"Direction names" in GTFS

[timMillet]

For the last update (2020-11-20) on the issue, please go to this comment.

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Hi everyone,

I’m opening an issue regarding “direction names” (also called “directions”, “route directions”, “direction destinations”, or “direction headsigns”) as some GTFS stakeholders already provide and consume these data. Before making any specification proposal, I would appreciate having your input on:

1. If you would like these data to be officially adopted in the GTFS specification.
2. On how these data should be modeled.
3. On the name you would give to these "direction names".

The needs are:

• Providing riders with more detailed information on directions, especially for routes with complex trip patterns (e.g: routes with branches). The direction name would be a piece of information complementary to the trip_headsign and/or stop_headsign.
• Being defined per route at the trip level, at the direction level (trips.direction_id), and/or at the stop_time level. The use cases would be:
  • trip and direction levels: defining a direction that is true for all trips going to the same direction at all their stop_times (e.g with the Red Line in Boston: direction “Southbound” for trips heading either to “Ashmont” or to “Braintree”)
  • stop_time level: defining a direction that is true for all trips going to the same direction at that particular stop_time (e.g: direction “Inbound” until the first downtown stop is reached, then “Outbound”)
• Being compatible with all king of general directions (e.g: “South”, “Southbound”, “Inbound”, “Clockwise”, “Loop”, “Intérieur”, “Sud vers Paris”, “T-Centralen”, “Fruängen/Norsborg”).

The current implementations are (Gdoc with more details):

• 1 new file with 3 to 4 fields: MBTA, MTC (SF Bay Area), Trillium, TriMet
• 2 new fields in already-existing files: Transit

Thank you for all your feedback!

[timMillet]

Thank you @antrim and @stevenmwhite for your feedback! Aaron - I added your recommendation to option D.

For general information, here is a synthesis of what was said by everyone since my last conversation update:

• Options A2 and D2 should be avoided, as trips of the same route-direction may have different direction names that are valid for the whole trip (e.g: stevenmwhite’s example, RER C). In these cases, options A2\D2 would force to assign direction names at the stop_time level.
• Options A2, D2, and E allow producers and consumers to unambiguously determine the preferred direction name to associate with a representation of a route-direction (e.g: on a timetable, on an app view).
• Options A/A2 and D/D2 are verbose (repetition of the same trip_direction_name or direction_name_id for every row for the same route_id and direction_id in trips.txt), but it’s easy for a software to duplicate a field on many rows.

[timMillet]

Converging to one modelization option

Following Aaron’s question in his last comment 15 days ago, we could say now that nobody else has an update on their opinion. So I guess It’s now the time to converge and choose one modelization, which I’ll try to do in this comment by following 3 steps:

• Compiling everyone’s opinion (in favor or against) for each modelization option.
• From the favorite options, highlighting the one that best meets the needs.
• Based on the 2 steps above, suggesting the best modelization option to converge to.

1. Community Opinions

Below is the compilation of everyone’s opinion for each modelization option. The goal is to highlight which option has the most stakeholder in favor and the less against. We can see that:

• Option D is the one with the most GTFS stakeholders in favor (4), but one stakeholder is against.
• Options A, A2, and E follow with 2 GTFS stakeholders in favor, but only the option E has no stakeholders against.
• Options B, C, and D2 received the least comments in favor.

Modelization option	Stakeholder in favor	Stakeholder against
Option A	2: Bliksem Labs B.V., Trafiklab	1: IBI Group
Option A2	2: Metropolitan Transportation Commission, IBI Group - maybe	1: GMV Syncromatics
Option B	0	0
Option C	1: Transit	0
Option D	4: Transit, GMV Syncromatics, Trafiklab, Trillium	1: IBI Group
Option D2	1: IBI Group - maybe	1: GMV Syncromatics
Option E	2: IBI Group, GMV Syncromatics	0

2. Supported Needs

Below is an array showing which needs (as defined at the beginning of the issue) are supported by the favorite options. I’ll do this exercise only with option D because it has the most GTFS stakeholders in favor, and option E because it has the most GTFS stakeholders in favor without anyone against. We can see that:

• Option D supports all the needs but one.
• Option E supports all the needs.

Needs	Option D	Option E
Defining direction names that are complementary to headsigns	Supported	Supported
Assigning direction names at the route-direction level	Not supported (but suggested in a way)	Supported
Assigning/editing direction names at the trip level	Supported	Supported
Assigning/editing direction names at the stop time level	Supported	Supported
Being compatible with all kind of general directions	Supported	Supported

3. Best Option

Based on these 2 points, I’d suggest moving forward with option E, even though option D has received the most opinions in favor. Option E has indeed no opponents and is the one that best meets the needs.

If you agree or disagree with this Best Option, please react to this comment with a thumb up 👍 or down 👎 , or comment below. If you thumb down, please let me know why, also in a comment below.

[antrim]

Option E looks good.

[timMillet]

Hi everybody,

Thank you for your feedback! We are looking for data producers and data consumers to make the first implementations of this proposal. Please let us know if you are interested! You can reach us in this issue or specifications@mobilitydata.org.

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