New measures need to be taken in order to reduce the negative impact of transport. This study presents various theoretical schemes for the introduction of road pricing in Belgium and analyses their impact on transport, the environment and welfare by using the PLANET model. The internalisation of external costs, while difficult to implement in the short term, improves welfare significantly. In order to improve welfare, a road tax system aimed at lorries exclusively should allow for a suitable differentiation according to the actual periods of transport. Extending the road pricing system so as to include vans has a positive effect on welfare and also avoids shifting part of the road freight to vans. Extending road pricing to all road motor vehicles (lorries, vans and individual cars) significantly improves welfare, road congestion and the average speed on the road network. On the other hand, it induces a very marked surge in the demand for rail and other public transport (buses, trams and metros), which would almost certainly exceed the capacity of existing infrastructures. Potential management problems of rail and other public transport such as buses, trams and metros could be avoided if the generalisation of the road pricing system to all road motor vehicles were combined with the withdrawal of subsidies for public transport.