I had earlier written some PT schema thoughts on my wiki page. I’ve since had some more ideas, which I figured I’d try sharing via diary and see how they are received.

Non-breaking extensions to PTv2

Classed by use cases. (I’ve probably missed some. Please do point them out.)

1. Simple routes

The Stereo system - stops + optional via-points to disambiguate route. No route segments - consumers should generate that themselves.

This makes it significantly easier to create and maintain bus routes, to say nothing of train routes. It also removes some cases of relation-breakage. OsmAnd already supports such relations, although it doesn’t display the route itself in route visualization, only the stops.

(I don’t know of anything else that supports this. Indeed, PT Assistant in JOSM complains about “stop not served” for such relations. If you know of anything that does, please share it.)

2. Stations + varying platforms (trains, buses)

Same as #1 but use stations instead of platforms.

3. Stations + fixed platforms

Same as #1 but maybe platforms should be part of a stop area relation (depicting the station? But isn’t a stop area distinct from a station?), so routers know which station a platform belongs to.

Alternatively, platforms should have the same name=* as the station. (Tag duplication alert)

4. hail_and_ride, ferry routes

Use PTv2. Stop positions to mark start and end of route, ways to show route.

Breaking-change ideas for PTv2

1. Multiple values for public_transport=* - introduces duck tagging goodness to PT, doesn’t abuse tag semantics (like e.g. highway=bus_stop or railway=station do), and supports multi-modal stops.
   • platform values - bus_stop, minibus_stop, share_taxi_stop, train_platform, metro_platform [1], etc
   • station values - bus_station, metro_station, railway_station, etc

[1] In India, “subway” is an underground pedestrian crossing or a sandwich place, never an intra-city mass transit railway. Duck tagging, to me, implies that tags are directly used by editors, rather than the editing software acting as a go-between, and that these tags should be as close to the editors’ vernacular as possible. To me, this entails that tags get regional variants, e.g. highway=* should be road=* in all applicable countries.

NB - I still don’t know what to make of stop positions. In the past I was of the opinion that they are useless outside of maybe marking the start and end of a route, but they may serve some niche use cases (can anyone please enumerate them?)