VTI has previously shown that there are socio-economic benefits of using longer and heavier road vehicles than the rest of the EU, i.e. 25.25 metres and 60 tons are permitted. The aim of the Co-modality project is to investigate the consequences of using even longer and/or heavier road and railway vehicles. This first subproject aims to answer which dimensions and weight limits with regards to road and railway vehicles that the Co-modality project should investigate further as well as the effects. A literature review has been conducted and to capture the views of Swedish stakeholders and transportation experts, a questionnaire survey was conducted. The respondents were invited to a hearing, too. The reason for the survey was to establish which road and railway vehicles would be in demand year 2030. The results show that no extreme changes are expected and that volume capacity was requested to a further extent than weight. For road vehicles, it is mainly a question of continuing to build on the European Modular System that combines different standardised load carriers. It allows member states to have different dimensions to those in other EU countries. For railway vehicles the demand is mainly for longer trains, but also heavier. Road safety, infrastructure, congestion, environment and transportation economy are the aspects that we identified as relevant for longer and/or heavier road and railway vehicles.