IN THE CONTEXT OF THE COMPLEXITY OF TERRORISM, STATE-OF-THE-ART METHODOLOGIES AND TOOLS HIGHLIGHT STRONG LIMITS AND DO NOT PROVIDE A COMPLETE SOLUTION. THANKS TO THE RESEARCH WORK CARRIED OUT IN TERAEYE AND SECUREMETRO WE HAVE STUDIED THE STATE OF THE ART OF THE CURRENT RISK ASSESSMENT METHODOLOGIES AND WE HAVE COMBINED THE MOST PROMISING APPROACHES TO REALISE A METHODOLOGY SUITABLE FOR CRITICAL INFRASTRUCTURES IN THE FIELD OF TRANSPORT (AIRPORTS, SUBWAYS, ETC.). THIS APPROACH WILL ALLOW US TO DEVELOP A PREVENT TOOLBOX ABLE TO ASSESS THE RISKS TO WHICH CRITICAL INFRASTRUCTURE IS EXPOSED TO TERRORISM, AND TO ASSESS ITS COST-BENEFIT EFFECTIVENESS ARISING FROM THE CHOICE AND IMPLEMENTATION OF COUNTERMEASURES, MINIMISING THE SUBJECTIVE FACTOR. THE INTERVENTION THAT WILL BE DEVELOPED IN THE PREVENT PROJECT CONSISTS OF SEVERAL DEVELOPMENT AND INDUSTRIALISATION ACTIVITIES, LISTED BELOW: 1. DEVELOPMENT OF THE RISK ASSES MODULE