This paper reports on the development of the "TAO Aide", an intelligent wheelchair with autonomous traveling capability. The wheelchair can accurately determine its position and direction using internal sensors and external assistance from the surrounding environment, including the Global Positioning System (GPS) and Radio Frequency Identification (RFID). It can also detect obstacles it encounters on the road using a laser range sensor. To confirm the effectiveness of our research results, for six months at the Aichi Expo 2005 we demonstrated the wheelchair system by offering trial rides to visitors. This paper describes the total system of "TAO Aide", the positioning method using GPS and RFID, and the autonomous traveling control based on accurate estimations of position and direction using Kalman filtering. Our experimental results at the Aichi Expo demonstrated that accurate trajectory following performance can be achieved using assistance from the infrastructure (GPS, RFID) and that "TAO Aide" could perform safe autonomous traveling without severe accidents.