紧急和公共运输车辆用优先占有和优先次序信号系统的数据字典和消息集(PRESTO

[中文适用范围]： 本国际标准涉及利用优先信号控制功能帮助应急车辆运行的系统。如图 1 所示，此类系统由交通管理中心、车载单元、路边通信单元和路边单元组成。公共交通工具（如公共汽车）也作为接收优先信号控制服务的目标。标准化范围包括以下通信相关的消息集和数据字典： - 路边通信单元与各个车载单元之间； - 路边通信单元与其他路边单元之间； - 车载单元与路边单元之间。 本国际标准仅涉及与优先信号控制相关的信息，不处理如现场情况等信息提供。由于必须根据各个城市和地区的条件处理公共交通工具，因此与车辆优先信号控制相关的消息和数据字典部分被视为可选。此外，标准化不依赖于所使用的通信介质类型。 [外文原描述]： ISO 22951:2009 relates to systems that use priority signal control functions to help emergency vehicles operate. This type of system is composed of a traffic management centre, in‑vehicle units, roadside communication units, and roadside units. Public transport vehicles such as buses are also targeted to receive priority signal control service. The scope of standardization includes message sets and data dictionary related to the communications as follows: between a roadside communication unit and each in-vehicle unit, between a roadside communication unit and other roadside units, between in-vehicle units and roadside units. ISO 22951:2009 concerns only information related to priority signal control and does not deal with information provision such as that of the situations at scenes. Since it is necessary to handle public transport vehicles in accordance with the conditions of individual cities and regions, the section in the messages and the data dictionary that are concerned with priority signal control for the vehicles are treated as an option. Furthermore, the standardization does not depend on the type of communication medium used.