This report contains a review of recent accident cost estimation studies and proposes a unit cost framework which is considered appropriate from both conceptual and empirical view points for the estimation of the social costs of road accidents in Australia. A detailed set of unit and total cost estimates for Australia in 1978 is presented, based mainly on existing data sources, supplemented by accident claims data from a sample of insurance companies and the Motor Accidents Board of Victoria. These preliminary cost estimates are also classified according to injury severity. Problems associated with accident statistics and data sources are discussed together with the estimation procedures. The report concludes that social costs provide only minimum estimates of the benefits gained from accident reduction, and that the use of average cost levels is constrained by the skewed distribution of most accident cost characteristics.