This study of vehicle aggressivity in head-on collisions analyzes the effect of vehicle-related factors in the bullet vehicle on injury outcome in the target vehicle. The variables that were considered and studied in the bullet vehicle included Average Height of Force (AHOF), crush-zone stiffness, vehicle type, and vehicle weight. As with previous research, a data-mining analysis of 107,000 collisions finds that an increase in the striking vehicle weight has the largest correlation with higher serious/fatal injuries. Unlike previous research which focused on crush-zone stiffness, this research finds that the second most important explanatory variable is AHOF, with a higher AHOF associated with higher injury risk.