In Germany, the development of ITS started even before 1990. Germany has developed guidelines and standards for the implementation of Intelligent Transportation Systems for traffic management on highways. However, until today a national framework for the integration of ITS in Germany is missing. Therefore the aim was to define recommendations for the implementation of a national ITS-architecture in Germany, based on the analysis of existing ITS-architectures worldwide. These recommendations can be separated into two parts. The first part refers to the process for the development, maintaining and updating of a national ITS-architecture. The second part contains recommendations regarding the national ITS strategy, the ITS framework architecture and the reference architectures. As a result of this research project, 40 recommendations for the implementation of a national ITS-architecture in Germany have been defined.