Background In Austria, bicycle helmets have been mandatory on public roads for children under 12 years of age since May 31, 2011 (23^rd amendment to the road safety act). The regulation was introduced as an awareness measure and is primarily designed to protect children from head injuries. Thus, there are no consequences for violation of the regulation.

Methods Post hoc evaluation of the effect of the helmet wearing legislation comprised the use of existing data sources about helmet wearing and the rate of head injuries. The main data source used for the analysis, the Injury Databases (IDB Austria), is quite unique for this purpose as it provides information on both the type of road user and the type of injury. The results on helmet wearing are based on regularly conducted counts, performed bi-annually since 2005.

Results After the introduction of the regulation a significant increase of the helmet wearing rate was observed in the target group: before the introduction about 65% of children under 12 wore a helmet, by 2014 the rate was 87%. This trend in helmet wearing was mirrored also in the development of the rate of head injuries of child bicyclists who were treated in hospital after an accident: before the helmets became mandatory 47% of the children under 12 years had head injuries, by 2014 the rate was 38%.

Conclusions As intended by the regulation, an increase in the proportion of children wearing a helmet and a decrease in the rate of head injuries was observed. However, both trends need to be further observed in order to evaluate the supposed effect of the legislation in the long run. By the time of the Safety2016 taking place, the most recent data on both indicators will be presented in addition to results given above.