The same Navigo pass that works on all the different validators, the same information about the next passage of a metro given on many transport applications... Behind these seemingly simple services lies interoperability.
For several years now, mobility has been undergoing a profound digital transformation. Every day, transport operators, local authorities, digital services and users rely on a wide variety of data to plan, circulate, coordinate fleets, analyse mobility or build new services.
In this ecosystem where the players are numerous and heterogeneous, one question becomes central: how to make everything work together?
This is exactly the role of interoperability, a founding principle of the PRIM platform.
What is interoperability?
Interoperability refers to the ability of different systems (software, APIs, databases, operators) to exchange information automatically, without manual intervention.
In concrete terms, it is the guarantee that the data produced by an operator can be understood, combined and reused by all the other players. It is based on three complementary dimensions:
1. Technical interoperability : It ensures that the data uses standard and documented formats that are understood by all. On PRIM, this is materialized by the use of standards defined by the CEN (European Committee for Standardization) within the framework of the Mobility Orientation Law: SIRI, NeTEx, GTFS.
2. Semantic interoperability : It ensures that data means the same thing everywhere: a stopPoint, a line, a journey, etc. European standards provide this common vocabulary. This vocabulary is defined by Transmodel, the European normative framework for the exchange of transport data.
3. Organizational and legal interoperability : It is based on rules of use : Open licenses (Etalab, OdBL, Creative Commons), Legal obligations (LOM law, European MMTIS regulation – MultiModal Travel Information Services), Clear responsibilities between actors.
With this framework,PRIM data can flow freely, feeding applications, analytics, or MaaS services.
Standards from the European framework
Digital interoperability is now a priority for the European Union. The Interoperable Europe Act and the European Interoperability Framework (EIF) set out a common framework:
· Shared technical standards,
· Reusability of solutions,
· Harmonization between digital public services,
· Digital transformation by 2030 aimed at building fully interoperable public digital systems.
· The standards used in PRIM : NeTEx and SIRI in accordance with European standardization and restricted to information sharing needs in the Île-de-France region.
They guarantee cross-border coherence and encourage the creation of reliable multimodal services in a context of competition where European players may be required to operate in the Île-de-France region.
The main standards used in PRIM
GTFS — Theoretical data : A widely used format, initially supported by Google and which is continuously evolving under the impetus of the Mobility Data structure. It describes the lines, schedules, stops, routes and services of a network.
NeTEx — Theoretical data (European standard): Structured format in XML, designed to represent an entire network: lines, stops, missions, fares, accessibility, calendars, etc. It is used in the IBOO, ICAR, ILICO APIs to describe the Île-de-France transport network.
SIRI — Real-time data (European standard): Standard for the exchange of dynamic data: passages, disturbances, positions. On PRIM, three modules are used:
· SIRI-SM (StopMonitoring): next passes to the stop mesh.
· SIRI-ET (EstimatedTimetable): next run-stitch runs.
· SIRI-SX (SituationExchange): disruptions and passenger messages.
It is used for the dissemination of real-time data.
How does interoperability materialize in practice in PRIM?
To illustrate the use of standards in a tangible way, here are two concrete examples from the daily operation of PRIM.
1. Aggregate the next multi-operator passes (SIRI-SM / SIRI-ET): When operators publish their real-time data via SIRI feeds, IDFM can automatically group the next passes of several networks on the same stop or run. A single API available on PRIM is enough to obtain the passages of buses, trams and trains, even if they come from different internal systems/SAEIV/Fluxes.
2. Describe a complete network with a single standard (NeTEx): The theoretical data of the network — lines, stops, missions, schedules, accessibility — are all structured in NeTEx. IDFM thus produces a coherent and complete network referential available on PRIM.
The structuring role of AOM d'Île-de-France Mobilités
Île-de-France Mobilités plays a key role in data interoperability:
· It sets the standards to be respected by operators.
· It guarantees the consistency of the standards at the territorial level.
· It applies the legal framework resulting from the LOM Law and the European regulation (openness, free of charge, free redistribution)
· It ensures the quality and standardization of the data integrated into PRIM.
Without this governance, data aggregation would be impossible or fragile.
Why interoperability is essential to MaaS
A MaaS (Mobility as a Service) service is based on a simple promise:
To offer the user a unified vision of all available modes of transport. To do this, you must:
· Comprehensive data (all modes),
· Homogeneous (common standards),
· In real time,
· Coming from dozens of different actors,
· Aggregated instantly.
Without interoperability, no MaaS can work. The NeTEx and SIRI standards, combined with the role of PRIM, allow precisely this continuous aggregation. PRIM thus becomes the technical infrastructure that powers passenger applications, route planners, innovative digital services and public policies.
Conclusion: PRIM, an interoperability engine at the service of the territory
Thanks to the use of open standards, a clear legal framework and the governance of Île-de-France mobilités, PRIM offers an environment in which mobility data can circulate freely, be combined and give rise to new services. This interoperability is not only a technical issue: it is an essential condition for building more sustainable, multimodal, fluid and accessible mobility to enable the development of MaaS services on a regional scale.