This paper examines the behaviour of 2 logistic regression models describing the risk of lower limb injury as a function of intrusion, delta-V, seating position, age and gender. The model is constructed using in-depth injury data collected by the UK Cooperative Crash Injury Study. Data on restrained front seat occupants in frontal collisions are used to build the model.

The model indicates that intrusion increases pelvis to knee and leg injury risk separate from the effect of delta-V. Increasing intrusion results in a much greater increase in injury across the normal variation seen in the field data. Drivers are between 2 and 3 times at risk of sustaining leg injuries as passengers with the same intrusion and delta-V levels. This may be a reflection of the additional hazard of the pedals and steering column or passengers could sit more rearwards than drivers. Females have a rapidly increasing risk of injury above the age of 40 while that risk for males only increases slightly.