The crash performance of motorcycle safety helmets can be determined by reconstruction of accident events and special examination of the safety helmet. A large number of motorcycle safety helmets were collected by the NHTSA Motorcycle Research Team at USC and disassembled and examined for crash performance. Accident dynamics were correlated with helmet damage to evaluate performance for retention, penetration resistance, and impact attenuation. Contact surfaces are identified and located, normal and tangential impact velocities are calculated, and the abrasion and compression signatures of the liner and shell are measured. These factors are related to injury prevention or injury causation and the critical elements of FMVSS 218. Special problems of impact signature identification are related and helmet tests for replication of accident conditions are described. A current summary of helmet analysis is included.