Head injuries are the most common cause of road users in real-world accidents. For pedestrian safety, this paper describes the developments of head injury risk curves and development of test tools, i.e., child and adult pedestrian headform impactors, for evaluation of safety performance of vehicle structure. For the development of head injury risk curves, relations between head injury risk and head injury criterion (HIC) are clarified based on accident reconstruction by means of headform impactors. In 2005, Japan introduced the type approval test for pedestrian head protection using the newly developed pedestrian headform impactors. For cyclist safety, this paper shows that wearing a helmet has a great potential in preventing cyclist head injuries based on impact experiments of the adult headform impactor against vehicle A-pillar and road pavement.
