An operator bidding across three countries quickly finds out that "send us real-time data" does not mean the same thing everywhere. France, the UK, Germany and the Nordics have each built their ecosystem around a different combination of GTFS-RT, SIRI and NeTEx, and none of these formats cover the same scope. Conflating the three is where most compliance delays on an export market start.
Three formats, three different jobs
GTFS-RT was built at Google to feed Google Maps: a lightweight binary format describing vehicle positions, trip updates and service alerts. Its strength is simplicity and mass adoption by consumer-facing aggregators.
SIRI (Service Interface for Real Time Information) is the European standard for real-time data (CEN, EN 15531). It is richer than GTFS-RT and also covers system-to-system exchange between control centres, not just distribution to passenger-facing apps.
NeTEx does not handle real time at all. It is the European format for exchanging static, structural data, lines, stops, scheduled timetables, fares, interchanges. It is the reference layer EU regulation is pushing as a common baseline, alongside SIRI for real time.
A tender that asks for "a NeTEx interface for real-time data" is revealing a basic confusion about what the format actually does, and that confusion is not rare.
What each market actually requires
France. The national access point, transport.data.gouv.fr, accepts both families, GTFS/GTFS-RT and NeTEx/SIRI, but the regulatory direction is toward NeTEx for the static reference layer and SIRI for real time, in line with the EU's multimodal travel information regulation.
United Kingdom. The Bus Open Data Service (BODS) requires a specific triad from bus operators: TransXChange for scheduled timetables, SIRI-VM for real-time vehicle positions, and NeTEx for fares. GTFS-RT mostly exists as a third-party conversion of BODS feeds, not as a native format.
Germany. Interoperability runs on VDV Recommendation 453 (system-to-system exchange between control centres) and VDV 454 (real-time interface to passenger information), both aligned with SIRI. The national platform DELFI then aggregates these feeds for multimodal passenger information.
Nordics. Norway, through Entur, built a NeTEx/SIRI profile that serves as a regional reference. Sweden's open-data ecosystem grew up around GTFS and GTFS-RT via Trafiklab, and is progressively aligning with the EU's NeTEx requirement for its national access point.
Italy and Spain. Neither market yet enforces a single national format. Common practice remains GTFS/GTFS-RT, driven by the pressure of Google Maps integration, while NeTEx adoption on the respective national access points is moving more slowly.
Portugal. The national access point, hosted by the Instituto da Mobilidade e dos Transportes (IMT) at nap-portugal.imt-ip.pt, collects mobility data under Regulation (EU) 2017/1926 and relies on DATEX II and NeTEx, with a national NeTEx profile adapted to Portuguese conditions. In the Lisbon metropolitan area, Carris Metropolitana's real-time data has been available in Google Maps since January 2024, and the operator states that this data is published in an open, public format.
Greece. The national access point, data.nap.gov.gr, is operated by a service of the Ministry of Infrastructure and Transport and offers real-time, historical and static datasets in several formats, without a single mandated format. In Athens, OASA publishes its bus timetable data as GTFS on the national open-data portal data.gov.gr, and its telematics system manages routes from OASA control centres in real time and feeds next-arrival information to passengers.
The common baseline: EU regulation
Commission Delegated Regulation (EU) 2017/1926, which governs EU-wide multimodal travel information services, requires each member state to make static data available through a national access point in a recognised European standard, in practice NeTEx and Transmodel. Commission Delegated Regulation (EU) 2024/490, adopted on 29 November 2023 and in force since 4 March 2024, revises that text: it extends the obligation to dynamic data such as delays, cancellations, disruptions and estimated arrival and departure times, phased in from December 2025. It still does not reduce real time to a single feed format, but SIRI remains the CEN-backed reference adopted by most European national access points.
This common baseline does not remove national variation. It sets a floor, every country then adds its own format details, update frequency and transmission channel requirements on top.
What this means for a multi-country vendor or operator
Three practical consequences follow from this fragmented landscape.
The format choice is not a one-time decision. A system that natively handles GTFS-RT, SIRI and NeTEx, rather than one built around a single format with converters bolted on afterward, avoids rebuilding the integration for every new market.
Static reference data and real-time feeds are not interchangeable when reading a tender. A specification can require one without the other, or both in different formats, so it needs to be read clause by clause rather than assumed to follow a single standard.
Update frequency and transmission channel vary as much as the format itself. UK SIRI-VM, French SIRI and German VDV 454 do not share the same latency constraints or authentication mechanisms, even when built on the same base standard.
Frequently asked questions
Are GTFS-RT and SIRI interchangeable?
No. They cover a similar functional scope, vehicle positions, schedule updates, but SIRI is richer and more widely used for system-to-system exchange in Europe, while GTFS-RT dominates distribution to consumer aggregators like Google Maps.
Does NeTEx replace GTFS?
Not technically. NeTEx is the European standard for static data, GTFS remains a widely used competing format for the same purpose. Both coexist on most European national access points.
Should a vendor pick one format to export across Europe?
No, that is rarely possible. The practical approach is a system that can natively publish in whatever format each market expects, rather than betting on full harmonisation in the near term.
Is this still changing?
Yes. EU regulation is pushing toward NeTEx for static data, and Delegated Regulation (EU) 2024/490 extends the obligations to dynamic data from December 2025, but each country keeps control of its real-time requirements and compliance timeline, so market-by-market verification stays necessary before every deployment.