block_trips_with_overlapping_stop_times: overlapping trips in a block Error

Two trips with the same block_id overlap in time on a common day, which one vehicle cannot do. Why it happens and how to fix it in trips.txt.

Updated on 21 October 2026

What this rule means

The block_id field of trips.txt groups the trips one vehicle runs in sequence. A vehicle runs one trip at a time, so two trips of the same block must not overlap. The rule fires when two trips sharing a block_id run on the same day (their service_id values have at least one date in common) and the span from the first to the last time of one trip overlaps the span of the other.

Severity: error.

Why it matters

Feed consumers use block_id to tell riders they can stay on board from one trip to the next, and to match real-time data to the right vehicle. An impossible block breaks both: "stay on board" connections announced wrongly, vehicle positions attached to the wrong trip.

Common causes

A trip moved in time without its block being reviewed.
block_id values reused from one period to the next while the two periods' calendars overlap.
Two services (weekday and Saturday, for example) carrying the same block_id and sharing dates because of an exception in calendar_dates.txt.
A block_id filled in by mistake with the route number or a commercial service code.

How to fix it

For each reported pair, first check the two trips' times in stop_times.txt: if one is wrong, correct it. If the times are right, the block is wrong: give one of the trips the block_id of the vehicle that actually runs it, or empty the field if that information is not known (it is optional). If the two trips were not meant to run on the same day, the calendar is what needs fixing.

In GTFS Express, the validation report names the trips involved. "Fix one by one" opens the row concerned in the editor; each correction is a retouche in the draft, and "Re-validate" checks that the block now holds.

Example

Trip T2 leaves before T1 arrives, with the same vehicle:

trip_id,arrival_time,departure_time,stop_id,stop_sequence
T1,07:00:00,07:00:00,S100,1
T1,07:40:00,07:40:00,S200,2
T2,07:30:00,07:30:00,S200,1
T2,08:10:00,08:10:00,S100,2

route_id,service_id,trip_id,block_id
L1,WKD,T1,B12
L1,WKD,T2,B12

If T2 is run by another vehicle, it gets another block:

route_id,service_id,trip_id,block_id
L1,WKD,T1,B12
L1,WKD,T2,B14