Model-based forecasts of future emissions are important tools for finding strategies to reach the Swedish transport policy objective concerning effect on climate and air pollution. In order for the calculated emissions to reflect the actual situation, input data on kilometrage, vehicle types and vehicle ages must be representative of the region of interest. High-quality forecasts of these variables are therefore of great importance when estimating future emissions. This report proposes a forecasting model system for the compositions and use of the Swedish car fleet, based on experiences from existing models in the literature. The system operates on two levels, an aggregated (national or regional) level and a disaggregated (household or personal) level. Forecasts of the total number of cars and total kilometrage are provided from the aggregated models whereas the disaggregated models provide the distribution of cars of different types and ages and the distribution of kilometrage over the same classification of cars. These results are then combined to give the final outcomes: the number and kilometrage of cars of different types and ages.