GTFS
An open standard for publishing public transport timetables, stops and routes as a set of text files, so any software can read the same data.
GTFS, the General Transit Feed Specification, is the common format in which public transport operators publish their timetables. A GTFS feed is a ZIP file of plain text tables: one for stops, one for routes, one for trips, and one for the time each trip reaches each stop, plus a few more for service days and fares. Because every feed has the same structure, a journey planner, a map or an analysis tool can read any of them without a custom import.
The format started in 2005 as a collaboration between Google and TriMet, the public transport agency of Portland, Oregon, and was first called the Google Transit Feed Specification. Today it is an open standard maintained by its community. The timetable part is called GTFS Schedule. A separate extension, GTFS Realtime, carries delays, cancellations and vehicle positions.
For accessibility analysis, GTFS is what makes public transport measurable. Departures per stop, waiting times and travel times by bus and train all come from the timetable. In Germany, DELFI publishes a nationwide GTFS feed, and it is the data behind our analyses for Agora Verkehrswende and Greenpeace. In GOAT, the public transport indicators run on GTFS, and since version 3.0 you can upload a feed for any region yourself.