This paper presents the design and evaluation of an online passenger information system for delivering personalized multimodal trip planning services through the integration of wireless and Web-based communication technologies. The goal of the system is to provide real-time travel information throughout the entire life cycle of an interurban trip. Before the full-scale deployment of this type of system, it is essential to assess its impact on the involved stakeholders through a pilot application. The proposed system (ENOSIS) has been implemented and evaluated for supporting travel decisions in Greece. An evaluation framework for assessing the impacts of the ENOSIS system is proposed, and the evaluation results of the ENOSIS pilot application are also reported. The evaluation results provide significant evidence of the technical and operational efficiency of the ENOSIS services, while it is shown that the proposed system is cost effective.