Real-Time Data in GTFS-realtime Format

GTFS-realtime is a new standard developed by Google for delivering real-time data. It is in Protocol Buffer format and needs to be combined with General Transit Feed Specification (GTFS) schedule data to be meaningful. The result is a highly efficient way to deliver data about many routes and vehicles at once using a minimum of bits and with total GTFS compatibility.

The MBTA has the following GTFS-realtime feeds available:

  • Bus predictions (in production)
  • Bus locations (in production)
  • Alerts (in production)
  • Systemwide predictions (all available data, including bus) (IN BETA)
  • Systemwide vehicle locations (all available data, including bus) (IN BETA)

This is not intended as a replacement to the MBTA-realtime or NextBus API's. API's and GTFS-realtime have different strengths: API's are easier to use on its own for queries of just one stop or one route; the GTFS-realtime feed lets you get information on everything at once, but needs to be sorted through using GTFS to make sense.

Use of the Feed

Access to the MBTA GTFS-realtime Feed is governed by the language in the MassDOT Developers License Agreement in addition to the following conditions:

• The MBTA reserves the right to suspend the data feed, modify the feed, or modify elements of the feed at any time in the MBTA's sole and absolute discretion.

• The MBTA will not guarantee any technical support of any kind to users.

• No user may execute polling commands more often than every 10 seconds.  A user that polls more often than that or otherwise overtaxes the MBTA's system may be suspended or terminated from the data feed.

More about GTFS-realtime

Google has published documentation on the GTFS-realtime format, including the .proto file which is necessary to interpret it.

More about Protocol Buffers

Google has published documentation on the Protocol Buffer fomat.

Accessing the Data

We currently publish the following:

• Bus predictions
Bus vehicle positions 
• Alerts
Systemwide predictions  BETA
• Systemwide vehicle positions BETA