This study examines the frontal crush behaviour of cars. The study shows that the specific energy absorption per unit mass properties of cars is independent of car size. Examination of car to car collision equations in this context shows that the mean deceleration experienced by a car: (1) is inversely proportional to car length; (2) is related to the square root of collision closing speed; and (3) is related to the inverse of both the fourth root of mass ratio and of the crush depth. It is hypothesised for any specific car population and given degree of occupant protection within this population that Relative Injury Risk is proportional to the 2.5 power of mean deceleration. The model derived is compared with published Relative Injury Risk data: (a) for collisions between similar cars, dissimilar cars; (b) for overall risk to cars of specific size within the car population; and (c) for individual car ratings derived from the analysis of accident data. Very high correlations were obtained. (A)
Abstract