Conclusion – what could work?

SUMMARY – solving the SMIDSY collision may sound simply but it’s not… whilst there is limited evidence that conspicuity aids reduce the collision rate, their use is far from a guarantee the rider will be seen… even when seen, drivers may still misjudge speed and distance… pink hi-vis, the night-time ‘ghost jacket’ and yellow lights would seem to be more effective than conventional hi-vis and DRLs…. but whatever strategy we do adopt, there’s no guarantee we will be seen…

I’ve almost finished the Science Of Being Seen puzzle, and I’m about to present my conclusions and my best suggestions. If you skipped straight to this page, be aware I’m not going into great detail to explain these statements. So if you don’t agree, want me to justify my position, have a question about a statement, or simply want more information than is on this page, backtrack to the relevant page(s) which will take you step-by-step through the research studies and show you my thought-processes.

CONCLUSION ONE – The opening ‘SMIDSY’ pages investigated how drivers fail to see motorcycles at junctions. Typically explained as a simple-sounding problem; “motorcycles are small, they are difficult to detect and it’s hard to judge their speed when they are seen”, it’s anything but. Firstly, the motorcycle may not be where it CAN be seen. If it is capable of being seen, physiological, perceptual and psychological reasons can result in drivers ‘looking but failing to see’. Even when seen, drivers misjudge speed and distance. The idea that drivers “don’t look properly” or even “don’t look at all” is largely a myth resulting from police reporting, and their need to apportion blame to one individual or another.

CONCLUSION TWO – Throughout the ‘Strategies’ section we focused on understanding “what doesn’t work” because it offers far better insight into “what might work”. Note I used the word ‘might’.

CONCLUSION THREE – Whilst we saw positive evidence that conspicuity aids DO reduce the overall rate of collisions, from the perspective of the individual rider they do not confer any kind of guarantee that a driver WILL see the approaching motorcycle. For that reason we have not seen a significant reduction in the collision risk to motorcyclists at junctions. Urban SMIDSY collisions remain the Number One crash that a rider is likely to have.

CONCLUSION FOUR – Alternative strategies are required for day and night, in urban and rural environments, and at junctions approached at different speeds. There is no ‘one size fits all’ solution.


CONCLUSION FIVE – At night in urban areas, retro-reflective materials worn above the waist are too high to be effective. Clothing with stripes or patches of reflective material are ineffective. A night-time tri-light light arrangement seems to help differentiate between motorcycles and other vehicles, and assists the driver to make better estimates of a motorcycle’s speed and distance than single or paired headlights.

CONCLUSION SIX – In daylight, light intensity and background constantly change so we must understand that any colour of clothing may stand out or blend in from moment to moment. We should consider changing hi-vis colour depending on where we ride and seaso. We should avoid hi-vis clothing that creates disruptive camouflage effects and adopt single-colour clothing, ideally matching the bike in order to present a quasi-human shape to the observer. Whilst riding lights-on (including the tri-light configuration) seems to be least effective at improving detection in a cluttered (ie urban) environment and small-diameter lights are less effective than bigger headlights, DRLs generally appear to be more effective at improving detection at distance in an uncluttered (ie rural) environment where the ‘triangle of lights’ also appears to help drivers acquire more accurate speed and distance information.

CONCLUSION SEVEN – whilst recent assessments suggest DRLs have more potential to enhance rider conspicuity than clothing, the growing use of white day running lights on cars, vans, trucks and similar vehicles has led to a conflict with the use of white DRLs on PTWs. Yellow lights used in the DRL role appear to be more effective.

CONCLUSION EIGHT – Whatever strategy we do adopt, there’s no guarantee we will be seen and we should stand ready to take evasive action.

So… is that it? Is there nothing else we can do? Not necessarily. I happen to think we can use what we know to come up with new ideas. For example…

PINK HI-VIS, SLEEVED HI-VIS for DAYTIME USE: For example, I have already suggested that pink hi-vis is almost certainly a better rural riding colour than Saturn Yellow, and that a plain-coloured jacket with matching sleeves offers a better silhouette than a hi-vis tabard or waistcoat, better still make the whole jacket hi-vis. I’m struggling to find a supplier of sleeved, pink hi-vis but if I do I’ll let you know.

Spiro 'ghost' jacket - photo courtesy of Mike Roberts
Spiro ‘ghost’ jacket – photo courtesy of Mike Roberts

NIGHT-TIME ‘GHOST’ JACKET: Patches of retro-reflective material placed higher up on jackets and ‘traffic vests’ are ineffective in urban areas, whilst patches placed lower to catch low-beam headlights reflect brightly but probably don’t help drivers identify the wearer as the rider of a PTW. A very recent development is a jacket that is entirely coated with retro-reflective material. Although above low-beam headlights, there is always some scattered light which makes reflective material ‘glow’ rather than shine. Being sleeved, these ‘ghost’ jackets create a human silhouette. I’d suggest they are far more conspicuous than ‘traffic vests’. Already adopted by cyclists and walkers, the first motorcyclists are starting to wear them. And they don’t cost the earth.

YELLOW DAYTIME LIGHTS: Given the growing conflict between new cars with day running lights, yellow lights offer an opportunity for motorcycle DRLs to be visually distinct again. As long ago as 1981, Olson et al looked at permanently illuminating the turn indicators when they were not flashing to signal a manoeuvre. There is some debate about whether a standard 21w bulb behind a yellow lens is bright enough to function effectively as a DRL but Olson et al found always-on amber ‘running lights’ increased the size of gap that drivers would leave when turning ahead of a motorcycle.

Classic bike indicator

Given the growing conflict between new cars with day running lights, yellow lights offer an opportunity for motorcycle DRLs to be visually distinct again. Paine et al (2005) argue that: “all that is required is the replacement of normal motorcycle turn signals”. 64th session of the United Nations Working Party on Lighting and Light-Signalling in 2011 a motion called for amber position lamps (APL) to be made mandatory on motorcycles. Espie et al (2014) concluded that:

“…results indicate that headlight configurations comprising additional yellow lights on the fork and on the motorcyclist’s helmet significantly improve motorcycle perceptibility by other vehicle drivers.”

Pintoa et al (2014) tested:

“…three conspicuity enhancements designed to improve motorcycle detectability in a car-DRL environment: a triangle configuration (a central headlight plus two lights located on the rearview mirrors), a helmet configuration (a light located on the motorcyclist’s helmet in addition to the central headlight), and a single central yellow headlight. These three front-light configurations were evaluated in comparison to the standard configuration (a single central white headlight)… The results revealed better motorcycle-detection performance for both the yellow headlight and the helmet configuration than for the standard configuration.”

Even though we have to be a little cautious in accepting the results without question – the study was laboratory-based, and involved “photographs representing complex urban traffic scenes [which] were presented briefly (for 250 ms)” – the results are in agreement with Espie et al (2014).

Yellow headlight

However, the benefits of yellow lights appear not to be confined to position lights alone. Espie et al (2014) also concluded that a SINGLE YELLOW HEADLIGHT had a significant positive effect, particularly in an environment full of white car DRLs. So why did they NOT suggest yellow headlights?

“In terms of application, it is probably not realistic to assume that [motorcycles] could be equipped with yellow frontal headlights, because they are less efficient for lighting the street.”

It’s true yellow lights are less effective in their primary role, which serves to confirm the point I made earlier about the essential conflict between the use of a headlight as a DRL with its main role of lighting the way at night. On the other hand, the paper did not consider:

  • that the majority of junction collisions happen in daylight
  • that of those collisions that do happen at night, most occur under urban street lighting, where the headlight’s role of illuminating the roadway is arguably relatively less important than conspicuity
  • that a yellow headlight is a simple modification that can be easily retro-fitted to the existing motorcycle fleet
  • that a yellow daytime headlight is not necessarily something that cannot be switched back to a white light for night-time use on unlit roads

The big plus is that compared with installing amber turn signal running lights which would require modification of the motorcycle’s wiring to carry both circuits, it’s an incredibly simple modification. There are two options:

  • if the machine is fitted with incandescent bulbs, a bulb replacement is a five minute job on most motorcycles. If you ride exclusively in built-up areas with street lighting, this may all that you need to do. No alterations to the wiring are needed. It can be carried out by nearly any bike owner.
  • if a bulb swap is not possible (for example, new machines are being fitted with LED bulbs), it may be possible to fit a yellow headlight cover secured by hook-and-loop fastenings. They are available as aftermarket parts for most popular bikes, protect the lens from stone chips and can be removed for night riding on unlit roads

In either case – and possibly a decisive factor in rider take-up – neither bulbs nor headlight covers are expensive. In my opinion, Espie et al (2014) based their recommendation on an incomplete understanding of what can be done to modify an existing PTW.

Motorcycles with headlight covers

‘Dim-high’ lights: If you are a more mature reader, you may recall that for a short time in the late 1980s, new UK cars were fitted with ‘dim-dip’ lighting. This low output setting reduced the intensity of the low beam headlamps to around 10% and 20% of normal brightness. They were not intended to be day running lights, but to provide a night-time low intensity ‘town beam’ diffused over the headlight’s larger surface. You should recall that the research into motorcycle DRLs has also suggested a larger diameter headlight to be more effective. That set me wondering if a ‘dim-high’ beam – thus avoiding the twin problems of driver dazzle on high beam and poor light distribution on low beam – would prove a more effective DRL. And that in turn reminded me of an idea that was floating around the courier community back in the early 1980s.  The tip was to replace the 5w ‘parking light’ bulb. Barely adequate for parking on unlit streets, it’s of no conceivable use as a DRL, but it does have the advantage of being offset in the headlight shell. That means it’s not focused like low beam.

Image result for 20w halogen side light bulbs

I replaced it with a 10w halogen bulb – as you can see, you can still get them from Lucas. The bulb was much brighter, but not so bright it would dazzle, and set off-centre in the lens it was more visible both ahead and to the side. The minus point was the cost and fragility of the bulbs. But modern LEDs offer a mix of intensity and longevity which would make this an easy retro-fitment to any machine with a conventional headlight. As far as I know, no-one has ever tested a ‘dim-high’ motorcycle headlight!

Combined with a yellow headlamp cover, it could turn out to be the best of both worlds – not only visually distinct from a white light, but also scattering light ahead across a wide angle. As far as I know, this hasn’t been tested either.

DON’T EXPECT TO BE SEEN: Regardless of everything I have said in the preceding sections, I believe the key point is to re-calibrate our conspicuity strategy completely: by all means use DRLs, reflective clothing and hi-vis but don’t EXPECT to be seen! I was making this very point years ago on a bike forum when one rider wrote: “it makes me feel more confident that I’ve been seen”. The moment we come to think that, we’re at risk because we’re mentally dropping our guard. Instead, we need to view the problem from the opposite end of the telescope and understand how other road users detect what’s around them. That’s how we gain an understanding of why hi-vis and DRLs might not work. It’s hardly a new idea. As far back as 1985, Donne and Fulton said at the end of a TRRL study into DRLs that:

“the use of even these effective aids is by no means a guarantee that a motorcycle will be seen in all circumstances and riders should be encouraged to recognise their vulnerability and ride defensively.”

BE PRO-ACTIVE: One of the points I repeat regularly is that conspicuity aids are entirely passive – they require the OTHER DRIVER to see us then take appropriate steps to ensure OUR safety. Here’s a tale I found on a motorcycle accident claims blog.

“I am a big believer in ‘hi-viz’ clothing. If it gets you noticed when you are out on your bike I think it is worth its weight in gold. I even went as far as ‘borrowing’ a hi-viz bag cover for my rucksack… wearing a bright white helmet and riding a bright white bike, I was pretty happy clocking up the miles safe in the knowledge that everyone and their dog will see me.

He then went on to describe his collision with a driver who didn’t see him!

Why the driver didn’t see the bike is immaterial (though it’s possible the bike was in a blind spot). What does matter is that having NOT been seen, the rider didn’t have any kind of plan to deal with the situation. He was relying 100% on his passive conspicuity aids and expecting to be seen. Unfortunately, the rider didn’t learn this lesson; instead he thought some extra lights would “draw the eye”. As we’ve seen, that’s not a guarantee.

Once we accept that expecting NOT to be seen is vital, then the importance of taking pro-active steps becomes obvious.  Remember, junction collisions are ‘two to tangle’ incidents – if the driver’s error sets up the circumstances in which the collision COULD occur, the motorcyclist still has to ride into it to COMPLETE the crash. In late spring 2018 I attended a Metropolitan Police BikeSafe course and one of the topics was how to deal with the threat from SMIDSY-style collisions. I was pleasantly surprised to discover that hi-vis clothing was a long way down in a discussion of possible strategies. Here’s what was discussed in the order it was mentioned:

  • move away from danger
  • see and be seen
  • lateral movement
  • slow down
  • hi-vis clothing
  • triangle of lights
  • horn

Notice that the use of hi-vis clothing and day riding lights – whilst promoted as a good thing – were not top of the list. To my mind, that’s an indication that the limitations of conspicuity aids generally. Instead, the course promoted pro-active responses; movement, setting up lines of sight, slowing down and using the horn. Once we begin to anticipate the need for pro-active responses, we are far less likely to be surprised when an emergency develops. Personally, I’d put reducing speed top of my own pro-active strategy list, because slowing down:

  • offers more time to do everything else including assessing the situation and deciding on our other responses
  • reduces stopping distance and the space required to swerve
  • mentally prepares us for evasive action and avoids us being surprised – No Surprise? No Accident!

Where did BikeSafe hear about lateral movement? As far as I know the original proponents are Duncan McKillop and Malcolm Palmer. Instructor and creative thinker Duncan McKillop proposed the ‘SMIDSY Avoidance Manoeuvre quite a few years back and produced a video of the manoeuvre which involves a ‘wiggle’ of the handlebars to make the headlight move. At least fifteen years ago, Malcolm Palmer, another former instructor, proposed what he called the Z Line. This involves changing position in the lane via a pair of smooth lateral movements forth across the width of the lane, first towards then away from the turning car. Both are aimed at creating lateral movement against the background to help drivers detect the oncoming machine.


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Last updated:

Wednesday 1 May 2019 – minor edit for clarity


de Craen, S.,  Doumen, M., Bos, N. & van Norden, Y. (2011) “The roles of motorcyclists and car drivers in conspicuity-related motorcycle crashes”, Stichting Wetenschappelijk Onderzoek Verkeersveiligheid SWOV, Leiden, Netherlands

Espie, S., Cavallo, V., Ranchet, M., Pinto, M., Vienne, F. et al. (2014) “Improving car drivers’ perception of motorcycles: innovative headlight design as a short-term solution to mitigate accidents” 10th International Motorcycle Conference, Sep 2014, COLOGNE, Germany. 11p.

Donne, G., L. and Fulton E., J. (1985) “The evaluation of aids to the daytime conspicuity of motorcycles” TRRL Laboratory Report 1137

FEMA (2004), “European Agenda for Motorcycle Safety”

Hole, G., J & Tyrrell, L. (1995) “The influence of perceptual ‘set’ on the detection of motorcyclists using daytime headlights” Journal of Ergonomics Volume 38, 1995 – Issue 7

Olson, P.L., Halstead-Nussloch, R., Sivak, M., “The effect of improvements in motorcycle/motorcyclist conspicuity on driver behavior,” Hum. Factors 23 (2), 237–248, 1981.

Paine. M., Paine, D., Haley, J. & Cockfield, S., (201?) “Daytime running lights for motorcycles”, Transport Accident Commission of Victoria Australia

Pintoa, Cavalloa and Saint-Pierre (2014), “Influence of front light configuration on the visual conspicuity of motorcycles”.  Accident Analysis and Prevention 62

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



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