[GTFS-Fares v2] Fare product/media transfer behavior

[tzujenchanmbd]

This PR covers the following questions regarding multi-leg transfer fares:

• Should fare transfers require that the same fare product is used on both legs?
• For a leg-to-leg transfer to match a row in fare_transfer_rules.txt, is it required that both legs have the same fare media type?
• Is it intended that multiple rows in fare_transfer_rules.txt can match a single leg-to-leg transfer?

In the November 2023 meeting, the working group leaned towards option one proposed in the spec modeling proposal, which allows producers to indicate in the fare_transfer_rules.txt whether specific transfer rules require the same fare product/media between two legs.

(For more detailed context, please see issue#420)

Changes in this PR

• Add fare_product_behavior, fare_media_behavior, and filter_fare_product_id fields to fare_transfer_rules.txt.

There are some data examples in the spec modeling proposal. For previous discussions, please see working group meeting minutes.

Please go through the changes and feel free to share your thoughts/questions here.

[jfabi]

The @mbta plans to begin producing fare_product_behavior, fare_media_behavior, and filter_fare_product_id, tentatively by 1 July. We'll check back here once these fields are up and running in production.

[jfabi]

The @mbta plans to begin producing fare_product_behavior, fare_media_behavior, and filter_fare_product_id, tentatively by 1 July. We'll check back here once these fields are up and running in production.

As of last week, the @mbta is now producing all three of these new fields in its GTFS-static feed, downloadable here.

[github-actions]

This pull request has been automatically marked as stale because of lack of recent activity. It may be closed manually after one month of inactivity. Thank you for your contributions.

[tzujenchanmbd]

Not stale

[tzujenchanmbd]

@felixguendling would Motis be interested in implementing this?

[felixguendling]

Yes, I think this makes sense and should be easy to implement in case it gets standardized.

[miklcct]

@leonardehrenfried

[leonardehrenfried]

Should it also apply to rider categories?

[leonardehrenfried]

For me this is no longer a theoretical question as Trimet's (Portland) feed would lead to a large number of possible combinations for each transfer.

For now I can add a frontend filter option that stipulates that rider category and medium must match but it would be nice if the spec would be more explicit.

[tzujenchanmbd]

Update:
The Fares v2 Working Group revisited this proposal during the May 27 meeting and confirmed the proposed changes.

Based on the discussion, to facilitate testing and adoption, we agreed to narrow the scope of this PR to focus on fare product/media behavior. The filter_fare_product_id field will be removed for now and can be added later if needed.

The behavior related to rider categories can be addressed in a separate change as well.

cc @jfabi @jll01