Have a way to explicitly communicate that a trip does not have any headsigns

[evansiroky]

Describe the problem

In some small and rural agencies, the vehicles they operate don't have any headsigns and may merely have a vehicle with the overall transit agency name present. As promoted in #485, the headsigns field is being said the be "recommended". Therefore this creates a tension in assuming that data is missing when the headsigns data is not included.

Use cases

Two examples from California are shown below:

Morro Bay Transit:

Dana Point Trolley:

I would assume there are other places throughout the world where headsigns aren't used or don't exist.

Proposed solution

There should be a some language within the specification that specifically notes how to note that headsign information is excluded. The spec could be rewritten so that when headsigns are not included, this constitutes an acknowledgment that headsigns aren't used for the trip in question. Otherwise, a flag could be added to note that headsings aren't used for a particular trip.

Additional information

No response

[stevenmwhite]

I'm not sure it's necessary to explicitly state with a flag that a vehicle doesn't have headsigns. I'd definitely prefer it to be with a language change in the spec to make this assumption clear if the data is not present.

The current spec is "This field is recommended for all services with headsign text displayed on the vehicle which may be used to distinguish amongst trips in a route." So I would assume that a vehicle does not have headsign text visible if it's not included. Or, of course, that the feed is not following the recommendation, but a user who is validating a feed they produce will get a warning here and then make a choice whether to include that info or go ahead without it. That's my take as a producer.

I think the main question here, however, is whether a consumer will do something different depending on whether the data is missing or whether there is in fact no headsigns. I'm particularly curious to hear how the UI of a consuming application may change if the data is missing vs. there is no headsign present.

[miklcct]

I am using GTFS-RT to add trips with ScheduleRelationship = ADDED which does not currently have the ability to specify a headsign yet, so my consumers make up headsigns using the station name of the destination.

If there is really no headsign of a public transport vehicle in the real world, I also think that making it up by using the station name of the destination is reasonable, unless the trip is a loop line (in such case, a vehicle without headsign will confuse users), so for me I don't think I need to distinguish between these two cases.