Service Interface for Real-Time Information (SIRI)TransportationReal-Time Transit
European Committee for Standardization (CEN)
| Version: 2
SIRI is a data format that enables the server to exchange real-time information about public transit schedules and arrival times. SIRI is now interoperable with GTFS-Realtime services
  • License: The SIRI schema is available for use free of charge and without warranty under public Licence. Copyright is retained by the respective national organisations that developed SIRI. The CEN standard documentation must be purchased
  • About the Publisher: CEN is an association that brings together over 30 European national standardization bodies. CEN is recognized by the EU and the European Free Trade Association
  • Updated by Publisher: 5/19/2013
  • Level of Use: By CEN regulation, members have to adopt the SIRI standard for real-time data exchange. Since its inception, many agencies that provided SIRI formatted APIs have begun additionally providing data in GTFS-realtime format or dropping their SIRI API
  • Open License: Yes
  • Transferable to other Jurisdictions: Facilitation of adoption across jurisdiction is unclear because the protocol is intended to exchange information at the operator to operator level. However, SIRI's modularisation permits users to pick and choose the services they wish to implement. SIRI can be used with GTFS static data, referring to the same unique stopIDs
  • Stakeholder Participation: Primary stakeholders of the SIRI protocol are defined as the purchasers and suppliers/product developers of public information transport systems. Contributors to the standard included equipment suppliers, transport authorities, transport operators, transport consultants from countries in the EU, public transit agencies in Germany, France, and the UK, and the EU Trident project
  • Consensus-based Governance: CEN Working Group manages the standard's governance. The group decides on changes made to the standard
  • Extensions: Official documentation cites that SIRI is an extensible standard. Publishers expect additional services will be added to the standard in the future
  • Machine Readable: Siri uses XML to define messages using real-time public transport vehicle or journey time data. The schema is encoded as a W3C .xsd. Has reusable sub schemas and type packages. Schema uses the SOAP protocol to exchange messages between servers.
  • Human Readable: Standard utilizes universally understood tags and semantics. Clear documentation of field IDs as a reference
  • Requires Real-Time Data: The protocol is able to handle real time transit schedule data
  • Metadata: There is a metadata section to the XML schema
Added to directory: 8/10/2017
Transit Communications Interface Profiles (TCIP)TransportationReal-Time TransitHardware
American Public Transportation Association (APTA)
| Version: 5.0.1
Cities use TCIP to structure their real-time public transit data
  • License: No information
  • About the Publisher: APTA is a non-profit organization that supports improvements in public transportation throughout the USA. APTA has published several standards for public transportation over the years
  • Updated by Publisher: 3/1/2016
  • Level of Use: City of Montreal and several cities within the USA have adopted TCIP. There is not formal list of all cities that have adopted this standard. As of 2013, vendors are the main users of TCIP
  • Open License: No
  • Transferable to other Jurisdictions: National Transit Institute provides the 'Transit Communications Inteface Profiles (TCIP) Standard Development Program.' This TCIP training provides classes to help ease the adoption of TCIP. APTA also provides the downloadable 'TCIP Implementation, Requirements and Capabilities Editor (TIRCE)'
  • Stakeholder Participation: Technical working groups composed of transit agency staff and representatives from vendors were the ones to develop TCIP (Reed 2013)
  • Consensus-based Governance: APTA allows users of the standard to add comments
  • Extensions: Cities have the availability to modify parts of the standard to meet their needs. For example, the New York City MTA modified TCIP's specifications (Reed 2013)
  • Machine Readable: Data is stored in zipped MS Word document files (.doc), which are not machine readable, but data can be also stored in XML
  • Human Readable: Lots of documentation regarding the standard, including definitions
  • Requires Real-Time Data: As the specification is primarily for real-time public transit data, it requires the data to be real-time
  • Metadata: TCIP data is organized into the following building blocks: Dialog Patterns, Dialogs, Messages, Frames, Elements, File Transfers). The Messages block allows for metadata. Also, there is a metadata field for TCIP artifacts
Added to directory: 8/30/2017
GTFS RealtimeTransportationReal-Time Transit
| Version: 1
GTFS Realtime is an extension to GTFS (General Transit Feed Specification) that allows public transportation agencies to provide application developers with real-time updates about the locations, estimated arrival times and other important information regarding transit vehicles.
  • License: Apache 2.0 License
  • About the Publisher: Google
  • Updated by Publisher: 8/26/2016
  • Level of Use: Widespread use by transit agencies globally
  • Open License: Yes
  • Transferable to other Jurisdictions: If a transit agency has the technology (Bus tracking by GPS) GTFS Realtime is transferable, with only several required variables.
  • Stakeholder Participation: It was developed by Google, a software developer, in partnership with transit agencies and developers
  • Consensus-based Governance: Contributions can be made to the GTFS Realtime project on the GitHub page, but all contributions are subject to a strict voting and discussion protocol, and contributors must sign a license agreement
  • Extensions: Third-party developers can define additional fields for GTFS Realtime but must contact the GTFS Realtime discussion Google group to be assigned an extension id so that they can use a unique protocol buffer
  • Machine Readable: The data is hosted over HTTP and consists of protocol buffers. Google's protocol buffers are used for data serialization and work as an alternative to XML. The data structure is stored in a gtfs realtime.proto file. The file produces source code to read and write the structured data and then retrieves it to and from a data stream using a variety of programming languages. Unique IDs such as VehicleID and StopID are compatible with static GTFS values
  • Human Readable: Many agencies have APIs in addition to protocol buffers that have responses in XML, JSON, and JSONP formats
  • Requires Real-Time Data: Every protocol buffer has an [optional] timestamp in the header indicating when the content of the feed was created.
  • Metadata: Protocol Buffer structure
Added to directory: 6/15/2017