Study finds that wearing hi-vis can INCREASE chance of collision while cycling

Agree dassie, the conclusion should be (if proven) that hi viz makes people adopt a more 'exposed' position on the road. The secondary thing to be tested is whether idiots in cars are more likely to hit you if you are in these positions.

Stoopid, researchers will often start with a theory they want to test or a large base sample and then as they progress find that the sample size diminishes. A nationally representative sample is usually 1,000 plus but if you then applied regular cyclists (10%) 100 sample, cyclists that wear hi viz (25%) 25 sample etc. you're soon down to a big caveat.

The other problem you have is if you just looked at 'sample' without methodology "The Nottingham study started with 76 accidents, then found 275 other cyclists to act as controls" it would appear that >20% of cyclists are wearing hi viz and having accidents...

It's the 21st century, technology has moved on, it seems archaic that there is even still a discussion about hi-viz.  A mandatory proximity detection system funded by the automotive industry and new motorised vehicles that cannot exceed speed limits would both be far more appropriate and effective in the long-term.

One last thing. 

"The researchers did go on to point out that the results “should be treated with caution” however, as they were based on only 76 accidents."

Why did they bother with the research if they only intended to use 76 subjects? Total waste of money and peoples time if they have to put that statement in. People who believe in the magic of high viz will continue to believe in it, people who dont wont. 

"the study suggests riders who believe they are more conspicuous may adopt more exposed positions on the road."

What exactly is a more exposed position then?  Drivers need to pass cyclists with the  required safe distance - end of.   I always assert my road space - never cycling in the  'gutter', whether I'm wearing high vis or not, and I expect drivers to overtake safely - as the law does.

Wasn't there an amercian study that looked at 30 years of research regarding high viz with motorcyclists and concluded that it made no difference whatsoever? In fact there was a small rise in accidents.

Being seen from 2 miles/500 yards/50 yards away means nothing when you're hit by a vehicle 0 yards away...who's driver was probably speeding/looking at the phone/distracted or just not paying attention. 

Having said that the vast majority of cyclists accidents are at junctions and side roads - it's relatively rare for someone to be hit from the front or behind, and yeah, it's all about how much the driver is rushing the looking part before they pull out....tunnel vision and so on. Loud motorcycles with headlights permanently on have exactly the same problem. People dont look long enough before they pull out to see everything or judge the speed of 2 wheeled riders before they make their move

Only 76 accidents? I wouldn't touch those conclusions with a barge pole, no matter the 'caution advised' label put on it by the researchers. it's also hard to compare with the Danish result as they say it's based on 7000 cyclists, and not how many accidents that goes up to. How many cyclists did the Nottinham study include? Or did they only look at accidents and what were the factors in them, and so ignore cyclists who have not been in an accident whether wearing hi-viz or not (which would be a foolish thing to do if you aim to draw conclusions on the efficacy of hi-viz clothing).

Anyone with a link to the actual study rather than simply journalists quoting each other?

The 47% figure from the Danish study is based on 126 (multiparty) accidents. The difference is that the Danish study started with 7000 cyclists, assigned hi-viz or not, then recorded what happened. The Nottingham study started with 76 accidents, then found 275 other cyclists to act as controls. What this does to the conclusions, i don't know..

https://www.sciencedirect.com/science/article/pii/S0925753517313528
http://www.sciencedirect.com/science/article/pii/S2214140516303796

Dagnammit - I saw an article on the Bristol Post and just made a Forum post about it.

http://www.bristolpost.co.uk/news/bristol-news/cyclists-who-wear-hi-vis-840505

Then, I spotted that Road.cc had picked up on the story.

And still of no use here in the UK until clothing manufacturers can design a high viz material, that will not stain with the black horrible waters that run down our roads when wet and ruin an expensive piece of kit.

I am always quite dubious about these sorts of studies. They all suffer from the same problem, of a rare incident (thankfully) and an unknown population being involved. Now depending on how you make these estimates it can skew your results (or impact any signficance testing). Because of these issues for each paper in favour of one thing you would be able to find another against it.

That being said, I do, owing to my own natural bias, welcome any evidence that removes unnecessary encumberance on cyclists. Or puts barriers in the way of people getting on their bikes and cycling. 

Hopefully these considerations will be taken into account when the government do their "evidenced based" review in the new year, and not just go, "well common sense says..." as with many things the common sense view is not always empirically proven.