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Great article on Hi Viz effectiveness - from the UK.

Discussion in 'Research, Studies, and Data' started by robsalvv, Jan 11, 2013.

  1. #1 robsalvv, Jan 11, 2013
    Last edited: Jan 11, 2013

    Why cycling in high-vis may be not as safe as you think

    A study of motorcyclists shows head-to-toe fluorescent yellow does not always ensure you are visible

    A couple of years ago I took a condensed version of the training programme for cycle officers with London's City police, a process which began with my instructor following me to assess my riding as we pedalled through the busy streets. His verdict? Mainly fine, barring what he insisted on terming a "mistake" - that even in early afternoon on a bright April day I was not wearing some sort of high-visibility waistcoat or jacket.

    High vis is a vexed subject for cyclists. Probably only helmets and light jumping cause more arguments. Ultimately, of course, what you wear on your bike is personal choice. Full Lycra gimp garb? Office clothes? Nothing at all? Go right ahead. Nonetheless, the debate merits an airing, for two reasons.

    First we have what you might call the cycling culture argument: the more non-cyclists see people on bikes dressed as if they were on a building site or directing airliners towards a runway, the more they implicitly absorb the message that cycling is inherently unsafe. It's not, and as cannot be pointed out too often long-term inactivity carries its own perils, less immediately obvious but statistically far more significant.

    Aside from the much-reported correlation of more cyclists making cycling safer overall, the connotations of a high-vis culture arguably also make cycling less accessible. Riding a bike is, if not actual combat then certainly some kind of specialist pursuit, goes the unspoken message. Don't try it unless you're young, fit and fearless.

    Such concerns about high vis can be tricky to put across. For one thing it's a nuanced argument, something I believe is actually illegal on some parts of the internet. But also, you're presumably asking riders to take a slightly greater immediate risk themselves for the sake of a future common good.

    Or are you?

    The Transport Research Laboratory (TRL), the Department for Transport-affiliated boffin repository which produces a wealth of studies each year, has been looking into this. They have examined decades of research on the ways by which motorcyclists can increase their visibility and thus avoid so-called Smidsy ("Sorry mate, I didn't see you!") collisions, such as cars pulling out in front of them.

    Yes, it's about motorbikes, which must be borne in mind when reaching any conclusions. That said, there is considerably more research on motorcycle visibility than there is on bikes, so it's worth examining even of you never get above 10mph on two wheels.

    The authors looked at 12 studies dating back as far as 1969, a number of which seemed to show that a fluorescent jacket or similar garb made riders more visible. However, the paper notes that many of these put the bikes against relatively uniform backdrops rather than the every-varying contrast of a moving landscape.

    One study, from 2011, appeared to show that drivers saw moving motorbikes more quickly if there was a greater colour contrast between the background and the rider's clothes. Another, from last year, concluded that depending on the road and traffic the most visible rider apparel could be a high-vis jacket, a white jacket or even a black jacket.

    The TRL's report says:
    The results are interesting in that they show the previously held assertion that a bright reflective jacket will improve rider conspicuity may not always be true ...​
    [T]he message seems to be that the most conspicuous outfit will be dictated by the lighting conditions and local environment at the time, which may be extremely variable within the confines of even a fairly short ride.​

    In the conclusion they add:
    Given that environments may differ over even fairly small changes in time or location, there is not likely to be a one-size-fits-all solution, meaning that motorcyclists need to be aware of the limitations of whichever interventions they use.​

    This is an important message. Albeit once again (I'm sorry) a nuanced one. I'm not encouraging anyone to throw out their high-vis vest. At the very, very least it most likely won't do any harm, beyond maybe getting you a bit sweaty, and it might do some good. But – and this is the key – don't head out there assuming you'll automatically be seen just because you've dressed head to toe in incandescent yellow.

    That said, the lessons only pertain to daylight hours. Virtually all high-vis items have reflective patches or strips, which are, without doubt, a boon after dark.

    As an aside, the same report also examines what's known about how to best ensure motorbike lights are spotted. These lessons are arguably one step again removed from cycling because of the evident difference in lighting strength. That said, I found it interesting that the studies seemed to show motorbike lights are most obvious to drivers when they stand out from the crowd, for example if they're a different shade or set up as a combination of sources.

    That ties in with the longstanding cycle light orthodoxy of flashing LEDs. I take this one step further by using two lights at the front and the rear, with differing flash patterns and, where possible, different shapes - hence my new, somewhat early-days-of-rave auxiliary back light.

    • Note: The TRL usually charge for reports so I can't link to the study. I've provided links to the two earlier papers I mention.


    TRL have got in touch to say they don't charge for PDF copies of reports. You have to register on their website but downloads are free. This is the link for the report relevant here.

    They've asked me to point out, too, that while they do a lot of work for the DfT they've been independent since the DfT sold them off in 1996.

    = =
    • Like Like x 2
  2. I mentioned in another thread that VicPol's latest issue of summer (mesh) jackets for their solos are black mesh with dark blue fabric. It's going to be difficult for their propaganda to persist in calling for hi-vis for motorcyclists if they don't see a need for their own riders.

    Good background stuff Rob: thanks.
    • Like Like x 1
  3. " For one thing it's a nuanced argument, something I believe is actually illegal on some parts of the internet."

  4. Especially since it's an OH&S matter for police.
  5. Having read the research the article was based on I think it's a beat up. The research is actually strongly supportive of refective ( which I take to mean hi-viz) clothing but does point out that it does not work all the time. Well nothing works all the time. But it works most of the time. The journalist tries to make out that the quoted research does not support hiviz when it does.

    There is much greater acceptance of hiviz by cyclists. I guess that is cultural. Look at the Tour de France - they are all in pinks and purples. Motorcyclists adopt a uniform that is black to the most part. It's about identity and fashion. I am not sure either of those are susceptible to rational argument.

  6. The article makes mention of the night time benefit of reflective stripes.

    By the way, riders wear black because it's the easiest colour to dye leather, covers the most defects and wears the easiest. It's got nothing to do with "uniform".

  7. Hi-viz and reflective are two different things. It's a basic point that needs to be understood before you can draw meaningful conclusions from any of the literature on the subject.
  8. You may well be right.

    All I know is most of the shops selling biking gear, you ask: "Have you any yellow jackets?" and they nod and point to a rack of jackets 85% back but with wee splashes of yellow.

    Ditto red.

    Ditto pink.

    Ditto blue.

    Plain black, in the dead of winter, does, admittedly, have some style, but in Ozzie summer.......
  9. Oh, and there I thought it was caused by the drugs. ;)
  10. Indeed. The Guardian journalist uses the term Hi Viz but the research paper he quotes does not. It uses the term reflective. The abstract is not clear if they mean hiviz reflective, bright colour reflective or some other reflective. However the research would be illogical if these riders were dressed in black clothing with reflective patches so the implication is that they were bright coloured at least.

  11. http://www.autoevolution.com/news/most-common-motorcycle-myths-debunked-part-3-46756.html

    Have a read.
  12. Is everything always so hard with you mate?

    Black is the most common leather colour and has become basic bike fashion, so textiles follow suit. It's not hard.
  13. So we agree. It's fashion.

  14. A fashion that's been in place for ~100 years can, I think, reasonably be dignified with the term "tradition". It's hardly new or a passing fad :D.
    • Like Like x 1
  15. #16 robsalvv, Jan 14, 2013
    Last edited: Jan 14, 2013
    Hahahah!Now right there is a measure of your mettle.

    It's the "fashion" in terms of, accepted convention, what riders expect, what sells etc etc... and it all started from the fact that black was the colour to dye leather, to be able to get the most from the available leather and cover over it's defects.


    Cognitive dissonance much???

    edit: ps you can buy any motorcycle clothing multicoloured, just don't expect it to stay nice looking very long and also keep in mind, it's possible that the multiblock colour pattern can cause you to disappear into the background as you are no longer a solid block shape to the vague cursory driver eye.
  16. It would seem that this message is hard for a noob to understand... but we'll persevere...
  17. A fashion that lasts 100 years is still a fashion I guess, but I have no problem with calling it tradition. The other word I used was cultural. What I was commenting on was not the origin of this tradition which I don't dispute but the disparity between these 2 groups of road users, cyclists and motorcyclists. While there are many difference between them they both share the fact that they frequently have their right of way abused by cars, can be inconspicuous in traffic and suffer severe consequences when they hit solid objects. The cyclists however embrace hiviz and bright colours while the motorcyclists detest it. Both these groups are aware of the research, (quoting the NZ literature review that the journalist rather misleadingly used):

    "Recommendation 2 – raise awareness of potential (and limitations) of high visibility and reflective clothing
    We do not feel that further validation work is needed to establish the usefulness of high visibility and reflective clothing. As a general principle, MSAC should continue to encourage riders to wear clothing that is inherently highly visible, reflective if possible, and clean, when riding.

    I ride bicycles and motorbikes. For the record my motorcycle suit for most of the year is mostly black though I have a much brighter setup for the cooler months and long trips. I do have a white helmet. My cycling gear is a lot brighter. Maybe that is the cognitive dissonance you speak of :)

    (I can't see any dissonance in my posts - where exactly?)

  18. #19 minglis, Jan 14, 2013
    Last edited: Jan 14, 2013
    and yet motorcyclists embrace armoured clothing, while cyclists do not. I'm kinda struggling to see your point. Seems like the cyclists colours has more to do with fashion than safety (else they wouldn't be relying on coloured lycra for protection.)
  19. I would argue that only a relatively small subgroup of potential cyclists have embraced brightly coloured lycra. I see plenty of folk who just want to use a bicycle as a cheap, green, fun means of transport rather than as some sort of statement or sporting activity (myself included when it's not 40+ outside :D) who have not.