Ghost trips on bus lines
by multimob — written on 2023-02-02
Here is one more challenge when dealing with GTFS data.
TEC Charleroi recently announced that they will cancel some trips on tram route M4, and new timetables will be published in February. So far, everything goes fine, timetables can vary with fewer or more trips on each release. From a technical point of view, this is standard procedure and it is very easy to deal with this.
But they acknowledge the reason: for various reasons (which can be a shortage of staff, or the need to close underground tram stations earlier than before, or to save on operating costs) those trips were already non-existing for several months.
This means that until now, several trips were on the official timetable printed everywhere, exported onto GTFS and announced by every app relying on this data… but passengers had zero chance to see a tram coming. Apparently, the information was posted locally, on paper posters in some of the stations.
The purpose of this post is not to discuss why those trips were cancelled, but to explore the potentially impossible challenge here, for whoever wants to provide correct PT information. There are a few things which we have no choice than blindly trust. The existence or location of stops can be fairly easily checked, even remotely if we have good aerial imagery or local correspondents sharing their survey notes, even itineraries can be surveyed manually, though it will take a lot of time. But checking timetables is another level.
So far, no solution, unfortunately. The only consolation can be that this problem of having "ghost trips" on tram route M4 will be gone shortly, and that this situation is thought to be extremely rare elsewhere.
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