Conspicuity - some new research

For those of you who attended the 'Biker Down' evening and got the 'conspicuity' talk, or just ride in hi-vis thinking it makes you more visible I though the following bit of research carried out on behalf of the Highways Agency that's just landed on my desk might be interesting - I've cherry-picked a few conclusions from the executive summary.

Road Worker Conspicuity
Daytime & Night Time
by S Helman and M Palmer Transport Research Laboratory September 2010

"Road workers are not highly conspicuous, even in hi-viz PPE
The first conclusion of this report is that road workers are not as conspicuous as has
been observed in previous studies that used ‗search‘ instructions, especially at night.
Detection distances of as low as 25 to 45m were observed in some night time conditions.
It is highly likely that road workers in general are not aware of this and are likely to
over-estimate their actual levels of conspicuity. "​

The test subjects weren't told what they were looking for - so the test effectively mimics the reactions of drivers to workers they encounter without warning. The relevance of this to motorcyclists who believe that hi-vis enhances conspicuity should be fairly obvious.

"There were no firm data in the current study to suggest that any one PPE colour or
design granted any advantages in conspicuity over any others..."​

The study did show that the background is important - yellow not showing up against white vehicles, for example. Wonder if they tested pink?

"Ankle markings and fluorescent trousers would be advantageous
Since the current HA Traffic Officer uniform does not have any ankle-markings, it would
be of benefit to fit such retro-reflective materials to the ankles of this PPE design,
particularly since low-beam headlamps will not effectively illuminate retro-reflective
material on a jacket. The results of the daytime Traffic Officer scenario suggest that
daylight conspicuity would be improved by the use of yellow fluorescent trousers by
Traffic Officers. "​

​

I've also made this point about the use of retro-reflective bands being too high up to be illuminated when drivers are on dipped beam. Reflective tape on the bottoms of panniers or integral to boots and trouser legs is more useful.

 

Absolutely no idea what point you are trying to make. Any white/hi viz/contrasting colour increases the chances of being seen..... a bit. It's not an invisible cloak of safety guaranteeing no harm will come to you, but it just raises the chances you will be seen one tiny step.

Try standing on any pavement in central London at 6:00pm at the moment and play spot the cyclist. You will ssson see that those with no light colours or hi viz are significantly more invisible.

From your first sentence are you trying to say HiViz doesn't improve visibility? because that's not what your article says.

 

What article?

 

If Roady lets me use a yellow highlighter I 'll go to the top of the page and make it easier to see.

 

Do you mean the paper I referenced?

 

I have no real opinion of this...but for some reason I get the monthly newsletter from White Dalton motorcycle solicitors. Their latest blog is in regard to the use of Hi-viz & although not the result of 'studies' or 'surveys', the opinions of several experienced bikers seem to be point to a slight perceived advantage in certain circs, like in fog/mist (& maybe twilight?). Other than that some say they 'feel safer' which mightn't always be good. Anyway, just my two pence worth.

 

I did write up a long article over on "another site" about the pros and cons of hi-vis and DRLs which covers the content of the presentation I did on Biker Down (minus the pretty pics) but the big problem with any claims that it helps prevents accidents at junctions (Sorry Mate... etc etc) is that in the period from before they were used to the current day where most riders use light and a significant proportion use hi-vis, there's been no discernable change in the % of bike accidents that have happened at junctions - if it worked, you'd expect to see a reduction in the % of accidents that happen where cars pull across the bike's path.

Interestingly, the same pattern of accidents tends to happen around the world in different cultures, which also tends to rule out the idea that it's something about British bike-hating drivers too.

Studies that have attempted to show the conspicuity aids work by looking at the accident rates involving riders that use them and riders that don't tend to show that riders who feel the need to make themselves 'safer' generally take more care in the first place; ie, they get a licence, they don't ride disqualified, they don't ride drunk.

Risk compensation ("I'm wearing hi-vis so the they must see me so I can rely on them not pulling out") is an issue that needs more examination.

 

i have never and will never wear hi viz on a motorbike

 

I dont particularly care about what other people wear whilst riding their bikes, but I can never see the time where I will get the hankering to wear hi viz. The big thing was that we as bikers had the option to, not be legally required to. Safety? If they cant see you with a headlamp on, they wont damn well see you whatever you wear.

 

The first line of your thread appears to cast doubt on whether Hi Viz makes you more visible. However the study that you refer to clearly states that differing forms or Hi Viz do have precisely this effect, but that the extent of the effects vary in different circumstances. The study deals with whether one form of Hi Viz is more effective than others, whether Road Workers have higher expectations than the reality, and how the effectiveness differs in different circumstances.

You state “- if it worked, you'd expect to see a reduction in the % of accidents” and therefore you appear to argue that because there are no accurate statistics available, it doesn’t work. I find this theory somewhat blinkered. There has not been a decisive wholesale change from non HiViz to HiViz in a measurable time period (the majority of riders reading this choose not to wear HiViz), so there is no trend that can be measured.
Without a majority change in a defined time period, change could only be assessed if there was a precise measurable statistic.

When crash helmets were enforced you had a defined period for the change and could measure the number of head injuries before and the number after. However, why motorists pull out, whether the ‘I didn’t see you’ is true or whether they simply reacted badly, is not a precise statistic that can be measured.

We have to remember that ‘I didn’t see you’ is always easier for someone to say than ‘I was fiddling with the radio, spilt my drink, was looking at the Sat Nav etc. so again you can’t even assess the number of accidents where conspicuity is a factor.

The only available statistics are therefore very vague and conclusions would have to take into account other changes in the time period such as whether there are a greater number of motorists on the roads, changes from white street lights to orange sodium etc.

The studies to which you refer show that where motorists are actively looking for a hazard detection distances were “often very high” where HiViz was used. Therefore the scenario you give of a driver looking before pulling out, would have greater chance of seeing a rider with HiViz. What they do with this information is the biggest variable, and if they don’t look they will never see.

Of course I agree that an important fact is to ensure we do not change our behaviour as a result of taking a particular action such as wearing HiViz, leathers, womens tights etc. However “I'm wearing hi-viz so they must see me so I can rely on them not pulling out” is an insult to the average biker’s intelligence
To make one point clear - I not trying to persuade others to use HiViz – what you do is your choice, and what I do is mine.

Therefore to promote the view that HiViz doesn’t work because there isn’t a statistic that says it does is narrow minded, and I am very surprised if that is the view being expressed at the Biker Down events. Is it Fire Brigade policy?

 

" I wear a Hi-viz in bed so I can be seen coming before I'm heard"

 

Yeah, but is that just an assumption on your behalf???

 

Sigh...

I try to post an addendum to the presentation that I thought might be interesting to those who listened to it, and because it's not a complete literature survey or covered by provisos left right and centre, my comments get taken out of context and picked to bits...

As I said, I've written plenty of other articles which give a balanced view of the pros and cons of the whole conspicuity argument, and I've not jumped to some snap decision, unsupported by evidence. In fact, far from it, but I can't possibly go into detail about the research that is available, or that proportion of it I have read over the last 7-8 years to support my own conclusions....

Firstly.

I didn't say "there are no accurate statistics available" - you inferred that. There are studies of accidents that provide snapshots along the time frame from "hardly anyone uses conspicuity aids" to "lots of people use conspicuity aids" and they do not show any significant reduction in the kind of accidents the use of conspicuity aids were supposed to prevent.

1) Accident analyses are available that span the gap in time between near-zero use of conspicuity aids (effectively pre-1980 - it was actually the Hurt Report in 81 that first flagged up conspicuity aids as a solution and led to widespread recommendations to use them) and widespread use (current day) - therefore there IS a baseline on which to examine how the use of conspicuity aids have affected accidents at junctions involving a bike and another vehicle.​

You're right that it's difficult to filter out external modifiers over a long time span, and there are also issues with direct comparisons... so...

2)There are also countries which required the use of day riding lights after legislation was introduced - so there are some studies from pre-switch on and others from post-switch. If I remember correctly, the data shows an initial drop in accident rates followed by a steady climb back to approximately the original figure.​

3) There are also studies that look at different countries, some where the use of conspicuity aids is widespread, others where it's non-existent allowing a comparison to be drawn.​

Secondly.

It's more recent research itself that throws doubt on the effectiveness of conspicuity aids in the context of motorcycle safety (I referenced one such study by the TRL carried out in 2003 in the presentation) now there is actually a decent length time frame in which to study the effects. It's not just my suppositions on the matter.

Thirdly.

My argument is NOT that conspicuity aids don't work per se, because there is plenty of research that shows how they can improve the ability of observers to spot particular objects, and there's plenty more research into how to improve the way they work (particularly in the field of emergency services). The presentation is intended to illustrate that the situation is far more complex for motorcyclists than "wear hi-vis, be seen", to the point that:

a) they don't work in the way that they have been (simplistically) promoted by road safety bodies to work
b) they don't work in the way that manufacturers of conspicuity aids suggest
c) they don't work in the way that motorcyclists have been led to believe they work

You may remember Sussex police stopping riders NOT wearing hi-vis vests, giving them a stern lecture about how they are a risk to themselves by not using it, and handing out a free one a couple of winters back. I'm trying to educate riders NOT to accept this kind of disinformation - it's simply not founded on meaningful evidence.

Yes, certainly there are some drivers who say "I didn't see you" who are, as you put it "fiddling with the radio" but there are many more accidents where the driver genuinely believe they looked properly - these accidents even have their own "looked but did not see" description. And it's an obvious reason why an analysis of collisions is NOT based only on anecdocal evidence from the scene of an accident!

So, fourthly.

To extend the knowledge gained from accident reconstruction, there has been a huge amount of work done monitoring where drivers actually look, what they focus on, and what they actually see and react to, starting with the sort of early studies done by a chap sitting next to the driver with a clipboard and report sheet trying to work out what they look at, to using sophisticated monitoring devices which track eye movement and reference it to objects in the field of view. And this kind of work has been extended with motorcycles as the 'target object' to see how drivers perceive (or not!) the bike.

These investigation have shown that there are a number of different reasons that drivers fail to see bikes which are not only in plain sight (ie not hidden by other vehicles or road furniture) but also, by the standards of conspicuity, highly visible:

- physiological (to do with the way the eye collects the visual image to pass to the brain)
- psychological (to do with the way the brain interprets the visual information the eye passes to it)
- faulty search strategies where the driver looks in the wrong place

Fifthly.

Education. The fact that these 'looked but did not see' accidents can be explained is why it's so important is that riders realise that in certain circumstances, it doesn't matter how much hi-vis gear they are wearing and how many lights they have on the bike, they simply won't be seen. And so other strategies of accident avoidance are important too.

And that's the overall message of the presentation - that it's our choice to use conspicuity aids, but it's important we understand limitations as well as benefits.

Nearly the end.

I didn't say "it doesn't work" - you inferred that too. I could resent the implication that I'm being narrow minded, but I won't because you don't know that I was myself a supporter of hi-vis and DRLs ten years ago. What's changed is that I have actually gone and looked at the evidence and research into its effectiveness, and thus learned that it's not a simple "it's bright so it MUST work" situation. In short, I've found that the evidence isn't "very vague", it's gaining in breadth and depth on an almost daily basis, as the study I referred to at the top of the page shows - it's a new one to me.

In point of fact, the presentation presents the evidence in exactly the same terms as you yourself have helpfully summarised the article at the top of the page:

"The study deals with whether one form of Hi Viz is more effective than others, whether Road Workers have higher expectations than the reality, and how the effectiveness differs in different circumstances."

Just substitute "presentation" for "study" and "motorcyclists" for "road workers".

Finally.

I'm not qualified to talk about 'fire brigade policy' but I will point out that my own motive for offering my time and effort to run the presentation on behalf of 'Kent Fire and Rescue' is to help riders understand some of the issues involved in conspicuity and thus to be able to keep themselves safer as they ride, so that they DON'T require the fire brigade to attend the scene of their own accident!

 

Spin, I would be really interested to read your original article on this, can you put up a link please?

 

Try this article on the blog... if you click on the "conspicuity" and "hi-vis" tags when you reach the bottom you'll find other articles/comments/snippets that I've written on the blog too!

 

It was interesting and thankyou for taking the time to share it. Some of us got where you were coming from. And if that sounds like a suck up to anyone.....BITE ME!

 

No problem. If I can stop one rider thinking "I must be seen because I'm using hi-vis / DRLs" and that accidents where a driver doesn't see a bike aren't always down to simple carelessness and bad driving, something has been achieved.

 

many interesting points there about how the brain percieves information, not sure it matters what colour you wear or how much reflective banding you display or even where its positioned on the body , if its acting the same as everything else moving in the same direction then chances are itll get overlooked . personally ( and please bear in mind its only a personal veiw) i ride as if im the hardest thing to spot on the road, anything in any colour moving along a continual trajectory can be processed by the brain as part of the scenery but if that trajectory is constantly changing the brain gets a " HANG ON WHATS THAT" signal and the eyes tend to latch on to it, a bit like a fly flicking about in your periferal vision. so using this theory i tend to change my road position quite a lot not just to extend my vision of the road ahead but also to get the attention of other road users.
Please dont take anything i have said as wrong, lights play a big part of this theory as can hi viz clothing because that bright colour that just moved laterally across the road instead of the normal moving towards you has just done something out of the norm and that would certainly make me look again.


peace out

Carnage