General Transit Feed Specification
The timetable, as data.
GTFS is the format agencies use to publish their schedules. It is how trip-planning apps know when the next bus is due.
A GTFS feed is a zip file of plain text tables. Each table describes one thing: the stops, the routes, the trips, and the time each trip reaches each stop.
Inside TransitAI Core, GTFS is the definition of the plan. Everything that happens on the street is measured against it, which is how a delay gets its meaning.
Timetables change a few times a year, so they come in through the batch lane.
stops.txt where vehicles stop routes.txt the lines riders know trips.txt each run of a route stop_times.txt when a trip reaches a stop calendar.txt which days service runs