Matching and delays

Vehicles to trips and routes

from gtfs_rt_kit import filter_by_route, match_vehicles

matched = match_vehicles(feed, gtfs)
for item in filter_by_route(matched, "15"):
    print(item.vehicle.vehicle_id, item.line, item.mode, item.trip and item.trip.headsign)

The route of a vehicle is resolved from its trip descriptor's route_id, then from the static trip, then from an optional route_hint callable. Each candidate is looked up as a route id first and as a short name second. filter_by_route() compares route ids, short names and raw route keys case-insensitively.

Some feeds encode the line elsewhere. The Warsaw feed, for instance, uses vehicle ids like V/15/7; pass route_hint=gtfs_rt_kit.warsaw.route_from_vehicle_id, or write your own Callable[[VehiclePosition], str | None].

Delays of a trip update

from gtfs_rt_kit import trip_delays

update = feed.trip_update_for(trip_id)
for stop in trip_delays(update, gtfs):
    print(stop.stop_id, stop.event, stop.scheduled, stop.predicted, stop.delay)

For each stop time update the arrival is used when present, otherwise the departure. An explicit delay in the feed wins; otherwise the delay is time - scheduled. Skipped stops are flagged with skipped=True.

The service date comes from the trip's start_date, falling back to the local date of the update's timestamp, or can be passed explicitly with service_date=. Scheduled times follow the GTFS definition ("noon minus 12 hours"), so trips past midnight and days with a daylight-saving change are handled correctly.

Delay of a vehicle

estimate_vehicle_delay(vehicle, gtfs) compares a vehicle's timestamp with the scheduled time at its current stop. It is a rough estimate that only applies when the vehicle is stopped at (or reported at) a stop of a known trip; otherwise it returns None.