The efficiency assessment of road safety measures is considered to be an extremely useful tool in decision making; in particular, cost-benefit and cost-effectiveness analyses are carried out in several countries, in a more or less systematic way.  The objective of this paper is to present findings from a review of current practices for road safety assessment worldwide gathered in various handbooks, manuals, research projects and other international reports.  This review comprises the preliminary results of the work carried out in the framework of the on-going Working Group on the assessment of the effectiveness of road safety measures, of the Joint Transport Research Centre (JTRC) of the Organisation for Economic Cooperation and Development (OECD) and the International Transport Forum (ITF). In particular, the most important international initiatives for providing standardized and accurate methods or tools for the estimation of safety effects of road safety measures are presented. Furthermore, the procedural and technical limitations of these methodologies are discussed in this paper, as is the lack of knowledge and data on the safety effects of road safety measures but also the potential for transferability of the assessment results.  Emphasis is given to the added value of the safety assessment process and the related results to the various stages of the road safety decision making at local, regional national and international level.