The paper headed by Mathematician Jake Olivier looks at cycling related hospitalisations due to head or arm injuries in NSW since 1990. The purpose of the paper is to examine the impact of Mandatory Helmet Legislation (MHL) in Australia.
Not surprisingly the wearing of helmets has an impact on head injuries. But what struck me is the graph that is part of the paper. It shows a sharp drop in the rate of injuries in the year preceding introduction of the new MHL laws in 19991/92. From there on it shows a gradual increase in arm injuries, and a smaller, nearly flat rate of increase in head injuries up to 2006. After that year both types of injuries clearly decline.
The authors suggest that this is the result of better cycling infrastructure, and not related to MHL. They say “… there was a five-fold increase from 2006 to 2010 in the number of bicycle strategies implemented by local government where the most common element was increasing bicycle infrastructure significantly”.
Pucher explains the need for infrastructure to cyclists: “Probably the most visible commitment of a city to cycling is a comprehensive system of separated bicycle paths and lanes, providing a reserved right of way to cyclists and sending a clear signal that bicycles belong.”
I just want to recap: The introduction of mandatory helmet laws in Australia led to a slower increase of head injuries compared to arm injuries in people riding bicycles, but an increase in safer infrastructure (i.e. separation of bicycles from cars) led to a decline in both types of injuries.