The aim of the project is to fundamentally refine the present knowledge of the dynamic fleet composition for the purpose of emissions computing, especially in the sections, where the significant insufficiencies of so far used data were identified. In this meaning insufficiencies include unrepresentative data for village roads and completely missing data for foreign cars. The related aim is to update present data and to propose a solution for future updates without large requirements on public budgets. Furthermore a computer application for work with the fleet data will be provided to users.