Since 1 May 2004, the European Union road network, and accordingly the stock of highway structures, has increased significantly. Ten new Member States have brought nearly 924 500 kilometres of roads into the European network. These countries have huge numbers of highway structures, which, mainly due to their history, do not constitute a solid and trouble-free infrastructure. Structures have been affected by a lack of maintenance, regular overloading and even by the use of poor quality materials for construction. In the near future, the same structures have to face increasing volume and weight of traffic and will therefore have to be reliably assessed and, if necessary, improved or replaced, with significant investment needs. The overall goal of the ARCHES (Assessment and Rehabilitation of Central European Highway Structures) project is to develop and promote fast and sustainable ways of raising the standard of highway structures in the new Member States and Central and Eastern European Countries to the level necessary for their full economic integration into the EU and for the future development of the Union. Building on the knowledge of previous recent EU projects, this project focuses on structural assessment and monitoring strategies to prevent deterioration, and optimum improvement of highway structures by the newest techniques, with a strong emphasis on full scale pilot applications.It is based on the following conceptual approach: • Developing more appropriate tools and procedures to avoid unnecessary interventions (repairs/replacements) in structures • Prevent the development of corrosion by simpler and less expensive techniques. • Implement faster, more cost-effective and longer lasting repair or strengthening techniques of sub-standard and unsafe bridges. Another important objective of this project is to help society and politicians understand the need for sustainable maintenance of their road networks, and to help infrastructure managers spend their resources in the most effective way.