The European road network, particularly TERN highways and TENT projects, is of major importance for the European economy and the mobility of the European citizens. A major task of highway owners and operators is to ensure a high availability of all important links. Even smaller disruptions due to traffic restrictions or failure of road network elements lead to severe traffic interferences resulting in high economic follow-up costs and negative environmental impacts. Such infrastructures also constitute attractive terrorist targets due to their accessibility and great potential impact on human lives and economic activity. Attacks may cause considerable damage, including structural damage or demolition, substantial human casualties, socio-economic losses (unemployment, relocation of firms, reconstruction costs) and socio-political damage (public uncertainty, confidence loss) and even environmental consequences, each being accompanied by the related costs. Particularly bridges and tunnels, key elements of the road network, are highly vulnerable to terrorist attacks due to their bottleneck function. The SeRoN project will undertake a holistic approach both at individual infrastructure object and at road network level. Its main objectives are to investigate the impacts of possible terrorist attacks on the transport network, in particular the resulting regional and supra-regional impacts on transport links and their economic impacts. SeRoN will focus on the development of a methodology which is to help owners and operators to analyse critical road transport networks or parts hereof with regard to possible terrorist attacks. It will evaluate planned protection measures for critical road transport infrastructures concerning their impact on security and cost-effectiveness. Finally SeRoN will give adequate recommendations concerning possible current and future threat situations and the related most effective security measures.