bugs do it, birds do it....
everyone does this across the plastic sheet...
and a reason for doing it. UNIFORMS !
PROPHYLACTICS ! bugs do it, birds do it....
Sepp Ruf
May 26, 2012, 6:03:51 AM5/26/12
to
Jay Beattie a ecrit:
involved, and whow, all the numbers match the Seattle findings:
70% Cabernet Sauvignon + 15% Cabernet Franc: 85%
70% Merlot + 15% Cabernet Franc: 85%
http://blogs.dallasobserver.com/cityofate/assets_c/2010/12/zach-galifianakis-wine-helmet-thumb-350x233.jpg
> Also, what the f*** is risky about going 11.9 mph
That's already exceeding their design limit:
http://www.froghomecreations.com/images/WINEBASKET.jpg
> (assuming you don't have a serious heart condition)?
A serious heart condition in Bordeaux? No way.
https://upload.wikimedia.org/wikipedia/commons/3/30/Coq_au_vin_rouge.jpg
> On May 25, 12:26 pm, AMuzi wrote:
>> New study news report:
>>
>> http://online.wsj.com/article/SB1000142405270230361050457741855369007...
>>
>> Their paper:
>>
>> http://ajph.aphapublications.org/doi/abs/10.2105/AJPH.2012.300711
Alright, I got a subscription to get a closer look at the science
>> New study news report:
>>
>> http://online.wsj.com/article/SB1000142405270230361050457741855369007...
>>
>> Their paper:
>>
>> http://ajph.aphapublications.org/doi/abs/10.2105/AJPH.2012.300711
involved, and whow, all the numbers match the Seattle findings:
70% Cabernet Sauvignon + 15% Cabernet Franc: 85%
70% Merlot + 15% Cabernet Franc: 85%
http://blogs.dallasobserver.com/cityofate/assets_c/2010/12/zach-galifianakis-wine-helmet-thumb-350x233.jpg
> Also, what the f*** is risky about going 11.9 mph
http://www.froghomecreations.com/images/WINEBASKET.jpg
> (assuming you don't have a serious heart condition)?
https://upload.wikimedia.org/wikipedia/commons/3/30/Coq_au_vin_rouge.jpg
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