This study examined vehicle "aggressiveness," defined as the tendency of a vehicle to inflict damage or occupant injury when striking other vehicles. Previous analyses of data on crash fatalities and injuries revealed that passenger car occupants were more likely to suffer severe injury if the striking vehicle was a light truck rather than another passenger car. Thus, light trucks seemed to be more "aggressive" than cars.

The analyses addressed the question of whether light truck aggressiveness is due simply to greater weight, or to structural factors as well. It was hypothesized that a vehicle's stiffness would contribute to its aggressiveness and on this basis it was predicted that, with respect to damage, vans would be the most aggressive vehicles, pickup trucks the next most aggressive, and passenger cars the least aggressive.

Analyses were made of the sources of vehicle damage and driver injury respectively in head-on, sideimpact, and rearend crashes in which the struck vehicle was a passenger car. Structural factors appeared to be predominant in causing damage to other vehicles, while weight seemed to play the major role in injury causation. The prediction regarding light truck types was supported.

Since light trucks were also found more likely to cause intrusion of the occupant space when striking passenger cars, analysis was made to determine if the intrusion contributed to injuries beyond the effects of delta-V. Various statistical analyses suggested that both factors contribute to driver injury.