[Closed] Neon yellow jackets reduced daytime accidents 40% in Danish RCT Study

Road.cc reported this, worth a read of the comments before we get going in this thread.

Yeah read those now, nothing invalidating the results there. Also note the accident reduction would likely be higher with higher adherence.

Does the study being sponsored by a company making hi vis clothing invalidate it? No.
Does the study move the onus onto the cyclist and not the drivers to maintain traffic safety? Also no.

Take homes for moi: hi-vis helps a lot in the day at least in Denmark and likely everywhere else, at night you likely want more reflective clothing - something that half reflective half hi-vis seems like a good idea to me.

The thing that jumps out at me there is that of 6,800 people 6.5% had an accident. That seems very high.

Those were all accidents including minor ones.

Yeah, but my jacket is orange and bright blue.

What percentage better/worse?

I note the study wasn't double blind, didn't compare distances for passing, mileage on road Vs cycle lane, time of year and may have been funded by a luminous jacket manufacturer and a company building motorways...

Obvs you can't double blind a study like this, unless you're only recruiting blind cyclists. But randomization with a large number of people takes care of averages such as mileage helping ensure that the two groups on avg have near identical habits.

The study as done by Aalborg university, not don't know where the motorway building company sponsorship theory comes from, in any case it wouldn't invalidate the result.

The thing that jumps out at me there is that of 6,800 people 6.5% had an accident. That seems very high.

That jumped out at me as well.

https://roadsafetygb.org.uk/news/cycling-study-shows-safety-benefits-of-hi-vis-clothing-5982/

The study was non-blinded*, and the number of reported single accidents (involving no other vehicle or individual) was significantly lower in the test group than in the control group.

Seems that there is all kinds of weird stuff in the results.

Those were all accidents including minor ones

True, but where are they are drawing the line with minor?

Participants were then asked to report any personal injury incidents they suffered over the course of the year.

As Bruce points out there are some funny things there.

As someone who drives too, in an area with a decent number of cyclists, I can absolutely believe this, based just on how well I notice people on bikes depending on what they're wearing.
As a side note I saw someone with a mirror finish helmet and it stood out so much that I ordered myself one that week.

Basing safety around visibility doesn't help if drivers aren't looking.

you’re only recruiting blind cyclists

You supply the bike, helmet, jackets, lights, shoes etc and ask them to use it all. You don’t tell the participants what is different in the control group (who you give the same gear but a different coat).

One can nitpick on the study day long, but AFAIK there are no better studies on the topic and it's abundantly clear that hi-vis works well in the day, not so well at night - logical.

For me this makes me reconsider wearing all black on the road in the daytime.

Like Mr Handsome said, you can pick holes in the methodology but when the results come back agreeing with a fairly uncontroversial hypothesis it becomes a bit pointless.

I wear a high Viz gillet on the road just about anytime other than mid day in the summer.

My commute at the moment involves a section of shitty, straight, fast, undulating (so not actually great sight lines and speeds sometimes drop).

Does wearing high vis mean cars pass too close, couldn't argue that either way although yes evidence is out there with the same effect from helmets. But closes passes aren't often the cause of accidents. SMIDSY is a thing SMITriedToPassTooCloseAndHitY isn't (that pickup in the US hospitalising 6 triathletes being a bit of an exception).

The study was non-blinded*, and the number of reported single accidents (involving no other vehicle or individual) was significantly lower in the test group than in the control group.

That would seem like a flag that something may be amiss in the results. But then it depends on how much the participants knew about the study.

You could for example tell them it was helmets Vs non helmets, then 'randomly' give out the high vis jackets half and half to each group.

Conversely it's perhapse easier to personally fudge your result for single accidents, but you can't really do the same about being hit by a car, you either were or weren't.

it’s abundantly clear that hi-vis works well in the day, not so well at night – logical

Entirely logical.

Unimpressed by the data here though.

For me this makes me reconsider wearing all black on the road in the daytime.

If you’re commuting all in black, in September, change that. Get flashing lights on as well.

If you’re commuting all in black, in September, change that. Get flashing lights on as well.

I'm not, but I have been training during the day in all black.

Also there's a strange cognitive dissonance among cyclists.

Tell them to wear high vis and they'll quote all sorts of things about added danger from close passes, claiming victim blaming or picking out holes in studies.

Mention lights and nothing short of 1000 badly aimed pulsating lumens is enough. Being seen isn't the goal, you have to be so visible that motorists actually have to stop as they can't see anything else.

I find motor bike riders are the same, riding around with their lights on while wearing normal coloured leathers. What is wrong with people? [ /sarcsam ]

Mention lights and nothing short of 1000 badly aimed pulsating lumens is enough. Being seen isn’t the goal, you have to be so visible that motorists actually have to stop as they can’t see anything else.

The thing which I have found most effective, and annoyed the most drivers, I came across by accident.
Out later than intended, only had a Joystick on my helmet, no rear light. Could still see where i was going but didn't fancy getting rear ended so I turned the helmet light around.
A white light pointing backwards confuses the drivers and makes them give you a very wide berth, very effective. Probably not legal, but it was the best I could do and I was surprised how much better it was.

When I was riding my road bike on the road (narrow country lanes) at night, I found using a bar light + helmet light and some ankle strap that also flashed - was great. Cars seemed to assume it was a UFO or a Tractor and quite a few actually stopped and pulled right over. Brilliant result.

Seemed to me that when they were confused, they took notice and care.

BTW at night I usually wear something like this, very effective imo.

The thing which I have found most effective, and annoyed the most drivers, I came across by accident...

My experience as a driver is that helmet lights end up pointing into my eyes and dazzling me so I can see less, not more. I'm glad it worked for you but I'd be wary of concluding that helmet lights = better visibility.

I'm aware that helmet lights can be useful for riding on poorly surfaced roads though so it's not a simple equation.

I’m glad it worked for you but I’d be wary of concluding that helmet lights = better visibility

No, what I meant was a white light pointing backwards helped. As Trimix said, if they are confused they pay more attention/give more room

And yet in four days in Copenhagen, where thousands of cyclists passed me, none were in hiviz. Everyone rides around, calmly, in normal clothes. This is probably because the Danish don't drive like pricks.

Black is faster though and more slimming.
That’s all that counts

I’m surprised how effective the jackets were at preventing accidents in daylight.

Florescent colours are primarily for daylight visibility. For hours of darkness, reflective elements create the visibility.

Most jackets combine the two but fabrics like the one yohandsome linked to above probably make you stand out a lot more. Retro-reflectives ensure light is directed back to source rather than bouncing off at an angle like a mirror, and this is why reflectives are so effective now.

It shouldn't be earth shattering that helping other road users see you reduces the chance of them hitting you. There's a variety of ways of doing it, whether it be lights, coloured clothing or reflectives at night.

For me this makes me reconsider wearing all black on the road in the daytime.

I avoid black if I can.

I go for brighter colours.

<span style="font-size: 0.8rem;">But not necessarily highviz yellow as I've also got a theory that drivers are over used to seeing it....</span>

I also go for lots of reflective flashes on things that move. Today was really grey/rain coming in. Sat behind mrs_oab I could see how much the reflective tape/spoke straws/pedals work. Lights on. Still had half a dozen cars on the one section of A-road manage to close pass or tailgait us.

Bright and reflective is more visible - but it doesn't increase driver care and intelligence.

Indeed, was a study really needed to show that people wanting to be noticed should wear bright clothes? Accepted wisdom of 'burglars wear black, builders on sites wear hi-viz' should be good enough to convince shouldn't it?

Indeed, was a study really needed to show that people wanting to be noticed should wear bright clothes?

Yes, as a 40% reduction is HUGE (more like 50% if adjusting for adherence), I don't think many expected that magnitude of effects in daylight. I certainly didn't expect the number of accidents to be cut in half.

I wore all black today, in the rain, without my lights on. Black beanie hat instead of helmet (I was in a bad mood cos I had to go find fuel in the rain, so wasn't feeling the give-a-shit vibe). No-one came near to hitting me, drivers overtook same as they do when I'm commuting. But... I did feel more vulnerable. I'm pretty sure it was all in my mind though.
I normally wear bright colours commuting, daytime lights and a fully reflective jacket.
It gives me a perception that I'm more safe, but that ****er who ain't looking, playing with their phone (like the one who nearly pulled out on me by the petrol station) they're gonna take you out, either way.

but that **** who ain’t looking, playing with their phone (like the one who nearly pulled out on me by the petrol station)

Equally, would a bright flash of yellow in their periferal vision been enough?

Wearing all black and almost getting hit, seems like more of an anecdote for the pro hi-vis argument.

Time of day really matters though (and the time of year). Nipping out for a spin on a day off midday doesn’t necessarily benefit from, or require, the same visibility “fixes” as commuting in the early mornings and the evenings.

It may do to you, but they had their phone against their face, stopped in time to not hit me, I'd say, exactly as they would've done if I'd been all in pink with a christmas tree on my head. Don't agree? Well then, that's the same as the Danish test the OP is on about. You can't test like for like without a time machine.

Time of day really matters though (and the time of year). Nipping out for a spin on a day off midday doesn’t necessarily benefit from, or require, the same visibility “fixes” as commuting in the early mornings and the evenings.

That's the interesting thing, hi-vis did more during the day then at dusk/dawn (perhaps surprisingly) and not so surprisingly than at night.

It doesn’t surprise me at all, if riders in both groups had reflective materials and/or lights on themselves, or their bike, or bags, in a country with compulsory use of daytime running lights for all motor vehicles. Anyway… compared to what? What were the control group wearing? I’m afraid I’m still taking that self reporting and goal informed (led?) trial with a giant pinch of salt.

Well that's obvious - hence why I personally avoid black and muted colours on the road.

Be more visible - reduce the probability of an accident.
Of course it doesn't reduce it to zero. It doesn't stop motorists not taking enough care etc.

For those arguing that "it doesn't help it the motorist isn't looking", or similar things, the reality is most accidents are NOT along the lines of a motorist with 100% attention on a phone so would crash anyway (some are of course, but the overwhelming majority are not).

Most accidents happen when a few factors combine at the same time. Being a bit more visible helps to reduce ONE of these factors, hence for example if a motorist becomes aware of a cyclist just a little bit earlier there is just that bit more time to react / change plan / not make the move that might have otherwise been made and the overall rate goes down.

The problem with riding in the middle of the day is it's still surprisingly dark in the woods at this time of year.

So any road ride will involve sections where you can be all but invisible to people as you're in shade and their eyes are adjusted for their bright sunlight.

It's one of the reasons I prefer going out on my fixie (with dynamos, lights and reflectors) on solo rides this time of year. It feels so much more visible than my pure road or cross bikes.

No-one came near to hitting me, drivers overtook same as they do when I’m commuting.

It's not like the darker you are the closer drivers pass until they eventually hit you.

What happens is that the darker you are the greater the chance of not being seen which would result in a hit.

they’re gonna take you out, either way.

Bear in mind this is statistics, so the real world isn't that black and white and there wil be a roughly normal distribution of outcomes is enough comaparable cases are compared.

At one end - a small percentage of cases that is probably right - they would indeed take you out anyway, like people who manage to crash into houses or illuminated bollards etc.

At the other end - there are alert, responsible people who would see you even if you were in full ninja mode on a dark evening in the rain (I hope this is a much larger proportion than that mentioned above).

Then in the middle, and more specifically around the boundary between the group that will take you out regardless and those paying "some" attention there are the cases where a bit of extra visibility can make the critical difference. The driver who is waiting for a gap on the OTHER side of the road and their attention is focussed there. The driver distracted by some personal issues. The driver who's A pillar happens to have lined up and hence blocked you when they checked the first time, who's also focussing on a gap on the other side of the road and has some personal issues on their mind. etc etc.. *

Given all of that should we really rely on good behaviour and full attention from others when there are things we can do to nudge some of the factors in our control in a favourable direction?

* How many people here can honestly claim that they have NEVER had any kind of near-miss - made to pull out then changed their mind at the last minute etc? Anyone? It's THOSE situations where a bit of extra visibility is one of the factors that helps nudge situations from being an "incident" into a "near miss".

OK, I've said my piece and will shut up now. (gets down off soapbox)

Yes, as a 40% reduction is HUGE (more like 50% if adjusting for adherence), I don’t think many expected that magnitude of effects in daylight. I certainly didn’t expect the number of accidents to be cut in half.

I found the far higher incidence of single accidents (accidents not involving another vehicle) in the control group more surprising.

I also found the number of reported accidents surprising for one of safest countries in the world for cycling.

So surprising, in fact, that it calls into question the whole study. I wouldn't be surprised if high-viz does reduce daytime accidents but I very much doubt the number is close to 40%.

It's a flawed study that seems to be seeking to shift responsibility for cyclist safety away from the people in the 1000 kg metal boxes.

I also found the number of reported accidents surprising for one of safest countries in the world for cycling.

Not that surprising, Danish people cycle a LOT. If only looking at accidents involving personal injury, the total number of accidents was 126 or 1.85% of the 6800 cyclists that year. The hi-vis group saw 48% less personal injury accidents, adjusting for adherence hi-vis could theoretically lead to as high as a 60% reduction.

And I don't see anything in the study (I can read Danish) that tries to shift responsibility over to the cyclist, to me that's a strawman argument against a good faith study.

Furthermore, comparing personal injury accidents with motorized counterparts only, the total number of accidents was 66 (0.9%). Here the hi-vis group saw a 56% reduction in accidents compared to the control group.

Re Orange beacon on the combine harvester, that's to warn other users that it's a very slow moving vehicle. Carried over from tractors that come in slow and fast flavours, fast is relative as it's usually 40mph max.

Here it is in English:

https://www.sciencedirect.com/science/article/pii/S0925753517313528

The reporting bias in this study is huge. To start with, people applied to be part of this study. This suggests that they have a strong interest in cycling safety. They are not representative of the general population and are motivated to find the jackets are safer.

That's part of the problem.

The hi-vis group saw 48% less personal injury accidents, adjusting for adherence hi-vis could theoretically lead to as high as a 60% reduction.

In theory so could wearing a non-High-vis clown costume.

The bigger problem is that the test was performed in Denmark and doesn't take account of the novelty factor. It is far less common to wear High-vis, helmets, etc than it is other places.

A major factor in accidents is 'look but not see.' The driver's eye takes in the cyclist but doesn't register them. If there is something unusual about the cyclist there is more chance of the brain registering something unusual and actually 'seeing' the cyclist.

The study itself says as much but without mentioning 'look but not see':

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 order for this study to be valid they have to do something about the inherent bias in the selection of participants and the reporting.

They also have to repeat it somewhere where high-vis is less of a novelty. Or perhaps a third group should be included with some sort of visually distinctive feature (it might be difficult to get people to ride in a clown costume for a year) in order to account for the novelty factor in the 'look but not see' issue.

And I don’t see anything in the study (I can read Danish) that tries to shift responsibility over to the cyclist, to me that’s a strawman argument against a good faith study.

I find it extremely suspicious when someone funds a study that seems to be pushing the idea that cyclists should bear more responsibility for their own safety. Especially when they seem to have found the magic bullet. They always seem to be pushed by people who are trying to sell something or who are trying to get people off their bikes and into their cars.

Finally, it's very irresponsible to go around saying that this study proves that high-vis reduces your likely-hood of an accident by 47% and maybe as high as 60%. You are basically giving drivers yet another excuse when they hit someone (drivers have plenty of excuses already).

Please stop pushing this as fact until more studies have been performed that address the issues in this one. You're making the roads more dangerous for all of us.

bigger problem is that the test was performed in Denmark and doesn’t take account of the novelty factor. It is far less common to wear High-vis, helmets, etc than it is other places.

Data please.

In theory so could wearing a non-High-vis clown costume.

Yes, probably not a bad idea. Even better, a hi-vis reflective one.

They also have to repeat it somewhere where high-vis is less of a novelty. Or perhaps a third group should be included with some sort of visually distinctive feature (it might be difficult to get people to ride in a clown costume for a year) in order to account for the novelty factor in the ‘look but not see’ issue.

They don't have to, but great if someone else does, this is so far the best study we have on the topic.

In order for this study to be valid they have to do something about the inherent bias in the selection of participants and the reporting.

Doesn't invalidate the findings whatsoever. In fact is should relate more to the crowd here on STW which I assume is somewhat safety minded.

I find it extremely suspicious when someone funds a study that seems to be pushing the idea that cyclists should bear more responsibility for their own safety. Especially when they seem to have found the magic bullet. They always seem to be pushed by people who are trying to sell something or who are trying to get people off their bikes and into their cars.

Finally, it’s very irresponsible to go around saying that this study proves that high-vis reduces your likely-hood of an accident by 47% and maybe as high as 60%. You are basically giving drivers yet another excuse when they hit someone (drivers have plenty of excuses already).

Please stop pushing this as fact until more studies have been performed that address the issues in this one. You’re making the roads more dangerous for all of us.

No, they don't claim it's a magical bullet, they found using highly visible colors really help drivers see you in daylight. Not that shocking, but interesting the effect size was as big as it was and not say in the 10-30% range which some (incl me) may assume. To think drivers will a) read this study and b) use it as excuse to drive more recklessly is frankly so paranoid I needn't argue against it. You're making the road more dangerous for yourself by not wearing something hi-vis, I suggest a clown costume.

Data please.

https://cyclingindustry.news/london-has-highest-helmet-use-in-europe-netherlands-almost-zero/

The researchers noted that, along with London’s high helmet use, there was also a correlation with high levels of high-visibility clothing, suggesting London’s cyclists have a higher perception of danger on the roads around them. 60.9% of London cyclists observed wore a helmet.

Or just look at literally any video on youtube of people cycling in Copenhagen. If you wear high vis you stand out like a sore thumb. In London you don't.

this is so far the best study we have on the topic.

What you mean is that this is the study tells you what you want to hear. It's not the only study out there and certainly not the best.

https://academic.oup.com/eurpub/article/25/3/517/2398658

https://injuryprevention.bmj.com/content/18/Suppl_1/A36.4?ijkey=9084e860128ac4c3911dbb731a9bb89513e31673&keytype2=tf_ipsecsha

Doesn’t invalidate the findings whatsoever. In fact is should relate more to the crowd here on STW which I assume is somewhat safety minded.

By having your participants apply to be part of the study it, without question, reduces the validity of the results. For one thing, all the participants in both the test and control group got a high-vis jacket at the end of it. If some of the participants are taking part because they are going to get a free high-vis jacket you would imagine they were keen on the idea to start with.

No, they don’t claim it’s a magical bullet,

Something that would reduce the number of car/cyclist collisions by 60% is a magic bullet.

To think drivers will a) read this study and b) use it as excuse to drive more recklessly is frankly so paranoid I needn’t argue against it.

Yeah, you're living in fantasy land now. Why do you think when the AA polled it's members they unsurprisingly found that the number one way to improve cyclist safety was to have all cyclists wear helmets?

Drivers will use absolutely any excuse to avoid responsibility for killing or injuring cyclists. The sentences handed down to drivers who kill and injure cyclists are laughable. A large reason for this is that there's an attitude that cyclists are somehow asking for it.

Not wearing a helmet or high vis is somehow used as a mitigation when it really isn't. You are helping this justification by repeating your ridiculous 'could be as high as 60%' statement.

Cyclist safety will only improve with better infrastructure and a change in driver's attitudes, not a magic bullet.

Not the right data.

What you mean is that this is the study tells you what you want to hear. It’s not the only study out there and certainly not the best.

You're comparing two observational studies with a randomized controlled one and claim they are "better".

Cyclist safety will only improve with better infrastructure and a change in driver’s attitudes, not a magic bullet.

You're claiming a ridiculous dichotomy, cycling safety will improve with both. This is like saying that a RCT study showing 50% reduction in cancer rates from eating a broccoli a day should be ignored because it's shifting responsibility onto the individual to eat healthier, and will make drug companies not invent better cancer drugs.

Maybe the UK is some sort of dystopia full of evil drivers, but your claims seem so excessive they border on paranoid. I'm pretty sure drivers also want better infrastructure to keep cyclist out of "their way". I guess drivers in Denmark will now start driving like maniacs after this study came out, only they didn't, so much for the attitude point.

I actually didn't "want" this result to be as strong as I'd prefer to keep riding in my black outfit and detest hi-vis.

I don't necessarily wear hi-viz all the time but I do go for jerseys in light colours. The only black one I have is a Gabba and I tend to stick an orange wind vest over that for visibility. Mind you I can't help thinking - why aren't all cars fluorescent yellow?

Not the right data.

Because it doesn't support your argument?

You’re comparing two observational studies with a randomized controlled one and claim they are “better”.

Yes, there are pluses and minuses in all processes but your prefered process is so biased it's results are pretty much useless.

You’re claiming a ridiculous dichotomy, cycling safety will improve with both. This is like saying that a RCT study showing 50% reduction in cancer rates from eating a broccoli a day should be ignored because it’s shifting responsibility onto the individual to eat healthier.

You mentioned something about a strawman argument earlier. I meant to say it at the time but I don't think strawman argument means what you think it means.

What you just said there is a pretty good example of a strawman argument.

But anyway, if it turns out your 60% number is correct then we should probably all start wearing high-vis.

However, the 60% number is almost certainly not correct. It's a distraction to the real solution which is infrastructure and driver attitudes.

Unfortunately useful idiots in the cycling community continue to do the motoring lobby's job for it by keeping the focus on high-vis and helmets.

It would be a strawman argument if you didn't imply we should only focus on motorist attitudes and infrastructure.

Yes, there are pluses and minuses in all processes but your prefered process is so biased it’s results are pretty much useless.

Yes the study is useless because you linked to two observational studies that fit what you believe better? Keep in mind I didn't believe / want to belive the result of the Danish study.

The 60% number is likely ballpark correct compared to wearing muted everyday clothing like most danes do (black, earth colors), it very well may be less in London where hi-vis is more normal, but I wouldn't be my life that this negates a 40-60% effect. So yes, you should wear something high visibility in daylight (and something reflective at night), at least until we have totally separate bike lanes (danish drivers are well behaved, but even there they saw a > 2% bodily injury accident rate / year in normal clothes). The end.

It would be a strawman argument if you didn’t imply we should only focus on motorist attitudes and infrastructure.

Until we find another factor that we know is going to improve cyclist safety we should only focus on infrastructure and driver attitudes.

Once your high vis clothing is proven to improve safety we can focus more on it. It is nowhere close to being proven.

The strawman comes into it because you chose to make a brocolli analogy rather than argue against the real issue which is that there is little evidence that there is any benefit to high-vis clothing. There is your study with it's very questionable methodology and a bunch of other studies that contradict it.

Stop pretending it's a proven fact.

The 60% number is likely ballpark correct compared to wearing muted everyday clothing like most danes do (black, earth colors), it very well may be less in London where hi-vis is more normal, but I wouldn’t be my life that this negates a 40-60% effect.

That's your theory. It's fine to have theories. My theory is that you'd be better off wearing a clown costume. There is about as much evidence out there for both our theories.

So yes, you should wear something high visibility in daylight

If people want to wear high-vis they should go ahead and do that. If people don't they shouldn't and they should not be seen as irresponsible until there is some actual evidence that there is a benefit to it.

Until then please stop doing the motoring lobby's job for them. They are doing more than enough damage by themselves.

There is your study with it’s very questionable methodology and a bunch of other studies that contradict it

Stupid danes doing such a totally useless study, you should suggest an improved methodology for them! Or perhaps Aarhus university was paid of by the Danish motoring lobby and/or hi-vis manufacturers?!

So what clown costume do you want to wear?

Stupid danes doing such a totally useless study, you should suggest an improved methodology for them! Or perhaps Aarhus university was paid of by the Danish motoring lobby and/or hi-vis manufacturers?!

So what clown costume do you want to wear?

I think you're getting upset now so let's just leave it there, shall we?

Not at all - just want to see your preferred clown costume :o)

I understand why cyclist's don't want to be made blamed for accidents casused by poor driving and poor infrastructure

But at the same time i'm quite bothered by how many cyclist's seem happy to ride in an outfit that makes them hard to see. I've seen riders all dressed in black in fog with no lights. I'm happy to support people having a choice about what they wear. But i worry that the don't make us wear hi viz argument has led to behaviour that puts cyclists at risk

I’ve seen riders all dressed in black in fog with no lights. I’m happy to support people having a choice about what they wear. But i worry that the don’t make us wear hi viz argument has led to behaviour that puts cyclists at risk

Are you talking about at night time?

If so, that's a bit different to what we're discussing here. Reflective stuff and lights makes sense in low light conditions just in terms of driver's eyes being able to detect your presence.

During the day I don't think the issue is that driver's eyes aren't good enough to see, it's the look but don't see problem which has been thoroughly documented.

https://www.londoncyclist.co.uk/raf-pilot-teach-cyclists/

That's why I suspect that in the case of this study it's the novelty factor that makes drivers take particular notice of an unusual looking cyclist rather than the high-vis making it easier for the eye to detect the cyclist.

Somewhere where most people wear high-vis during the day (like in London) I suspect the effectiveness of high-vis is greatly diminished and possibly non-existent because drivers brains are used to seeing florescent yellow everywhere so it doesn't cause the eye to stop mid-scan.

In low light conditions reflective gear and lights is a no-brainer (and a legal requirement). High-vis during the day needs more research and a better understanding of what the actual problem is.

And it certainly shouldn't be anywhere near better infrastructure and driver attitudes in terms of priorities for road safety.

@BruceWee - I agree with the thought that people are too used to seeing lumi yellow, and actually standing out requires other colours.

See my approach.

Mind you I can’t help thinking – why aren’t all cars fluorescent yellow?

I seem to remember some data a few years back where black, dark grey etc,. cars were involved in more accidents. Don't have the data, didn't study it as the data in this thread has been and so on but worth looking into if you are really interested.

I found the far higher incidence of single accidents (accidents not involving another vehicle) in the control group more surprising.

Yes, me too. Can anyone suggest an explanation? I wonder if self-selection is a factor here.

Yes, me too. Can anyone suggest an explanation? I wonder if self-selection is a factor here.

The authors of the paper suggest a reason and claim to have corrected for it. I've only skim read. I can see other possible reasons: every time I go on my bike with my safety jacket I am reminded it is dangerous and subconsciously take more care; wearing the yellow jacket puts me off cycling so I don't ride as much; the definition of single person accidents was sufficiently vague that if I swerve to avoid someone but don't his them I am recording as a single person accident and the jacket reduces those.

I do think it is a leap to assume that the data would be transferable to the UK. It is interesting though - as it clearly suggests that a large part of the "Danish problem" is not seeing rather than not looking. Given there were still accidents perhaps no all of the problem. As others have noted cycling is different in Denmark and the UK. I don't think anyone else has noted that at many cycle path - road intersections the cyclist will have right of way, that could also be important, to my mind if you have look to give way and don't see someone that is a risk. In the UK without our backwards approach of cyclists almost always giving way at those crossings it would be more important for cars to be visible!

To add some anecdote probably biased by having read this thread yesterday - on my drive to the tip yesterday I was travelling along a 3/4 mile long fairly straight road with multiple parked cars, pedestrian and moderate traffic. At about 1/2 a mile I see a cyclist ahead wearing a red jacket or top. By the time I get to ~ 1/4 mile I can see he is not alone and has another rider with him who is mostly in black but has a red frame and some red on his helmet. His top wasn't black buy was a dark colour (dark blue/grey). Only when I was about 100m away at most did I realise there was actually a third rider in the bunch who was all in black, with a black frame, black cycling shoes etc. There are people who will rightly say its the drivers responsibility to spot the cyclist - this study is just validating one method of doing that is bright clothing.

I think it would have been a better study if they had given different designs (e.g. black, red, yellow, black/white striped jackets) so the subjects all had the same level of inconvenience and the importance of yellow would be more apparent - the headlines are hi-vis helps but actually its just "visibility"! Even then it may not be that transferable to other countries where hi-vis is prevalent amongst people on pavements, delivery drivers etc. What I do "notice" round here is runners (on road not pavement) wearing a kind of washed-out neon yellow that camouflages very well with the foliage at certain times of year.

Are TrygFonden a jacket manufacturer? It looks to me as though they are more like RoSPA? I think the other thing that is not clear is did they commission the study or did the authors design the study then ask them to fund it.

The one thing cyclists need to remember when considering visibility is that motorists still manage to crash into trucks they didn't see...

See my approach.

Putting the wife between yourself and any potential accident is pretty inspired

I call total bullshit on the drivers excuse of being so used to seeing lumi-yellow, being a thing.

Lumi Yellow is only any good at increasing visibility if it increases contrast against the background. That is why the RAF paint their training aircraft black to improve contrast against the sky, they found that red is actually the worst colour, which make the Red Arrows doubly impressive or dangerous depending on your point of view. In my experience as a driver, in daylight hours cyclists in bright pink and orange are visible from much further away than the black ninjas who can be almost invisible against freshly laid tarmac, depending on the time of year neon yellow can be worse than black as it tends to blend in with the fields and hedgerows.
Thats why I don't wear hi-viz yellow kit in daylight in the countryside where the background is often lush green fields and hedges, instead pink or orange are my preference, admittedly it is pretty hard finding men's kit in fluo pink.

I call total bullshit on the drivers excuse of being so used to seeing lumi-yellow, being a thing.

I don't think we know enough yet to call bullshit on anything. It seems certain that during daylight hours Saccadic masking plays a significant role in accidents.

What I haven't seen is too much information on what causes the brain to register something unusual mid-scan and cause attention to be diverted back towards the hazard.

I'd like to see more research to give us a better understanding of what minimises saccadic masking and then apply the findings to more targeted research into how this would apply to road safety.

There is a guy who has made it his life's work to look at safety for motorcyclists and especially why they are hit by other road users. He looks at studies carried out all over the world and lectures on it. The parallels between bicycle visibility and motor cycle visibility are clear.

These are his conclusions:

https://scienceofbeingseen.org/conclusion-what-could-work/

In particular:
CONCLUSION SIX – In daylight, light intensity and background constantly change so we must understand that any colour of clothing may stand out or blend in from moment to moment. We should consider changing hi-vis colour depending on where we ride and seaso. We should avoid hi-vis clothing that creates disruptive camouflage effects and adopt single-colour clothing, ideally matching the bike in order to present a quasi-human shape to the observer.

When I attended one of his lectures (Biker Down, set up with Kent Fire and Rescue to reduce the number of KSI's involving motorcyclists), he showed several photos of riders who had put flashes of reflective tape on their bikes and clothing. This just causes disruptive camouflage. He made the point that you need to create a silhouette that "looks" like a human on a bike. If the human brain isn't sure what it is looking at, it freezes and takes no action. If it sees something it regards as recognisable and human the thought process is much quicker so better decisions are made.

For hi vis the colour is critical. In urban areas, yellow works OK, in rural areas in autumn it's like wearing camouflage. He showed us this photo:

[img] [/img][/url][url= https://flic.kr/p/2mxi8M9 ]hi vis1[/url]

The most effective colour to wear is pink. Most of you won't like that. But anecdotally since switching to wearing only pink on the road I have far fewer issues with people pulling out on me. As far as the close pass is concerned, hi vis probably makes no difference. The driver has seen you but for whatever reason decides to pass closer than they should. This is very different to the driver not seeing you and hitting you or forcing you to take avoiding action.

Being seen works. Hi Vis helps with that.

But anecdotally since switching to wearing only pink on the road I have far fewer issues with people pulling out on me.

I have a pink high viz waistcoat.
It's worn more on the Autumn/Winter commutes, and always around the time the clocks change*.
It has "CAREFUL NOW" printed on the back, it seems to get me noticed.

* When millions of people seem to forget how to drive in the dark

Being seen works. Hi Vis helps with that.

Interesting conclusion given what the entire article was saying.

Notice that the use of hi-vis clothing and day riding lights – whilst promoted as a good thing – were not top of the list. To my mind, that’s an indication that the limitations of conspicuity aids generally.

The conclusion I would draw is that high-vis might help but other factors are going to help a lot more.

It was interesting to read about lateral movement. It's not something I'd really thought of much and it's never something that's presented as an option for cyclists. Probably because cyclists are 'supposed' to ride close to the kerb and any lateral movement would probably have to be from the inside to the middle where some moron might be trying an overtake.

I might try taking command position when approaching junctions from now on and see if some swerving makes me more visible. No doubt some drivers are going to be upset.

Daytime lights are also something I almost never run but probably should. I might try figuring out how to run a three amber light set up on my bike.

He showed us this photo:

4 cyclists stood still against an oversaturated photo of autumn parkland. Yep, very conclusive. Yellow hi-viz = camouflage
😆

For me this makes me reconsider wearing all black on the road in the daytime

NC500 route, dreich weather last week, the ones in dark colours without lights were so much harder to see as they just disappear into the background. And that's me as a cyclist looking for bikes. Now imagine the tourist in a hired camper who can't even stay the correct side of the white line because they're looking at the view.

4 cyclists stood still against an oversaturated photo of autumn parkland. Yep, very conclusive. Yellow hi-viz = camouflage

It's important to remember what you're actually trying to achieve. You're trying to cause something to trip your brain to overcome the saccadic masking. For that to happen the contrast has to be huge (and possibly unusual).

It's not the same as playing Where's Wally 🙂

he showed several photos of riders who had put flashes of reflective tape on their bikes and clothing. This just causes disruptive camouflage. He made the point that you need to create a silhouette that “looks” like a human on a bike. If the human brain isn’t sure what it is looking at, it freezes and takes no action

If, as a driver, you see flashes of reflective tape moving down the road in front of you, can't work out what it is and decide to take no action then you really shouldn't be on the road. That may not help the person that you've just driven over at the time, but if we allow this ridiculous attitude in drivers then it makes little difference what we wear.

During the day I don’t think the issue is that driver’s eyes aren’t good enough to see, it’s the look but don’t see problem which has been thoroughly documented.

I'm sorry, but I can give you an anecdote from just last night of how that isn't true.

I'm living in Cambridgeshire at the moment, so sight lines are about as perfect as you can get on the roads.

On one section I could probably see 2+ miles up the road, including a cyclist commuting home in a high vis jacket quite a way ahead. But I still got a jump when a 2nd cyclist "appeared from nowhere" when they were about 100m in front of me. He was in the shade of a small group of trees (at about an hour before sunset) and I only spotted him when he passed a gap and was lit up by the sunlight.

No lights, no high vis, some sort of black/purple rapha-esque kit. And basically invisible unless you caught him in the sunlight.

I saw him in plenty of time to slow down and overtake. But it was scary quite how invisible he was.

Obviously it's the drivers fault if they hit him, but he wasn't making it at all easy.

moving down the road in front of you, can’t work out what it is and decide to take no action then you really shouldn’t be on the road.

You're conflating concious decisions with your brain subconsciously processing information.

Your brain is wired up to see things it need to see, like predators. You see a large animal, you make a decision to run away, and Darwin handles the rest.

So the animal develops camoflauge (say, bright orange stripes...) and all of a sudden you don't see it, and you never get to make that decision to run away from the tiger (or avoid the cyclist).

I’m sorry, but I can give you an anecdote from just last night of how that isn’t true.

Are you sure that saccadic masking wasn't actually the issue?

It sounds like you were scanning ahead and were able to see the cyclist when they were suddenly illuminated because there was a gap in the trees (a sudden change that disrupted the scan and caused you to re-fixate).

Did they disappear again when they went back into the shade or were you still able to see them?

If you were still able to see them then clearly the issue wasn't that they were invisible, it's just that as you scanned the road you were missing them because there was nothing about their appearance to cause you to stop and re-fixate.

During daylight hours, if you physically can't see a human sized object on the road even when you know it's there, then that's a different issue and a trip to the optician is needed.

@boriselbrus

Interesting - I completely understand the point trying to be made about hi vis sometimes being rather camo with the foliage and I still think in some settings with all the other hi-vis on the pavement etc, I assume its one or both of these reasons that railworkers wear orange rather than yellow.

I think a lot of what applies to motorbikes is probably true for cycling BUT:
- from front or rear the colour of the bike is much less important
- our helmets are typically smaller
- we often peddle which creates movement
- motorbikes in the UK usually have a fairly large light at the front a sizable yellowy-orange number plate at the rear.

so whilst I can get on board with a lot of what Kevin Williams is saying his example picture you posted seems to contradict this:

adopt single-colour clothing,

the police officer who stands out best is the one wearing only a tabbard/vest as there arms are contrasting. I'm not sure exactly what he means by dazzle style camo - I've seen it on ships but not consciously on the road. Interestingly all the emergency services use battenburg to make themselves more visible whilst motorway services, long vehicles etc tend to use chevrons. I've never notices an issue with interpreting them in the scene. Even top to toe in dayglo pink - there will be moment when you happen to be beside an icecream van, or some bus covered in a huge ad for bulb electricity or something and you blend in. A 2 colour approach seems much less likely to be invisible, and perhaps even the lower speeds on a bike mean a fraction of a second whilst the driver's brain works out what they just saw are less critical?

Ever been to Denmark? Proper cycling infrastructure everywhere, no hills/twisty roads, big straight roads with 40/50 limits, laughably low population density outside of KPH. And most importantly everyone rides a bike

Not really even comparable to the entitled shitshow that is the average UK road

@desperatebicycle
Free Member
He showed us this photo:

4 cyclists stood still against an oversaturated photo of autumn parkland. Yep, very conclusive. Yellow hi-viz = camouflage

You completely missed the point. Hi vis only works if it contrasts with the background. Yellow hi vis against autumn leaves = camouflage, a black jacket in an Arctic whiteout = very visible.

@poly Totally agree on the differences between motorbikes and bicycles. Helmets and bike colour are probably irrelevant.
I don't disagree on the point about having 2 colours to avoid blending in with a single colour background, but the point Kevin makes is that it is important to immediately be identified as a cyclist /motor cyclist as then the driver knows what to do with that information.

Having black clothing with reflective stripes doesn't look like anything. The driver comes up behind you at 50mph on an unlit lane and sees reflective flashes. What is the driver seeing? Is it a tin can in a hedge? Is it the light of a car a mile up the road? Is it a gatepost? Is it a small thing a long way off or a large thing much closer? While the driver is processing this, he is in effect frozen. If there is a vehicle behind he won't brake, besides you don't brake every time you see a reflection - they are mostly tin cans. Now the driver is pretty much on you. The same happens if you are on the road and a car is waiting to pull out of a side turning.

That's why it's important to look like a cyclist even with just a casual glance.

@boriselbrus

it is important to immediately be identified as a cyclist /motor cyclist as then the driver knows what to do with that information.

how important do you think to tell the difference between bike and motorbike at a glance? As ebikes increase typical speeds for many cyclists does it become important that drivers can appreciate that the "at a glance" expected sp

Having black clothing with reflective stripes doesn’t look like anything. The driver comes up behind you at 50mph on an unlit lane and sees reflective flashes.

That's where I'm struggling a bit. If it's me on an unlit lane he'll be seeing a flashing red LED that is distinctively a bike (or maybe horse/runner/dog). I have driven up behind people without lights who have retro reflective pin strips or trim and actually they are fairly obviously bikes (or at least people).

As your link says "CONCLUSION FOUR – Alternative strategies are required for day and night, in urban and rural environments, and at junctions approached at different speeds. There is no ‘one size fits all’ solution."

However the one thing that makes a bike at night stand out as a bike very quickly is pedal reflectors - yet almost all of us swap the supplied pedals out for something else. This study was not about night safety though.

they are mostly tin cans. Now the driver is pretty much on you. The same happens if you are on the road and a car is waiting to pull out of a side turning.

Whilst I accept that the typical driver's response to not being able to process what they are seeing is to push the right foot down rather than lift it up, I'm not quite so sure it applies coming out of a side road. Clearly, plenty of collisions happen there - but I'm sceptical that they looked, saw something, couldn't process/understand what it was and proceeded anyway - as the site you linked to puts it there are at least 4 different reasons for "SMIDSY" - ‘looked but COULD NOT see’; ‘looked but FAILED TO see’; ‘looked, SAW AND FORGOT’ and ‘looked, SAW AND MISJUDGED’. You really want a strategy for being visible that helps all 4.