Most racing organizations require drivers to wear protective head covering, usually in the form of a crash helmet. The added weight and inertia of such helmets can, under certain kinds of conditions, actually contribute to injury rather than reduce it. The problem may be accentuated by use of current, full-coverage style crash helmet. This paper discusses a simulation approach to the evaluation of additional injuries which may exist in rear-end collisions. The simulation model used has been validated by other work, and measured values of helmet mass and inertia are included for various types of helmets.