Do bicycle lights make any difference to cyclist safety?

After a week where cyclist safety in London has hit the headlines, it might seem strange to look at this issue. I was pleased to represent the RDRF at the Bow roundabout protest organised by the London Cycling Campaign addressing issues about danger to cyclists and pedestrians there.


Spot the RDRF Chair at Bow roundabout protest (Photo London Cycling Campaign)

But actually the comments by the Commissioner of Transport for London on this subject – bike lights, that is – tell us a lot about the way “road safety” is thought of. Here are his comments:

I think the interesting thing is the safety record of the Barclays cycle hire bikes is very, very good and I’ll tell you why. Because they’re big, they’re quite slow and they’ve all got lights on the front and the back and the lights flash all the time – and actually, I wish every cyclist in London had decent lights on the front and the back.”

So let’s look at the evidence:


I have written before at some length about the safety record of people using these bicycles.   Now, the record might not be as good as I (or Sir Peter Hendy) make out. Nevertheless, they don’t seem to have a worse record than that of other bicycles being used in London, or as bad as some feared.

The reasons, as I and others – apart from Sir Peter – have suggested are:

  1. Danger in central London, contrary to some public perception, is lessened by slow motor vehicle speeds, the need for drivers to watch out on congested streets, and a number of cyclists creating greater pressure on motorists to watch out (Safety in Numbers, Critical Mass etc.)
  2. The reputation of “Boris Bike users” as incompetents (tourists unfamiliar with the streets or otherwise) can lead to drivers taking more care near them.
  3. Against these arguments concentrating on adaptive behaviour by motorists there is an argument that a lot of Bike Hire use is off the main highway (e.g. on paths In Hyde Park and elsewhere).

By contrast, Sir Peter suggests that injury and death to users is reduced because  Barclays Hire Bikes:

  1. Are big. I’m not sure how this works – possibly a more European style bicycle leads to users having a less frenetic style of cycling. The weight might lead to greater confidence on the part of the user, which is fine, but if anything tends to lead to more involvement in collisions. This may anyway be contradicted by the reputation for (some) Hire Bikes having inadequate brakes.
  2. Are slow. As stated in A, this could lead to a (no doubt welcome) more sedate, Continental urban style of relaxed cycling. But there is no actual evidence for this leading to lower casualty rates. There is not even a simple comparison of relative cycling speeds.
  3. Have flashing lights front and back. It is unclear whether Sir Peter is praising lights in general or flashing ones in particular. There is certainly no evidence that I am aware of the effects specifically of flashing lights – looking, for example, at whether flashing grabs motorists’ attention more than continuous ones, or leads to confusion as to precise location of the cycle. The flashing lights are not very obvious during daytime, so presumably the issue is lighting in the hours of darkness. Let’s consider the evidence on this matter.


  1. How likely are cyclists to be injured during the hours of darkness?

According to the latest figures compiled by Transport for London (for 2012), about 28% of London’s casualties arise from incidents occurring during the hours of darkness, the same as in 2011. In 2010 , which one can assume was roughly similar to 2011, 22% of pedal cycle casualties occurred during hours of darkness. In other words, using the usual “road safety” conventions, collisions for cyclists are less of a problem in hors of darkness than for other road users. Now, I am not saying we should follow this convention. All the differential indicates to us is what we know already – cyclists are less likely to tarvel in hours of darkness compared to hours of light compared to other types of road user. It just suggests that there may be no reason for looking specifically at these kinds of collision in particular.

The real issue is:

2. How significant is the non-use of cycle lights in collisions involving cyclists?

The best thing to do is consult the “contributory factors” as specified in the completion of STATS 19 forms by officers of the Metropolitan Police Service. As professionals know, these are limited by being the opinion of the investigating officer arriving at the scene of the incident after it has occurred. Nevertheless, it is the one source of evidence the authorities (such as Sir Peter’s transport for London) have, and in my view gives a good base – easily accessed by professionals through ACCSTATS – to inform us.

In this case, the relevant factor is number 506:

506 Not displaying lights at night or in poor visibility Poor visibility includes twilight or other poor light conditions and/or weather related conditions (e.g. rain or fog). Includes cyclists riding at night without lights as well as motor vehicle driver/riders who have failed to turn on their lights (whether intentionally or not).

This can be easily searched for, so I took a quick look (and it can be done quickly) at the last year’s Pedal Cyclist figures for the Borough I have been working for. The usual confidentiality applies, so I am keeping some of the information vague without changing any of the relevant statistical details. I can say that in a Borough with just under the average number of cycling casualties for a London Borough for 2012 (at just over 100), the total number where 506 was included as a contributory factor was – one, or under 1%.  Also, the proportion of incidents occurring in hours of darkness was actually over the 22% figure quoted in section 1 above at 27%

Of course, at this low level in other years, or in other boroughs, the number might go up. I would urge colleagues working in other boroughs – or stakeholders such as the local branch of the LCC – to try to look at this figure. Again, it really does not take long to access.

But there is more to it than this. The MPS have made a commitment to include factors not just on a “tick-box” basis, but if they believe they were actually contributory. In the one case I looked at there were other factors involved which I would have through more relevant than the non-use of bicycle lights.


3. What is the real significance of use or non-use of bicycle lights for cyclist safety?

If the use of lights seem to be of marginal relevance to cyclist safety on the brightly lit streets of London, why is it that their non-use can arise such ire? Why are they regarded as being of such importance?

Of course, I am not suggesting that cyclists should not use lights. And there may be situations on unlit paths, particularly to alert pedestrians, where – apart from the legal requirement – they are more than advisable.  All I am doing is what I have been suggesting in the last few posts (here, here , and here ) on Hi-Viz arguing that the stress on cyclists and pedestrians buying lights or Hi-Viz can act as a diversion from what needs to be done for real road safety – safety for all road users.

Safety issues are always culturally defined, essentially expressing power interests often – as with all ideology – without being aware of it. Recommendations for achieving safety on the road are often, if not always, picked out of a hat as what is thought to be “obvious”. We need to see them as not obvious at all – instead confirming the prejudices that bolster the current inequitable status quo.

At the very least we should expect that Sir Peter Hendy – probably the most important transport professional in Britain – makes his judgements based on some real  evidence.


3 thoughts on “Do bicycle lights make any difference to cyclist safety?

  1. AdamJackson

    “From my personal experience as a consistent commuter, I can say a set of quality front and rear bike lights can ensure great cyclist safety on and off road. My front bike light helps me see and hit the trail ahead quite neatly in the dark, even when I’m riding in extreme bad-weather conditions!
    Boosting the level of safety, the rear bike light makes me clearly visible to the motorists in the rear, eliminating any chances of my being hit from behind. It is important, however, that you find out reliable bike light units for maximum safety during dark hours.

    1. rdrf Post author

      Mr Jackson: I’m sure your company only sells quality bicycle lights.
      However, I don’t think that changes the evidence I give, and the context in which cycle lights exist. I have to say that (a) I was not talking about illuminating off-road train with a powerful front light and (b) a rear bike light does NOT “eliminate and chances of ..being (hit) from behind”

  2. Pingback: The Tour de France is welcomed to South Yorkshire – with this “road safety” rubbish | Road Danger Reduction Forum

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