Mandatory hi-vis had no influence on number of cyclists involved in collisions according to Italian study

Rich_cb wrote:

Here's a link to the Danish randomised controlled trial mentioned in the article. The best piece of research done on this topic by a country mile. They found hi-vis reduced your risk of being in an accident with another road user by a third. https://www.sciencedirect.com/science/article/pii/S0925753517313528

So, lots of nice percentage data but still inconclusive. A wise man (Churchill) once said that statistics are like a drunk with a lamppost; used more for support than illumination.

You see what you want to see but I do not see anything in the reports conclusion about Hi-Vis reducing risk of being in an accident with another road user by a third. What I see from the report is this:

Quote The external validity of the experiment is challenged by the fact that the effect is assumed to change if the environment changes. For instance, the effect will most likely decrease if an increasing number of cyclists start using a bright-coloured bicycle jacket because the jacket will not attract as much attention when more cyclists use it. In this study, the participants were spread across the country (Fig. 3), and the likelihood of being in a group with multiple bicycle jackets is small. This also means that the found effect represents an average of the effect in big cities, small cities and rural areas, although some variation between these areas is expected. The external validity is also influenced by the fact that other road users’ risk may increase when attention is directed to cyclists with bright-coloured jackets at the expense of other cyclists. These considerations are not specific to bright-coloured jackets but are generally valid. Overall, the assessment of the external validity is that the effect will most likely decrease as jacket use increases, but not to a degree that may compromise a general positive effect of a yellow jacket. Unquote

You still need to change the mentallity of the drivers rather than make a case for Hi-Vis. This was not even a subject case twenty years ago, so why now? By the way, I ride with bright colours on the majority of rides/commutes and sometimes I wear black. In my experience it makes no shred of difference.

Pushing50 wrote:

So, lots of nice percentage data but still inconclusive. A wise man (Churchill) once said that statistics are like a drunk with a lamppost; used more for support than illumination.

You see what you want to see but I do not see anything in the reports conclusion about Hi-Vis reducing risk of being in an accident with another road user by a third. What I see from the report is this:

Quote The external validity of the experiment is challenged by the fact that the effect is assumed to change if the environment changes. For instance, the effect will most likely decrease if an increasing number of cyclists start using a bright-coloured bicycle jacket because the jacket will not attract as much attention when more cyclists use it. In this study, the participants were spread across the country (Fig. 3), and the likelihood of being in a group with multiple bicycle jackets is small. This also means that the found effect represents an average of the effect in big cities, small cities and rural areas, although some variation between these areas is expected. The external validity is also influenced by the fact that other road users’ risk may increase when attention is directed to cyclists with bright-coloured jackets at the expense of other cyclists. These considerations are not specific to bright-coloured jackets but are generally valid. Overall, the assessment of the external validity is that the effect will most likely decrease as jacket use increases, but not to a degree that may compromise a general positive effect of a yellow jacket. Unquote

You still need to change the mentallity of the drivers rather than make a case for Hi-Vis. This was not even a subject case twenty years ago, so why now? By the way, I ride with bright colours on the majority of rides/commutes and sometimes I wear black. In my experience it makes no shred of difference.

So you didn't see the statistically significant difference between the control and the study groups?

Or you chose to give more weight to an assumption?

Even that assumption concludes that the hi vis will continue to offer a protective effect.

Studies into collision rates of cars have found that brightly coloured cars have fewer collisions despite there being a lot of them so perhaps the saturation assumption is not as significant as you think.

I agree that we need to change the mentality of drivers but that is an incredibly difficult task that will take years to achieve, I can decrease my own risk instantly by making myself more visible.

Rich_cb wrote:

Pushing50 wrote:

So, lots of nice percentage data but still inconclusive. A wise man (Churchill) once said that statistics are like a drunk with a lamppost; used more for support than illumination.

You see what you want to see but I do not see anything in the reports conclusion about Hi-Vis reducing risk of being in an accident with another road user by a third. What I see from the report is this:

Quote The external validity of the experiment is challenged by the fact that the effect is assumed to change if the environment changes. For instance, the effect will most likely decrease if an increasing number of cyclists start using a bright-coloured bicycle jacket because the jacket will not attract as much attention when more cyclists use it. In this study, the participants were spread across the country (Fig. 3), and the likelihood of being in a group with multiple bicycle jackets is small. This also means that the found effect represents an average of the effect in big cities, small cities and rural areas, although some variation between these areas is expected. The external validity is also influenced by the fact that other road users’ risk may increase when attention is directed to cyclists with bright-coloured jackets at the expense of other cyclists. These considerations are not specific to bright-coloured jackets but are generally valid. Overall, the assessment of the external validity is that the effect will most likely decrease as jacket use increases, but not to a degree that may compromise a general positive effect of a yellow jacket. Unquote

You still need to change the mentallity of the drivers rather than make a case for Hi-Vis. This was not even a subject case twenty years ago, so why now? By the way, I ride with bright colours on the majority of rides/commutes and sometimes I wear black. In my experience it makes no shred of difference.

So you didn't see the statistically significant difference between the control and the study groups?

Or you chose to give more weight to an assumption?

Even that assumption concludes that the hi vis will continue to offer a protective effect.

Studies into collision rates of cars have found that brightly coloured cars have fewer collisions despite there being a lot of them so perhaps the saturation assumption is not as significant as you think.

I agree that we need to change the mentality of drivers but that is an incredibly difficult task that will take years to achieve, I can decrease my own risk instantly by making myself more visible.

When I had a red car people pulled out on me all the time. Bright red like a f***ing fire engine only way it could have been more bright would have been hi vis. I haven't seen cars on sale like that.

People either dontvlook or they make decisions based on the size of the vehicle and therefore threat of harm to themselves

Rich_cb wrote:

Here's a link to the Danish randomised controlled trial mentioned in the article. The best piece of research done on this topic by a country mile. They found hi-vis reduced your risk of being in an accident with another road user by a third. https://www.sciencedirect.com/science/article/pii/S0925753517313528

Despite the number of posts aimed at Rich_cb, I'm nor sure I've seen any serious criticism of the content of his/her original post.

I do see a lot of whataboutery, strawmen, personal opinion and anecdote as evidence but nothing that seriously challenges the findings of the study.

Some posters raise legitimate wider issues (e.g. the bigger problem is with driver attentiveness and attitudes - I think we all agree) but I don't see anyone presenting good evidence against the idea that hi-vis reduces certain types of risk by a moderate to significant degree under current circumstances.

Duncann wrote:

Rich_cb wrote:

Here's a link to the Danish randomised controlled trial mentioned in the article. The best piece of research done on this topic by a country mile. They found hi-vis reduced your risk of being in an accident with another road user by a third. https://www.sciencedirect.com/science/article/pii/S0925753517313528

Despite the number of posts aimed at Rich_cb, I'm nor sure I've seen any serious criticism of the content of his/her original post.

I do see a lot of whataboutery, strawmen, personal opinion and anecdote as evidence but nothing that seriously challenges the findings of the study.

Some posters raise legitimate wider issues (e.g. the bigger problem is with driver attentiveness and attitudes - I think we all agree) but I don't see anyone presenting good evidence against the idea that hi-vis reduces certain types of risk by a moderate to significant degree under current circumstances.

I just think that suggests you haven't been careful in reading the posts disagreeing with Rich_CB.

The question is whether focussing on high-viz, promoting it, or (worst of all, though I acknowledge Rich_CB isn't arguing for this) making it compulsory, has a net beneficial effect or a net negative effect on overal health-outcomes.  The Danish study does not appear to even be asking that question.

Talking about 'under current circumstances' ignores the question of how 'circumstances' are themselves a concequence of collective behaviour and attitudes.

As other posters have said, whether it's in the self-interest of any given individual cyclist to choose to wear the stuff, is a different question  - and not one that's any body else's business but the cyclist concerned (or, arguably, their parent or partner).

Duncann wrote:

Rich_cb wrote:

Here's a link to the Danish randomised controlled trial mentioned in the article. The best piece of research done on this topic by a country mile. They found hi-vis reduced your risk of being in an accident with another road user by a third. https://www.sciencedirect.com/science/article/pii/S0925753517313528

Despite the number of posts aimed at Rich_cb, I'm nor sure I've seen any serious criticism of the content of his/her original post.

I do see a lot of whataboutery, strawmen, personal opinion and anecdote as evidence but nothing that seriously challenges the findings of the study.

Some posters raise legitimate wider issues (e.g. the bigger problem is with driver attentiveness and attitudes - I think we all agree) but I don't see anyone presenting good evidence against the idea that hi-vis reduces certain types of risk by a moderate to significant degree under current circumstances.

Hi-viz may well be effective. Flashing lights, bright colours - even helmets - have their arguments at a micro level. But the argument is about how effective they actually are - and whether the unintended consequences are worth any benefits.

If you believe, as I do, that PPE is only a tiny piece of the puzzle, and that focusing on cyclist PPE while ignoring pedestrian and driver PPE is part of a harmful (even if elements are well-meaning but ignorant) culture that alienates and victim blames cyclists, then you'd see other factors being dragged into the argument as an appeal for prioritisation, not 'whataboutery'.

Hi-viz works, so what? So we 'win' that argument and lose much larger ones. It was accepted* at my former employer, one of the world's largest engineering firms, that to rely on PPE was to accept that you couldn't make an environment safe and cross your fingers.

* accepted in this context means to be the prevalent viewpoint of many prominent engineers, fellows of all-sorts of societies, academics and experts in safety in dangerous workplaces, backed by proper evidence via extensive root-cause analysis and studies.

ktache wrote:

I think Atwarwiththemotorist  has a fine take on high viz

https://waronthemotorist.wordpress.com/2017/10/28/new-road-safety-campai...

And of course it is not just bright yellow illuminated bollards which are not visible enough for drivers to avoid hitting. Motorists run into many stationary objects which are not hiviz. Walls, bus stops, trees, parked cars, fences, houses etc. These obviously need the hiviz treatment.

A woman in her bath had life changing injuries from an errant driver. Perhaps she needed a yellow tabard?

https://aseasyasridingabike.wordpress.com/2015/12/26/audis-in-houses/

An assortment of houses which were not visible enough for drivers to avoid them.

FluffyKittenofTindalos wrote:

Is there any data on the effect on visibility of cyclists not wearing any clothes at all?

 

I haven't heard of many Smidsy incidences with those 'naked bike ride' events.  But that's purely anecdotal.  Needs some randomised controlled studies I suppose.

and a couple of strategically placed graphs

Pushing50 wrote:

It does not matter which colour clothing I am wearing, if it is reflective, whether it is night or day, how many lights I have either flashing or on constsant glow, how many lumens I am providing, where I ride in the lane, how fast I am travelling, whether I am riding single file or two abreast, in a cycle lane or not, if I use hand signals at junctions and whilst overtaking parked vehicles; I will invaribly have some dick in a motorised vehicle either pull out on me or close pass me anyhow. It is the mentality of the herds that need to be altered, not the colour of the cloth.

This. 

If people are looking then they will see you no matter what you are wearing.  If they aren’t then they won’t. 

Bikebikebike wrote:

Pushing50 wrote:

It does not matter which colour clothing I am wearing, if it is reflective, whether it is night or day, how many lights I have either flashing or on constsant glow, how many lumens I am providing, where I ride in the lane, how fast I am travelling, whether I am riding single file or two abreast, in a cycle lane or not, if I use hand signals at junctions and whilst overtaking parked vehicles; I will invaribly have some dick in a motorised vehicle either pull out on me or close pass me anyhow. It is the mentality of the herds that need to be altered, not the colour of the cloth.

This. 

If people are looking then they will see you no matter what you are wearing.  If they aren’t then they won’t. 

 

And if they can't see a mildly overweight bloke on a bicycle in broad daylight, regardless of whether or not there is also use of flashing lights and/or fluorescent clothing, then they shouldn't be driving.

Bikebikebike wrote:

If people are looking then they will see you no matter what you are wearing.  If they aren’t then they won’t.

I find the surest way to be seen is to not wear hi-viz and have no lights after dark.  Not only will drivers absolutely spot you, they will also point you out to all their passengers while making derogatory comments.  

Tony wrote:

Bikebikebike wrote:

If people are looking then they will see you no matter what you are wearing.  If they aren’t then they won’t.

I find the surest way to be seen is to not wear hi-viz and have no lights after dark.  Not only will drivers absolutely spot you, they will also point you out to all their passengers while making derogatory comments.  

As well as advising everyone else they come across of your presence