"Gemma_k" wrote in message
news:1143255900.438754@teuthos...

"Jules" wrote in message
...
This report in the BMJ was _years_ ago wasn't it?

It's all originally based upon the 'safety in numbers' principle doen by
P L Jacobson - Safety in Numbers: More walkers and bicyclists, safer
walking and cycling. Summary he

Objective: To examine the relationship between the numbers of people
walking or bicycling and the frequency of collisions between motorists and
walkers or bicyclists. The common wisdom holds that the number of
collisions varies directly with the amount of walking and bicycling.
However, three published analyses of collision rates at specific
intersections found a non-linear relationship, such that collisions rates
declined with increases in the numbers of people walking or bicycling.
Data: This paper uses five additional data sets (three population level
and two time series) to compare the amount of walking or bicycling and the
injuries incurring in collisions with motor vehicles.

Results: The likelihood that a given person walking or bicycling will be
struck by a motorist varies inversely with the amount of walking or
bicycling. This pattern is consistent across communities of varying size,
from specific intersections to cities and countries, and across time
periods.

Discussion: This result is unexpected. Since it is unlikely that the
people walking and bicycling become more cautious if their numbers are
larger, it indicates that the behavior of motorists controls the
likelihood of collisions with people walking and bicycling. It appears
that motorists adjust their behavior in the presence of people walking and
bicycling. There is an urgent need for further exploration of the human
factors controlling motorist behavior in the presence of people walking
and bicycling.

Conclusion: A motorist is less likely to collide with a person walking and
bicycling if more people walk or bicycle. Policies that increase the
numbers of people walking and bicycling appear to be an effective route to
improving the safety of people walking and bicycling.

This work was then looked at by D Robinson, you can view it he

http://www.bfa.asn.au/bfanew/pdf/pub...in_numbers.pdf

It shows that the safety in Numbers principle 'works' for Australia, and
draws the conclusion that discouraging cycling by whatever means (even if
'safety focussed') is more detrimental to public health than encouraging
it.

The helmet stuff comes in to the mix because there was an approx 30%
instant drop in the numbers of cyclists at the time of mandatory helmet
wearing. And now she's published another article, which I can't access
until I get to work on Monday..... :-)

And.... look out soon for some South Australian research on the Safety in
Numbers principle..... to be published.


I wonder if there's a volume of bicycle traffic, a critical mass if you
will, where motorist behaviour changes substantially. There's probably a
point where it stop being considered the behaviour of the radical nutbag and
starts being something that most or at least a lot of people do.