Childhood cycling fatalities in South Australia before and after the introduction of helmet legislation.

In the years following the introduction of legislation in Australian states mandating the wearing of helmets, there was a decline in the number of deaths. Debate has occurred, however, as to why this occurred. The Traffic Accident Reporting System database, which records data for all police-reported crashes in South Australia, was searched for all cases of deaths occurring in the state in bicycle riders aged ≤14 years from January 1982 to December 2001. The numbers of deaths were then compared over the 10-year periods before (1982-1991) and after (1992-2001) the introduction of helmet legislation, and also on a yearly basis from 1982 to 2001. Comparing the numbers of deaths in the two periods before and after helmet legislation in 1991 showed a marked decrease in cases from 36 to 12. However, in examining the numbers of deaths per year in greater detail, it appears that these were already steadily reducing from nine cases per year in 1982 (2.9/100,000) to two cases in 1991 (0.67/100,000) to a virtual plateau after 1991 (ranging from 0 to 2 cases annually). It seems that the introduction of compulsory bicycle helmet wearing in South Australia came at a time when the numbers of child cyclist deaths had been steadily declining over the preceding decade. While helmet wearing clearly protects children who are still riding bicycles, the reasons for the reduction in numbers of deaths appears more complex than legislative change and likely involves a subtle interaction with other behavioural and societal factors and preferences.