Latest from Science Of Being Seen

‘Science Of Being Seen’ (SOBS)an in-depth investigation of the most common motorcycle crash of all – the ‘Sorry Mate I Didn’t See You’ or ‘SMIDSY’ collision.


SOBS looks at why motorcycles aren’t seen at junctions. The aim is to offer a better understanding of how, where and why these collisions happen, and to give riders some simple and practical strategies for staying out of trouble.
SOBS was originally created by myself (Kevin Williams MSc) over the winter of 2011-2012 as the third ‘accident prevention’ module of Kent Fire & Rescue’s pilot ‘Biker Down’ course. SOBS explores a range of problems: 

‘looked but COULD NOT see’ collisions, where for various reasons – including ‘beam blindness’ and the ‘constant bearing issue’ – it was physically impossible for the driver to see the motorcycle in the run up to the crash
‘looked but FAILED TO see’ collisions, where the bike was in a place it could be seen but visual perception issues meant that the driver failed to spot the bike
‘looked, SAW AND FORGOT’ collisions where short term visual memory and workload issues meant that the driver was likely to have seen the bike but mentally lost track of it
‘looked, SAW AND MISJUDGED speed and distance’ collisions, which tend to happen on faster roads

SOBS takes an objective look at the effectiveness or otherwise of the usual ‘passive safety’ conspicuity aids – hi-vis clothing and day-riding lights (DRLs), before suggesting some general rules to make them more effective.

Finally, SOBS looks at how motorcyclists can use pro-active techniques to avoid being caught up in a SMIDY collision. 

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What’s wrong with this hi-vis colour scheme?

Answer – it’s ‘disruptive camouflage’

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!

What about headlight modulators

(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.

In any case, they are illegal in many countries.

Thanks to ‘Paul’ for alerting me to the link.

The five flavours of conspicuity

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
:: attentional conspicuity
:: search conspicuity
:: behavioural conspicuity

Let’s have a look at what these terms mean.

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.

SOBS October 21 Could a new motorcycle lighting design ‘save lives’?

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.

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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.


Each investigation of a research article like
this one takes hours of my time. I give that time
freely to the SOBS project because I believe it
can make a difference by helping riders achieve
a better understanding of the SMIDSY collision.

Your one-off donations or regular subscriptions
help me keep the project updated with the very
latest research into motorcycle crashes.


‘Pigeon vision’ – why it’s not a thing

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.


Eye contact – an entirely faulty concept

and why we should forget it

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.

tractor and motorcycle SMIDSY
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. 

catch the regular LIVE ONLINE TALK SERIES events – next dates:

AUGUST’S LIVE EVENT – ‘SOBS – the full presentation’
WEDNESDAY 3 AUGUST 2022 at 20:00. Tickets cost £5

SEPTEMBER’S LIVE EVENT – ‘Riding Systems – what they
are, and why we need to apply them systematically’

WEDNESDAY 7 SEPTEMBER 2022 at 20:00. Tickets cost £5


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!

Head to to find out how I can help you develop a genuinely defensive mindset when riding!

*** SCIENCE OF BEING SEEN LIVE ONLINE *** The in-depth detail

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:

:: peripheral vision
:: involuntary eye movements
:: eye movement planning

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.

WEDNESDAY 8 JUNE 2022 AT 20:00 Tickets cost £5


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.



*** SCIENCE OF BEING SEEN *** Second Chance – rescheduled to Wed 8 June

Unfortunately, I went down with a thumping headache on Wednesday afternoon last week, so the SOBS In-Depth webcast that was due to go live at 8pm that evening had to be cancelled – I could barely focus on the screen, so rather than push on with a second-rate performance, I decided to put it back a week to Wednesday 8 June.

So if you hadn’t booked for the original event, you have a SECOND CHANCE!

The ‘SCIENCE OF BEING SEEN’ (SOBS) presentation is an in-depth investigation of the most common motorcycle crash of all – the ‘Sorry Mate I Didn’t See You’ or ‘SMIDSY’ collision at junctions.

In this SCIENCE OF BEING SEEN – IN-DEPTH – which alternate with the FULL version of SOBS – I’ll be taking a look at how we scan the scene around us and explain that we don’t capture camera-like images of the world around us – discover the role played by fixations and saccades as we attempt to gain situational awareness, and explaining why lateral motion may be important in helping a driver see us. .

Even if you have already seen the full version of SOBS, the additional detail will help you understand why drivers occasionally don’t see bikes… and why riders often fail to realise there’s a threat!

Use the booking link here for information about how the webcast runs.

*** SCIENCE OF BEING SEEN *** The importance of lateral movement

*** SCIENCE OF BEING SEEN *** The importance of lateral movement
“Where other drivers turn across the path of a motorcyclist, this can be because the motorcyclist…is not seen by the driver…This points to the need to improve driver awareness of motorcycles, as well as raising awareness among motorcyclists of this issue, which is a key factor in many collisions. By running headlights during the daytime and wearing high visibility clothing, motorcyclists can help to improve their visibility to drivers.”

That’s from Transport for London’s ‘Motorcycle Safety Action Plan’ published back in 2016. I don’t know if there’s been an update since, but essentially it ignores one very big problem behind the ‘Sorry Mate I Didn’t See You’ SMIDSY collision.


The motorcyclist also has to be aware that they have to position TO BE SEEN. When plans like this ignore this issue, it’s hardly surprising that so many riders still seem completely oblivious to the problem – OUT OF SIGHT, OUT OF MIND.

In researching the Science Of Being Seen #SOBS, I found that there were actually THREE causes of these crashes.

LOOKED BUT FAILED TO SEE: These are the visual perception failures where a bike that is capable of being seen isn’t spotted. These make up around 1 in 3 of all junction collisions, and for a variety of reasons to do with the way the eye ‘sees’ the world and the brain processes the visual feed, these drivers simply didn’t pick out the presence of a motorcycle even though it was there to be seen. These ‘Looked But Failed To See’ crashes are so common they are actually referred to as LBFTS incidents in the research literature.

Causes include ‘saccadic masking’, which happens when our vision shuts down as we turn our head, a narrow field of clear vision which leaves much of our ‘worldview’ dependent on peripheral vision, and ‘motion camouflage’ where the bike simply ‘grows’ against the background and the driver’s brain fails to detect it.

I have a very good clip of a Spitfire simply ‘appearing out of nowhere’ as it flies directly towards the camera. It’s visible if you look in the right place, but with our attention focused on the presenter, it falls outside our narrow cone of clear vision and in peripheral vision, and is effectively invisible. It’s only when it’s scarily close that it simply ‘pops out’ at the viewer.

And I think we’d all agree that a Spitfire is rather bigger than a motorcycle!

The problem is that lack of lateral movement to attract our attention, and there’s a very specific form of motion camouflage that happens when two moving vehicles are on a collision course. This problem has a name – it’s known as the ‘Constant Bearing, Decreasing Range’ issue. It’s a term used in navigation and flying which means that some object, usually another ship viewed from the deck or bridge of one’s own ship or another aircraft viewed from the cockpit, is getting closer but staying at the same angle – or maintaining the same absolute bearing.

If they both continue on the same course at the same speed, they WILL collide. And it CAN happen on the roads. Just ask yourself where; for example, when you’re approaching a roundabout and another vehicle is on an intersecting course and will arrive at the same time, or when approaching a cross-roads and another vehicle is approaching head-on. Since neither vehicle will appear to move relative to the background, it can be difficult for either driver / rider to perceive the other, even when in clear view. I’ll be coming back to this in a moment.

LOOKED, SAW AND MISJUDGED: And then there is a second type of driver perception error where the driver actually sees the bike, but thanks to the tall and narrow shape of a motorcycle, simply misjudges speed and distance and therefore miscalculates the all-important ‘time to collision’. Once again, it’s a well-known phenomenon in the research and accounts for a further 1 in 3 of junction collisions, usually on faster roads. These are ‘looked, saw and misjudged’ errors.

From the point of view of the rider, the result is that the driver begins a dangerous manoeuvre. Unfortunately, the driver often recognises for themselves half-way through that it’s not going to end well. The rider will often see this change-of-mind when a driver starts to turn across the bike’s path then stops again, frequently ending up stranded across the road ahead of the bike.

This happened in front of me years ago when I was couriering. With a car coming the other way, I had no ‘out’ to the right of the emerging car but had just enough room to turn behind it and shoot obliquely between the gate posts from which the vehicle had just emerged, braking safely to a halt on an immaculate grassy lawn.

The ‘looked but failed to see’ and ‘looked, saw and misjudged’ errors are the classic ‘driver fails’. And it’s always been assumed that advice to use improved scanning techniques would reduce the frequency of these errors. But speaking plainly, the crash stats over the last fifty years of ‘Think Bike’ campaigns fails to turn up any significant change to the frequency of car – bike collisions. And that’s because the human eye and brain were never designed to work at the speed of traffic. The crashes happen because the weaknesses are effectively built-in.

LOOKED BUT COULD NOT SEE: But there’s a third category of error. In around one in five collisions, the rider simply wasn’t where the driver was able to see the bike when the driver looked. The driver ‘looked but COULD NOT SEE’ the bike because it was hidden.

And it’s easier for a bike to go missing than you may realise.

Just watch the video.

Watched it? That was an object the thickness of a PEN blocking our view of the approaching bike.

Now, remember the Constant Bearing issue? Think about what’s happening here. The bike’s not only not moving relative to the background, the fact that it’s on a constant bearing means it’s not moving relative to the vision-blocking pen. And it’s scary how close the bike got before it moved out to where you could see it.

The pen is a Vision Blocker. Think about how many objects there are around us that block lines-of-sight – post boxes, telegraph poles and trees, moving and parked cars, hedges and walls, people walking along the pavement…

…even another motorcycle on a group ride!

Now, I want you to watch the video again. This works best full screen on a PC monitor if you stand about five paces away from the screen. This time stretch your arm out, then hold your hand up vertically with the palm facing away from you, so that you’re looking at the back of your hand. Cover up the policeman and his pen. When do you see the bike now?

Now go sit in your car’s driving set and take a look at the A pillars supporting the front windscreen. If you look at the width of the pillar nearest you, you’ll find it’s about the width of your hand, and it’s about the same distance from your eyes as your hand was when you stretched your arm out.

If you’re still not ‘getting it’, get a friend to walk towards your car whilst trying to hide in the blind spot – they’ll know when they’re in it because they won’t be able to see YOUR eyes. It’s scary just how close they’ll get before you spot them. And a bike’s not much wider than a person.

So now… combine the Constant Bearing problem with the blind spots created by the car itself.

As you approach a vehicle, check where the driver’s head is relative to your line of approach. If their eyes are behind one of the pillars (and the B pillar supporting the doors and the C pillar behind the passenger doors are just as big a problem when approaching from the side or behind), then you’re NOT VISIBLE. You CANNOT BE SEEN.

And we can’t rely on drivers predicting that there MIGHT be a bike they can’t see.

So ask yourself: “how can I bring the driver’s eyes into MY own line-of-sight?”

The answers should be fairly obvious. To ‘break’ motion camouflage and the Constant Bearing problem, all we need to do is change position and speed and thus create some LATERAL movement – hopefully the driver will now see us though a wise rider would still be prepared to take evasive action.

And specifically, we want to identify, then move out from behind, any ‘Vision Blocker’ in order to bring our bike into the driver’s own line-of-sight. That way we ‘uncloak’ our bike, and at least give the driver a CHANCE of seeing us.

Sadly, reading the comments on the FB post where I spotted this video, it’s depressing how many simply missed the point.

There were the usual bunch of “car drivers don’t look properly” or “aren’t paying attention” theorists, though a minor logic check would tell them that if they weren’t ‘paying attention’ they’d be bouncing off everything around them and not just bikes.

Then there were the “car drivers are distracted by their phones” comments. Certainly, you’re at far higher risk of a collision if you are a mobile phone fiddler when driving, but relatively few police investigations into crashes in the UK suggest that the collision can be pinned on mobile phone use as a primary cause. That’s all covered in SOBS.

But my ‘favourite’ comment was probably:

“This just shows that we need to make bikes more visible.”

If you’re in a position where you CAN’T ACTUALLY BE SEEN, how on earth does the writer think that ‘making a bike more visible’ is going to work?

In terms of sage advice, it’s right up there with:

“Drivers, check your blind spots.”

How exactly? They are called blind spots for a reason.

If you want to find out more about the problems of being seen on two wheels, why not sign up for the next presentation of ‘Science Of Being Seen’, on Wednesday evening?

APRIL’S LIVE EVENT – ‘SOBS – the full presentation’
Science Of Being Seen is a 45 minute talk covering
human visual perception and motorcycle conspicuity,
and explains why conventional hi-vis clothing and
day-riding lights have proven less than successful at
preventing junction collisions. Discover how to use
Survival Skills ‘proactive measures’ in your own riding.
WEDNESDAY 6 APRIL 2022 AT 20:00 Tickets cost £5.

The original video was shown here:

Last call for Science Of Being Seen Wed 1 Dec

Wednesday 1 December @ 8 PM

A few years back, Howard Askew attended one of our ‘Biker Down’ courses in Kent – where Biker Down originated as you probably know – and where I was delivering the original ‘SOBS’ presentation.

Tickets cost £5.

Some time later later he sent me this comment on the course and SOBS in particular:

“For sure the course was very good about what to do in the event of an accident, but 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.”

And that absolutely nails the function of SOBS as part of Biker Down.

When Jim Sanderson and I first got involved in discussions about the pilot course of what would become the national Biker Down campaign, we both agreed that there was a need for a pro-active, crash prevention module.

Managing the accident scene and treating casualties are both vital skills.

But it would be better if the rider attending BD didn’t end up needing someone else delivering those skills to the rider.

And so SOBS was born. And as Biker Down was picked up by fire services across the UK, so the majority of those courses delivered a version of SOBS as the third, proactive module.

SOBS was created over the winter of 2011 – 12. I delivered my final presentation for KFRS at Rochester in February 2020, just before we went into lockdown.

For many years individual fire services were pretty much left to run Biker Down in their own time, but it’s finally been acknowledged as a ‘national initiative. And so the fire services have now decided to bring all the modules ‘in-house’.

And that means they have decided to move on from SOBS.

On the one hand, a fresh look can be a good thing.

On the other I’m disappointed because SOBS is a unique safety intervention in that it seeks to give genuinely science-based information to riders and help them make better-informed choices and I think it’s a shame it will no longer be delivered to UK riders.

But with all the work I’ve put into the SOBS project I certainly don’t want to leave it sitting on the shelf, and that’s why I’m running an online webcast every two months, as well as making myself available to clubs and groups for presentations either in person or online.

Make a date here online, or book me for a talk for your group – it’s your choice. But you’ll be giving yourself or your riding buddies a chance to see the presentation which has gone international, being showcased by RoadSafetyGB here in the UK, on the REVVtalks series in the USA and not least as part of the Shiny Side Up rider road shows in New Zealand.

what’s illegal and what’s plain common sense’
Get tips that work from a sixteen year courier veteran.