The evidence clearly demonstrates that cycling becomes safer the more people engage in it - and this is also true for pedestrians.
By Nicholas Kevlahan
Published August 08, 2012
A new fact sheet by the European Cyclists' Federation titled Safety In Numbers [PDF] demonstrates that higher rates of bicycle use result in lower numbers of casualties. The reason is that cycling is safer for each cyclist when more people do it.
The concept of 'Safety in Numbers' is not new. It was first demonstrated in 1949 by Smeed with regard to motor vehicle use when data from 62 countries showed that road fatalities per vehicle were lower in countries with more driving. The relationship - an exponential curve - has become known as Smeed's Law and has stood the test of time well, being verified in examinations of data across 42 years in the UK and 110 years in Australia. As can be seen in the below graph of Walking and Cycling in California, it can be just as easily adapted to cycling figures which show a perfect 'Smeed curve'"
I found this fact sheet by following a link from a Guardian article proposing that the so-called "Zil Lanes" in London, currently dedicated to Olympic athletes and officials, be converted into bike lanes once the games are over.
Although I've known this for a while, it is really amazing how much absolutely (not just relatively) safer cycling becomes as more people cycle:
These figures need to be widely publicized, since anything that decreases the rate of cycling will likely lead to increased fatalities (and certainly increased relative risk) - and of course, the reverse is also true.
The fact sheet also cites a fascinating study showing that increased numbers of pedestrians crossing at intersections lead to large reductions in relative risk of pedestrian injuries. The study was carried out in ... Hamilton!
Leden also examined police reported injuries to people walking at some 300 signalized intersections in Hamilton, Ontario, Canada. The number of collisions increased with the 0.32 to 0.67 power with increasing numbers of pedestrians. That is, where there were greater numbers of pedestrians, fewer pedestrians were involved in crashes.
The referred study is: Leden L. "Pedestrian risk decrease with pedestrian flow. A case study based on data from signalised intersections in Hamilton, Ontario". Accident Analysis & Prevention, 2002.
In Hamilton attempts to make our roads more convenient and attractive to pedestrians are often rejected on the grounds that Hamilton is exceptional: what works elsewhere won't work here. This attitude is especially surprising when you realize that Hamilton data has actually produced some of the most widely-quoted research on pedestrian safety at intersections and one-way streets!
I don't really want to get into the helmet debate, but epidemiologically speaking, helmet laws that lead to reductions in cycling (or slow its growth) will certainly lead to increased rates of injury.
This seems like a paradox until you realize, as noted by the European Cyclists Federation, that it is driver behaviour (along with road infrastructure) that is the determining factor for injury and death rates for cyclists.
[N]ot only are policies that increase the numbers of people walking and cycling a good way to improve safety, but laws should be revised to reflect the premise that the number of collisions with vulnerable road users is determined largely by motorist behaviour.
More cyclists lead to motorists being more respectful, accepting and aware of cyclists on the roads. Cyclist behaviour becomes normalized and more predictable for motorists. This has what has happened in places that have seen big increases in cycling: London (UK), New York, Denmark, and the Netherlands.
The single most effective way to make cycling safer is to increase the number of cyclists. The evidence over whether helmets even make cycling safer for individuals in the low-speed crashes typical of commuter cycling is itself unclear, and the safest cycling country (Denmark) has very low rates of helmet use, but very high levels of cycling overall.
That said, I always wear a helmet when cycling in Hamilton and encourage others to do so, but I didn't when using the Velib' in Paris and almost no one else does.
Velib' station in Paris (RTH file photo)
with files from Ryan McGreal