Considerate Cycling 31: Cycling Safety Data. More Questions Than Answers

Dighton Street Looking South West

Last month, The Department for Transport published an extensive set of comparison tables of road safety data from all of the English Local Authorities. There are hours of fun to be had clicking around the regions, looking for surprises and trying to make sense of it all. Tables can be created dynamically on line and downloaded as comma-separated variable (csv) files.

What I have done is focus on Bristol, where I live, walk and cycle. I chose to move to Bristol from Leeds a couple of years ago, partly because I don’t have and don’t want a car. Bristol is a compact city with less than half a million people, and walking and cycling are the most effective ways of getting about for most of my journeys. When I see people trying to use cars for similar trips I sometimes wonder why they bother. I suspect some of them ponder the same question.

Maybe safety and security are part of the story? What follows compares Bristol with Leeds, and the other core cities outside London and with two county authorities bordering on Bristol. I hope that I can make some sense of the comparisons, and say something about the way that comparative data ask more questions than they answer.

Look at Figure 1 for example. Note that Bristol is sown in bright red. I have left London out of this because London is so much bigger and because London has a completely different set of problems with very different structures. As far as mileage goes Bristol is a tiddler. Only Newcastle and Nottingham have less. There’s a question right from the start. Wasn’t Bristol the place where they made Concorde? Surely it must be huge? Maybe it should be? The elected Mayor George Ferguson probably wishes it was. But the fact is that Concorde was made in South Gloucester and at least some of the people who worked on it lived in North Somerset. Commuter village Backwell in North Somerset is only 15 miles by road (mostly Highways Agency roads) from Filton Airport in South Gloucester. To all intents and purposes there are both part of Bristol, in the same way that Bramhope and Rothwell (though different) are both parts of Leeds.

Figure 1 Total length of roads managed by each of ten local transport authorities 2012

Another view of road mileage can be seen in Figure 2, which shows how many yards of local authority road there are per person.

Figure 2 Total length of roads in yards, per person, managed by ten local transport authorities 2012

The nature of South Gloucester and North Somerset looks clearer. They are both large in area relative to their population. Bristol is less like them and more like the other core cities. Only Birmingham looks odd, given its population. Major trunk roads and motorways account for more proportionately of Birmingham’s road network, and those roads are managed by the Highways Agency.

Figure 3 moves on to the heart of the question about safety. The measure is “KSI” (people killed or seriously injured). KSI is the brutal statistic for assessing the consequences of badly managed or carelessly used roads. The bars of Figure 3 are Cyclist KSIs on the roads of each Local Authority, per 100,000 people in the Authority, for the year 2011. In each case the “seriously injured” considerably outnumber the fatalities.

Figure 3 Number of cyclists killed or seriously injured per 100,000 people in each of ten local transport authorities in 2011

As I used to ask my A Level Sociology students: “What stands out in this graph?” The choice of colour emphasises Bristol’s figures of course but only Nottingham comes close to it in scale. Bristol’s neighbours in South Gloucester and North Somerset have numbers that are a quarter of those experienced just up the road.

How can this be so? Are Bristol cyclists mad? Should I leave my bike in the shed? Should I stick to walking? Figure 4 shows comparative results for pedestrian KSIs

Figure 4 Number of pedestrians killed or seriously injured per 100,000 people in each of ten local transport authorities in 2011

The scales are different, so don’t be mislead into thinking pedestrians are better off (except in Liverpool and South Gloucester). What shows up in Figure 4 is that Bristol’s comparatively bad record for cycling KSIs is not matched for pedestrians.. The question arising here is why does Bristol look so bad for cycle casualties compared to the pedestrian result? What about car occupants? Some answers on that score are shown in Figure 5 below.

Figure 5 Number of car occupants killed or seriously injured per 100,000 people in each of ten local transport authorities in 2011

More questions! Bristol is now outstripped by all the core cities. Even the North Somerset numbers for car occupant casualties are worse than Bristol’s. What is going on? Do people do more travelling in some places than others? Figure 6 shows the average number of miles travelled by road per day per person.

Figure 6 Number of miles travelled per person per day by road in each of ten local transport authorities in 2011

The suggestion from Figure 6 is that journey distance isn’t a factor either. A blogger worth her readership would, at this point ask “Have I made a mistake?” The quick answer would be visible in the source (in this case, the DfT Comparison data from which the graphs were drawn). Table 1 is a copy of the relevant figures for the years 2005 to 2011.


Cyclist KSIs per 100,000 people per year

Local Authority
























































Newcastle upon Tyne








City of Bristol








South Gloucester








North Somerset








Table 1 Cyclists killed or seriously injured per 100,000 people resident in each of ten local authorities 2005-2011

It’s clear enough. Nottingham and Bristol have had more than their fair share of serious and fatal cycling casualties over six years, and both have been returning data that suggest a turn for the worse. We do know (see ) that the year 2011-2012 saw Bristol’s toll of KSIs down to 41, with no fatalities among them. The big question we are left with is “Why have the figures got so much worse in Bristol since 2005?

Answers might be found in the ways that data are collected, recorded and analysed but I suspect that they are more likely to be provided in practical professional efforts to observe and improve the basic infrastructure and management of Bristol’s roads. There are plenty of examples of cycling provision (or lack of provision) that run counter to Department for Transport guidance (see LTN 2/08 Cycle Infrastructure Design downloadable from )  and there are plenty of places that have been identified as in need of improvement in the next few years. New facilities as they go in will need to have a more robust cycle safety audit.

One more graph might be of interest. It compares the sums of money spent by each of the ten Highways Authorities on road safety measures in 2011.

Figure 7 Amount spent per person per year on road safety measures in each of ten local transport authorities in 2011

I would be pleased to hear more questions about the subject but there is one big one that I want to start a fresh blog with, and that is “How significant are the casualties that arise when no other people or vehicles are involved?” Nearly all the data behind this report are taken from standard Police Road Traffic Accident (RTA) Reports. An additional set of cyclists end up in A&E after tumbles and collisions with no one else around.

Principal Reference

2011 Census: Method of travel to work, local authorities in England and Wales” (Office for National Statistics 2013)


I was unable to find the “casualties per billion miles” data for each local authority. But this comparison of percentages cycling looks very interesting.


Figure 8 Percentages from population sample surveys in ten local transport authorities in 2011 saying they cycle at least once a month.


8 thoughts on “Considerate Cycling 31: Cycling Safety Data. More Questions Than Answers

  1. The main reason for the increase in ksi cyclists in bristol could be the increase in number of cyclists – circa 70% increase in 10 years (see However, you’d normally expect the ksi per cyclist to go down as more people cycle- looks like this might not be the case in bristol which is a bit worrying! Worth further investigation. If you’re really keen detailed accident data can be downloaded here

  2. Thanks for that link Chris. It’s one I hadn’t seen before. Bristol City Council have been very helpful in providing data from the same RTA forms that generated those national data and the situations they reveal are definitely complex. I am also aware of data from medical sources where many additional causalities result from (mostly) icy roads with no other vehicle or person involved. My feeling is that a lot of the casualties now taking place could be avoided if roads and paths were designed, redesigned and maintained with vulnerable users in mind. The good news is that Bristol does seem to be on the verge of quite a lot of new work in these areas. Fingers crossed!

  3. The dataset that would help make sense would be ‘miles cycled per 100,000 population’. I’m certainly aware from having lived in both cities that the number of people cycling in Leeds is significantly smaller than in Bristol – I only see a handful of others on my daily ride. We’re a growing number everywhere however.

    Bristol has a couple of very good segregated paths – the Bristol-Bath railway in particular, so I’m surprised figures are so comparatively bad, but maybe they encourage people from the suburbs into the city and on to a less-well provisioned roads.

    What I am seeing in Leeds is some limited new provision (usually as part of a bigger road scheme) but very poor maintenance on the existing network. A recent scheme has just seen some new signage and entrance barriers added on a decent section of track in East Leeds, but done nothing to tackle the crumbling and potholed tarmac. There’s also a lot of ‘shared pavement’ tracks popping up, cluttered with street furniture and frequently blocked by parked vehicles, roadworks, ambling pedestrians with headphones unable to hear your bell. These are of limited use to the serious cyclist as they tend to force you onto a series of signalled (and slow) crossings at roundabouts rather than letting you rejoin the carriageway and take your ‘right of way’ if you’re confident enough to do so.

  4. Forgot to say – great blog! Really enjoy it. This link might also be of interest . Similar to the DfT one, but it shows the individual cycle accidents across the whole UK by severity. You can also cluster them. I think Bristol are currently bidding for some money to improve cycle safety on key routes such as A38 Gloucester Road, where a lot of the collisions are apparently caused by drivers pulling out of the side roads.

  5. JF and Chris – thanks to both of you! I am trying at the moment to track down the latest data on KSIs by distance travelled by local transport authority by transport mode. I shall report back if I Find that. I did refer to the issue in an earlier blog here: At that time I think I could only find national aggregates. Data on miles per cyclist are not easy to find and (I believe) of uncertain reliability.

  6. Not quite what was requested, but I have added one more graph that might (or might not) be connected with Bristol’s relatively high casualty rate. Bristol has more people who admit to cycling that the other core cities. Only South Gloucester (which to all intents and purposes IS part of Bristol) gets close to Bristol’s 24%

  7. Sam – the earlier blog was really interesting (must read your back catalogue!! 🙂 Interesting to note that only 1% were caused by skipping red lights.

    I’ve recently put in a request to Bristol Council for them to release all their cycle count data as part of the OpenData initative. That would really help answer the question. Please consider putting in a request to for the cycle count data. Sounds like both of us (and many others) would be interested to see it and use it. I’ve had a positive initial discussion with them about it, but a gentle nudge from another direction would help!

  8. That seems like a sound plan Chris. My experience so far is that Bristol are well-disposed to provide data. I also discovered only today that Cyclescape (being used by some BCyC people to log “pinch points” and other local deficiencies) has layers that identify individual incidents on their map layers. Is this you? These click through to a lot more info – like this: The amount (and complexity) of what gets shared now is very encouraging.

    I would not be surprised if I am not a long way behind everyone else on this – the explosion in data and its re-use is making geeks of us all.

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