Abstract
Highway accidents are not an earthquake, but they do represent a world-wide catastrophe. In this paper a simple mathematical model is introduced to measure the magnitude of highway safety using a scale concept analogous to the Richter scale in seismology. The procedure is proposed as a diagnostic aid. It presents an overall picture and can be used as a policy guide. It will facilitate comparison of two or more highway networks or comparison of the same network in different years, enabling trends to be objectively examined. Statistical data for road accidents in several countries has been analysed and some results are presented.