ATIS (Advanced Travel Information Systems) are complex systems, dealing with a large amount of heterogeneous data from various sources. The exchange and integration of such data is therefore demanding, particularly for small mobility service providers with few IT (Information Technology) resources. To face this problem, this work illustrates an IT infrastructure to support information and service integration. On a conceptual level, this paper presents a travel information system architecture and respective information flows between components, eg, intermodal routing, pricing and accounting. As realization, the authors developed and tested a communication adapter that enables and eases information exchange between the ATIS and heterogeneous second party service providers, eg, carsharing operators. Furthermore, the authors developed a method of extending traditional public transportation routing using the exchanged information about sharing services. This enables travelers to query intermodal itinerary information combining public transport, bikesharing as well as carsharing services using a single application. The overall system was tested in a three-month testing phase. Initial results are promising.