Prediction time is the same across stops
Prediction time decreases across stops
After talking to a few agencies, it looks like the first can occur in systems that don't have a high precision of scheduled arrival/departure times in static GTFS stop_times.txt. So, if they have the same scheduled times across several stops, and the RT system is schedule deviation-based, it will also predict the same RT arrival/departure times across stops. So agencies may want to ignore this in certain cases (although ideally the system would provide better predictions).
The second case is always an RT error - the bus should never travel backwards in time when moving between stops.
So, we should split out these two cases into different rules.
Question - do we downgrade the first case to a warning? Maybe we make E022 specific to traveling backwards in time, and add a warning for the first case?
Also, let's rename the rule to make it easier to understand (e.g., predictions vs stop_time_update).
Issue by barbeau Feb 12, 2020 Originally opened as https://github.com/CUTR-at-USF/gtfs-realtime-validator/issues/365
Summary:
E022 rule currently flags two cases:
Prediction time is the same across stops Prediction time decreases across stops After talking to a few agencies, it looks like the first can occur in systems that don't have a high precision of scheduled arrival/departure times in static GTFS stop_times.txt. So, if they have the same scheduled times across several stops, and the RT system is schedule deviation-based, it will also predict the same RT arrival/departure times across stops. So agencies may want to ignore this in certain cases (although ideally the system would provide better predictions).
The second case is always an RT error - the bus should never travel backwards in time when moving between stops.
So, we should split out these two cases into different rules.
Question - do we downgrade the first case to a warning? Maybe we make E022 specific to traveling backwards in time, and add a warning for the first case?
Also, let's rename the rule to make it easier to understand (e.g., predictions vs stop_time_update).