OneBusAway is a collection of open-source tools and libraries designed with one goal in mind:
Making public transit easier to use.
Rider information can be anything from maps and schedules to real-time arrivals and service alerts. Check out the YouTube video to see an example of the services OneBusAway offers:
The core features of OneBusAway are contained in the OneBusAway Application Suite. Check out the OneBusAway Application Suite wiki page for details.