I’ve put a new twist on the SCIENCE OF BEING SEEN (SOBS) presentations!
As you’ll know if you’re a regular here, my project is an in-depth investigation into the ‘Sorry Mate, I Didn’t See You (SMIDSY) incident between motorcycles and other vehicles where a vehicle turns into the path of a motorcycle. Whilst some of these ‘right-of- way violations’ (ROWV) result in an actual collision, rather more are near-misses, and there are plenty of incidents where the driver starts to move then spots the bike at the last second and stops again, causing a heart-pumping moment for both.
The project started as the background research for a 30-odd minute presentation originally created for Kent Fire and Rescue Service’s (KFRS) ‘BIKER DOWN’ courses, a three-module intervention with sections on accident scene management, relevant first aid aimed at likely injuries in a bike crash, and of course my section – the ‘accident prevention’ module.
SOBS looked at the kind of errors drivers made that caused them to miss a motorcycle in the landscape, why hi-vis clothing and day-riding lights have proven less effective in preventing the collision than was hoped, and offered some strategies the rider could use to stay out of trouble if possible, and the importance of effective evasive action if staying out of trouble didn’t work.
The KFRS team ran the first pilot course with SOBS as the third module in early 2012 and we were soon nominated for – and won – a Prince Michael of Kent International Road Safety Award later that year. I continued to deliver SOBS every course for KFRS, and Biker Down itself went national with most FRS across the UK picking it up, and many of those ran a version of SOBS as their own third module.
The effectiveness of SOBS has been shown by the number of people who’ve openly started to talk about some of the drivers’ visual perception problems – blind spots created by the vehicle itself, motion camouflage, saccadic masking, workload issues etc.
Although uncredited, I also provided Biker Down Canada with the background material they used to create the new ‘Thinking Biker’ video that’s replaced SOBS as the third module of Biker Down here in the UK.
So, I’m now developing SOBS further on my own. There’s the website of course, at http://www.scienceofbeingseen.org, the work of many years of collating and cross-referencing scientific papers. There’s also the SOBS paperback. And I take the talk directly to bike groups across the country in person.
Though the talk has in the past been given from the perspective of the motorcyclist, I’ve also had some drivers attending them – and the feedback was they they also found the insights into driver error very interesting.
A key point in engaging with drivers is the fact that there’s no ‘didn’t look properly’ blame going on during my talk.
In fact, I make the point that the vast majority of drivers DO look, and in the vast majority of case DO look perfectly well – after all, with 1.4 million bikes on the road covering around 3 billion miles with 40 million drivers around them, the result is just 100 fatal collisions plus around 1000 injury crashes occuring every year.
I don’t think anyone has ever tried to estimate the number of times drivers and riders meet each other at junctions, but it’s quite obvious that compared with the number of opportunities for things to go wrong, the actual number of serious errors is actually tiny. Nearly every driver spots nearly every bike!
And that makes it as hard for DRIVERS to understand the cause of a ‘looked but failed to see’ LBFTS incident as it is for the RIDER to understand why a bike, apparently in plain sight, can go missing.
Thus the SOBS talk has now got an offshoot – SOBS for DRIVERS.
The science remains the same, of course. But the emphasis of the talk has been shifted – to explain why drivers miss bikes of course, but also to try to explain some rider behaviour which can contribute to the problem – activities such as filtering, how a rider’s lack of awareness of just how ‘Vision Blockers’ interrupt lines-of-sight plus a tendency to overrate a driver’s chances of seeing a bike in mirrors can lead to them riding in blind spots where they can’t be seen, plus a trusting tendency to leave it all for the driver to sort out.
Once again, there’s no blame aimed at the RIDER – but I do aim to explain that whilst most riders are aware of the issues of the SMIDSY, few have any real insight into the driver’s issues because when the riders themselves are driving, they too nearly always spot other bikes!
And finally, I suggest some strategies – such as slowing down the side-to-side scan we all make at junctions to reduce the risk of saccadic masking, a pause when making the check to the right to let a bike ‘uncloak’, and ‘bobbing the head’ in the car to look around the blind spots created by the vehicle itself.
So, if you belong to a DRIVER group and you’re reading this, why not drop me a line and we’ll see if I can’t arrange for a presentation to your own group, either in person or via Zoom?
*** SCIENCE OF BEING SEEN *** Is the retinal blind spot a problem? Each of our eyes has a blind spot. This is where, as I’m sure most of you will know, visual information is not detected. These blind areas are due to lack of the specialised photoreceptor rods and cones responsible for capturing light and transmitting visual signals to the brain. The optic nerve carries visual information from the eye to the brain, and the blind spot is caused by the optic nerve’s attachment to the retina where it exits the eye.
The retinal blind spot is a natural feature of the human visual system and covers somewhere between 15 and 20 degrees of our vision in each eye. The diagram shows the approximate location of the blind spot in a healthy left eye. The right eye would be a mirror image.
Recently, I’ve seen a number of articles suggesting that the blind spot is a factor in ‘looked but failed to see’ crashes – or at least, one of the reasons.
One article claimed that cars could go missing in the driver’s retinal blind spot, another suggested that drivers would fail to spot cycles as they approach a junction where the driver is about to turn:
“This blind spot can automatically create problems when driving. If you are not looking and actually moving your head when at junctions for example, you stand the risk of not seeing a narrow object such as a cyclist, because they could be in your blind spot, or even something larger at times.”
The article went on to suggest that “the brain makes up, or fills in what it believes to be there!”
And of course, motorcyclists have read these articles and started reporting on the internet that the retinal blind spots is to blame for collisions where drivers don’t spot motorcycles.
So is the retinal blind spot really a problem?
Almost certainly not. It’s pretty obvious that we don’t have a pair of gaping holes in our visual field, and until we actually try to find them we’re not actually conscious of the presence of the retinal blind spots.
That’s because unless we have lost the sight in one eye, we have binocular vision. That is, the field of vision of each eye overlaps. That means anything in the blind spot of one eye is always going to be within the visual field of the other eye.
As part of the normal processing of visual data, the brain takes the detail and information from both eyes and interpolates – fuses – the images from both eyes into one coherent view.
This means the missing visual data created by the retinal blind spot in one eye is filled in by the brain by using visual data from the other. It’s the same reason we don’t have ‘pigeon vision’ as claimed in a recent FortNine video, and this is why we don’t see our own nose.
Similarly the retinal blind spot is simply not perceived under normal circumstances. In fact, to find the blind spot in one eye, we usually have to cover up the other.
================================= WHAT IS SCIENCE OF BEING SEEN? (SOBS) SOBS is my in-depth investigation into the ‘Sorry Mate, I Didn’t See You (SMIDSY) collision between motorcycles and other vehicles. It’s based firmly on science, not speculation and aims to quash some persistent myths about just why junction collisions happen, and show motorcyclists there are straightforward techniques we can employ to stay out of trouble! FIND OUT MORE – http://www.scienceofbeingseen.org WATCH OUT FOR LIVE ONLINE TALKS
The second point to make is that to make a detail scan of any particular area, we have to look directly at it, to bring it into the narrow cone of clearly focused, colour vision which is right in the centre of the visual field, and just 5 degrees across.
If we look along a road towards oncoming traffic, we examine the scene with our foveal vision. Even if our brain failed to perceive a motorcycle that was in the blind spot of one eye, it would be visible in the other eye since the two retinal blind spots are offset to opposite side.
And it’s even unlikely that the approaching motorcycle would be in the blind spot since, it’s offset to one side and mostly below the ‘horizon’ created by our foveal zone.
So, I’d suggest that for normally sighted people with binocular vision, the retinal blind spot is not a problem.
However, there are a number of diseases and conditions that can cause blind spots or scotomas in the eyes. These blind spots can be temporary or permanent, and they may affect a small portion of the visual field or a larger area, depending on the underlying cause. Some common conditions that can lead to blind spots include:
Glaucoma
Macular degeneration
Optic neuritis
Retinal detachment
In short, regular eye tests are essential for detecting eye problems early, even if you don’t currently have any noticeable symptoms. And should you experience any sudden or persistent vision changes, including the appearance of blind spots, you should seek immediate medical attention.
That’s far better advice than telling motorcyclists drivers don’t see them because of retinal blind spots.
IF YOU THINK THIS POST HIT THE SPOT please pay it forward to other bikers!
*** SOBS *** “Plus ca change” – from the archives The full expression in French is, as I recall from O Level days: “the more it changes, the more it’s the same thing”. And I was reminded of that as I was looking through some old editorials that featured in my ‘blog before blogs were invented’ back in 2001.
Think Once, Think Twice, THINK BIKE – screen grab from the very first ‘Think Bike’ video ca. 1975
What was I writing about? It was an article written in the weekly paper Motorcycle News which suggested that:
“…the reason that car drivers did not see motorcycles was because they were looking in the wrong place. It seems that some research into the way that drivers look for hazards had revealed that experienced drivers looked too far away and failed to spot bikes close by, whilst inexperienced drivers didn’t look far enough down the road and failed to see bikes travelling at speed.”
That particular piece of research threw some light on one of the complex sequence of visual perception issuess that can result in the ‘looked but failed to see’ LBFTS error – that is, what happens when the driver DID look but failed to spot a motorcycle that WAS visible.
Right now in 2023 you probably won’t be surprised to know that the LBFTS issue is now examined in depth in my ‘Science Of Being Seen’ (#SOBS) project, as one of the three types of error that result in drivers failing to react correctly towards powered two wheelers approaching an intersection:
:: looked and COULD NOT see
:: looked but FAILED to see
:: looked, saw but MISJUDGED speed and distance
SOBS was researched over the winter of 2011 and launched with Kent Fire and Rescue’s pilot ‘Biker Down’ courses in early 2012 and was used by many Biker Down teams until 2020 when the course was absorbed into the fire service generally during a COVID reorganisation.
But long before I put it all into a coherent body of thought to create SOBS, I’ve always attempted to make sense of the findings of research into car / motorcycle collisions.
It really kicked off in 1995 when I made the switch from courier to rider trainer, and was told that I had to tell CBT trainees that using hi-vis clothing and riding with their lights on in daytime would help protect them from the LBFTS collision.
My courier experience said that that was a dangerous strategy, and what was actually needed was a far more proactive approach which involved not being where a car driver’s error would put me at risk. And thanks to the internet, I was able to start reading scientific papers online and discover the findings of research into the collision issue.
But of course, the needs of journalism have never let reality stand in the way of a good story. As I wrote back in 2001:
“In best MCN style, instead of making something constructive from this research, it was instead used to justify the claim that because car drivers were going to knock us off anyway, we might as well not bother with Hi-Vis clothing or daytime lights.”
If that sounds a totally bonkers conclusion, it was, and actually still is.
Talking about the need to understand why these LBFTS errors happen and then do something about them, I continued:
“…it doesn’t absolve us from taking some responsibility for the situation.”
The sad fact is that this kind of article offers riders an excuse to offload all the responsibility for ‘two to tangle’ collisions persist and live on in biking folklore. Riders ‘know’ that it’s the driver who causes the crash because magazines like MCN told them twenty-plus years ago, and continue to state as fact that “drivers don’t look properly”.
But claims like this continue to be made, and continue to allow riders to duck the fact; whilst it may be driver error that sets up the crash, the biker still has to RIDE INTO IT to make it happen. For every driver that makes the LBFTS error, there’s a rider who failed to predict ‘what happens next’.
I continued:
“It’s true many riders rely on lights and bright clothing and assume they will be seen. Big mistake. Many riders still don’t understand how position of the bike and other traffic / road layout etc. influences how much drivers can see and what they are looking for, so they don’t take active steps to put themselves into a position where they can be seen, nor make allowances for the car driver’s problems: for instance busy junctions mean the driver is looking for the smallest gaps to get out into the traffic, looking for traffic coming from several different directions and may well have pedestrians wandering around too. The amount of attention he has to spot YOU and decide what to do is limited.”
I also noted the consequences of speed in confusing drivers looking at an approaching motorcycle:
“Whilst general awareness of bikes has increased, for every car driver who thinks I am further away than I am and does pull out, there seems to be another who waits for 5 minutes for me to reach the junction and won’t pull out till I’m past. Many drivers (and bikers – I’ve had them pull out on me) are hopeless at judging distance, but more particularly it’s SPEED that confuses them. Again it’s something that riders rarely consider. Not only does approaching junctions at high speed make it very difficult for you to get out of trouble, but it also relies on the driver to make the right judgement.”
And I concluded:
“Contrary to what MCN appears to believe, just because the research tells us what we knew already, there is no excuse for not doing something about it, and it’s pretty irresponsible of them to feed the natural tendency we all all have to blame someone else for our own lack of awareness.”
So that’s where we were getting on for a quarter of a century ago. And despite writing on the topic for even longer, I still encounter plenty of riders stating as fact that “drivers don’t look”.
I met one the other week who claimed I had no evidence for my analysis of crashes – I do, and it’s all documented in SOBS.
And the fact is it’s pretty easy to prove the ‘drivers don’t look’ claim is nonsense by playing a simple numbers game.
There are 1.3 million bikes on the road, and around 40 million drivers. If all those drivers never looked ‘properly’ and thus never saw any of those 1.3 million bikes, NONE OF US would get much further than the end of our own road. In fact, there are around 100 fatalities that result from collisions between motorcycles and cars at junctions, and around 1000 serious injuries. It’s still far too many, but that means 1,298,900 riders DON’T have a serious incident. Even if there were 10,000 minor injuries, that would still be 39,988,900 drivers who don’t take out a motorcycle.
The only conclusion is that vast majority of drivers clearly [sic] DO see the vast majority of bikes.
I continue to build new research into SOBS, with the aim of helping riders and drivers alike understand WHY these visual perception failures continue to happen, and to give both groups of road users some help in avoiding the vision errors on the one hand, and staying out of trouble on the other.
I’ve commented often enough on how the emergency services have done a lot of research into what’s best at transforming a visible vehicle (ie, one that is in your line of sight and capable of being seen) into a conspicuous vehicle (ie, one that stands out against the background). And if you’ve taken a ‘Biker Down’ course you may well have heard my ‘Science of Being Seen’ presentation delivered to you.
So what you’re looking at are two machines from Ambulance Victoria’s paramedic motorcycle unit in Australia. After a three year trial found motorcycle paramedics have a better response time than traditional ambulances, they’ve been added permanently to the strength.
The BMW F700GS motorcycles are specifically designed for emergency services, and come factory fitted with warning devices, better braking systems, satellite navigation, upgraded suspension, dual batteries, and wiring already in place for all communications equipment. They carry a smaller version of defibrillators, trauma kits and medications used by other paramedics.
The bikes responded to almost 3000 cases last and move through “…heavy traffic… through traffic jams to get to accident scenes quickly… and access Melbourne’s bike paths and walking tracks”.
So that’s their function and given what they do, it’s a bit of a puzzle the way these bikes are dressed up.
The multiple colours and broken patterns are a pretty good imitation of a disruptive camouflage pattern – specifically designed to make objects harder to see!
(Originally published on FB 25 March 2019, mildly edited)
What about headlight modulators?
Headlight modulators have been the subject of investigations on a number of occasions, and some US-based riders swear by them. So I was interested to be sent the link to this particular promotional video.
The video starts with a demo of the rear modulator…
…unfortunately, I didn’t even SEE it first time the video ran, which should tell you something.
I know the bike’s not going very fast, but arguably, by the time it comes on it’s too late – the bike’s already slowing. Given that the usual cause of a rear-ender is being tailgated by a vehicle that’s too close to slow down when the bike ahead decelerates, what’s needed is a ‘pre-braking’ warning, not something that comes on at the exact same moment. How you achieve that, I’m not sure.
And there’s a more serious issue. The flashing light around the index plate is actually pulling your eyes AWAY from the important signal, which is the brake light. I can conceive of a situation where the driver’s eyes are pulled down to the flashing lights and fails to react to the brake light. After all, flashing lights around the index plate are usually there for decorative purposes rather than any function.
So what about the front modulator?
You can certainly see it but it’s a bit irritating, to say the least. Can you imagine driving against a long line of bikes, all flickering away on high beam?
In any case, the result of US research seems to be that it enhances DETECTION at long distances – we’re talking hundreds of metres away. So maybe a less irritating modulator may have some benefit on the kind of fast, flat and straight roads they have in parts of the US or perhaps Australia. I can see one use being to alert drivers who might consider overtaking towards the motorcycle.
However, as an anti-SMIDSY device in urban areas, my impression is that modulators appear ineffective, and as far as I can tell from research, the modulator doesn’t appear to have any significant conspicuity benefit when the range is twenty metres or less.
Why is this distance important?
Because in an urban context it’s the crucial distance at which you MUST be seen. Collision dynamics in slower-moving, denser in-town traffic – the circumstances in which most SMIDSY-style crashes occur – clearly indicate that at the moment the the driver makes the final and crucial ‘looked but failed to see’ (LBFTS) error, the bike must be with twenty metres, and probably within a dozen metres or so.
It doesn’t actually matter if we’re spotted 500 metres away or fifty metres away – the ‘Last Chance Saloon’ for the rider is the last check the driver makes before turning into the bike’s path. Why? Two reasons. If the bike is further off when the error happens, either the emerging car will clear the bike’s path and it will be a near-miss, or the rider has sufficient space to hit the brakes hard and stop which means it’s another near-miss.
So the implication is that the bike actually has to be much closer than most riders realise before the LBFTS error will inevitably result in a collision.
What’s clear from looking at the crash stats is that neither hi-vis nor DRLs seem to have made any difference to the overall pattern of crashes, and so the ‘Sorry Mate’ collisions at junctions remain as frequent as ever, despite significant numbers of riders in hi-vis riding kit and virtually every bike in the UK now using lights in daytime.
I doubt we’d see any difference if modulators were legalised for use in the UK either.
Of course, the counter-argument is that modulators will help drivers see you further off, then they will remember you’re there, but I’m not convinced. There’s no evidence that it works for ordinary lights despite trials suggesting bikes with lights are seen at greater distances than bikes with no lights.
So, from a personal perspective, just as I don’t rely on DRLs or hi-vis clothing, I’d rather back my ability to see the driver and anticipate the error than put my faith in a modulator.
Once again, I’ve had to respond to a comment on an article about why drivers fail to detect motorcycles in traffic. I was flagging up the difficulties of seeing bikes that are hidden by other vehicles – and thus “not visible” – when the ‘drivers don’t pay enough attention’ comment surfaced.
Not paying attention? Well, a little logical thinking should tell us it’s hard to ‘pay attention to something we can’t see. But is it true that drivers wander round in some kind of daze? Have a think about this.
There are 40 million drivers in the UK, but there are only around 100 fatal collisions at junctions, and maybe 10x that result in serious injuries. That’s 1100.
What about the minor bumps that don’t result in anything serious? Even if we multiplied by another factor of ten, and assumed that there are around 10,000 actual crashes involving bikes and cars at junctions each year, that means that 39,990,000 drivers DON’T crash into a bike each year.
There are around 1.3 million riders, who cover around 3 billion miles on the roads and during that time they have innumerable opportunities to encounter a car at a junction. So far as I know no-one has ever counted the number of junctions, nor calculated the number of interactions that there must be between riders and drivers.
The inference is obvious. The overwhelming majority of drivers DO see the overwhelming majority of powered two wheelers.
And that means those drivers clearly DO pay enough attention to avoid us as well as all the other vehicles they encounter. Even if ‘not paying attention’ were the ONLY reason that cars and motorcycles come to grief at junctions, the fact is that a lack of attention is NOT a driver’s default behaviour, despite what far too many riders believe and repeat.
The fact is, we never even notice the hundreds of drivers who get it right ahead of us, we only ever remember the occasional negative outcomes when someone gets it wrong.
Anyway, moving on…
…once we know that the vast majority of drivers DO look for motorcycles and see them, it’s necessary to look for explanations other than ‘not paying attention’.
If the rider is VISIBLE – that is, where the driver CAN see the bike – one explanation that goes back to the earliest days of research into these crashes is low CONSPICUITY.
Conspicuity can be defined as the properties of an object that cause it to attract attention or to be readily located by an active search. As I mentioned on Tuesday, visibility and conspicuity are NOT interchangeable terms. If a bike’s not visible to the driver, how conspicuous is it matters not a jot.
As Malc reminded me recently, conspicuity can be further broken down:
SENSORY CONSPICUITY – this refers to the motorcycle’s ability to attract visual attention, which in determines the ease with which the motorcycle can be detected within the environment during an active search. Size, movement, brightness and contrast against the background all play a part.
ATTENTIONAL CONSPICUITY – this differs from sensory conspicuity as it refers to the degree to which the motorcycle will attract the observer’s attention when they are not actively searching the environment and the bike is unexpected.
SEARCH CONSPICUITY – of course, when we’re at a junction, we’re looking around for other vehicles. And search conspicuity is a measure of just how easy it is for the observer to locate a motorcycle quickly, reliably and accurately when actively scanning the environment.
It should be fairly obvious that attentional conspicuity and search conspicuity are linked. When given an instruction to search specific objects, it seems performance of the detection task improves, even when the target objects are harder to see because they have low sensory conspicuity. Not too surprising, really.
This is the basis of the ‘Think Bike’ campaigns – when drivers are reminded to actively search for motorcycles, the theory is that they will see more of them.
Unfortunately, the theory doesn’t seem to be born out by the results – we’ve been running ‘Think Bike’ campaigns since the mid-70s, yet there doesn’t seem to be any significant’ reduction in the number of collisions that occur at intersections. It may well be that the reminders are forgotten rapidly. Or there may be an element of ‘saturation’ with these campaigns, accompanied by a belief that the crashes only happen “to others”. Of course, statistically – as we’ve just seen – that’s actually correct. The vast majority of drivers will never have a collision with a motorcycle in the whole of their driving career.
BEHAVIOURAL CONSPICUITY – this concerns the the ability of an object or organism to attract attention through its behaviour. For a motorcyclist, this could include actions such as lateral change of position within the lane to generate a movement against the background, the use of brightly-coloured clothing (hi-vis) or day riding lights, including the headlight modulators popular in the US, and the use of sound.
This is the basis of the ‘Ride Bright’ campaigns, which also began in the mid-70s – in fact, I was one of the very first riders to start using my headlight in daytime, and to wear a hi-vis Sam Browne belt.
Has it made any difference? Having looked, I can’t see any obvious difference in the crash rates at junctions between countries which have a lights-on rule (such as France) and those which don’t. Bikes in the UK have come with a hard-wired low beam as a day riding light for quite a few years now, yet once again, it doesn’t seem to have had any effect on collisions.
I’ll add a fifth form of conspicuity:
COGNITIVE CONSPICUITY – research studies have suggested that so-called ‘dual drivers’ who are both cyclists and motorists had fewer collisions with cyclists and detected them at a greater distance in all situations, irrespective of cyclist visibility. Similar results suggest similar outcomes for motorcyclist drivers too. The conclusion was that having experience of either of the vulnerable forms of transport offers those road users an advantage when behind the wheel of a car in terms of processing the visual field and detecting the two-wheelers.
This is why some people advocate that all drivers should be given some training on powered two-wheelers. Unfortunately, as far as I know, a short course of bike training has very little effect long-term. It looks like you need to be a life-long cyclist or motorcyclist for the the awareness of cycles and motorcycles to filter through into driving.
CONCLUSION – my reading of the research, and my investigations into actual crash data tells me that as motorcyclists, we really should not be placing too much faith in any kind of conspicuity.
The biggest problem is that hi-vis clothing and day riding lights are, by their very nature, passive protection; that is, we rely on others seeing us and taking the appropriate action to keep us out of trouble.
As I said at the end of my response to the person saying the issue is ‘lack of attention’, the fact is that COLLISIONS by their very nature are ‘two to tangle’ incidents – one road user sets it up, the other rides into it. Accident studies the world over show that very significant numbers of junction collisions could have been avoided BY THE RIDER if that rider had:
a) seen the crash coming b) known what to do to STAY out of trouble (evasion) c) known what to do to GET out of trouble (avoidance) d) reacted to the threat in time!
I’m still absolutely convinced our safety lies in our own hands. Be pro-active and take responsibility, don’t rely on others to get it right. Do that, and it doesn’t matter whether it’s ‘not paying attention’ or conspicuity issues that cause us not to be detected. It won’t matter because we’ve already the potential problem and dealing with it.
That’s the claim being put forward by press reports of a new study published in the journal Transportation Research Part F: Traffic Psychology and Behaviour earlier this month. The press release from Rice University’s News and Media Relations department was headlined:
“New motorcycle lighting design could save lives… Alternative to one-headlight setup helps other motorists see bikes almost a second sooner.”
Not surprisingly, it’s already been republished in several locations where motorcyclists are likely to read it.
The press release refers to a new research paper, entitled ‘Effect of Motorcycle Lighting Configurations on Drivers’ Perceptions of Closing’ and authored by Bradley W. Weaver and Patricia R. DeLucia from Rice University, Houston, in Texas is based on Weaver’s PhD dissertation.
The study looked at motorcycles at night. Weaver said in a press release:
“Because motorcycles are smaller than many other vehicles, it is more difficult for other drivers to accurately judge their motion on the roadway. It is particularly difficult at night when a motorcycle has only a single headlight because other drivers can’t see the motorcycle’s full height or width.”
The aim of the study was: “to better understand how drivers perceive an approaching set of motorcycle headlights during nighttime driving and to determine whether alternative motorcycle headlight configurations improve drivers’ perceptual judgments of closing for an oncoming motorcycle”.
In other words, the scenario they were investigating was the one where a vehicle is planning to turn across the path of one coming the other way, rather than the classic ‘SMIDSY’ collision where a vehicle pulls out from a side road.
And to do this, they set up a simulator study in which a ‘driver’ saw approaching lights in various configurations of lights including a standard car light configuration, plus a variety of arrangements of lights representing motorcycles. The participants – all drivers, and most with no experience of riding motorcycles – had to press a key on the keyboard when they detected that the light was actually moving towards them.
Illustration from ‘Effect of motorcycle lighting configurations on drivers’ perceptions of closing during nighttime driving’ Bradley W.Weaver, Patricia R.DeLucia Transportation Research Part F: Traffic Psychology and Behaviour Volume 90, October 2022, Pages 333-346
I managed to get hold of the PDF of the paper, and I’ve now had a chance to read it.
There are some interesting conclusions.
Firstly, the standard car headlight configuration was most rapidly detected as moving towards the participant. None of the motorcycle lighting configurations were detected as moving as rapidly.
Secondly, drivers find it easier to detect this ‘looming’ movement when a single motorcycle headlight is ‘big’ rather than ‘small’. As far as I remember, this is consistent with a study done here in the UK back in the 1960s.
Thirdly, they also looked at the popular ‘tri-light’ configuration where the single headlight is supplemented with two additional lights. I’ve previously reported studies have suggested positive benefits for the tri-light arrangement at night, and their results also suggest this light configuration that helps accentuate both a motorcycle’s height and width is superior to a single headlight when it comes to detecting movement towards a driver.
Four, they also looked at ‘fully accentuated’ lighting systems that were either:
:: horizontal – a flat row of lights going right across the front of the machine :: vertical – a row of lights from the bottom of the bike to the top of the rider’s helmet :: combined – both horizontal and vertical lights
They compared these arrangements against a standard single headlight, a motorcycle with a tri-headlight configuration, and a car’s headlights.
Their results indicated that the headlight configuration that accentuated BOTH a motorcycle’s height and width, or the configuration that accentuated ONLY the motorcycle’s HEIGHT were better than the single headlight or the motorcycle with a tri-headlight configuration.
Of the two, the vertical light arrangement was detected as moving toward the observer sooner.
And so the authors concluded:
“…the fully accentuated vertical motorcycle headlight configuration may be better in terms of practicality because it requires fewer headlights and therefore costs less.”
And they also pointed out that “…motorcyclists would need to wear a helmet-mounted headlight” admitting that it wasn’t a “very common practice” and that “buy-in from motorcyclists would be needed”.
The paper also flagged up a potential problem, although they didn’t identify the real issue. The authors said that “motorcyclists turning their head would change how the oncoming motorcycle appears”, but that’s not actually the problem.
Although the lights in the diagram of the experimental configuration are smaller, there’s no information on BRIGHTNESS – or if there is, I missed it.
If these additional lights actually produce as much light output as the bike’s standard headlight from a smaller lens – as do many of the auxiliary lights currently used by motorcyclists – then a rider with a helmet mounted light turning his or her head to look directly AT a vehicle will actually dazzle the driver. We have low-beam lights for a reason.
I’ve had precisely this problem with cyclists, using powerful helmet-mounted lights. One blinded me completely in the middle of a left-hand bend on a narrow road – I could neither see the cyclist, nor the hedge on the inside of the bend. This is not a trivial problem, and in my opinion precludes the use of bright lights on the helmet.
SURVIVAL SKILLS delivering science, not speculation GOT A QUESTION about riding bikes? Drop me a line and I’ll give you a research and evidence-based ACCURATE ANSWER!
Of course, the biggest question of the lot is how much ‘time’ does the vertical light configuration buy the rider?
The answer is that the study found that other motorists were able to see motorcycles “up to 0.8 seconds sooner”.
“Just under a second might not seem like a lot, but reducing a driver’s response time to a potential collision can make a difference between life and death” said DeLucia.
Well, it depends on how far away the bike is, and whether or not the lighting configuration actually stops drivers initiating a turn.
So let’s put the 0.8 second gain in context. The simulation had the motorcycle travelling at 30 mph. That’s 13.4 metres per second. So the maximum extra distance was just 10.7 metres. And you’ll note that the study said ‘up to’ 0.8 seconds.
The study says “when the scene started, the oncoming motorcycle was 750 to 850 ft (228.60 to 259.08 m) from the participant”, but the important point is where was the bike when the driver actually detected the moving motorcycle?
IF I’ve read the results correctly – and to be honest I’m not entirely sure that I have so I’m happy to be corrected – the ‘bumper to bumper’ distances at the moment the lighting configurations were detected as moving ranged from an average of 209 feet for the car lights configuration, to an average of 185 feet for the single motorcycle headlight configuration.
But remember where the bike first became visible – well over 200 metres away.
If my interpretation is correct, and assuming the worst case scenario where the bike first appeared 750 ft or 228.6 metres away, the bike had moved 56 metres before it was spotted. That means it was detected as moving when over 170 metres away.
To put that in perspective, that’s still well over TWELVE SECONDS from the time the bike would reach the observer’s position. And crucially, the study did NOT look at whether the driver would have actually initiated a turn across the motorcycle’s path. The fact is that at that distance, there’s no threat to the rider anyway – the car would clear the rider’s path with time to spare.
And so I’m not sure what the practical benefit of being seen 0.8 seconds – or eleven metres – sooner actually is.
There are also several practical problems which weren’t considered. As I’ve previously stated when helmet-mounted lights have been proposed, there are the problems of:
:: attaching them to a helmet :: powering them :: ensuring that the lights, plus any batteries, do not compromise the primary role of the helmet, which is to protect the head in a crash – you’ll probably remember that the latest ECE helmet standard requires that a helmet be tested with options like cameras and radios already attached
Finally, it’s worth pointing out that this was a simulator study. More importantly, the description of the method says “participants downloaded the needed experimental files” and that participants were required to “measure the width of their screens, which the experimenter would then use to calculate the correct viewing distance”. This implies that the study wasn’t run on standardised equipment in a controlled environment, but run on participants’ own computers and screens in their own home. There seems to have been no test to confirm that the various participants got comparable results with each other. The weakness of the study should be obvious.
My conclusion is that it’s an interesting study, but I’m far from convinced that the proposed vertical lights actually create any significant benefit to the rider, that claims that the ‘design could save lives’ are unproven and exaggerated, and compared with conventional lights, there’s little consideration of the practical issues, including the potential for significant inconvenience to other road users being dazzled by a helmet-mounted light.
If you want to make yourself more visible in night-time traffic I’m still of the belief that different-coloured lights are a sound choice.
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Does the way pigeons see the world explain some motorcycle crashes?
Ryan over at FortNine recently put up a video entitled ‘how pigeons explain a common motorcycle crash. The presentation says that pigeons “suck at assessing how fast a particular vehicle is closing on them”. And he points to some research that shows that in a particular speed zone, they take off at the same distance from a car no matter what the speed the car approaches at. He says that the pigeons learn the typical speed of cars in their zone. Ryan then says this is because pigeons lack ‘binocular disparity’ and the ability to judge approach speed.
What’s binocular disparity? Because we have two eyes which both offer a view of a particular object, each eye gets a slightly different flat 2-D image from the light that falls on to each retina.
Imagine a tree behind a car. The view of eye is at a slightly different angle, which means each eye will show the tree at a slightly different position relative to the car. The brain can uses these different images to extract depth information. This is binocular disparity.
Ryan then says that we can use binocular disparity “to judge how fast an object is closing on us”, and explains that this is known as ‘stereopsis’ and that “within thirty metres it’s the main method of gauging the speed of other vehicles”.
“Unless” he adds…
…”you’re a pigeon” because pigeons have their eyes on either side of their head.
And he then explains that as we’re sitting at a junction, we only have one eye turned towards the junction:
“Same handicap, see? Only one eye is looking because the other is blocked by my nose”.
He then says that this isn’t so much of a problem when tracking cars because “one eye can still track using the apparent change in size to gauge closing speed”. The problem with motorcycles is that because they are “skinny”, they “don’t show much enlargement” until the bike’s on top of the observer.
Same angle, same distances… the car appears to ‘grow’ more than the bike
This is actually the phenomenon known as looming, and it’s well-known that it is easier to judge speed and distance for cars than bikes – for some reason, our brain measures the lateral growth of a car better than the vertical growth of a bike.
OK, so that’s the basis for the video. It’s plausible-sounding, particularly as it’s well-known that the brain ‘edits out’ the fact that our nose is actually visible in both eyes but I’d say there are significant flaws in the reasoning.
PIGEONS DO HAVE BINOCULAR VISION – Despite having eyes on either side of their head, and though they may turn their heads to scan you with one eye, even for pigeons the fields of view of their two eyes do overlap. Not by much, but pigeons WILL look straight at you and when they do that they are seeing you with both eyes. See the photo.
And although I have no proof, I’d suggest they DO need good depth perception – if they didn’t, they’d never manage to land on a narrow branch. They look directly ahead of them when landing.
HUMANS HAVE A WIDE FIELD OF BINOCULAR VISION – For human vision, the overlap is around 120° – that means we have monocular vision ONLY for around 40° at each side of our field of view. Yes, the bridge of the nose occludes part of each eye’s visual field, but nothing like the extent of a pigeon.
PERIPHERAL VISION DETECTS MOVEMENT AND LIGHT – The pigeon’s eyes are on either side of its head because it’s a prey animal. The eyes give a ‘wrap-around’ field of view with only a very small blind spot directly behind its head. Humans do have a bigger blind spot, but even staring directly ahead, our eyes are sensitive to movement and lights at 90 degrees since that angle falls within our peripheral vision. And once something is detected, our instinct is to turn our head to look straight at it.
The nose restricts around 40° of our total vision either side, but when we want to ‘look’ at something we turn our heads to focus both eyes…
‘USEFUL’ AND FOCUSED VISION IS MORE RESTRICTED – Within that binocular field, the so-called ‘useful’ field of vision – the visual area from which information can be extracted in a single glance without eye or head movements – is restricted to around 10° either side of our line of sight.
Even more crucially, if we want to extract detail information, then we have to aim our gaze and use ‘foveal’ vision. This is where we get the clear, colour and focused image of the world. The bad news is that it’s a tiny cone, just 5° across at the point our gaze is focused. This is down to the construction of the human eye.
TO SEE DETAIL WE TURN OUR HEADS – It’s simply not possible to gain full situational awareness by relying entirely on the peripheral vision. If we want to look at something in detail, we have to bring it into the centre of our visual field, into our gaze. Mostly, this is a function of the anatomy of the eye; the fovea, the central portion of the retina, has the highest density of photo receptors. It’s also connected to a much larger part of the visual cortex in the brain, where the visual data is processed.
Whilst peripheral vision can provide useful information to fill out situation awareness, for a detailed study of a particular object we need to turn our eyes onto it.
So when we want to see something in detail – including the involuntary response that happens when we detect movement or light in peripheral vision – we do the same ‘eyes front’ thing that the pigeon does when it needs to land. At junctions we don’t stare straight out of the windscreen, trying to work out what’s coming from each direction via peripheral vision from both eyes simultaneously; we turn our heads to search in each direction in turn, in order to point these foveal cones of vision towards the specific area we’re searching.
Tracking, we’re keeping the bike firmly in the middle of our visual field… Image taken from ‘Look harder for bikes’ road safety video
Ryan talks about the issue of ‘tracking’ vehicles. The fact is we achieve this by looking directly at them. That implies we’ve already seen them and we’re not attempting to detect them. The difficulty of judging speed and distance occurs when we’re already looking at them.
DRIVERS TURNING INTO SIDE ROADS MISS BIKES TOO – If the pigeon vision issue really was a thing, how can we explain the fact that there are TWO collision types at junctions?
Whilst the collision with the driver who emerges from the turning on the nearside is the more common, a significant number of crashes involve an oncoming driver turning INTO the side road and across the driver’s path.
If the ‘looked but failed to see’ issue was really down to a chunk of the visual field being viewed only through one eye, these collisions shouldn’t happen – they’d be ideal circumstances for full binocular vision to detect the bike, then judge its speed to a nicety.
FAILED TO SEE ERRORS HAPPEN CLOSE UP – Ryan says that stereopsis is “the main method of gauging the speed of other vehicles… within thirty metres. I’ve no reason to argue with that, but let’s actually think about the collision dynamics.
30 mph is 13.4 metres per second. So thirty metres is something over two seconds away. Research into collisions suggests that the safe ‘cut-off’ when a rider is almost certain to avoid a collision is three seconds out from the crash – so something under fifty metres away at 30 mph. But at 60 mph, it’s getting on for one hundred metres away.
If Ryan’s figures are right, at rural road speeds the error happens well outside the limits of stereopsis. Even at urban speeds, the error in spotting the bike could happen right at the limits.
But even if the error did happen within the zone covered by stereopsis, there’s a second consideration. Even a rider who’s taken by SURPRISE! should be able to stop fairly comfortably within twenty five metres. I can – and have – stopped in about ten metres from 30 mph.
The three main reasons for collisions and junctions; the driver looked but COULD NOT see… the driver looked but FAILED to see… the driver looked, saw but MISJUDGED speed or distance…
So if the bike actually HITS the car, the error MUST have happened closer. A LOT closer. If a driver somehow fails to detect a motorcycle less than twenty five metres away, I don’t think it’s a speed / distance misjudgement (with one exception – see below). It’s far more likely the driver simply didn’t SEE the bike.
And that can happen because either the bike wasn’t VISIBLE when the driver looked (one in five of collisions) or the perception error was caused by one of the many PERCEPTUAL issues that fall under the ‘looked but failed to see’ umbrella (one in three collisions).
The bulk of ‘looked, saw but misjudged speed and distance’ errors (one in three collisions) seem to happen on faster roads where the bike is beyond the range of stereopsis, and we use the rate of change in size to judge approach speed – and now the difficulty in judging the lateral growth of a motorcycle most likely becomes crucial. The size of the machine only grows by a quarter, despite the distance halving.
(And dismiss the ‘driver didn’t look’ theory too – the proportion of collisions where the driver was distracted is tiny. If drivers genuinely ‘didn’t look’, they’d be bouncing off pedestrians, bikes, and buses – as well as other cars – every few seconds.)
OR THE RIDER WAS SPEEDING – Oddly enough, that researcher who found the pigeons scattered at the same distance from the car no matter what speed he approached at found something in common with drivers. We too gain a sense of how much time we have to turn at junctions based on the TYPICAL speed of vehicles.
So if ANY vehicle – not just a motorcycle – is travelling significantly quicker than average, that vehicle is far more likely to have a collision. It’s not the speed that caused it per se, although more speed means more difficulty stopping and a bigger impact if the rider hits something, other road users simply aren’t expecting the vehicle to be travelling at the excess speed, so don’t detect the anomaly easily and thus are more likely to turn across the rider’s path.
The horizontal line represents the speed limit, the vertical bars of the same colour represents the speed of the rider estimated by police
I don’t think it’s any coincidence that in a study of fatal bike crashes in the London area a few years ago, the majority of the deaths in the lower speed limits involved riders who were exceeding the limit. The horizontal lines in the chart represent the speed limit. The vertical bars are the estimated speeds of the riders who died.
AND DRIVERS COLLIDE WITH CARS TOO – Research from the Netherlands a few years ago looked at car-motorcycle and car-car detection errors, and adjusted the rates for EXPOSURE – that it, how many bikes and how many cars a driver would encounter in the same time frame. And what they found was that far from picking out bikes to collide with, drivers actually made the ‘looked but failed to see’ error in front of another car just as often as they made the error in front of a two-wheeler.
We always have to be a little careful about taking data from one country and exporting it to ‘fit’ our own roads and in this case the Netherlands has many more mopeds on the roads than the UK so there’s the possibility that drivers were more ‘bike-aware’. But there’s other evidence that hints that in countries where most vehicles are two-wheelers, bikers crash into bikers at much the same rate as car drivers.
We also have to remember that our own PERSONAL stories are looking through the opposite end of the lens. We may think that drivers are more likely to make a mistake in front of us on our bike than other riders, but the fact is we’ll encounter many more cars than bikes on a ride.
AND A FINAL NAIL – I didn’t even mention the fact that a substantial minority of the population have various eye issues which makes stereopsis impossible, yet manage to drive successfully.
CONCLUSION – The FortNine videos that Ryan fronts are often informative as well as entertaining to watch. But in this particular instance, I think the reasoning he uses is flawed. And hopefully I’ve explained this clearly enough that you can follow my own arguments. I’d be interested in your comments too, of course.
BUT HERE’S WHERE I DO AGREE – If there’s one bit of the video that I absolutely concur with, it’s Ryan’s comment after showing the old mid-70s ‘Think ONCE, think TWICE, think BIKE’ TV advert. I wonder where he found that?
Made in the mid-1970s, it’s still one of the best ‘think bike’ ads
He says about ‘think bike’, “he’s not wrong, but it’s not useful either. If we’re dealing with a sensory problem then imploring drivers to see better is like imploring a deaf person to listen up. I’d rather take my own responsibility…”
Spot on. Be proactive. Don’t wait to be seen. Assume you won’t be detected and ride with that in mind.
You can watch the FortNine video here:
You can find out more about the Science Of Being Seen project here:
I’m available to deliver the Science Of Being Seen (SOBS) presentation to clubs and groups around the UK IN PERSON, or anywhere in the WORLD via a WEBCAST, and at reasonable cost too.
Here’s a snippet from an article on an online motorcycle magazine site, in a series about how to avoid common crashes. Not surprisingly it’s starts with the SMIDSY collision with a vehicle turning at a junction.
This particular statement leapt out at me:
“The number of drivers who have pulled out on while I’ve been maintaining eye contact with them while wearing a clear visor is very worrying. The shock in the face of the driver is the scariest thing to me, it means that person looked to the right, made full eye contact me and still pulled out while I was sounding my horn and taking evasive action! Frightening stuff.”
Now, just think about that for a moment.
Looking our way? The best we can say is “they MIGHT see us”
The writer says that enough drivers have pulled out whilst he’s been maintaining eye contact for it to be ‘very worrying’.
Does that suggest anything to you?
Might it be that if drivers continue to pull out whilst ‘making eye contact’ than in fact they AREN’T actually seeing the bike?
And the writer has actually spotted this, but hasn’t actually realised that the ‘shock in the face of the driver’ is a big clue.
That ‘shock’ is the moment the driver actually SPOTS the bike. The shock is the result of the SURPRISE! at seeing it.
Take a bit of time to watch drivers at junctions. Watch HOW they look in our direction. You’ll often see a snap of the head . That’s the moment we’re detected. You’ll often see the driver then track us by moving his or her head.
That’s when the driver really does look at us, rather than in our direction.
I say ‘really does look at us’ because eye contact is an entirely faulty concept.
The eye’s foveal zone – the part of the visual field that gives us clear and sharply focused colour vision – is just a few degrees across. Anything out of this zone is fuzzy.
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You can test this easily by holding your arm out, sticking your thumb up in the air then looking at the thumb nail. Now look at the top knuckle on your thumb. Even though it’s just a centimetre or so below your nail you MUST move your eyes and refocus.
And remember too, that the eye has a depth of field just like a camera. Think how hard it is to focus on an object if there are other things in the same direction but at a different distance. We can have the same problem with a camera, trying to focus on a small object when there are other things in front of it and behind it.
In the case of a bike, it’s entirely possible that the driver we were so busily trying to make eye contact with was actually looking at and focused on the car ten metres behind us.
So that’s another reason why trying to make eye contact is pretty much a waste of time – the driver can appear to be looking straight at us whilst focused on a car behind us. The motorcycle ahead of it never registers in the driver’s consciousness. It’s not ‘carelessness’ or ‘not looking properly’, it’s just how our eyes work.
So here’s a question for you. If the writer keeps ‘making eye contact’ yet it clearly doesn’t work, why keep trying to make something of it?
My advice? Forget it and assume we’ve not been seen. We’ll be far better prepared when the driver does make the ‘looked but failed to see’ error and pulls into our path!
WANT TO IMPROVE YOUR PRACTICAL RIDING SKILLS? Head to www.survivalskillsridertraining.co.uk to find out how I can help you develop a genuinely defensive mindset when riding!
Imagine driving down this road. What if a vehicle appears from left, and turns right across your path? How soon will you see it? And when will the driver see you…
…if he or she sees you at all?
Junction collisions – the so-called SMIDSY ‘Sorry Mate I Didn’t See You’ crash are the most common accidents involving motorcycles AND cars. Yes, drivers get it wrong in front of other cars too!
And even more alarmingly, many riders and drivers fail to spot the developing collision until too late.
Why? Isn’t it easy to scan a junction? Unfortunately, the process doesn’t work in the ways most of us think. And so we ALL make errors which lead to the so-called ‘Looked But Failed To See’ (LBFTS) error.
Here’s the bad news. We’ve been investigating this driving error for over half a century, and whilst the research papers have a very good grasp of just how we all scan junctions, little of that work has filtered down into road safety and rider education. Many of us still firmly believe that if a driver didn’t see the bike (or even another car) then that driver “didn’t look properly”.
Nothing could be further from the truth.
This in-depth presentation from Kevin Williams, creator of the ‘Science Of Being Seen’ project aims to show just how drivers and riders alike acquire visual information which informs us about the world outside the windscreen or visor.
Howard A – “…you were the only person who was giving strategic advice on avoiding becoming a casualty and made a Despatch Rider from 1978 to 1985 think outside of the box. It’s all about avoiding those nasty accidents.”
Wednesday’s evenings LIVE ONLINE TALK will focus on how the brain makes use of the intersection of:
to gain a better understanding of how road users visual attention , and identify just how visual data acquisition can break down thanks to phenomena such as motion camouflage and saccadic eye movements, leading to the LBFTS error.
I’ll conclude with some pro-active strategies for identifying situations where this driver error is likely, and what the rider can do to minimise the risks.
DESPITE ITS IMPORTANCE TO ALL BIKERS, SOBS RECEIVES NO FUNDING and all research, writing and webhosting is paid for out of my own pocket. All income from presentation tickets and book sales is ploughed back into the project. Buy a ticket and you’re helping not just yourself but every other biker who wants to know more about the SMIDSY collision. Thanks in advance.
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