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  1. #1
    Vegan on a bicycle smasha's Avatar
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    TRL (NZ) study on hi-viz

    TRL - Literature review of interventions to improve the conspicuity of motorcyclists and help avoid 'looked but failed to see' accidents

    TRL_motorcyclists_conspicuity_2012.pdf

    while not directly focused on bicyclists, this study is still relevant in the mandatory hi-viz debates that are popping up.

    Here's the "sound-bite" highlights from the report that caught my attention, along with some comments...

    * "The lowest priority for validation [ie, the study suggests this is not worth looking into as a serious recommendation] would appear to be the use of high-visibility jackets and other clothing. The literature suggests that these are generally effective, but in principle (unlike lighting interventions) they do not appear to offer the same day and night effectiveness; even reflective materials require car headlights to be shining on them to be effective at night, and this is not always the case in practice at junctions, especially when car headlights are dipped."

    * "When the findings from Hole et al. (1996) and Rogé et al. (2011) are also considered [in addition to Gershon et al. (2012], the 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."

    * "Again at the furthest viewing distance on the urban traffic circle the white jacket was best (although not significantly so for detection times under search conditions), and on the rural road the black jacket was best. [...] The results [Gershon et al. (2012)] are interesting in that they show the previously held assertion that a bright reflective jacket will improve rider conspicuity may not always be true."

    * "Interestingly the data from this study [Hole et al. (1996)] showed that plain dark clothing was more conspicuous against a light semi-rural background, but also against an urban background."

    * "Although most studies reviewed show benefits of bright clothing, dark clothing may be better if the background is also brightly coloured. In line with the underlying mechanisms proposed, higher contrast with background surroundings to enable better visibility, search conspicuity, and attention conspicuity would be beneficial. 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."

    * “The level and significance of the benefits afforded by conspicuity aids varied between the sites at which they were tested...It is not possible, on the basis of the work described, to recommend the use of a single aid to conspicuity which might be expected to be effective in all circumstances...the use of even...effective aids is by no means a guarantee that a motorcycle will be seen in all circumstances” (Donne & Fulton, 1985, p13).

    * "There are limitations to all interventions, not least because conspicuity typically depends on a high visual contrast with the background, and this can vary from situation to situation."

    * "[Hole et al. (1996)] illustrates the need to consider any conspicuity aid (in this case a measure of search conspicuity) as situational; since the key underlying factor that seems to determine conspicuity is contrast with a background, the usefulness of a conspicuity aid will vary with background."

    * "Another development in the field has been an appreciation of the role of aspects of conspicuity other than visibility. For example, Brooks and Guppy (1996) found that car drivers who had relatives who rode a motorcycle were less likely than average to be involved in a collision with a motorcyclist; one suggestion for this effect is that for these drivers, motorcyclists are more ‘cognitively conspicuous’ (i.e. expected). Recent data from Crundall, Crundall, Clarke and Sharar (2012) are also relevant here; car drivers who also have experience as motorcyclists look in different places for motorcyclists at junctions when compared with other experienced car drivers and with novices. Again the suggested mechanism for this is that their experience as motorcyclists gives them an appreciation of where to look, and this ‘cognitive conspicuity’ aids detection." -- This is consistent with both the "safety in numbers effect" and that bicycling safety can be improved simply by making it "normal", accessible, convenient, and something people can do with little fuss (eg helmets and hi-viz). When motorists, their friends and their families ride cycles, they are more alert to the presence of cycles.

    * "This finding [Langham (1998)] is important in that it demonstrates two things. First, that there are individual differences in the ability to detect stimuli in complex traffic scenes, even when they are being searched for directly; ‘one-size fits all’ solutions are thus unlikely, especially in very challenging viewing environments (such as cluttered backgrounds and long viewing distances [eg urban vs rural settings])."

    * "[Fulton et al. (1980)] illustrates that measures that improve visibility may not always contribute to changes in behavioural responses seen at junctions." -- Hi-viz doesn't address SMIDGAF.

    * "In addition, the acceptability of specific interventions to motorcyclists is an issue to be considered, especially when trying to understand the likely public health benefits." -- Similar to bicycle helmets, even if it looks good on paper, there are often unintended consequences of "mandatory use" that outweigh any benefits to society, overall.

    * "Important caveats on the ubiquity of interventions all make theoretical sense in that they rely on limitations as to the actual contrast differences obtained in some settings (for example a light colour of clothing on a light coloured background)."

    * "Findings such as those of Gershon et al. (2012) and Hole et al. (1996) have shown that those conspicuity interventions that are most effective vary with different background contexts; this is entirely compatible with the theoretical underpinnings of the way conspicuity works (see Section 3.1)."

    * "[Aitken et al. (2012), Wellington, NZ] identified some positive [motorcycle] rider attitudes towards high-visibility clothing but that the common barriers given to wearing the clothing were image, cost, practicality and availability. They also found a prevailing attitude that high-visibility clothing does not improve safety and that it is the other road users who are at fault. Some interviewees described such clothing as ‘uncool’ and ‘non-professional’, and that such gear was not thought socially acceptable."

    * "Seven segments [of motorcyclists] were derived from the interviews [Christmas, Young, Cookson and Cuerden (2009)]. These were ‘riding hobbyists’, ‘performance disciples’, ‘performance hobbyists’, ‘look-at-me enthusiasts’, ‘riding disciples’, ‘car aspirants’, and ‘car rejecters’. The segments differed in terms of their attitudes to safety gear (as well as in other ways) and the authors conclude that ‘motorcyclists’ should not be considered as a single entity when any safety intervention is to be proposed, with a wide range of interventions and strategies likely to be needed according to the rider segment identified as the target audience." -- This is similar to the heterogeneity of bicyclists. Some types of bicyclists happily wear hi-viz, while others would just give up riding if hi-viz was compulsory.

    * "Riders should be made aware of the inherent limitations of any aid to visibility or conspicuity; special attention should be paid to making riders aware that there is no ‘one-size-fits-all’ solution (for example because of different contrasts with backgrounds) and that even if they have been seen by a car driver waiting at a junction, this does not mean that the car driver will have appraised their approach speed accurately (especially at night)."

    * "During the period of time when reviewing the draft, Cris [Burgess] was riding his motorcycle to work and was struck from behind by a bus. Thankfully, Cris sustained only minor injuries in the collision. The irony of the fact that at the time of the collision he was wearing a bright orange high-visibility jacket, and riding a motorcycle with daytime running lights, is not lost on the authors."

    * "Official casualty data from New Zealand in 2010 showed that there were nearly twice as many fatal junction crashes involving motorcycles on rural roads as there were on urban ones (11 versus 6). However, there were more than six times as many serious and slight injury accidents involving motorcyclists at urban junctions as there were at rural ones (158 versus 24, and 307 versus 48 respectively)." -- This is similar to the distribution of fatal/non-fatal bicycle crashes in rural/urban environments.

    * "If the focus is to be on reducing fatal accidents, then targeting rural locations would be preferred although it should be noted that, in statistical terms, the numbers of fatal accidents are small and are likely to be subject to wide variation on a year by year basis." -- This is similar to my comments made in my submission at the coroner's Wellington Hearing, June 2012.
    "When I see an adult on a bicycle, I do not despair for the future of the human race." - H.G. Wells

  2. #2
    Lover of Old Chrome Moly Myosmith's Avatar
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    * "Although most studies reviewed show benefits of bright clothing, dark clothing may be better if the background is also brightly coloured. In line with the underlying mechanisms proposed, higher contrast with background surroundings to enable better visibility, search conspicuity, and attention conspicuity would be beneficial. 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."
    Very interesting highlights from the study. I found the above quote to be on the mark as far a cyclist's (or any other pedestrian/traffic) safety. IMHO it is very important to realize that no matter what color your bike/clothing is, how much reflective material you have, or how many steady or flashing lights you mount, there will always be limitations based on surrounding circumstances. The most important piece of safety equipment is and will always be what is between your ears.

    I hope people don't take these excerpts as an overall indictment of hi-viz and reflective clothing but rather as a reminder of their limitations. I'm still a believer that hi-viz and reflective wear has its place and is helpful under many conditions but I never assume that drivers see me. I've had a driver look straight at me, a 200+ pound six-foot rider with a silver and white helmet, wearing a fluorescent orange windbreaker on a red bike with all silver aluminum trim, in broad daylight, supposedly make eye contact, and yet turn directly in front of me only to startle with shock when they actually realize that I'm there. I guess it's true that there is a difference between looking at something and seeing it.
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  3. #3
    Been Around Awhile I-Like-To-Bike's Avatar
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    Quote Originally Posted by smasha View Post
    while not directly focused on bicyclists, this study is still relevant in the mandatory hi-viz debates that are popping up.
    Though there may be such debate on Internet discussion lists, I am not aware of ANY mandatory Hi-viz clothing requirements for bicyclists being proposed by any government agency anywhere in the U.S.

  4. #4
    Vegan on a bicycle smasha's Avatar
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    Quote Originally Posted by I-Like-To-Bike View Post
    Though there may be such debate on Internet discussion lists, I am not aware of ANY mandatory Hi-viz clothing requirements for bicyclists being proposed by any government agency anywhere in the U.S.
    who said anything about the US?

    don't worry though... give it time and it'll start making the rounds, there.
    "When I see an adult on a bicycle, I do not despair for the future of the human race." - H.G. Wells

  5. #5
    PatronSaintOfDiscBrakes dynaryder's Avatar
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    Quote Originally Posted by I-Like-To-Bike View Post
    Though there may be such debate on Internet discussion lists, I am not aware of ANY mandatory Hi-viz clothing requirements for bicyclists being proposed by any government agency anywhere in the U.S.
    Bright colored clothing(daytime) and reflective gear(nighttime) is required on military bases. The Navy requires their personnel to wear reflective vests off-base when riding motorcycles,not sure if they have to wear them on bicycles or not.

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  6. #6
    Randomhead
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    in France, all road users not in a motor vehicle at night are required to wear reflective vests. I don't know if this will spread to the U.S. or not, seems a little invasive

  7. #7
    Cycle Year Round CB HI's Avatar
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    Quote Originally Posted by dynaryder View Post
    Bright colored clothing(daytime) and reflective gear(nighttime) is required on military bases.
    Check on that claim please.

    No base I know of requires bright clothing (day or night).

    Reflectors and light requirements match state law for which the base is located.

    Reflective bolero is required for active duty personnel engaged in PT on the road or sidewalk on an Army base.
    Land of the Free, Because of the Brave.

  8. #8
    PatronSaintOfDiscBrakes dynaryder's Avatar
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    Quote Originally Posted by CB HI View Post
    Check on that claim please.

    No base I know of requires bright clothing (day or night).
    It is required(I'm retired military) it's just not always enforced.

    Langley was anal about it,Ft Myer generally doesn't care.

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  9. #9
    24-Speed Machine Chris516's Avatar
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    Quote Originally Posted by dynaryder View Post
    It is required(I'm retired military) it's just not always enforced.

    Langley was anal about it,Ft Myer generally doesn't care.
    While I am not in the military, I have taken a shortcut through Ft. Myer many times, and unless there has been something on me to indicate that I am not military, they have never stopped me. Which is pretty ignorant of them. I do have a reflective vest, in addition to my hi-vis jacket. But I rarely wear the hi-vis vest, since it basically covers my hi-vis jacket, and is nowhere near as bright.

  10. #10
    Cycle Year Round CB HI's Avatar
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    Quote Originally Posted by dynaryder View Post
    It is required(I'm retired military) it's just not always enforced.

    Langley was anal about it,Ft Myer generally doesn't care.
    It may be a local area commander requirement, but certainly not service wide and certainly not Navy for bicyclist.

    I would be interested in any cite you have.
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  11. #11
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    Excerpted, and...I added the underlining and bold for emphasis:

    Quote Originally Posted by smasha View Post

    * "When the findings from Hole et al. (1996) and Rogé et al. (2011) are also considered [in addition to Gershon et al. (2012], the 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."


    * "Although most studies reviewed show benefits of bright clothing, dark clothing may be better if the background is also brightly coloured. In line with the underlying mechanisms proposed, higher contrast with background surroundings to enable better visibility, search conspicuity, and attention conspicuity would be beneficial. 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."

    * “The level and significance of the benefits afforded by conspicuity aids varied between the sites at which they were tested...It is not possible, on the basis of the work described, to recommend the use of a single aid to conspicuity which might be expected to be effective in all circumstances...the use of even...effective aids is by no means a guarantee that a motorcycle will be seen in all circumstances” (Donne & Fulton, 1985, p13).

    * "There are limitations to all interventions, not least because conspicuity typically depends on a high visual contrast with the background, and this can vary from situation to situation."

    * "[Hole et al. (1996)] illustrates the need to consider any conspicuity aid (in this case a measure of search conspicuity) as situational; since the key underlying factor that seems to determine conspicuity is contrast with a background, the usefulness of a conspicuity aid will vary with background."



    * "This finding [Langham (1998)] is important in that it demonstrates two things. First, that there are individual differences in the ability to detect stimuli in complex traffic scenes, even when they are being searched for directly; ‘one-size fits all’ solutions are thus unlikely, especially in very challenging viewing environments (such as cluttered backgrounds and long viewing distances [eg urban vs rural settings])."



    * "[Aitken et al. (2012), Wellington, NZ] identified some positive [motorcycle] rider attitudes towards high-visibility clothing but that the common barriers given to wearing the clothing were image, cost, practicality and availability. They also found a prevailing attitude that high-visibility clothing does not improve safety and that it is the other road users who are at fault. Some interviewees described such clothing as ‘uncool’ and ‘non-professional’, and that such gear was not thought socially acceptable."

    * "Seven segments [of motorcyclists] were derived from the interviews [Christmas, Young, Cookson and Cuerden (2009)]. These were ‘riding hobbyists’, ‘performance disciples’, ‘performance hobbyists’, ‘look-at-me enthusiasts’, ‘riding disciples’, ‘car aspirants’, and ‘car rejecters’. The segments differed in terms of their attitudes to safety gear (as well as in other ways) and the authors conclude that ‘motorcyclists’ should not be considered as a single entity when any safety intervention is to be proposed, with a wide range of interventions and strategies likely to be needed according to the rider segment identified as the target audience." -- This is similar to the heterogeneity of bicyclists. Some types of bicyclists happily wear hi-viz, while others would just give up riding if hi-viz was compulsory.

    * "Riders should be made aware of the inherent limitations of any aid to visibility or conspicuity; special attention should be paid to making riders aware that there is no ‘one-size-fits-all’ solution (for example because of different contrasts with backgrounds) and that even if they have been seen by a car driver waiting at a junction, this does not mean that the car driver will have appraised their approach speed accurately (especially at night)."

    * "During the period of time when reviewing the draft, Cris [Burgess] was riding his motorcycle to work and was struck from behind by a bus. Thankfully, Cris sustained only minor injuries in the collision. The irony of the fact that at the time of the collision he was wearing a bright orange high-visibility jacket, and riding a motorcycle with daytime running lights, is not lost on the authors."

    I wouldn't disagree with the observation that there is no 'one size fits all solution'. It's true that contrast with background can have a great bearing on the ability of road users to be seen by each other. This is something that's essential for people that are vulnerable road users, to be acutely aware of, and which unfortunately, many such people seem to be lacking awareness of.

    Hi-vis gear...that is...gear with either color or reflectivity, or used in combination with each other can help a lot to enable greater visibility in many road situations. Being aware of one's basic visibility to other road users within the surroundings they're traveling, and being prepared with gear that will reduce their chances of blending into the background and not being seen for that reason, is important.

    Which isn't to say that everyone riding a bike or walking along the road or street should have to at all times, wear neon orange, green or yellow clothes, to be seen by people driving. It pays though, to know when using it can be helpful, and to have it on hand, to pull out and use as needed, if the desire or need to use it all times, isn't there.

    Within the last several months, use of hi-vis gear has been debated at length, on the main bike weblog/forum for Portland, in response to several articles posted there by the weblog's publisher-editor. One article written, had as its subject, the city's transportation agency's recommendation going into dark fall winter months, by way of a public awareness campaign, that drivers be especially aware of people walking and biking on the street in darkening condition, and that people walking and biking consider wearing hi-vis gear to enable people driving to more easily see them. Reaction from numerous people commenting in response to the article, was resentment that the transportation agency would make the recommendation about wearing hi-vis gear. These people seemed generally to feel the agency was taking a 'blame the victim' tack.

    In a later article touching on the subject of hi-vis, it came to be noted that the publisher-editor themself, doesn't like hi-vis gear, mainly the lurid colors, I suppose. Said: "...it's ugly...". Won't wear it, prefers gear such as black rain coats when it's raining...believes adequate compensation for low visibility that gear may tend to provide, by use of bright lights and reflective bits here and there on bike and person. Which is doing better than some of the stealth ninjas on the street.

    I think the bike apparel business could be doing a lot better job of making their hi-vis gear more visually appealing, stylish and fashionable, and versatile. More effective use of reflective tape in colors besides silver and orange, some of it on garments of other colors besides the standard hi-vis neon green, yellow, and orange. Companies that design and make motorcycle jackets and suits seem to have some good looking designs with hi-vis, but...maybe it's just me, but I don't see examples as appealing in bike gear.

  12. #12
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    Quote Originally Posted by smasha View Post
    TRL -

    * "Another development in the field has been an appreciation of the role of aspects of conspicuity other than visibility. For example, Brooks and Guppy (1996) found that car drivers who had relatives who rode a motorcycle were less likely than average to be involved in a collision with a motorcyclist; one suggestion for this effect is that for these drivers, motorcyclists are more ‘cognitively conspicuous’ (i.e. expected). Recent data from Crundall, Crundall, Clarke and Sharar (2012) are also relevant here; car drivers who also have experience as motorcyclists look in different places for motorcyclists at junctions when compared with other experienced car drivers and with novices. Again the suggested mechanism for this is that their experience as motorcyclists gives them an appreciation of where to look, and this ‘cognitive conspicuity’ aids detection." -- This is consistent with both the "safety in numbers effect" and that bicycling safety can be improved simply by making it "normal", accessible, convenient, and something people can do with little fuss (eg helmets and hi-viz). When motorists, their friends and their families ride cycles, they are more alert to the presence of cycles.
    This bit was the most interesting to me.

    I've thought for a while that in states where new motorists have to log a certain number of driving hours with an experienced driver before getting their licenses, they should also be required to log a certain number of rides on a bike as well. I'm not sure how such a thing would end up working on the ground, and there would have to be a lot of caveats related to physical ability to ride, of course.

    But I suspect that making sure that a lot of motorists have spent some time on a bike would help them understand how to predict bicycle behavior, lane location, etc. If they understand why a cyclist might take the lane (to avoid getting doored, to go around double-parked cars, etc), then maybe they would get less ragey when they have to pass us, for instance.

    This study suggests that motorists would not only empathize with cyclists more, but they would actually be able to see us better.

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