Agencies Providing Real-Time Data

As a part of the Transit Appliance Project, I’ve been evaluating what transit agencies have real-time data; here’s a (non-exhaustive) list, focused primarily on U.S. agencies (note: these are only agencies that provide an API, not any agency with a real-time feed):

• TriMet, Portland, OR, custom JSON[-P] feed, XML may also be available. GTFS-realtime is also available.
• San Francisco Muni, via NextBus.
• Bay Area Rapid Transit (BART), San Francisco, CA, custom XML feed. Their Google Group is very responsive and helpful. GTFS-realtime is also available.
• AC Transit, Oakland, CA, via NextBus.
• Los Angeles Metro, both via NextBus and a custom XML API.
• Unitrans, Davis, CA, via NextBus. Their GTFS is hosted by Sacramento RT.
• MBTA, via NextBus. They have a GTFS at http://www.eot.state.ma.us/developers/ that has stop ids to match NextBus. They have a trial up for rail arrivals.
• Transport for London (TfL), custom XML API.
• Washington Metropolitan Area Transit Authority (WMATA), custom XML/JSON[-P] API; has real time arrivals for rail, but only positions for buses (no arrivals).
• DC Circulator, via NextBus. I couldn’t find any public GTFS.
• Chicago CTA, custom XML API for buses, no arrival data for trains yet.

I know that there are a ton that aren’t on here; as I do more research, I’ll put more up.