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.

2 thoughts on “The five flavours of conspicuity

  1. I like the idea that we take responsibility for our own ride and we pay attention to junctions and other vehicles (2 wheeler as well!) This will hopefully help us to anticipate and evade that potential conflict. Wandering minds isn’t just a car driver’s issue… is it?


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