The OneBusAway (OBA) transit traveler information system has existed as a service for transit riders since the summer of 2008 at http://onebusaway.org. The current primary use of OneBusAway is to provide real-time next bus countdown information for riders of King County Metro (KCM) in greater Seattle (Ferris et al., 2009). OneBusAway does this by using the underlying data feed from KCM’s Automatic Vehicle Location (AVL) system and the prediction algorithms developed by Dr. Daniel Dailey and others from the Electrical Engineering department at the University of Washington (Maclean and Dailey, 2002). OneBusAway provides a more user-friendly interface to KCM’s AVL data by providing multiple means to access the data, including a website, a standard telephone number by which arrival information is read by the computer, an SMS interface for text-messaging, a website optimized for internet-enabled mobile devices, an iPhone application, and an Android application. The OneBusAway interface that has received the most attention to date has been the location-aware native iPhone application (Ferris et al., 2010a), shown in Fig. 1. OneBusAway is being developed as an open-source system to allow other developers to enhance the code in conjunction with the project team, as well as allowing other transit agencies to access the code and use it themselves.