GTFs

GTFS, the General Transit Feed Specification, is a data format for public transportation schedules and related geographic information. It provides a common structure that allows transit agencies to publish public transit data in a machine-readable form, enabling trip planners, map services, and apps to ingest and present schedules and routing information. The format originated with Google in the mid-2000s to support Google Transit and has grown into an open, community-maintained standard used worldwide.

GTFS data are delivered as a collection of CSV text files contained in a ZIP archive. Core files include agency.txt (operator information), stops.txt (locations and attributes), routes.txt (service lines), trips.txt (individual trips on routes), stop_times.txt (timed stop sequences for trips), and calendar.txt or calendar_dates.txt (service calendars and exceptions). Optional files add detail: shapes.txt (geographic routes), transfers.txt (transfer rules), frequencies.txt (headways), fare_attributes.txt (pricing), and translations.txt (multilingual names). The feed_info.txt file may provide metadata about the feed. GTFS is primarily a static schedule specification, though it can be extended with additional data fields.

GTFS-Realtime is a complementary component that provides real-time updates, such as vehicle positions, trip updates, and service alerts, using a separate protobuf-based format. Together, GTFS and GTFS-Realtime support near-real-time trip planning and live transit information.

Governance and adoption: The specification is maintained by a community of transit agencies and developers, coordinated through organizations such as MobilityData and the Open Mobility Foundation. It is widely adopted by agencies and major mapping and transit apps, promoting interoperability and data integration across platforms.

Limitations include reliance on publishers for data quality and timeliness; GTFS captures planned schedules and static data, which may require real-time feeds to reflect deviations.