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Hi vis discussion thread (read post #1)

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  • #932
    Chuchote
    Closed Accounts Posts: 5,368 ✭✭✭Chuchote


    Mm. It's hard to know how to test fluorescent efficiency otherwise, though?


  • #933
    tomasrojo
    Registered Users Posts: 11,740 ✭✭✭✭tomasrojo


    There was a case-control study (a Ph.D. in fact) as well (which, while nowhere near the optimal type of study, is I guess a good bit better than self-selected, self-reporting participants).
    Miller, P (2012) The use of conspicuity aids by cyclists and the risk of crashes involving other road users: a population based case-control study.

    The link now requires a log-in.

    It found no statistically significant difference between hi-viz wearers and those not wearing it.

    It's not a very well studied area, as far as I can make out. There was an Australian study where they got drivers on a track to look out for cyclists wearing hi-viz of various kinds, and none. The problem was, once in a study situation, the drivers became very good at spotting everyone. They did find that fluorescent tops were no use at night (at least, no better than wearing a black top), and reflective material worked much better on the knees and ankles than on the torso.


  • #934
    magicbastarder
    Moderators, Category Moderators, Arts Moderators, Sports Moderators Posts: 48,182 CMod ✭✭✭✭magicbastarder


    tomasrojo wrote: »
    They did find that fluorescent tops were no use at night (at least, no better than wearing a black top)
    hmm; the first question i'd ask would be about the conditions. did they mean at night on an unlit road, or at night in general?
    a fluoro top is clearly going to reflect more light than a black one, so i would expect it - all other things being equal - to be more visible than a black one, even if it's use at night in urban areas which drags the average up.


  • #935
    tomasrojo
    Registered Users Posts: 11,740 ✭✭✭✭tomasrojo


    magicbastarder wrote: »
    hmm; the first question i'd ask would be about the conditions. did they mean at night on an unlit road, or at night in general?
    a fluoro top is clearly going to reflect more light than a black one, so i would expect it - all other things being equal - to be more visible than a black one, even if it's use at night in urban areas which drags the average up.

    There's a link on the hi-viz Wikipedia page, but the test was carried out at night, on an unlit track, as far as I recall. It's not all that controversial to say that fluorescent materials don't work well at night, though I was surprised that they came out as poorly as black. Fluorescent tops per se (without reflective stripes) don't work by reflecting light (despite the RSA and AGS' insistence on calling hi-viz "reflective clothing"); they work by absorbing UV light and re-emitting it as visible light; there is not much of a UV component in artificial light, so fluorescent materials fluoresce hardly at all at night. The reflective stripes on most hi-viz clothing, on the other hand, do work by reflecting light, and they are effective at night, provided there is incident light coming in at the correct angle for it to be reflected back to the observer. The Australian study looked at fluorescence and reflectivity separately.


  • #936
    magicbastarder
    Moderators, Category Moderators, Arts Moderators, Sports Moderators Posts: 48,182 CMod ✭✭✭✭magicbastarder


    i'm going to convince the neighbours (as in remove any reasonable doubt) that i'm weird by going out to photograph some black cycling clothing beside some fluorescent clothing, under sodium lights outside the house. back soon.


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  • #937
    Chuchote
    Closed Accounts Posts: 5,368 ✭✭✭Chuchote


    Surely yellow is brighter than black when seen in the light of headlights?
    tomasrojo wrote: »
    The problem was, once in a study situation, the drivers became very good at spotting everyone.

    Which means we should be pushing for every driver to play "I Spy the Cyclist", and especially for children to play it, to train them in automatically seeing cyclists who are now semi-invisible to them.
    They did find that fluorescent tops were no use at night (at least, no better than wearing a black top), and reflective material worked much better on the knees and ankles than on the torso.

    Interesting. The councils and the companies that work for them have obviously read this too; council workers and contractors now wear yellow jackets and trousers with reflective loops around the ankles and wrists.


  • #938
    magicbastarder
    Moderators, Category Moderators, Arts Moderators, Sports Moderators Posts: 48,182 CMod ✭✭✭✭magicbastarder


    magicbastarder wrote: »
    i'm going to convince the neighbours (as in remove any reasonable doubt) that i'm weird by going out to photograph some black cycling clothing beside some fluorescent clothing, under sodium lights outside the house. back soon.
    the jacket is on the right - a crane brand, i.e. aldi, greenish jacket, and you can see some reflective patches on it. on the left is a gist pair of bib leggings with bright(ish) stitching.

    399905.jpg


  • #939
    tomasrojo
    Registered Users Posts: 11,740 ✭✭✭✭tomasrojo


    Chuchote wrote: »
    Surely yellow is brighter than black when seen in the light of headlights?

    A lot of the "yellow" of fluorescent materials is the UV light that has been converted into yellow-region light by the process of fluorescence. Without reflective stripes, fluorescent garments are not especially conspicuous at night. Though I would think they should be more conspicuous than black, despite what the study might have found. To be fair, that study was in the context of looking at a moving cyclist from a car. In that scenario, they just both performed badly, I suppose.


  • #940
    tomasrojo
    Registered Users Posts: 11,740 ✭✭✭✭tomasrojo


    The study (I'm working from memory now) was about sighting incidents; the fluorescent tops (minus reflective details) were spotted as often as the black tops.


  • #941
    magicbastarder
    Moderators, Category Moderators, Arts Moderators, Sports Moderators Posts: 48,182 CMod ✭✭✭✭magicbastarder


    i can understand - what distinguishes fluorescent from merely yellow is the UV portion of the incident light, so the yellow is all you get under sodium lamps. but it still reflects a hell of a lot more than black clothing does.

    an interesting (moderately related) pub quiz question is how bright is the moon. it reflects about as much light as coal does.


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  • #942
    Chuchote
    Closed Accounts Posts: 5,368 ✭✭✭Chuchote


    A small test:



  • #943
    chicorytip
    Registered Users Posts: 4,079 ✭✭✭chicorytip


    Those Sam Brown belts, I think they are known as, provide excellent illumination particularly on dark country roads.
    The wearing of helmets ought to be made compulsory.


  • #944
    CramCycle
    Moderators, Sports Moderators Posts: 24,402 Mod ✭✭✭✭CramCycle


    magicbastarder wrote: »
    the jacket is on the right - a crane brand, i.e. aldi, greenish jacket, and you can see some reflective patches on it. on the left is a gist pair of bib leggings with bright(ish) stitching.

    I can see both of them pretty well, in a suburban area, I imagine the yellow would actually blend in more with the sodium yellow, whereas the black would contrast. In the light of the newer white lights, I imagine they would both stand out well for different reasons. One for not reflecting light, the other for not. I find those white lights to be awful on my eyes after awhile.

    Personally in an urban area, either would be fine. In a rural area, depends on the road and the conditions. I would still prefer lights, and in a rural area, lights and some reflective strips around my pedals/feet and all round the rest of me (more likely to meet someone with full beams and a beam of light that might hit them and reflect back at the driver.


  • #945
    CramCycle
    Moderators, Sports Moderators Posts: 24,402 Mod ✭✭✭✭CramCycle


    Chuchote wrote: »
    A small test:

    I would not have thought my eyesight was the best in the world but I seen both the flouro and black jersey just fine in low light, at the same time as well. Shocked at how practically invisible the reflective one was though.

    Still shows one thing crystal clear though, there are no substitutes for good lights, and nothing else is even remotely suitable in nearly all conditions in regards specific cycling attire.


  • #946
    magicbastarder
    Moderators, Category Moderators, Arts Moderators, Sports Moderators Posts: 48,182 CMod ✭✭✭✭magicbastarder


    CramCycle wrote: »
    I can see both of them pretty well, in a suburban area, I imagine the yellow would actually blend in more with the sodium yellow, whereas the black would contrast.
    eh.. i've had a couple of beers, so am not legally fit to drive right now - but if you're claiming that the leggings are as visible as the top, i really need to check how strong the beer i have been drinking is...


  • #947
    tomasrojo
    Registered Users Posts: 11,740 ✭✭✭✭tomasrojo


    magicbastarder wrote: »
    i can understand - what distinguishes fluorescent from merely yellow is the UV portion of the incident light, so the yellow is all you get under sodium lamps. but it still reflects a hell of a lot more than black clothing does.

    Yeah, I would assume that yellow is more conspicuous in the dark than black. I don't find it surprising that fluorescent alone didn't do well in the Australian study, but, as I said, I was surprised it didn't do better than black.


  • #948
    CramCycle
    Moderators, Sports Moderators Posts: 24,402 Mod ✭✭✭✭CramCycle


    magicbastarder wrote: »
    eh.. i've had a couple of beers, so am not legally fit to drive right now - but if you're claiming that the leggings are as visible as the top, i really need to check how strong the beer i have been drinking is...

    If the background was black, the yellow would be more noticeable, if it was yellow, the black would be. I am suggesting that if you have difficulty seeing either as they sit in front of you, then yes, you probably have had enough for the night :pac: In the ic the are both equally visible to me but for different reasons, the yellow is garish, the black contrasts.

    I was also suggsting that in cases where your eyesight may not be great there woud be times where the black would be more noticeable than the yellow but also vice versa.

    As I said before, anyone who has an issue seeing either in the cold light of day, probably should not be operating a vehicle of any sort, in a suburban setting with sodium light, I fully expect both to be quite visible, one may be more than the other but if you can't see one of them, then, again, you should not be operating a vehicle. In a dark rural setting, I would expect both to be sh1t.

    In all cases, good lights, with good spread patterns, trounces them all for visibility and neither makes you more visible as you are already visible.


  • #949
    magicbastarder
    Moderators, Category Moderators, Arts Moderators, Sports Moderators Posts: 48,182 CMod ✭✭✭✭magicbastarder


    CramCycle wrote: »
    If the background... was yellow, the black would be.
    yes, but...
    i would guess - given that the wall the clothes are hanging on is a normal enough 4" concrete block wall, that this is closer to the average background on an urban cycle - that a bright yellow jacket is much more likely to contrast against the background than unreflective black clothing.
    i find it hard to envision a context where a cyclist, at night in an urban area, consitently won't contrast with the background, because the background is a similar consistent bright yellow/green/orange to what the cyclist is wearing.
    obviously as sodium is monochromatic, all the background needs to do is reflect as well as the hi-vis does to that wavelength; but put it this way, i'm happy enough with my bright jackets, and dark leggings (because bright leggings are not as easy to find). i'd prefer relective strips on the legs rather than bright patches, but this is gut feeling rather than anything else.


  • #950
    Chuchote
    Closed Accounts Posts: 5,368 ✭✭✭Chuchote


    magicbastarder wrote: »
    i'd prefer relective strips on the legs rather than bright patches, but this is gut feeling rather than anything else.

    At some stage the reflective sticky-tape I've ordered from China will arrive; assuming there's some to spare, you're welcome to have some to make ad hoc strips if you'd like. My purpose is to improve the size, visibility and scariness of the starey eyes on the back of my bike, put there on the basis of behavioural studies of consumers showing that they unconsciously notice staring eyes.*




    *For instance, if you put a load of sweets and an "honesty box" for people to put in payments, a far higher percentage will drop in a few cents if there's a poster behind the table showing a human looking towards them; the same principle is behind various brands that have stylised large eyes on their packaging.


  • #951
    Lumen
    Registered Users Posts: 31,008 ✭✭✭✭Lumen


    chicorytip wrote: »
    The wearing of helmets ought to be made compulsory.
    http://www.boards.ie/vbulletin/showthread.php?t=2057030568


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  • #952
    tomasrojo
    Registered Users Posts: 11,740 ✭✭✭✭tomasrojo


    chicorytip wrote: »
    Those Sam Brown belts, I think they are known as, provide excellent illumination particularly on dark country roads.

    Funnily enough, I saw one Sam Browne-wearer early light on my suburban commute this morning, wearing it over a black jacket. It was quite eye-catching, with the angular yellow shape, as seen from behind, and the strong contrast with the black. Then again, maybe it stood out because you don't see them so much anymore.

    I have some out-of-character fondness for Sam Brownes, because at least they are compatible with normal clothing.


  • #953
    magicbastarder
    Moderators, Category Moderators, Arts Moderators, Sports Moderators Posts: 48,182 CMod ✭✭✭✭magicbastarder


    yeah, i saw a sam browne belt on a cyclist recently, and it certainly was massively more eye catching that the pitifully weak flashing red LED he had on the bike.


  • #954
    Chuchote
    Closed Accounts Posts: 5,368 ✭✭✭Chuchote


    tomasrojo wrote: »
    Funnily enough, I saw one Sam Browne-wearer early light on my suburban commute this morning, wearing it over a black jacket. It was quite eye-catching, with the angular yellow shape, as seen from behind, and the strong contrast with the black. Then again, maybe it stood out because you don't see them so much anymore.

    I have some out-of-character fondness for Sam Brownes, because at least they are compatible with normal clothing.

    They used to be particularly good because gardaí on point duty wore them so they had the "A COP :eek:" factor.


  • #955
    07Lapierre
    Registered Users Posts: 8,207 ✭✭✭07Lapierre


    tomasrojo wrote: »
    I have some out-of-character fondness for Sam Brownes, because at least they are compatible with normal clothing.

    Totally agree! I wear one in November/December/January over my cycling jacket. I much prefer them to the RSA Hi-Viz "Waistcoat" type!


  • #956
    tomasrojo
    Registered Users Posts: 11,740 ✭✭✭✭tomasrojo


    One of the reasons for their relative fall from favour is probably that they're just more expensive than waistcoats that close with velcro; reflective material is pricier than fluorescent dye, buckles, studs and adjusters add to the price. The RSA don't give them out for free very often, that's for sure.


  • #957
    cdaly_
    Registered Users Posts: 6,440 ✭✭✭cdaly_


    Chuchote wrote: »
    At some stage the reflective sticky-tape I've ordered from China will arrive; assuming there's some to spare, you're welcome to have some to make ad hoc strips if you'd like. My purpose is to improve the size, visibility and scariness of the starey eyes on the back of my bike, put there on the basis of behavioural studies of consumers showing that they unconsciously notice staring eyes.*

    I have taken the reflective strip off a free hi-vis vest and repurposed it as reflective accents on shoes, jackets etc. Don't need to await the slow boat.

    PS. Pics of starey eyes please?...


  • #958
    magicbastarder
    Moderators, Category Moderators, Arts Moderators, Sports Moderators Posts: 48,182 CMod ✭✭✭✭magicbastarder


    i've heard about large eyes being used in bike parks to unsettle potential thieves; i can't remember the source, possibly read it on here a year or two ago.


  • #959
    Chuchote
    Closed Accounts Posts: 5,368 ✭✭✭Chuchote


    cdaly_ wrote: »
    I have taken the reflective strip off a free hi-vis vest and repurposed it as reflective accents on shoes, jackets etc. Don't need to await the slow boat.

    PS. Pics of starey eyes please?...

    At the moment they're small; when I get the tape I'm going to put big blue circles on a white eye-shaped background (both blue and white cut from reflective tape) with black around for eyelashes.

    399928.JPG


  • #960
    Rogue-Trooper
    Registered Users Posts: 1,854 ✭✭✭Rogue-Trooper


    Chuchote wrote: »
    My purpose is to improve the size, visibility and scariness of the starey eyes on the back of my bike
    magicbastarder wrote: »
    i've heard about large eyes being used in bike parks to unsettle potential thieves; i can't remember the source, possibly read it on here a year or two ago.
    Chuchote wrote: »
    Not-so-scarey-starey-eyes pic

    Oh, I was imagining you had something more like this on the bike...............

    59e0362d692497e9ac2828deb9a3d926.jpg

    More effective, no?!!


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  • #961
    Carawaystick
    Registered Users Posts: 8,779 ✭✭✭Carawaystick


    chicorytip wrote: »
    Those Sam Brown belts, I think they are known as, provide excellent illumination particularly on dark country roads.
    The wearing of helmets ought to be made compulsory.

    I bet any light provides much better illumination than any sam browne belt...


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