The Korean high speed railroad is scheduled to open in 2004. For railroad-based integrated transfer system, it is essential to develop the intermodal information system for easy transfer to other travel modes. The understanding of mode choices by KTX passengers is crucial for the intermodal transportation planning. Recent development of Intelligent Transportation Systems(ITS) made it possible for railroad users to access the transportation information in a cabin or waiting areas at the station. Development of intermodal transportation information system will influence the relative demand for traveling by train from competing other transportation modes. The research is focused on a general overview of the ITS with an emphasis on intermodal transportation information system.