In a 2014 Danish study 6800 participants were randomly assigned to two groups: Given a neon yellow jackets with reflective strips to use daily (77% adherence) or nothing to act as a control group (using normal everyday clothes). They then looked at accidents over a year.
The total amount of accidents in daylight was 169 for the jacket group and 273 for the control group - a 40% reduction in accidents (same reduction in serious ones). In darkness the reduction was around 25%.
I'm surprised how effective the jackets were at preventing accidents in daylight.
Links to the studies here: https://www.build.aau.dk/projektsider-centre/cykeljakken/
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.