Sunday, 16 September 2012

The London Assembly and Safety in Numbers

Last Tuesday's meeting of the London Assembly's Transport Committee, which included its second session examining cycling safety, was quite fascinating. The previous session had allowed a considerable number of people to have their say, including representitives of the LCC, CTC, British Cycling, and the Cycling Embassy of Great Britain (including me). In this second session the speaking guests were restricted to a few "experts": Dr Rachel Aldred, Director of the Sustainable Mobilities Research Group at the University of East London; Karen Dee, Director of Policy at the Freight Transport Association; Ben Plowden, Director of Planning for Surface Transport at TfL; Steffen Rasmussen, Head of Traffic Design, Municipality of Copenhagen; and Roelof Wittink, Director of the Dutch Cycling Embassy. 

To have had these two last mentioned addressing the Aseembly Members was I think particularly remarkable. For people like me have been saying to London local government for decades that we need to get some experts from those European countries where very high cycling rates have been achieved to explain to us what is actually needed (if not to put them actually in charge of making the necessary changes, which would be even better). This was the first time, to my knowledge, that something like this has actually happened: that any level of UK Government has sought advice on cycling from experts from the continent. This is a very welcome and long overdue development.

The exchanges can be heard on a (very long) webcast available on this page*. Another blogger has already commented on the contribution to the debate of Richard Tracey, Conservative AM. I'm not going to give a full account of the session here, but I've transcribed, in a very approximate style, missing a lot out, but keeping, I hope, a fair essence of what was said, a few points that I felt were highly significant from around the 1 hour 50 minutes mark to the 2 hours 10 minutes mark.

In this section of the debate, Assembly Members were asking the experts about trends in cycling levels and cycling safety in London and elsewhere, and about the concepts of "Critical Mass" and "Safety in Numbers". Ben Plowden, questioned at length on the London statistics, had held to the the view that safety for cyclists in London was getting better over time, taking into account the increasing number of cyclists, with the particularly large number of deaths last year (16) being possibly only a statistical "blip".
Darren Johnson AM, to Roelhoff Wittink: 
In the Netherlands there's been a growth in cycling, but there hasn't been a comparable growth in casualties as there has been in London. Could you say something about that? 
Cycling grew in the 70s and 80s because of our policies, and safety increased along with it. It has to do with the level of cycling but also with the measures that you take. 
Do you put it down to a critical mass of cyclists on the road? 
That's a very important  explanation, but, also, if you move people from driving to cycling, you have fewer people causing the troubles for cyclists on the roads. Segregation where you have more than 30km/h is very important. We also disconnect the main routes for cyclists from the main routes for cars, so you have less intersections where you have both high volumes of cyclists and high volumes of cars. I had a look at some your roundabouts, some kilometres from here. The roundabouts we have in the Netherlands slow drivers down but your roundabouts allow drivers still to have a speed of 40km an hour – that's really impossible for cyclists. 
[Steffen Rasmussen is asked to comment] 
There might be something about a critical mass of cyclists, we need more reasearch on the issue of critical mass, I don't know of any research specific to Europe. Infrastructure is extremely important, and we have a lot of work still to do in the City of Copenhagen. 
[Comments are invited from others, and Racheal Aldred speaks] 
You expect trends in deaths to get better year on year because health care gets better, but when you compare modes, you see it's becoming safer year on year for those in cars, but for cyclists the improvement is much less. I think it's important to compare casualty rates for different modes of travel. The casualty rates for London per kilometre is 30 times greater for cyclists than for car drivers. That's a very big disparity. Comparable figures from the Netherlands (from SWOV) gives you a figure of 4 to 1. It's around 25 to 1 for the UK as a whole. There's an issue there, as we are trying to get people to switch from cars to cycling. In the Netherlands last year there were 4 right-hook deaths in the whole of the country, with their much higher cycling rate. They are doing something much better.  
I want to say something about "Safety in Numbers". This idea has been much discussed. A paper by Jacobsen in 2003 was the original use of the term "Safety in Numbers". He used five data sets, but three of them are cross-sectional, so there is a methodological issue; you can't tell whether you are getting the number of cyclists from safety or the safety from the number of cyclists, because it's at the same time. He used two other data sets that are longitudinal that give you a better insight into that. One of them was from the Netherlands, where he found as you got more cyclists, you did indeed get safer cycling, if you look at at a time series. Interestingly, the other data set was from the UK. He found but data for the UK was very different. It was all over the place; it wasn't showing a consitent improvement in safety related to the number of cyclists. I could talk about this at much greater length than I think you want to hear. There are many mechanisms likely to be going on. I don't think you can say more cyclists always leads to safer cycling. There are different mechanisms going on. It depends on the culture, the infrastructure, the legal context. 
Could it be that the cycling rate is still too small in London to make a difference, we haven't reached that critical mass where the risk becomes acceptable? 
What is an acceptable risk level is decided socially. Do we say that at 1%, 2% 5% cycling it gets acceptably safe? It's confounded because as you get more cycling you get more pressure for better cycling conditions, so that will feed into safety. There's a lot of things going on. 
Ben Plowden: 
I've been cycling in London for many years. You used to see hardly any other cyclists on the road, but it's very different now. I think you can get a "virtuous circle" where you get more cyclists, and improved behaviour by road users, leading to a "tipping point" where things change significantly. Now I see in some places 40 cyclists at every cycle of the lights. That must be having an effect on people's perception. 
I think it is worth noting that Jacobsen's original idea of "Safety in Numbers" was in terms of presence on the roads, not in terms of a log-term cultural shift. In Grays Inn Road, when you've got 40 cyclists around you during rush-hour, it might be relatively pleasant, but late at night, when there are no other cyclists on the road and the traffic is flowing freely, it's a very different experience. You need continuity and consistency.

So, to sum up, it seems that the Director of Planning responsible for cycling in London, and perhaps the Green Assembly Member, expect cycling to automatically become safer as more people do it. On the other hand, those who have studied the subject in detail, and have real experience, know that cycling has to be made safe though the provision of infrastructure that separates cyclists physically from dangerous and intimidating motor traffic.

Personally, having studied the Netherlands, I think there is such a thing as a "critical mass" of cyclists. But it is something quite different to what all these people are thinking of. It is a phenomenon that occurs far further down the line of cycle growth than the regime they are considering. It's not at 2% modal share, or 5%, or 10%. And it's not a physical, "presence on the road" thing, it's the political phenomenon that Rachael Aldred alluded to. It's the "Dutch Effect": what happens when you have, probably, more than 51% of the entire population cycling regularly: a point that was passed in the Netherlands long ago (it is possible participation has never been below this level in the last century).

When you are in this happy situation, absolutely anything is possible for cycling. No expense is too great, no rearrangement of the urban or rural fabric too extreme to be worth doing for the comfort and convenience of cyclists, because virtually everybody wants it, there is little controversy about it, it is accepted, rather like massive state funding of health, railways, and roads for cars are accepted and non-controversial in the UK. I think that until we reach that happy state, politicians who wish for more cycling are going to have to be very pro-active and visionary. It will be vain for them to hope for a magical "tipping point" at some far lower level of cycling uptake, where it will all become easy and semi-automatic. It won't be like that. It will always be a struggle.

As a  post-script to this discussion, I quote from a recent post on the CTC blog written by Roger Geffen, the CTC's Campaigns and Policy Director. He writes about a report on cycling safety in various European countries by the European Traffic Safety Council (ETSC):

ETSC rightly recognises though that you cannot measure cycle safety simply by looking at casualty numbers. Comparisons should be based on the risk of a casualty per mile cycled (or per trip, or per hour – but at any rate, it should be relative to some measure of cycle use). Otherwise you fall into the trap of claiming that Dudley and St Helens are far safer for cycling than Cambridge(!), or, even more absurdly, that Britain is far safer than the Netherlands (as Road Safety Minister Mike Penning claimed in Parliament), simply because places with low cycle use obviously have fewer cyclist casualties. That doesn't mean they are "safer" - indeed, CTC's "Safety in numbers" evidence shows the exact opposite. 
ETSC then shows that Britain is one of only 3 EU countries to measure cycle use at the national level on an annual basis – the others being (you guessed it!) Denmark and the Netherlands. Two others, Sweden and Norway, also measure it reasonably frequently. ETSC compares cycle use and cycle safety in these five countries and, once again, finds clear evidence of the “safety in numbers” effect: cycling is safest in the places with highest cycle use. 
CTC has documented this relationship in the past, based both on a comparison of EU-wide data from a wider range of dates, and of figures from within Britain. However, until now our only source of comparable data on local cycle use within Britain was the national census, which only comes out every 10 years and covers cycle commuting only. It was good enough to show the “safety in numbers” relationship exists, but not to compare how local authorities are actually performing. 
Unsurprisingly, ETSC’s report shows that Britain is performing worst of the 5 countries in their comparison, in terms of both cycle use and cyclists’ safety. But hey, at least we are measuring this!
Here's my question: I've pointed out before how the Director of the Dutch state road safety organisation, SWOV, has said that the simple interpretation of "Safety in Numbers" – that simply having more cyclists automatically gives you safer cycling – is wrong. You have read the exchanges above. You may even have read this essay on the As Easy As Riding A Bike blog on the subject. And you may have read Freewheeler's biting satire Minutes of the Crapborough Cycling Campaign:

Also in Holland they have safety in numbers. Sam said if we could just get more people cycling in Britain then everyone would become as safe as in Holland.

Sam then showed a very interesting diagram showing how safety in numbers works in Holland. Here we see a typical Dutch street scene where a lorry driver pauses before turning. Dutch lorry drivers are used to being surrounded by lots of cyclists, which is why they take extra care at junctions.

My question is:

Is Roger Geffen of the CTC the only person in UK cycle campaigning who still believes in the simplistic nonsense of "Safety in Numbers"?

*Unfortunately the GLA website uses a Windows Media format for its videos that doesn't normally play correctly on Macs (it may be silent). The solution I have found is the free, open-source program VLC, which does play these videos correctly on the Mac.


  1. I suspect that Roger Geffen is not only person in UK cycle campaigning who still believes in the simplistic nonsense of "Safety in Numbers", there are a few other. Mainly those who don't want to admit that it is infrastructure that makes cycling safe and only when it is safe will you get higher modal share for cycling.

  2. In your previous post on the topic, you say <<["safety in numbers" theory] does seem to be largely confined [in the English-speaking world]>> (sorry for altering so much your quote), and I was largely of the same opinion. Therefore, I have been greatly surprised to discover the following French study, that paraphrases almost step by step the various English language studies on the topic (benefits outweigh risks by a factor of 20 to 1, safety in numbers, less exposed to pollution than car occupants, etc.), to an extent that I suspect a research grant scam.

    I haven't read it in depth, but I found this article that summarises it:

    If your French is up to scratch, I figured you could find it interesting.

  3. I can't comment on DrawingRings blog without setting up some sort of account and logging in (which I'm too lazy to do) so I'm commenting here. However, I think it has some relevance to the safety in numbers argument.

    On his 11th Sept blog, DrawingRings shows a graph indcating a 30% decrease in car usage in the last decade. This seems to correlate quite nicely with the change shown on the "KSI per 100000 cyclist journey stages" figure in the current blog (17th Sept). In fact if you overlay the two graphs and rescale, the correspondence is quite striking.

    So you might hypothesise that the data suggest that the KSI rate for cyclists has simply been a function of the number of cars on the road over the past decade. Cyclist numbers may not actually be a significant factor in London. If that is the case, and if you want to decrease the KSI rate beyond this situation (say to the levels enjoyed by the Netherlands and Denmark), and are unwilling to adopt measures to decrease the number of cars in your jurisdiction, then you have to separate cars and bicycles. At bottom, I think this reinforces your point about London being some considerable distance from achieving critical mass.

    The corollary of course is that if e.g. TfL (to pick one example at random) wish to claim success in road safety, they can be proud that that they achieved it by reducing the numbers of cars on the roads. Let's have more of the same please!

  4. "It will be vain for them to hope for a magical "tipping point" at some far lower level of cycling uptake, where it will all become easy and semi-automatic. It won't be like that. It will always be a struggle.

    Well. Lots to do then ...

    Thanks for this David, I particularly liked Rachel Aldred's comments about "it's all really complicated!". Well it is. I've been persuaded (largely by David Hembrow's writing) of the primacy of infrastructure, but it's useful to remember that infrastructure has to be (a) done correctly (b) accompanied by lots of other stuff - there *is* a place for the "soft measures" (though on their own there will do little). This has to keep being repeated to politicians.

    This is on my mind at the moment because I'm going to visit Milton Keynes on Saturday. It has cycle infrastructure that is *almost* correct. But not quite. And there are lots of other things that were not quite right, and were not done when the place was designed - so MK doesn't have anything like the amount of cycling it should have.