Security is critical to transport systems as they are often appealing targets for terrorist attacks. The significant costs of potential damage make effective security policies a key concern for transport decision makers. This Round Table examines the contribution economic analysis can make to improving security in aviation and maritime shipping by identifying methods for quantifying the benefits of security measures and assessing their effectiveness, and examining techniques to allocate resources targeting the highest risks. Table of contents in English -Summary of Discussions -Rational Behaviour, Risk Aversion: High Stakes for Society by Andre de Palma (France) -Economic Impact Analysis of Terrorism Events: Recent Methodological Advances and Findings by Peter Gordon, James E. Moore II and Harry W. Richardson (USA) -Towards a Risk-Based Aviation Security Policy by Robert W. Poole Jr (USA) -Security and Risk-Based Models in Shipping and Ports: Review and Critical Analysis by Khalid Bichou (United Kingdom)