Previous studies have shown steering hub airbags to be effective in reducing the rate of serious head and facial injuries for drivers of passenger cars involved in frontal impacts. However, real world accident data shows that approximately 3% (50 out of 1680) of drivers in a sample of crashes received an AIS 3+ head injury despite a steering hub airbag having deployed. For struck-side occupants with deployed head protection 12% had an AIS 3+ head injury. This paper examines the nature and mechanism of the specific head injuries together with the surrounding crash characteristics in order to identify further occupant protection requirements beyond the scope and capability of the airbag. The in-depth case review has revealed that, among cases within the CCIS database, only 0.5% of those with deployed frontal head protection but 12% of those with deployed struck-side head protection show potential for improvement in occupant head protection.