I am 34. I recently had a bike accident which has stopped me rfom working for 2 months so far. From now to the moment I die, whenever I use a bike I will be extremely cautious for some situations before I was more or less careless. I suppose such kind of happenings teach you better for when you are at older ages you can avoid such accidents as much as possible. I am not a researcher on these topics of course, but I am an avid bike user and I think I will be prone to less accidents at older age just because of the experience gained.

Dear Luc, I will take a look. But this picture shows 65 as the highest age. In the Netherlands risk goes up for higher age indeed, but for lower age the shown risk might be more or less correct. Could it be that there were hardly any elderly cyclists in this study? The risk decrease for lower age is somewhat in agreement with the Dutch findings, although I would rather say risk decreases between 10 and 35, is constant between 35 and 60, and increases (a lot) for higher values. 

Other explanations: some bias in the collected data on distance cycled.

The difference between male and female: I'l have check some references there. 

maybe are more distracted

Luc,

Thoughts that cross my mind:

- the gender issue could be result of lower physical asserttiviy and the cautiousness paradox (being more cautious sometimes evokes more dangerous behaviour with cardrivers)

- the age result: is it possible that older people are driving their bikes more on calm moments with less traffic? which I think migt also be a partial explanation for the gender differences (I see much more women bringing children to school by bike, than men, and school hours and school environments are high risk).

Makes any sense?

Yves

Indeed in the Netherlands the risk of a serious road injury is higher for males than for female riders for young riders, but the oter wa around for elderly riders. The risk increases sharply for highest ages. The picture (in Dutch) shows the risk for 2005-2009 averaged ( based on N=50000, approximately). males are in read (left) , females in blue (right) It is taken from 

http://www.swov.nl/rapport/R-2012-08.pdf (in Dutch), page 70

Explanantions for the SHAPES results are probably to be found in the data collection method (the data on distance travelled may have been a problem). If the results are indeed correct, this is quite amazing. In that case I have no explanation really. Few elderly included, would be my gess (I see a zero risk for one of the observations in the SHAPES diagram; that suggests low numbers).

The risk for elderly people is high because their riding skills decrease while their vulnerability increases (many broken hips among elderly riders, which is a serious injury indeed).

Risks for male is high because the cycle faster (racing bikes), and they are less careful in general, and a guessed explanation for the higher female risk at high age can be that some women start ccycling at high age after having lost their husband, and have then less experience. But this is not a research finding.

@Xochitl

Experience can certainly be a factor, but one which is hard to disentangle from a general decrease in risk taking behaviour with age (perhaps based on near misses or real accidents)

@Vincenzo

Distraction is certainly one of the top causes cited by cyclists involved in an accident in Belgium. However is it unclear to me why women would be more distracted than men (in Belgium and the other way around in other countries)

@Yves 

The population was limited to those of working age and mainly focussed on commuting so probably not due to differences in time activity pattern.

However on the gender issues I think you may have a point. Some of the men in the study reported really long commuting distances along e.g. canals where accident risk (per km cycled) is probably very low. On the other hand women seem to take trips more often in the rush hour (e.g. AB modelling by Beckx et al) and in town centres with more intersections and therefore higher risk (while their risk aversion while driving/cycling) may still be higher than that of men)

@Henk

Thank you for the Dutch graph. The reversal of male/female risk ratio with age is really interesting. The SHAPES sample was limited to those of working age (

Another suggestion that has been made to account for the unexpected gender difference is that women could be more faithful reporters of minor accidents than men.

That’s an interesting issue. I have experience almost the except same surprise when I was analysing minor bicycle crashes with the Dutch Periodic Regional Travel Survey (PRRS), see http://publicaties.minienm.nl/documenten/prov-2011-periodiek-regionaal-onderzoek-verkeersveiligheid

Like the Shapes study, it is based on self-reported crashes and bicycle use.  In the appendix (including all tables for this survey), page 113, Table H11, T4, you see estimated bicycle crash risks. It depends a bit on the years you look at, but generally crash risk is higher for females than for males and decreases with age. According to this table it even seems to decrease after 65 years of age.

 We should of course be aware that the figures in SHAPES and PRRS are about minor crashes, most of which don’t require any medical treatment. The figures Henk refers to are about more severe crashes and therefore better account for the increased frailty of older people, i.e. it would be possible that they don’t have more crashes but rather that they are more likely to incur serious injuries if they have a crash.

However, I do believe that, as suggested by Henk, self-reporting of bicycle use also plays a role. In the same table I referred to in the PRRS Appendix (page 113), you see that kilometres cycled per year reported by those above 65 are only some 20% less than by those between 50 and 64 years. However, according to our National Travel Survey (NTS) the number of kilometres by those above 65 reduces by some 50%: http://statline.cbs.nl/Statweb/publication/?VW=T&DM=SLNL&PA=81128NED&D1=1&D2=0&D3=0&D4=23,26,30,34,37&D5=a&D6=0&D7=a&HD=150116-1331&HDR=G1,G2,T,G6&STB=G4,G5,G3

Our Census data also allow the distinguish between gender. This shows a similar difference. PRRS suggest a much smaller a much smaller difference in bicycle use between males and females than NTS.

I noticed this problem when I was doing research using crash data from PRRS, but also combining the same crash data with exposure data from NTS. When using NTS you find a significantly increased risk among the elderly: http://injuryprevention.bmj.com/content/18/4/240.short

This is more consistent with what you would expect. Although specifically designed to measures mobility, NTS is also a (travel diary) survey. So we can’t be completely sure about which source is best. More research on this may not be a bad idea given our reliance on exposure data for safety research. Maybe it’s time to have a panel of cyclists/bicycles equipped with GPS.

Best wishes, Paul

I think it is related to the level of exposure; meaning that women may be less frequently riding bikes and so is for older people.

The numbers should be normalized to reflect the actual number of users for each category. Try that.

Obviously good exposure data is key.

A new study from Australia finds similar result:

"After adjustment for exposure in hours, or for the risks associated with different infrastructure utilisation, the rates of crashes and medically attended injuries were found to be greater for females than males,"

Article An exposure based study of crash and injury rates in a cohor...

Apparently the same is hypothesized in London as well, although the possible reasons are not at all clear.

http://www.londoncyclist.co.uk/all-the-hallmarks-of-a-typical-london-cycling-death/