fast_travel_between_consecutive_stops: implausible speed Warning
Between two consecutive stops of a trip, the distance and the times imply a speed the mode cannot reach. Common causes and the fix in stop_times.txt.
What this rule means
For each trip, the validator takes two consecutive stops in stop_times.txt, measures the distance between their positions in stops.txt and divides it by the time between the departure from the first and the arrival at the second. If the resulting speed exceeds the plausible limit for the route's mode (route_type), for example more than 150 km/h for a bus, it raises this notice. Severity: warning.
The limits depend on the mode: a train may run far faster than a tram. The report gives the computed speed and the two stops involved.
Why it matters
A warning does not block a delivery in GTFS Express, but an impossible speed nearly always points to wrong data. Riders get an unrealistic travel time, and a journey planner may offer a connection that does not work on the street.
Common causes
- A stop with wrong coordinates, placed in another town or at latitude zero.
- A typo in a time,
08:05:00instead of08:50:00. - Two distant stops sharing the same time, because a stop in between was removed or times were rounded to the minute.
- Times shifted by one hour on part of the trip.
How to fix it
Check the position of both stops first (stop_lat, stop_lon). If they are right, correct arrival_time or departure_time in stop_times.txt so that the running time matches the real distance.
In GTFS Express, the validation report lists each occurrence with its trip and its two stops. "Fix one by one" opens the stop_times.txt row in the editor with the field flagged, and the trip's timetable helps spot the odd value. The correction becomes a retouch in the draft, then "Re-validate" runs the check again.
Example
Stops STATION and NORTH_PARK are 9 km apart, yet the trip takes one minute:
trip_id,arrival_time,departure_time,stop_id,stop_sequence
T12,08:04:00,08:05:00,STATION,5
T12,08:06:00,08:06:00,NORTH_PARK,6The real time was 08:16:00:
trip_id,arrival_time,departure_time,stop_id,stop_sequence
T12,08:04:00,08:05:00,STATION,5
T12,08:16:00,08:16:00,NORTH_PARK,6See also the guide Validate a GTFS feed and the list of rules.