What is SIRI?
SIRI stands for Service Interface for Real-time Information. It is a CEN technical specification, CEN/TS 15531, that defines how to exchange real-time information about public transport operations as XML. Like NeTEx, it builds on the Transmodel reference model, so the concepts match.
What does it carry?
- Estimated timetables: updated departure and arrival times, including delays.
- Vehicle monitoring: where vehicles are.
- Stop monitoring: what is leaving a stop soon.
- Situation exchange: disruptions and other messages to passengers.
How it works
SIRI describes services in modules, and data can be exchanged by request and response or by subscription, so a consumer receives updates when something changes. The data refers to the planned journeys in a matching NeTEx dataset.
How it is used in MMTIS
SIRI is the European standard for dynamic public transport data. Real-time feeds are published or described through National Access Points. GTFS Realtime is also widely used in practice. See all data formats.
Typical data flow
A producer publishes real-time estimates for planned journeys. A consumer, such as a journey planner, either asks for them at intervals or subscribes and receives changes. The consumer then applies the updates to the matching trips and stops in the timetable. See SIRI vs GTFS Realtime and how journey planners use the data.
Typical pitfalls
- Identifiers that do not match the timetable data.
- Feeds that are slow or go down without monitoring.
- Different national profiles and module choices.
Getting started
- Documentation and community: siri-cen.eu
- Check your National Access Point for the expected profile and modules.
Frequently asked questions
What does SIRI stand for?
Service Interface for Real-time Information.
Is SIRI the same as GTFS Realtime?
No. They solve a similar problem. SIRI is the European CEN standard and is XML based. GTFS Realtime is an open format using Protocol Buffers and is widely used in practice.