As the numbers of cyclists has increased in the Dublin City area — including many inexperienced cyclists, and, reportedly, many apparent reckless ones — the death and injury rates have declined:
Data and limitations: The 2011 data for serious injuries is provisional. While all deaths are significance, the numbers of deaths and injuries are so low that the data on such may be not “statistical significance” to analyse. It is worth noting that given that the figures are so low, small increases in the death rate may occur in the future. Further detail and discussion on the death and injury figures can be found here.
The Dublin City Council canal traffic counts data is the only available data for yearly changes in the volumes of cyclists in Dublin (automatic counters have been put in place at limited amount of locations around Dublin, but only recent data is available).
With a recent marked increase in cyclists on Dublin City roads road (45% more cyclists entering central Dublin since 2006, 26% more regularly cyclists since 2006 across Co Dublin, and 5,000-7,000 Dublin Bikes trips a day since September 2009) if the death and injury rate had remained stable, such would represent a decline compared to the amount of cyclists. Thus the recorded data shows a notable decline, in percentage and actual terms.
Analyses/discussion: It may not be possible to firmly linked the rise in cyclists numbers and the death and serious injury rates, but we can say that it is clear that an increasing amount of cyclists does not mean higher deaths and serious injuries, and that it can mean fewer deaths and serious injuries.
Where a link between an increasing amount of cyclists, and a reduction in the death and injury rate has been established, it is called the “safety in numbers” effect. Does the above data show safety in numbers for cycling in Dublin?
In his article ‘Safety in numbers: more walkers and bicyclists, safer walking and bicycling’ (see Injury Prevention), public health consultant Peter Jacobsen found that in Europe and North America where the number of those cycling and walking increased there was a lower frequency of collisions between these groups and motorists. He says this result is “unexpected” as it is “unlikely that the people walking and bicycling become more cautious if their numbers are larger, it indicates that the behaviour of motorists controls the likelihood of collisions with people walking and bicycling. It appears that motorists adjust their behaviour in the presence of people walking and bicycling.”
Similarly, the increase of cycling in Dublin has been accompanied by complaints from cyclists and non-cyclists that most or many new and/or current cyclists are somewhere between inexperienced and reckless  . However, despite an increase of inexperienced cyclists on Dublin’s road, the data shows that the death and injury rates have not increased. The opposite has happened, death and injury rates have continued to decline.
Conclusion: If cyclists in Dublin are as reckless as it is report and there has been a marked increase in inexperienced cyclists on the roads, cyclist behaviour seems to have little to do with the death and injury rate. Motorists seem to have adjusted their behaviour to an increasing amount of cyclists around them.