Guaranteed access to mobility for all is one of the conditions for the participation of all individuals in an inclusive society. On the one hand, there is a significant increase in the availability of multimodal mobility services for people. On the other hand, the increase in the movement of people using different mobility services makes traffic management an even more difficult challenge to overcome. Traffic management must move from the traditional management of traffic volumes to managing the different types of available vehicles. For this purpose, the EU-funded TANGENT project is developing new complementary services for optimising multimodal traffic operations. Data from heterogeneous data sources must be appropriately shared between the stakeholders involved in the project to enable the development and testing of these innovative services. This paper presents the methodology adopted by the TANGENT project for formalising the TANGENT Data Sharing Governance model and adequately managing and facilitating data-sharing tasks.