智能交通系统 通过传输协议专家组提供的交通和旅行信息 第 2 代 (TPEG2) 第 17 部分：速度信息 (TPEG2-SPI)

[中文适用范围]： 本文档定义了用于向旅行者报告速度信息的 TPEG 速度信息 (SPI) 应用程序。 速度限制通常通过路边标志向驾驶员指示。 始终了解速度限制的驾驶员更有可能安全驾驶，从而提高道路安全。 大多数限速标志是静态的，多年来保持不变，因此可以通过导航系统地图数据库获得。 然而，可变信息标志、临时标志（例如道路工程）的数量不断增加，并且速度限制也发生了变化，这些都尚未反映在地图数据库中。 通过TPEG-SPI应用，可以准确地提供限速信息，从而区分不同的车道和不同的车辆类型。 TPEG-SPI 还可以通过向导航或驾驶员辅助系统及时提供有关当前位置和速度限制值的信息，让驾驶员了解当前允许（最大）速度。 这些数据被视为信息性数据，旨在以紧凑的方式进行编码，以最大限度地减少带宽消耗。 TPEG2-SPI 支持直接和间接速度限制。 直接速度限制用于显示允许车辆行驶的最高速度的标志。 这种限速标志可以是静态的或动态的。 间接速度限制是指其他道路使用者的速度。 主要使用本车前方的车辆作为参考。 [外文原描述]： This document defines the TPEG Speed information (SPI) application for reporting speed information for travellers. Speed limits are usually indicated to the driver through roadside signs. Drivers who are aware of the speed limit at all times are more likely to drive safely, which improves road safety. Most speed limit signs are static and remain unchanged for years and are thus available through navigation system map databases. However, there is an increasing number of variable message signs, temporary signing (e.g. for road works) and also changed speed limits which are not yet reflected in the map databases. With the TPEG-SPI application, speed limit information is offered in an accurate way so that different lanes and different vehicle types can be differentiated. TPEG-SPI also allows the drivers to be aware of the current allowed (maximum) speed, by delivering timely information about the current position and values of speed limits to the navigation or driver assistance systems. These data are seen as informational and are intended to be encoded in a compact way to minimize bandwidth consumption. TPEG2-SPI supports direct and indirect speed limits. Direct speed limits are used for signs showing a maximum speed at which a vehicle is allowed to travel. Such speed limit signs can be static or dynamic. Indirect speed limits refer to the speed of other road users. It is primarily the vehicle in front of the own vehicle that is used as a reference.