BS PD CEN ISO/TS 17426:2016

BS PD CEN ISO/TS 17426:2016

• specifies the Contextual Speed Information Service, namely the general requirements regarding theprovision of the Contextual Speed Information Service, the data flow supporting the service, andthe presentation of the service result,
• specifies the requirements to be fulfilled by the Contextual Speed Information Service,
• specifies the ITS Station (ITS-S) application processes of the vehicle ITS station, roadside ITS station,central ITS station, and personal ITS station that are required to instantiate the Contextual SpeedInformation Service,
• specifies sets of communication requirements and objectives (profiles) using the methods definedin ISO 17423 to select the level of performance (best effort or real-time, etc.), confidence and security(authentication, encryption, etc.) for each Contextual Speed Information Service communicationflow between ITS stations,
• selects relevant functions and procedures provided by the ITS station facilities layer (seeISO 17429), and
• specifies messages, messages sets structure, content, and syntax to be used by the Contextual SpeedInformation Service.

This Technical Specification considers the scenario for the transmission of Contextual Speedinformation from the infrastructure/roadside to the vehicle, for onward presentation to the vehicle'sdriver. This scenario foresees that the calculation of Contextual Speed information is performed on theInfrastructure side, not within the vehicle.Mandatory speed limits or advisory speed recommendations are output of the Contextual SpeedInformation Service which (in the scenario considered in this Technical Specification) is run by theRoad Operator in its Traffic Control Centre or comparable infrastructure (e.g. Roadside ITS Station). Totransfer this information to the vehicle (and therefore the driver) over the air (wireless communication),defined messages are required. These messages are specified in this Technical Specification.When Contextual Speed information arrives in the vehicle, further pre-processing might be necessarybefore the Contextual Speed information, and, if available, additional explanations on speed limitsor recommendations, can be presented to the driver. This Technical Specification specifies therequirements that need to be fulfilled when processing the messages. It does not specify how the vehiclehandles the incoming messages.The production of information supporting this application, its qualification and its relevance are out ofthe scope of this Technical Specification.This Technical Specification addresses Use Case 1 "Provision of mandatory speed limit information intovehicle - for driver awareness purposes" and Use Case 2 "Provision of advisory speed information intovehicle - for driver awareness purposes".Cross References:ISO 21217ISO 24102-3ISO 24102-6ISO/TS 17419ISO/TS 17423ISO/TS 17425ISO/TS 17427ISO/TS 17429ISO/TS 18750 ISO/TS 19321ISO/TS 14823:2008ISO/TR 17465-1ISO/TR 25102 ISO/IEC 8825-2:2008ISO/IEC 9646-1ISO/IEC 9646-7