Describe the problem

We have received multiple messages from agencies confused by an error (stop_without_zone_id) found in validation reports forwarded to them by the National Transit Database. I've investigated the error and am wondering if the way the spec handles zone_id requirements should be clarified, and if so, whether such a clarification would break backwards compatibility. I'm not sure, because it is a conditional requirement, and adding the exception I propose below would be easing a restriction, not adding a new one.

The current requirement is essentially: If fare_rules.txt contains records, then presence of zone_id is required for all stops in the dataset.

However, there are cases where you could define a fare_rule without the use of zone_ids, for example, with route-based fares. In my opinion, a feed should still be valid with partial zone_id presence IF those stops without a zone_id are present in stop_times records with a trip_id whose route_id is present in a fare_rules.txt record with only fare_id and route_id defined.

Use cases

Consider the following example

fare_rules.txt

stops.txt

Given that stop_id=111 is present only in route_id=50 trips, you can determine that any itinerary that includes the stop will have a fare of fare_id=7549 since it belongs to route_id=50. Giving the stop a zone_id would be superfluous because there is no fare rule that zone would belong to.

Proposed solution

Is it possible to modify the conditional requirement, adding the following exception to the rule?

"Required if providing fare information using fare_rules.txt, unless stop is present only in stop_times.txt records with a trip_id whose route_id is present in a fare_rules.txt record with only fare_id and route_id defined."

Ideally written in a less confusing way 😅

Additional information

I have attached an example dataset you can run through the validator to see the stop_without_zone_id error in question.

stop_without_zone_id_feedTEST.zip

You will find several stops without zone_ids accounted for by route-based fares that trigger the error.

To my knowledge, feeds containing the stop_without_zone_id due to this reason have passed validation of consumers like Google.