Proposal: Add cyclist position availability fields to VehiclePosition and CarriageDetails

[oliver-sturrock]

Problem

Transit passengers traveling with bicycles have no way to know whether a bike rack or storage area will be available on an approaching vehicle. Typical transit buses have only 2–3 external bike rack positions. When full, cyclists are denied boarding and must wait for the next vehicle or abandon their transit trip.

The Santa Clara VTA confirmed this problem in a USDOT SMART Grant pilot (FAIN: 69A3552341049), finding that denied boardings are a measurable service quality issue and that no transit agency in North America currently provides this data through standard feeds.

Proposed Solution

Add two new optional uint32 experimental fields to VehiclePosition and CarriageDetails:

Field	Message	Description
cyclist_positions_available	VehiclePosition (field 12), CarriageDetails (field 6)	Positions currently available
total_cyclist_positions	VehiclePosition (field 13), CarriageDetails (field 7)	Total capacity

This follows the same pattern used for occupancy_status, occupancy_percentage, and multi_carriage_details.

Working Producer Implementation

Sportworks Global LLC has a public GTFS-RT feed demonstrating the proposed fields:

• Feed URL: https://cascadia-metro-gtfs-rt.sportworks.com/gtfs-rt/vehicle-positions
• Static GTFS: https://cascadia-metro-gtfs-rt.sportworks.com/gtfs-rt/gtfs.zip

The feed has been validated against protoc, Python gtfs-realtime-bindings, and Node.js gtfs-realtime-bindings — all pass without errors. Full validation results will be included in the pull request.

Pull Request

A PR with the proto and reference.md changes will follow shortly.

Contact: Oliver Sturrock, olst+gtfs@silverfallscapital.com, Sportworks Global LLC / Silver Falls Capital

[skinkie]

total_cyclist_positions is data that should be part of the static data, not distributed within every message.

[gcamp]

I agree there should be a static version of total_cyclist_positions, but having it in real time also makes sense. For operational reasons, vehicles are sometimes switched. It's also why we have vehicle accessibility in real time.

[doconnoronca]

I've been working on my proposed vehicles.txt addition to GTFS that includes a bicycle capacity value, but until that is widely adopted including a total_cyclist_positions value would be quite useful in the real time information.

[oliver-sturrock]

total_cyclist_positions is data that should be part of the static data, not distributed within every message.

Yes, it makes sense to include this in the static data also.