Intro2 About Science Of Being Seen – or SOBS

Since the mid-1970s, motorcyclists have been encouraged to to use what are often called ‘conspicuity aids’ – to wear light-coloured or hi-vis clothing and helmets, and to ride with their lights on – in order to reduce the risk of collisions with other road users who might otherwise not see them.

Many road safety organisations, as well as police, magistrates and insurance companies, have taken this advice as a statement of self-evident fact:

  • motorcyclists not using conspicuity aids have been told they have not been making themselves “more visible”. They have been found partly responsible for collisions where the other road user violated the motorcyclist’s right of way. They have even been denied full insurance payouts in no-fault collisions.
  • drivers not seeing motorcycles where the rider was using conspicuity aids, and thus causing a collision, have been told that should have seen the bike, and if they didn’t, then they “didn’t look properly”.

As a new rider back in the mid-70s, I too took the advice to ‘ride bright’ on trust. I was an early adopter of hi-vis clothing and day riding lights (DRLs). But after passing out from university, I spent sixteen years covering around half a million miles as a motorcycle courier in and around London.

And the more miles I covered, the less convinced I became that the basic premise behind the use of conspicuity aids was actually sound; as well as my personal experience of dodging errant drivers who failed to see my hi-vis clothing or my lights, I also picked up a number of similarly clad riders who’d just had a “Sorry Mate, I Didn’t See You” ‘SMIDSY’ collision with another road user. It wasn’t unusual to hear the rider say something along the lines of: “but I had my hi-vis and my lights on – he / she should have seen me”. Quite clearly, the driver hadn’t. At first, I thought the problem was probably restricted to inexperienced riders, but over time, I realised that experienced riders using conspicuity aids also got taken out by the SMIDSY collision.

I stopped using hi-vis and turned my headlight off in fine weather. I failed to detect any difference in whether or not drivers saw me coming. As by now I was expecting not to be seen, I was ready on the occasions when drivers did fail to see me. Then I became a motorcycle instructor and not only had to tell new riders about the supposed benefits of conspicuity aids, I had to wear hi-vis and use the lights when I was working, as did the trainees. Despite several highly-visible bikes travelling in convoy, we still had to deal with right-of-way violations (ROWVs) from time to time. I was less than happy at having to tell CBT trainees about the ‘benefits’ from the use conspicuity aids. I wasn’t convinced they contributed much to safety but I began to suspect that the advice contributed much to overconfidence and a failure to avoid avoidable collisions. So during this time when I was delivering CBT on a regular basis – the mid-1990s to mid-2000s – I started to look into the research behind the use of conspicuity aids so that I could better add cautions to the standard CBT advice on hi-vis and DRLs. NOT relying on conspicuity aids became a central plank of my post-test courses, first delivered in 1997. I also have to credit a number of eye-opening forum discussions with another CBT instructor named Ian Kew.

What qualifies me to write about SOBS?

Before getting involved in riding motorcycles for a living, my own background was in the life sciences at degree and post-degree level. Now, if there is one thing that a background in science achieves, it’s to teach us that it’s never a good idea to accept something we’re told on trust alone. Any time we hear something stated as fact, we need to assess the evidence carefully to distinguish between fact and opinion.

An opinion is a form of mental shorthand, where we draw on a limited selection of facts or ideas to form a personal belief that something is probably true.

But, as the Oxford Dictionary says, an opinion is… “a view or judgement formed about something, not necessarily based on fact or knowledge”.

We are all entitled to opinions, but opinion is nearly always simply something that we believe but which falls short of – often well short of – of absolute proof. What we THINK is not FACT. For example, consider the statement “light-coloured clothing makes motorcyclists more visible”. What we need is to ask ourselves:

“Who says this? Is there any evidence to support this statement? Am I really looking at a fact? Is it an opinion that is not supported by fact? Or is it a simple coincidence?”

If we can ask questions such as these, we are in a far better position to make our own judgements about what is and isn’t true.

We have to be careful to avoid making up our own ‘facts’ as bogus support for our opinions. Even when we know something as a fact, it doesn’t mean that it is relevant to the question we’re trying to answer. One of the most important checks is to understand that “correlation does not imply causation”. A correlation occurs when a change in one variable is also seen in a second variable – the two sets of data appear to follow each other.

If there is a causal relationship between two things, one process (the cause) is directly responsible for causing the second process (the effect), and more importantly, the link can be demonstrated. For example, our summer days are warmer than winter days because our half of the planet receives more hours of sunlight. The extra sun causes the ground and atmosphere to heat up.

But it may be pure chance. For example, between 1999 and 2009, the number of people drowning in swimming pools rises and falls in line with the number of films that Nicholas Cage appeared in. Unless there are a significant number of people who hate Cage so much they are prepared to leap into pools and drown every time he releases a new movie, this is a good example of a correlation which has no causal relationship. And this is where we get to motorcycle safety. Many claims for the effectiveness of conspicuity aids, as well as some studies carried out on a non-scientific basis, confuse correlation with causation.

Not so long ago a police force launched a year-long motorcycle safety intervention. Casualties dropped that year. A statement was duly released claiming the safety programme had been a success. The next year, figures were back up despite the intervention running for a second year. It’s almost certain the first year drop was simply chance. If there was a correlation with anything, it was with an exceedingly wet summer – the distance travelled by riders goes down when it rain. The fact that summer had a safety campaign running was a coincidence.

Look critically at any statement, and try to see if there is a solid, logically-reasoned explanation behind it.

And if we can’t see such an explanation? Then it’s wise to put our belief on hold until we see something better.

But it is also important we listen with an open mind. Just because something doesn’t agree with what we think we know – or even what we’ve been told in the past – doesn’t mean it has to be right. And we need to be sure we’re not making up our own facts to support our opinions.


Since you’re here, I’ve a small favour to ask.

Researching, documenting and constructing the ‘Science Of Being Seen’ site has, as you’ve probably realised, taken many hours of hard work. As it stands, I believe the information here is of immense value to each and every motorcyclist, to help understand and defend against the most common crash wherever you are in the world.

The content is not hidden behind a paywall, access is entirely free.

But to keep working on the SOBS project, I need your help to continue to improve the content and keep it updated with the latest research. All work on this project is carried out in my own time and I don’t have sponsors. If you feel able to make a small donation to the upkeep and continued development of SOBS, why not buy me a coffee? Each contribution is much appreciated. Each cuppa keeps me awake and writing! Thank you.