The purpose of this study was to evaluate the effectiveness of frontal restraint systems in reducing the potential for head injuries, specifically brain injuries and skull fractures. The US DOT NASS database files from 1991-1998 were evaluated for drivers and right front seat occupants in frontal crashes. Of the total driver and right front seat occupants in this data set, 3.83% sustained a brain injury without skull fracture, 0.05% sustained a skull fracture without a brain injury, and 0.16% sustained both brain injury and skull fracture. The incidence of head injury was lowest among occupants who were restrained by belt alone (2.76%) and by both airbag and belt systems (3.51%). The unrestrained population had a 10.39% incidence of at least one type of head injury. In general, for maximum AIS≥2 head injuries, air bag effectiveness was greatest between 16-45 kph crash ΔV. For the more severe maximum AIS≥3 head injuries, the airbag restraint had its greatest effect up to 35 kph. It can be concluded that brain injury in frontal crashes is substantially reduced with the presence of a restraint system and the use of both airbag and belt restraint offers the greatest protection across all ΔV categories. Restraint system effectiveness for the non-head-injured occupant is variable but, generally, the belted occupant sustained the lowest percentage of injuries. Skull fractures in frontal impact were relatively rare and the incidence appeared to be unaffected by the presence of a restraint system.