The objective of this paper is to determine how policy instruments targeting a modal shift of long-haul freight transport from road to rail or shipping might affect the distribution of freight tonne-kilometers across the different modes of transport in Sweden. The analysis is conducted in two steps. First, possible developments of freight tonne-kilometers until 2030 and 2040 are compared to base figures for 2017. This is done by developing a set of alternative forecast models where different assumptions and scenarios prevail and analyzing these using Sweden’s national freight transport model SAMGODS. Second, the effects of two hypothetical modal shift policy instruments – a wear and tear tax for road traffic and an ecobonus scheme to promote shipping by rail and sea – are analysed with respect to modal split in the base year of 2017 and for the forecast year 2040. The analysis involves the aggregation of calculated modal shares across each of the SAMGODS model's vehicle/ship types – i.e., six road freight vehicles, eleven freight train variants and 22 ship types. Given the conditions that are assumed in the forecasts, the amount of freight tonne- kilometers is calculated to increase by between 31% and 53 % between 2017 and 2040. The increase is generally largest for maritime transport, followed by road transport and smallest for rail transport. The concept developed in this paper can be useful in studying impacts of different types of technology shifts and policy packages.