The aim of this work is to validate a new 3D anatomic human head model by simulating a direct head impact of a Nahum's experiment and then to replicate the head impact caused by a motorcycle accident. At the validation level, model responses were compared with the measured cadaver test data in terms of impact force, head acceleration and five epidural pressures. Model response duplicate closely Nahum's experimental head response. After this validation, a numerical replication of a real head impact in motorcycle accident was realized. This simulation was based on the experimental accident reconstruction executed by the Transport Research Laboratory (UK). The results of this simulation were compared to the medical observations for the injured motorcyclist considered in this study. In this motorcycle accident replication, a good correlation was found between numerical head response, in terms of intracranial stress, and observed brain injuries in autopsy.