Motorcycle accident data have been collected in Glasgow, Hannover and Munich as part of a COST action and the data have been used to create a database comprising 218 cases. The purpose of the study was to improve the knowledge of head and neck injury mechanisms. The criteria for inclusion was that a helmet was worn at the time of the accident and that a head impact, although not necessarily a head injury, had occurred. Sixty-seven percent sustained a head injury and 28.2% a neck injury. Also notable were the 53% with a thorax injury and 73% with leg injuries. It is not surprising that when the injuries were subdivided into MAIS that as the MAIS increased so did the proportion with a head injury, from 38% for MAIS 1 to 85% for MAIS 3 and greater. Eighteen cases were replicated with drop tests of a helmeted headform and in 13 cases where the motorcyclist sustained a head injury the rotational acceleration was approximately 9,000 rad/s2 or greater.