Abstract
Two concepts of safety in transportation are presented. One is termed the "system design" definition and the other is the "casualty" definition. A discussion of accident statistics is provided, along with a look at the conceptual structure of safety data systems. Accident mitigation efforts are analysed, and safety data needs are discussed. It is concluded that safety is an essential criterion of the effectiveness of all transportation modes. A more consistent and coherent safety policy would require more sophisticated data bases than are currently used. However, if they were employed, limited resources could be allocated more effectively and all modes could be measurably improved.