Severity of cyclist head injuries caused by impacts with vehicle structure and road surface

For cyclist fatalities in 2014 in Japan, the head was the most frequently injured body region. In the present study, the authors analyzed the features of cyclist head injuries in real-world traffic accidents using the data of patients who were taken to the emergency room in Dokkyo Medical University Koshigaya Hospital in Japan, from 2011 to 2013. The results indicated that the percentage of skull fractures was the highest among cyclist head injuries. Assuming that a helmet can prevent head injuries sustained by cyclists in traffic accidents, the effect of wearing a helmet was investigated in impact tests against a vehicle and road pavement. In the tests, the severity of potential head injuries was determined from the Head Injury Criterion (HIC) obtained in an adult pedestrian head-form impactor with and without a helmet. The impact location selected for a vehicle was the A-pillar because the pillar had much higher stiffness than the vehicle bonnet or windshield. It was found that the HIC values for the head-form impactor wearing a helmet were much lower than the HIC values for the head-form impactor not wearing a helmet in both the head-versus-A-pillar impacts and head-versus-pavement impacts. The results suggest that wearing a helmet could reduce the possibility of skull fracture in cyclists.