Hi vis jacket

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TonyR
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Re: Hi vis jacket

Post by TonyR »

stewartpratt wrote:
edocaster wrote:Interesting. Is there an example of the latter study?


Yes:
http://eprints.nottingham.ac.uk/12855/


The critical extracts from a lot of data:


Low-cost, easy to use retro-reflective and fluorescent clothing and accessories (’conspicuity aids’) are widely available. Their effectiveness in reducing the risk of cycling collisions is currently unknown...........The results of this study show a non-significant increase in the odds of a crash for users compared to non-users of conspicuity aids whilst cycling. ......... No reduction in crash risk could be demonstrated.

Interesting also that the crash risk was not increased by not using lights.
Psamathe
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Re: Hi vis jacket

Post by Psamathe »

TonyR wrote:
stewartpratt wrote:
edocaster wrote:Interesting. Is there an example of the latter study?


Yes:
http://eprints.nottingham.ac.uk/12855/


The critical extracts from a lot of data:


Low-cost, easy to use retro-reflective and fluorescent clothing and accessories (’conspicuity aids’) are widely available. Their effectiveness in reducing the risk of cycling collisions is currently unknown...........The results of this study show a non-significant increase in the odds of a crash for users compared to non-users of conspicuity aids whilst cycling. ......... No reduction in crash risk could be demonstrated.

Interesting also that the crash risk was not increased by not using lights.

But maybe the "The results of this study show a non-significant increase" means that we really can't conclude anything. I.e. the data show nothing significant.

Ian
JohnW
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Re: Hi vis jacket

Post by JohnW »

stewartpratt wrote:There is, of course, the very credible hypothesis that the two cyclists who were wearing hi-viz distracted significantly from the one who wasn't. In other words, that had none of you been wearing hi-viz, rather than you all going unnoticed, none of you would have gone unnoticed.

This is one of the likely problems of conspicuity aids: they become an arms race, and those without can be placed at greater risk as a result. If the above hypothesis holds true, which wouldn't be at all surprising (it's certainly an oft-cited concernw hen it comes to daytime running lights) then it becomes at least possible that using hi-viz simply gets us to the point where everyone has to use it, but no-one is actually better off as a result: we all dress like radioactive bananas for nothing.


I'm sorry stewart, but I can't agree with you. I believe that we all have a responsibility to ourselves, to our families and to others, and I believe that being seen is a good way to keep us safe from motorists. I believe it's rational common sense to realise that a driver who can see you has a better chance of avoiding you than one who can't. Hi-viz conspicuity aids are not a 100% guarantee of course but bandying words in the hope of victory in a debate isn't going to help.

There is (thankfully) quite an increase in the number of impressionable young cyclists on the road just at the moment, and arguing that they should be inconspicuous, and should melt into the background would be dangerous and, in my opinion, irresponsible.

I wear cycling tops which are in the brightest orange that I can find and, truthfully, there have been occasions when motorists have said something along the lines that they wouldn't have seen me if I'd "not been wearing that". It doesn't happen every day of course, but it does happen.

True, I've been on the receiving end of shouted insults, for looking like a Belisha Beacon for example, but this world has it's share of bad mannered scroats, and I can't do anything about that.
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mjr
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Re: Hi vis jacket

Post by mjr »

JohnW wrote:I'm sorry stewart, but I can't agree with you. I believe that we all have a responsibility to ourselves, to our families and to others, and I believe that being seen is a good way to keep us safe from motorists.

My emphasis: remember that.
I believe it's rational common sense to realise that a driver who can see you has a better chance of avoiding you than one who can't. Hi-viz conspicuity aids are not a 100% guarantee of course but bandying words in the hope of victory in a debate isn't going to help.

I believe it's rational common sense that drivers can see things that aren't bedecked in hi-vis, else they'd be crashing into a lot more stuff than they do, like buildings, trees, other cars, and so on. Yes, some crash into those things, but an excuse of "I didn't see that house/fallen tree/car because it wasn't bright yellow/orange/pink" usually fails the laugh test.

Instead of bandying words, please post whatever evidence you have that hi-vis helps. So far I think it looks like the best evidence is that it is makes no significant difference.

There is (thankfully) quite an increase in the number of impressionable young cyclists on the road just at the moment, and arguing that they should be inconspicuous, and should melt into the background would be dangerous and, in my opinion, irresponsible.

It probably would, which is why you're the only person putting forward that argument. I think the argument being put forward is that hi-vis is no better than decent contrast for oneself and wearing hi-vis then can make things worse for others because bad drivers start to expect all riders to wear hi-vis and get an easy excuse for running over a non-banana... and we have a responsibility to others, don't we?
MJR, mostly pedalling 3-speed roadsters. KL+West Norfolk BUG incl social easy rides http://www.klwnbug.co.uk
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Psamathe
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Re: Hi vis jacket

Post by Psamathe »

One aspect of "visibility" often overlooked is that we (incl. car divers) tend to spot things that are moving better or differently from objects that are not moving (irrespective of hi-vis). Maybe part of our evolutionary history, maybe relevant today, but things that are moving can represent more of a threat to us than stationary objects some distance off. So our perception is geared to be more sensitive to movement. Which might have explain why all the "hi-vis" research has not yet proved anything. Or maybe why it could be more important for a stationary (or slow moving/walking) person than a moving cyclist.

But I'm no expert and an certainly open to other opinions on this.

Ian
JohnW
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Re: Hi vis jacket

Post by JohnW »

mjr wrote:..............which is why you're the only person putting forward that argument.................


But I'm not the only person........................

I have two personal experience examples. Both on my commute, and therefore at a busy time of day on the roads.

Example one was en-route for work, at a junction where a minor lane comes into the road from the left. Someone was filtering in from my left and screeched to a halt just inches from me. He apologised profusely - he'd been looking over his right shoulder, found the road from his right to be clear and pulled away - straight into me. The screech of brakes was impressive. I was in my hi-viz orange. He told me that the hi-viz was what had 'saved' me because it was the "blaze" of colour that he saw.

Incidentally (and irrelevant to the subject), he was one of those decent blokes, and was more upset than I was - he was shaking like a leaf.

Years before that, before fluorescent hi-viz and reflectives, I was heading from home one wet evening at dusk - my orange track-suit top was of little use as a visibility aid, and a car pulled out from my left and hit me. The driver was another decent bloke - not driving dangerously, he genuinely hadn't seen me - he stopped and apologised and brought me and the broken bike home in his car.......and he offered his insurance details. This was in the days of (N)Ever-Ready flickering glow-worms, but in those conditions, fluorescent hi-viz stands out like a beacon.

I say all this with the caveat that hi-viz is only one form of contrast, which is more effective in dusk time than ordinary contrast - in fact hi-viz isn't as relatively effective in good light as it is in poor light.

I'm not going to enter into a debate for the sake of winning a debate - or losing it if I'm not as clever as you (you'll have your opinion about that) - but I know what I see.

Soldiers wear camouflage so that hopefully the enemy can't see them and therefore has less chance of hitting them........it doesn't work like that on the roads.
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[XAP]Bob
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Re: Hi vis jacket

Post by [XAP]Bob »

The question to ask is whether you can ever see people - high zis does make it possible to observe things from far, far away, but that distant identiciation simply isn't needed with rubber tyres and steering.

Theory:
Colour vision is very limited, flourescent clotging may make a "super white" item on peripheral vision, but the actual colour isn't relevant until looked AT, when the cones in the fovea can be used.

Retroreflectives are really useful, but since we all have red reflectors to the rear (don't we?) and some of us add white retroreflectors to the front we're already visible as we cross lights (I.e. the distance the motorist can see)
For a motorist coming out of a sideroad we won't be in headlight range anyway...

The benfit should be clearly observable, it just isn't...
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
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stewartpratt
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Re: Hi vis jacket

Post by stewartpratt »

irc wrote:Given a road environment where almost all other road user are either motorized or non HiViz pedestrians I am confident we are a long way from
being invisible in a sea of HiViz jackets.


The anecdote above suggests otherwise, in localised scenarios.
irc
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Re: Hi vis jacket

Post by irc »

TonyR wrote:
stewartpratt wrote:
edocaster wrote:Interesting. Is there an example of the latter study?


Yes:
http://eprints.nottingham.ac.uk/12855/


The critical extracts from a lot of data:


Low-cost, easy to use retro-reflective and fluorescent clothing and accessories (’conspicuity aids’) are widely available. Their effectiveness in reducing the risk of cycling collisions is currently unknown...........The results of this study show a non-significant increase in the odds of a crash for users compared to non-users of conspicuity aids whilst cycling. ......... No reduction in crash risk could be demonstrated.
.



The report states
Residual confounding may have occurred if conspicuity aid users were taking more risks when encountering similar traffic conditions to non-users. This could not be measured but may go some way to explaining these results. If cyclists over-estimate the likely effect of their conspicuity aid use this could result in over compensation and a net increase in crash risk.


So it is likely that the apparent higher number of crashes for HiViz users was due to risk compensation. As always, HiViz, lights, helmets etc are secondary to route choice and riding style in determining safety. I frequently see experienced commuters riding in the doorzone while wearing helmets, HiViz and on a bike with good lights.
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mjr
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Re: Hi vis jacket

Post by mjr »

JohnW wrote:
mjr wrote:..............which is why you're the only person putting forward that argument.................


But I'm not the only person........................

No? Please show who else here is "arguing that they should be inconspicuous, and should melt into the background".

Similarly, who has seriously mentioned wearing camouflage? Yet that's another thing you've argued against. You might find it fun to engage in such exercises, but it's not helpful to make up silly positions and then argue against them.
I have two personal experience examples. Both on my commute, and therefore at a busy time of day on the roads.

Anecdotes aren't great - at best, they can suggest things to test. I've anecdotes too, being clipped by a car and pulled out into by a van while I was wearing hi-vis, while I've had no similar incidents riding mostly in black and white, or dark blue. But who cares? Let's look at the studies, some of the whole population and some of representative samples, which were summarised above. That's rational, isn't it?
MJR, mostly pedalling 3-speed roadsters. KL+West Norfolk BUG incl social easy rides http://www.klwnbug.co.uk
All the above is CC-By-SA and no other implied copyright license to Cycle magazine.
Edwards
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Re: Hi vis jacket

Post by Edwards »

JohnW wrote: I believe that we all have a responsibility to ourselves, to our families and to others, and I believe that being seen is a good way to keep us safe from motorists. I believe it's rational common sense to realise that a driver who can see you has a better chance of avoiding you than one who can't. Hi-viz conspicuity aids are not a 100% guarantee of course but bandying words in the hope of victory in a debate isn't going to help.


John apologies for just quoting this bit, I have not done so to dissect it word for word and try to turn the meaning around.
I have quoted this bit to state I whole heartedly agree with you on the above point. I have come to this decision after many years working on roads and other dark dangerous environments. As I a person who observes the world around him then believes what I have seen for myself, I know that I can see some things easier than others and bright colours are one of them.
Keith Edwards
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TonyR
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Re: Hi vis jacket

Post by TonyR »

Psamathe wrote:
TonyR wrote:
The critical extracts from a lot of data:


Low-cost, easy to use retro-reflective and fluorescent clothing and accessories (’conspicuity aids’) are widely available. Their effectiveness in reducing the risk of cycling collisions is currently unknown...........The results of this study show a non-significant increase in the odds of a crash for users compared to non-users of conspicuity aids whilst cycling. ......... No reduction in crash risk could be demonstrated.

Interesting also that the crash risk was not increased by not using lights.

But maybe the "The results of this study show a non-significant increase" means that we really can't conclude anything. I.e. the data show nothing significant.

Ian


Not true. We can conclude from the study that hi-viz does not appear to reduce accidents. The "non-significant" bit in the text just indicates that the apparent increase in accidents amongst hi-viz wearers is probably not real but down to chance variations.
edocaster
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Re: Hi vis jacket

Post by edocaster »



This one seems to have the largest database. But it's not about specific hi-viz clothing, but rather about 'conspicuity aids' in general, including lighting.

'Class three' had the results which appear to point to a reduced crash rate among those who claim to be ‘occasionally conspicuous day & night’ (which I assume wasn't someone's interpretation of a flashing light...). But that group had less of everything, and only nine crashes in total. Basically, it seems to be a group which claimed a relatively high number of miles, with relatively little in the way of conspicuity aids.

Of the remaining groups, only classes one and four seem to ride in the dark, and both groups use conspicuity aids - as you'd expect, if riding in the dark. Their crash rates tell us little about hi-viz clothing.

So, comparing class three and the two other classes which ride in the dark, there's a big imbalance of data, as class three had a handful of crashes and claimed a lot of miles. Perhaps sometimes in the dark.

Leaving aside risk compensation, there are some very specific caveats which reflect the data above: 'we attempted to account for lighting condition at the time of the crash by creating composite patterns of using conspicuity aids' and 'Self-reported cycling exposure and use of conspicuity aids may not be accurate.'
sloblock100
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Re: Hi vis jacket

Post by sloblock100 »

GET YOURSELF SEEN! Cyclists Get Yourself Seen: http://youtu.be/1MFuSMz1zh0
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'Germans'?
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Cunobelin
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Re: Hi vis jacket

Post by Cunobelin »

JohnW wrote:
I'm sorry stewart, but I can't agree with you. I believe that we all have a responsibility to ourselves, to our families and to others, and I believe that being seen is a good way to keep us safe from motorists. I believe it's rational common sense to realise that a driver who can see you has a better chance of avoiding you than one who can't. Hi-viz conspicuity aids are not a 100% guarantee of course but bandying words in the hope of victory in a debate isn't going to help.


Given the formal safety assessments and risk assessments making it an enforceable requirement for employees, and the accidents that DO occur customers without HiViz....



Do the customers have a responsibility to themselves, to their families and to others, and I believe that being seen is a good way to keep us safe from motorists. I believe it's rational common sense to realise that a driver who can see you has a better chance of avoiding you than one who can't. Hi-viz conspicuity aids are not a 100% guarantee of course but bandying words in the hope of victory in a debate isn't going to help.
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