16 Strategies – are dipped headlights effective DRLs?

SUMMARY – the 1975 Ride Bright campaign in London encouraged riders to ride lights-on in daytime… studies proposing safety interventions nearly all state that dipped headlights are effective in reducing collisions… but the claim is often based on laboratory studies or poor quality evidence from the roads… when legislation forced riders to switch on headlights in daytime in Malaysia, 80% complied but the overall reduction in collisions was only around 7%… the pan-European MAIDS study found that in collisions with drivers who did not see the motorcycle, 69% of riders were using their lights… we cannot rely on day riding lights to be seen…


About the time I started riding in 1975, the ‘Ride Bright’ hi-vis clothing and lights-on campaign was launched in London. As I’ve previously mentioned, it was the first time riders were first officially encouraged to turn lights on during daytime, and as we were told that they helped drivers see bikes, I thought I might as well try it out.

Motorcycle headlight.jpeg

As it happened, it didn’t go well. I discovered very quickly that a 1975 125 Honda with 6v electrics couldn’t run with the headlight on all day long in London without flattening the battery. Neither could my next bike, a 1972 Honda 250 since I fitted it with a 60/55w halogen conversion kit – the best that bike could manage was the pilot light. It was only at the end of 1978 when I bought a Honda CB400-F2 that I finally got a bike that was just about capable of powering a dipped headlight full-time.

You may be wondering if I found the switch from lights-off to lights-on riding having any effect on my personal safety? Good question, so here’s my own entirely anecdotal history. Lights-off, I had one very minor coming-together in my second year of riding, when the van ahead of me left into a side road, but used it for a U-turn, pulling straight back into my path. I almost avoided contact but fell over at rather less than walking pace. That bump aside, I avoided any collisions through several years of riding lights-off in London traffic. When I bought the CB400-F and could ride with a dipped headlight without worrying about the battery, I nearly always rode with lights on. Result? No SMISDYs either.

Motorcycle headlight on.jpeg

Even when I started riding full-time as a courier, I avoided any junction collisions, despite clocking up some serious miles in London. But other riders around me continued to have them. I picked a couple out of the gutter myself, despite the fact that “the driver should have seen me because I had my lights on”. I began to wonder whether lights really were as effective as we were told. And once I started working as a motorcycle instructor and had to tell other riders to turn them on for their safety when delivering CBT, I really started to personally question the advice. Nevertheless, it wasn’t until the summer of 2002 or 2003 that I turned my lights off again. Result? No SMIDSYs.

Ironically, that was the very time that the European Motorcycle Manufacturers’ Association (ACEM) made the switch to always-on lights on bikes via the simple expedient of removing the off switch. Here’s the statement issued from Brussels on July 20th, 2001:

The motorcycle and moped manufacturers represented by ACEM have adopted the following commitment: Starting from 2002, we, Powered-Two-Wheelers (PTWs) manufacturers represented by ACEM, will begin to introduce on the market models fitted with “Automatic Headlamp On”. By June 17th 2003, all new vehicles will comply with that specification. Automatic Headlamp On (AHO) specification means that headlamp will illuminate as soon as the engine has started. There are two main benefits from the adoption of AHO: 1. The conspicuity of PTWs is likely to be improved, 2. A growing number of countries require that PTWs are used with their headlamps on at all times, therefore there is a cost saving through specification harmonisation and simplification of switch-gear.

m headlampon1 89024

This was in response to the “Convention on Road Traffic” which took place in Vienna in November 1968. It recommended that signatory countries implement compulsory lights-on for motorcyclists during daytime. 21 out of the 25 European Member States have introduced legislation according to this recommendation.

Ironically, the page on the ACEM website which contains this statement has a photo of two scooters with their lights on. I wouldn’t say that particular photo is particularly compelling evidence for the effectiveness of day-riding lights.

Currently, I have two bikes, one with permanent lights-on and the other where the lights are nearly always off in daytime except in poor riding conditions. Since 2010, they have both been used for training so they both run over the same routes on a regular basis. I’ve put in around 80,000 miles combined. Result? No SMIDSYs. OK, my evidence is only anecdotal, and I could be a statistical freak, unusual and unrepresentative of the wider riding population. Watching some YouTube channels, I do wonder if that might be the case. So let’s look at the research on day riding lights and motorcycle conspicuity. Guess what? Things get complicated.

In literature reviews, particularly those written with a eye on casualty reduction, there are nearly always statements stating that dipped headlights used as DRLs are effective in reducing crashes. Here’s something typical, taken from a 2014 paper entitled: “Influence of Front Light Configuration on the Visual Conspicuity of Motorcycles”:

“By enhancing the visual contrast with the background, DRLs [day-riding lights] make motorcycles more conspicuous. Many accident studies agree that DRLs improve motorcycle safety and help in significantly lowering fatal motorcycle accidents.”

Another very recent literature survey study by Davoodi & Hossayni (2015) makes an even more unequivocal claim:

“Switching on the motorcycle headlights will guarantee that it will be distinct from the background, though the light level is low.”

(My bolding by the way). It all sounds quite conclusive. And it creates a chain of belief:

  1. high level road safety bodies, from the global World Health Organisation via pan-national groupings such as the EU, down to national and regional level bodies, are keen to reduce motorcycle casualties, either citing the cost in human lives or, more prosaically, the cost to the public health
  2. some national and state-level governments have created legislation enforcing lights-on for riders during daytime, others have mandated always-on lights that the rider cannot turn off
  3. official road safety campaigns advise motorcyclists of the safety benefits of riding with dipped headlights as DRLs during the daytime
  4. organisations like the police, accident investigators, magistrates and judges and insurance companies will take the position that riders involved in crashes who were NOT using dipped headlights as DRLs must have contributed to their own problems
  5. riding organisations, the authors of better riding books and magazine journalists promote the use of dipped headlights during daytime
  6. and at the bottom of the chain, ordinary motorcyclists like you and me are under pressure to conform and to ride lights-on

Perhaps it’s not surprising that many riders (although not all) accept the advice, often without question. Here’s what the writer on a unofficial safety website has to say:

“Almost any type of light added to the front of your bike will serve the purpose of making you more visible to oncoming traffic.”

So what are those claims for the effectiveness of DRLs based on? The answer is that they reference results in laboratory studies, field trials and analysis of accident data.

Are laboratory studies reliable evidence? The use of photographs and videos of is a common method of testing the effectiveness of conspicuity aids in the laboratory. A study might show a number of volunteers photos or video of a number of motorcycles and riders with or without the various kinds of conspicuity aids under examination. Each subject’s response is recorded and deductions are drawn about how effective the aids might be. These studies are can be set up quickly and relatively cheaply, and often produce apparently-conclusive results.

However, we need to remember that the results ONLY APPLY TO THE CONDITIONS IN THE TRIAL. It’s usually assumed that laboratory and trials produce results that will apply in real life but fundamentally, photographs lack movement, which we know to be an important ‘attractant’ that would draw a driver’s conscious attention towards the motorcycle in the traffic stream. Even when displaying high-quality video on a large high definition screen, it’s debatable if a flat 2D picture is relevant to the real-world task of scanning and processing the visually-complex and dynamic 3D environment we actually encounter in the real world. Certainly Helman et al (2012) warned about studies where “inferences [are] made from findings in simplified laboratory settings and applied to the usually more complex reality of the situation in the real world”.

But some of the laboratory studies don’t even use photo-realistic scenes. Some have used poorly ‘photoshopped’ images or CGI models which are patently unrealistic. Here’s one:

Badly photoshopped day riding lights

It’s snipped from the text of a research paper claiming to find experimental support for the use of permanently-on turn signals from Victoria, Australia. Even at the poor resolution in the PDF, you can see the crude pixels representing the yellow ‘lights’ and how the headlight has been blanked out with a grey blob – the gleam of the dipped beam is visible on the road surface – which isn’t even the same colour as an unlit headlight lens. Colour saturation is almost non-existent so that the photo is monochrome, with only shades of grey. If that really is the standard of the photos that were presented to subjects, it’s hardly surprising subjects found the bright blobs stood out.

Other papers have used photos of bikes with real lighting systems. But in one study, the motorcycles were parked at the side of the road – they were both clearly visible and obviously not part of the traffic stream. In another, the researchers specifically asked the subjects to pick out the motorcycles. One more tasked the subjects with finding ‘vulnerable road users’. In both cases, this ‘primes’ the subjects so they know what to look for, and predisposing them to see the motorcycles within the scene. It skews the results. Rather better are a few recent high-quality simulator studies where the ‘driver’ has a more immersive experience and doesn’t know the object of the exercise with responses being followed by eye-tracking hardware.

The second option, field trials could prove more reliable. Earlier, I mentioned a study where a motorcycle was ridden around and around a roundabout by a researcher to see how often vehicles pulled out in front of the bike. (The answer, by the way, was none.) Although the study is old, the plus is that none of the drivers realised there was any kind of experiment going on. Not too surprisingly, this kind of trial has fallen out of favour because of the risk to the experimenter riding the bike! Practical trials are now more likely to be held on closed test tracks. Whilst the movement of the machine is realistic, it’s difficult (if not impossible) to recreate congested street scenes, which arguably limits relevance to real-life urban traffic. These studies are more likely to be of use in examining detection of motorcycles at a distance. A few in-car studies have used sophisticated eye-tracking hardware to see what the subject is actually looking at – these can be used to monitor how drivers detect motorcycles.

The third option is to look at road casualty statistics. One such study from New Zealand compared the injury rates of riders using conspicuity aids and those who weren’t. The authors concluded there were positive results in terms of injury reduction for riders using conspicuity aids. But, and it’s a big but, they weren’t specifically looking to see if DRLs made motorcycles more conspicuous – just whether the riders who did crash got hurt. Yet the study is sometimes cited in literature reviews as supporting the effectiveness of DRLs in terms of increased conspicuity. Other researchers have questioned the methodology and pointed out the conclusions are inconsistent with the results.

Driver looking 2

We could check casualty statistics  before and after the introduction of a law making it mandatory to use DRLs. If the lights-on shift was effective, we’d see an immediate reduction after the change. A useful – and relatively easy paper for the non-scientific reader to absorb – is a 2012 TRL paper (Helman et al) with the exhausting title of “Literature review of interventions to improve the conspicuity of motorcyclists and help avoid ‘looked but failed to see’ accidents”. It highlights the disadvantages of laboratory studies and the advantages of crash statistics:

“It should however be noted that such analyses [of road casualty statistics] do have the advantage that they seek to measure directly the impact of an intervention in the real world and thus do not require that inferences be made from findings in simplified laboratory settings and applied to the usually more complex reality of the situation in the real world.”

One such piece of  lights-on legislation was enacted in 1992 in Malaysia. A second law came into force in Singapore. Helman et al (2012) concluded:

“The data collected within each study showed that there was a significant reduction in the number of conspicuity-related collisions following the implementations of the laws.”

So I looked one up. It’s entitled: “Preliminary Analysis of Motorcycle Accidents: Short-term Impacts of the Running Headlights Campaign and Regulation in Malaysia”. Here’s how the Malaysian study described the pre-existing problem:

“About 50 per cent of motorcycle accidents in this country occur at junctions and 38 per cent of the incidents involve other vehicles crossing motorcycle’s paths. In most cases, motorcycles are found to be moving straight ahead. Daytime accidents constitute about 73 per cent of the motorcycle accidents and about two thirds of the riders involved in multiple accidents are on their right-of-way.”

If you’re at all familiar with crashes in the UK and the EU – where approximately 66% (DfT 2015 figures) and 55% (from the MAIDS study) respectively of motorcycle accidents occur at junctions – then the circumstances will sound eerily familiar. So it’s not unreasonable to assume that the underlying issues are much the same, despite the very different driving conditions in Malaysia and Europe. So what was proposed to tackle the collisions?

“Based on this analysis, improved motorcycle conspicuity was proposed, and a nation-wide ‘running headlight’ Campaign and Regulation were implemented in July and September, 1992, respectively.”

In other words, almost 20 years after the UK offered riders the lights-on advice, Malaysian motorcyclists were ordered to turn their lights on in daytime. Over 80% complied immediately. And the results?

“Detailed analysis on the impact of running the headlight campaign and regulation in the districts of Seremban and Shah Alam revealed that there had been a sizeable drop (6.9%) in multiple vehicle-day time motorcycle accidents in the study areas.”

More specifically…

“Conspicuity-related accidents while motorcycles are going straight ahead or turning on the right of way, MSTOX, were found to have dropped significantly immediately after the campaign by about 22%.”

[MSTOX? I had to look that up. It’s YANA (yet another new acronym). It means ‘motorcycles moving straight or turning when other road users cross’.] I’ve emphasised the word significantly. You’ll recall that the TRL paper stated that the results of the lights-on legislation led to a “significant reduction in the number of conspicuity-related collisions”.

So here’s a question. What do we mean by ‘significant‘? On the one hand we’re measuring results numerically so it could mean statistical significance. In other words, the result measured by data gathered is not likely to have occurred randomly or by chance, but is instead likely to be attributable to a specific cause – in this instance the legislation. That’s certainly a reasonable conclusion from the study.

But the term significant has a broader interpretation, meaning ‘worthy of attention’.  From the wider perspective of road safety, I’d certainly argue these results are of significance because a 22% reduction in casualties is a great return on investment, particularly as the only cost to the country is drafting, passing and enforcing the legislation.

But from your perspective and from mine, from that of the rider, are the results of significance? Are they worthy of our attention? The points I’m going to make should serve a caution in how you and I view these results and how what is meant by having significance varies with perspective.

Firstly… if 22% – or just over one-in-five collisions – where “conspicuity was judged to have been an issue” were prevented by DRLs, then what about the collisions where conspicuity was an issue yet the lights DID NOT HELP? Obviously 78% – or just under a four-in-five crashes –  still happened when the driver did NOT see the motorcycle. From your perspective and mine, I’d argue that number is of considerable significance.

Secondly… what exactly is meant by collisions where “conspicuity was judged to have been an issue”? Presumably, it means ONLY those collisions where the motorcycle WAS in a place it could have been seen in the moments before the collision. We know that junction collisions include:

  • ‘looked but could not see’ crashes where the rider wasn’t in sight until the moment of collision (maybe hidden by other vehicles whilst filtering, by pedestrians or roadside furniture, or by the car’s own structure) – evidence suggests that the motorcycle is actually out of sight at some point in the run up to the collision in one-in-five junction collisions, perhaps as many as one-in-three
  • ‘looked, saw and misjudged’ crashes where the driver spotted the bike and simply made the wrong decision

If that’s the case, that would explain why the OVERALL reduction in collisions was a much lower figure – around 7%. That’s still of statistical significance and would still be welcomed as a road safety success. But what about the rider’s perspective? Would you or I see a 7% reduction in the odds of meeting a driver about to make the ‘looked but failed to see’ error as making riding significantly safer? I doubt it. Sure, it’s better than nothing, but it’s nowhere near the benefits claimed by Davoodi & Hossayni (2015) who said, you’ll recall, that: “switching on the motorcycle headlights will guarantee that it will be distinct from the background…” 

And here’s another problem. Although it might seem obvious that before-and-after data must be directly linked the change, it’s not necessarily the case. The TRL literature survey noted that:

The nature of conducting comparison studies of road casualty data means there is an inherent difficulty in mitigating completely the potential confounding factors, as there will often be changes over time or between locations that may partially  explain any changes seen in data before and after the change of interest. What must usually be attempted is to balance the data to take into account such confounding factors, which in itself presents challenges as there is introduced a certain degree of subjectivity as to what an appropriate balancing approach should be.

In other words, there may be other factors affecting the results measured. Not all riders were recorded as having turned their lights on, so did the riders NOT using lights crash more often than the riders using their DRLs? We don’t know. What about riders who used lights before the change – what was their crash rate before and after? Did the positive result come increased awareness – “wow, there are a lot of bikes on the road!” – rather than increased conspicuity. What happened longer term when drivers got used to bikes with lights on – were the benefits maintained or perhaps the lights lost the ‘wow’ factor? That’s been suggested as happened with hi-vis clothing. What happened when cars started using day driving lights – that’s a question I’ll be coming back to.

Do we get comparable results elsewhere? It’s reported that the 1982 Austrian hard-wiring law “reduced the number of victimised motorcyclists in daytime multiple accidents by about 16%”. The Austrian and Malaysian results may be at the high end of the scale. Although negatively critiqued – which means we shouldn’t regard this Australian study as fully reliable either – Hentlass (1992) concluded that in daytime multi-vehicle motorcycle accidents occurring in the late 1980s , DRLs had the potential to affect about 2% of motorcycle collisions in Victoria.

Ultimately, the conclusions drawn by any research depends on how the researchers understand the issues and what assumptions they make about what was, and what wasn’t, relevant. What happens if different researchers look at the same data?

An example of this problem is presented in two research papers from the 1980s, both of which were published in the American Journal of Public Health and used broadly the same data, yet produced conflicting results.Muller (1982) examined motorcycle fatalities in the 50 US States and the District of Columbia between 1975 and 1980, seeking to determine if there were overall differences in the rates of motorcycle fatalities between states where daytime headlight use was mandated and those in which it was not. The analysis suggested that there was no significant difference between the two conditions.Zador (1985) conducted ostensibly the same study (although using data from 1975 to 1983) and found that there was a significantly lower fatal accident rate in states where daytime headlamp use was mandated.The difference in these findings appears to arise due to the assumptions made in each study as to which data should be included or excluded, and how to balance for confounding factors. For example, Muller excluded single-vehicle crashes from the analysis, but Zador included them, arguing that a fifth of all single-vehicle crashes result from attempts by motorcyclists to avoid other vehicles and so related to conspicuity.

In other words, what was essentially the same data was taken by two sets of authors, given different analyses, producing totally different results!

Can studies carried out in one country be applied to another? It’s usually assumed to be true, and we do know that the SMIDSY collision happens wherever cars and bikes share the road. On the other, there are significant differences from from nation to nation and even from state to state in big countries like the USA. The density of motorcycles within the traffic stream varies dramatically. In Malaysia, according to 2009 World Health Organisation figures quoted in the TRL paper, powered two- and three-wheelers made up 47% of the traffic (it could have been even more in 1992), yet motorcycles in the UK are less than 1% of traffic. Look at the two very different environments in the photos.

Can we be sure results from a jurisdiction where almost every other vehicle is a motorcycle or three-wheeler can apply to our own roads where fewer than one in one hundred vehicles is a bike? With so many two- and three-wheelers in the traffic stream in Malaysia, how many of the recorded collisions actually involved a pair of them? That would be interesting to know!

To settle the debate once and for all, what we need is the accident data would allow us to answer a pair of simple questions:

  • how many riders have ‘looked but failed to see’ collisions whilst riding WITH lights?
  • how many have collisions riding WITHOUT lights?

As far as I know – and I’m open to correction – we don’t have that data. About the closest I can find is from the pan-European ‘Motorcycle Accident In-Depth Study’ of motorcycle crashes (MAIDS). That study found that in collisions where the primary contributing factor was the failure of another vehicle operator to detect the motorcycle, headlights were in use in 69% of these accidents (ACEM 2004). We don’t know the overall proportion of motorcyclists who were using DRLs at the time of the study, which means we still can’t say if collisions were evenly distributed between riders using DRLs or if there was some positive benefit. Nevertheless, it is evident that at the time of that study, large numbers of motorcycles with lights-on were still not being seen by other road users.

So perhaps we should pay more attention to historical data from the UK. Pre-1975, the use of DRLs must have been close to zero. Although no-one seems to have recorded the growing proportion of motorcycles with lights-on, by the time of a 1986 national survey into the characteristics and attitudes of motorcyclists, “57 per cent of respondents agreed that ‘Motorcyclists should use their headlights in daylight'” (Hobbs et al, 1986). Although I cannot find up-to-date figures, my own observation is that in London at least, the majority of motorcycles now use DRLs, probably because they are permanently-on, on new bikes.

So… if:

  • no other factors had changed
  • DRLs had a significant benefit in terms of crash reduction

….we’d expect to see a reduction in the numbers of ‘looked but failed to see’ SMIDSY collisions at urban junctions. We’d expect to see an increase in the proportion of other sorts of crashes.

Unfortunately, the latest data reveals the urban SMIDSY collision still dominates and makes up two-thirds of urban crashes. We cannot honestly point to the evidence from UK accident statistics and say that DRLs have had anything more than a minor positive effect.

What about the riders NOT using DRLs when the majority do? Wouldn’t they have a higher crash risk if DRLs had an important role in reducing ‘looked but failed to see’ collision? In response to concerns, Hole & Tyrrell (1995) investigated whether “drivers might scan for lights rather than for motorcyclists per se”. What they found in a laboratory experiment was that when 60% of PTWs used DRLs, the bikes with lights were more quickly detected than those not using lights. They suggested their subjects developed a ‘set’ for responding to motorcycles on the basis of headlight-use, even when this was an unreliable guide to the motorcyclists’ presence. Interestingly, their results did not show an increased collision risk from NOT using DRLs.

What about outside the UK? Wherever we look, whether lights are voluntary or compulsory, across Europe, North America, Asia and Australasia, junction collisions remain a significant problem for riders and the latest research is becoming rather less certain about the positive benefits. In a literature review in the section entitled “Conspicuity of the motorcycle: Daytime Running Lights (DRL)” which referenced a number of different papers published over thirty years,  de Craen et al (2011) concluded:

“Many studies have been conducted on the detection of motorcycles with or without DRL. In general, DRL enhances the conspicuity of motorcycles during daytime (e.g. Thomson, 1980; Torrez, 2008). However, most studies report this effect to be dependent on the specific situation, e.g. on the characteristics of the environment (Hole, Tyrrell & Langham, 1996), the motorcycle’s speed (Howells et al., 1980 as cited in Pai, 2011), or the weather conditions (Pai, 2011). Hole and Tyrrell (1995) concluded that DRL is most effective at large distances between motorcycle and observer and that in urban environments DRL is not as effective as in rural environments. In 1996, Hole, Tyrrell and Langham concluded that the effectiveness of DRL is dependent on the amount of clutter in the background. This could explain the smaller effect of DRL in urban environments found in the 1995 study.“Some studies report that the use of DRL decreases the risk of fatal or serious injury crashes of motorcyclists. However, these studies have some methodological problems that were not properly addressed. Therefore, the changes in motorcycle crashes could be minor.”

There’s an interesting observation for you – that DRLs are “most effective at large distances between motorcycle and observer and that in urban environments DRL is not as effective as in rural environments”.

Headlight in shade

So let’s sum up. Motorcycle conspicuity and the use of DRLs has been under the spotlight since the 1970s when the earliest research supported safety campaigns which told motorcyclists to turn on their dipped headlights during daytime, and that by doing so, we’d make ourselves more conspicuous, and that we would in consequence be safer. But we don’t see big drops in the absolute numbers of ‘looked but failed to see’ collisions. Recent European data tells us that headlights were in use in 69% of collisions. In the studies referenced above, the most optimistic claim based on analysis of real-world collision data states around 20% of ‘looked but failed to see’ collisions are prevented. The most pessimistic suggests only 2% of crashes would be prevented.

If we assume that a 10% reduction is more likely (and I still think this is optimistic) then for every ‘looked but failed to see’ crash prevented, nine out of every ten will still happen. It’s hard to comprehend how Davoodi & Hossayni were able to state so unequivocally that “switching on the motorcycle headlights will guarantee that it will be distinct from the background” – it’s a reckless and virtually unsupportable claim. From what I’ve read, AND FROM THE POINT OF VIEW OF AN INDIVIDUAL MOTORCYCLIST, I would go no further than to say that their use moves the odds slightly in favour of the rider:

  • dipped headlights used as DRLs make motorcycles somewhat more likely to be seen but are in no way a guarantee that a driver will spot a PTW
  • where there is a benefit, it’s more likely to be on faster, rural roads than in urban areas

My SMIDSY-dodging courier experience demonstrates the key point – just like hi-vis clothing, DRLs are a passive aid. Passive aids ONLY have a benefit IF the other road user firstly SEES the motorcycle, then takes a COURSE OF ACTION which avoiding putting the rider at risk. Even when my lights are on, I assume I won’t be seen, and ride accordingly. It’s absolutely vital we don’t fall into the “I had my lights on, the driver should have seen me” trap.

Biker, Think.

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Last updated:

Friday 30 April 2021 – new information added about the “Convention on Road Traffic”, Vienna, November 1968 recommending compulsory lights-on for motorcyclists during daytime
Wednesday 1 May 2019 – minor edit for clarity
Friday 14 December 2018 – added results of Austrian DRL legislation

References:

Davoodi, S., R. and Hossayni, S., M. (2015) “Role of Motorcycle Running Lights in Reducing Motorcycle Crashes during Daytime; A Review of the Current Literature”. Bull Emerg Trauma. 2015 Jul; 3(3): 73–78

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

Helman, S., Weare, A., Palmer, M. & Fernandez-Medina, K. (2012) “Literature review of interventions to improve the conspicuity of motorcyclists and help avoid ‘looked but failed to see’ accidents”. TRL Road Safety Group 5 PPR638

Hentlass J., (1992) “Literature Review for Inquiry into Motorcycle Safety:, Appendix to Inquiry into Motorcycle Safety in Victoria, Parliament of Victoria, Australia

Hobbs, C., Galer, I., and Stroud, P. (1986) “The characteristics and attitudes of motorcyclists: a national Survey” Transport and Road Research Laboratory Department of Transport Research Report 51

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 https://doi.org/10.1080/00140139508925191

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

“Automatic Headlamp On” ACEM – The Motorcycle Industry in Europe – ACEM – The Motorcycle Industry in Europe

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Photo credit Paul Townsend
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