Modern public passenger travel is not possible without the extensive use of IT technologies. At the interface to the passenger, applications on static systems and also, increasingly, on mobile devices play an essential role. Beginning with the passenger’s desired journey, they include timetable information, ticket purchase, passenger care and smooth connections when services are disrupted. Today, public passenger services are being more attractive, with up-to-date individualized information available to travelers throughout their journey. The combination of satellite location with other localization technologies inside buildings and vehicles is essential for the development of integrated location-based services. All of these passenger applications must be secured by UPS systems.