Desk
Feeds & Standards
GTFS, GTFS-Realtime, GTFS-Flex, GBFS, GOFS, and the specifications themselves.
06entries
On this desk
Explainers
Roundup
September 2026 roundup: alert images go final and an unwritten GTFS rule gets written
What moved on the transportation data layer from early August to early September 2026: two GTFS merges on the same day, MDS 2.1 emergency zones prototyped in Seattle, and three proposals in the queue that would change what a feed carries.
Explainer
GTFS-Flex: dial-a-ride in the GTFS spec, and who actually publishes it
GTFS-Flex has been part of the core specification since March 2024, and the validator polices it with 29 dedicated checks. We read every feed in the Mobility Database to see how many agencies actually use it.
Explainer
MDS, GBFS, and CDS: the shared-mobility data stack, mapped
Three specifications cover the same scooters, bikes, and delivery vans, and practitioners routinely pick the wrong one. Here is what each was built to answer, why MDS requires a public GBFS feed, and where the boundary between them actually falls.
Explainer
What GTFS is, and how a transit feed fits together
GTFS is the open format that puts transit schedules into your maps app. Here is what a feed contains, how its files join together, and why it became the default for transit data worldwide.
Explainer
What GTFS-Realtime is, and how a feed works
GTFS-Realtime is the standard for live transit data: what a feed carries, how Protocol Buffers structure it, and why the quality rests on the systems behind it.
Explainer
How real-time arrival predictions actually work
The countdown on the sign is a prediction, not a readout of a bus you can see. Here is the data chain behind it, from the vehicle's GPS to the feed the sign reads, and the three ways agencies turn location into a time.