About twenty years ago, the research activities aiming at the development of the optimal maintenance and rehabilitation strategies (models) of roads and bridges started in several countries, including Hungary. In the first foreign models, the deterioration depending on time and other parameters was given by Markov transition probability matrices. Due to the inaccuracies and inconsistencies of earlier models, a continuous model upgrading could have been carried out by many researchers world-wide. Besides, basically new models appeared in the literature, which are able to describe the actual processes more reliably. The research work of the authors of the paper has concentrated on Pavement Management Systems (PMSs) and Bridge Management Systems (BMSs). Since a common financing of roads and bridges is typical, a combined model of road pavement and bridge managements was developed by the authors increasing considerably the efficient use of available funds.