# ITS Feed > Reporting and explainers on the data and technology layer of transportation: transit feeds, technical standards, interoperability, data quality, and agency systems. Every figure traces to a source cited by an inline link. Measurements are US customary. Published by the team at Veodyn. Canonical: https://its-feed.com/ --- ## Latest - [September 2026 roundup: alert images go final and an unwritten GTFS rule gets written](https://its-feed.com/articles/roundup-2026-09/): 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. (Roundup, published 2026-09-04) - [Agency data in OpenStreetMap: the map has your stops, not your identifiers](https://its-feed.com/articles/transit-data-in-openstreetmap/): OpenStreetMap mappers have already placed most of the objects an agency wants to contribute, and placed them well. What the map lacks is the agency's own IDs, which is the one thing only the agency can supply. (Explainer, published 2026-08-27, updated 2026-08-28) - [GTFS-Flex: dial-a-ride in the GTFS spec, and who actually publishes it](https://its-feed.com/articles/what-is-gtfs-flex/): 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, published 2026-08-21) - [Open-loop tap-to-pay: what happens between the tap and the charge](https://its-feed.com/articles/open-loop-tap-to-pay/): The gate opens before anyone has checked whether the card works. Here is the back office behind contactless transit fares: deny lists, aggregation, deferred authorization, and why most 2026 launches shipped at adult full fare only. (Report, published 2026-08-14) - [August 2026 roundup: the NTD goes public, MDS 2.1 ships, and alerts get a clock](https://its-feed.com/articles/roundup-2026-08/): What moved on the transportation data layer from mid-July to early August 2026: FTA's Transit Moves America dashboard, a federal question about whether real-time data counts as service quality, the MDS 2.1 release, and two new GTFS-Realtime alert fields. (Roundup, published 2026-08-07) - [MDS, GBFS, and CDS: the shared-mobility data stack, mapped](https://its-feed.com/articles/shared-mobility-data-stack/): 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, published 2026-07-31) - [AI in transit: where it's real and where it's a demo](https://its-feed.com/articles/ai-in-transit/): Transit agencies are running machine learning in production today, but not in the places the marketing points to. Here is what the working deployments have in common, and why the ones that stall usually stall on data rather than on models. (Explainer, published 2026-07-24) - [July 2026 roundup: open-loop fares, the NTD's new rules, and MDS 2.1](https://its-feed.com/articles/roundup-2026-07/): What moved on the transportation data layer from mid-June to mid-July 2026: World Cup open-loop fare launches, new National Transit Database reporting rules, MDS 2.1 in preview, and AI landing in agency software. (Roundup, published 2026-07-16) - [What GTFS is, and how a transit feed fits together](https://its-feed.com/articles/what-is-gtfs/): 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, published 2026-07-15) - [What GTFS-Realtime is, and how a feed works](https://its-feed.com/articles/what-is-gtfs-realtime/): 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, published 2026-07-14) - [What intelligent transportation systems actually are](https://its-feed.com/articles/what-are-intelligent-transportation-systems/): Intelligent transportation systems is a broad label that hides a precise idea. What ITS covers, what it looks like on the street, and why 253 of the 304 standards in the national architecture are about nothing but getting data from one system to another. (Explainer, published 2026-07-13, updated 2026-08-21) - [How buses talk to traffic lights: transit signal priority](https://its-feed.com/articles/transit-signal-priority/): Transit signal priority lets a late bus ask a traffic signal for a few more seconds of green. Here is the request-to-grant message chain, how it differs from emergency preemption, and how NTCIP 1211 lets mixed-vendor buses and controllers interoperate. (Explainer, published 2026-07-06) - [Mobility as a service: what actually stuck](https://its-feed.com/articles/mobility-as-a-service/): Mobility as a service promised one app to plan, book, and pay for every trip on a subscription. The flagship consumer bundle went bankrupt. Here is what the idea got right, what it got wrong, and which pieces survived. (Explainer, published 2026-06-29) - [Bus bunching and headway: why three arrive at once](https://its-feed.com/articles/bus-bunching-and-headway/): Three buses arriving nose to tail is not bad luck. It is a feedback loop in frequent service, where a late bus falls further behind and the one behind it catches up. Here is the mechanism, why agencies measure headway instead of schedule, and what they do about it. (Explainer, published 2026-06-25) - [Ghost buses: why the app shows a bus that never comes](https://its-feed.com/articles/ghost-buses/): A ghost bus is a prediction with no vehicle behind it. Here is how a transit app generates one, the four ways it happens, and how Chicago drove its rate down. (Explainer, published 2026-06-23) - [How real-time arrival predictions actually work](https://its-feed.com/articles/how-real-time-arrival-predictions-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. (Explainer, published 2026-06-19) - [What the National Transit Database actually holds](https://its-feed.com/articles/national-transit-database/): The NTD is the federal record of US public transit: who rides, what it costs, and who has to report. Here is what it holds, who files it, and how to pull the numbers yourself. (Explainer, published 2026-06-18) - [Fare payment modernization: account-based ticketing, fare capping, open-loop](https://its-feed.com/articles/fare-payment-modernization/): Agencies are moving fare logic off the card and into a back office. Here is what account-based ticketing, fare capping, and open-loop payment each mean, and which agencies have made the switch. (Explainer, published 2026-06-17) ## Lanes - [Feeds & Standards](https://its-feed.com/topics/feeds-standards/): GTFS, GTFS-Realtime, GTFS-Flex, GBFS, GOFS, and the specifications themselves. - [Interoperability](https://its-feed.com/topics/interoperability/): NTCIP, TMDD, and the work of getting agency systems to exchange data. - [Quality & Compliance](https://its-feed.com/topics/quality-compliance/): Validation, conformance, feed health, and reporting such as NTD and SB125. - [Agency IT](https://its-feed.com/topics/agency-it/): Transit agency data modernization, core systems, and procurement. - [Data Platforms](https://its-feed.com/topics/data-platforms/): Catalogs, tooling, and the mobility-data platforms practitioners build on. - [AI in Transportation](https://its-feed.com/topics/ai/): Machine learning applied to the transportation data and technology layer. ## Elsewhere - [Events](https://its-feed.com/events/): Curated industry events on this beat. - [About](https://its-feed.com/about/): What ITS Feed covers, how it is edited, and who publishes it. - [Site index for agents](https://its-feed.com/llms.txt): Every page, grouped by lane (llmstxt.org). --- Source: ITS Feed, https://its-feed.com/ ITS Feed is an independent editorial site on the data and technology layer of transportation, published by the team at Veodyn. Figures trace to the sources linked inline. Site index for agents: https://its-feed.com/llms.txt