Abstract
THE DATA ANALYSED CONSISTS OF THE JOINT DISTRIBUTION OF SEVERITIES OF INJURY TO VEHICLE DRIVERS IN HEAD-ON CRASHES, STRATIFIED ACCORDING TO THE RELATIVE MASSES OF THE VEHICLES. ON THE BASIS OF SOME FAIRLY STRONG ASSUMPTIONS, A MODEL IS DEVELOPED WHICH RESULTS IN THE JOINT DISTRIBUTION BEING BIVARIATE NORMAL. THE PARAMETERS ARE INTERPRETABLE IN TERMS OF THE EFFECT OF VELOCITY CHANGE ON INJRUY SEVERITY, AND THE RELATIVE VARIABILITY OF VELOCITY CHANGE AND OF INJURY SEVERITY AT A PARTICULAR VELOCITY CHANGE. THE PREDICTIONS MADE BY THE MODEL ENJOY A CONSIDERABLE DEGREE OF SUCCESS. (Author/publisher).