The paper's objective is to suggest a model for determining optimal lifetime of passenger car based on minimization of CO2 emission. The life cycle was modeled by eight main life cycle sequences. Combining the mathematical interpretations of the itch life cycle sequence is developed an optimization model. In this paper is suggested a new mathematical interpretation of following sequences: use, repair, distribution of passenger car and distribution of passenger car's parts. Comparison of the obtained numerical results was performed on examples for the data of new passenger car fleet from the EU14 countries. Special attention is given to analysis of dependencies between the optimal lifetime of passenger cars and Directive 2000/53/EC, trends of changing car weight, model year, kilometer driven and regulatory limit of the specific CO2 emission. The optimal lifetime in case where petrol car is replaced by diesel car was analyzed too.