可变信息标志（VMS）安装在交通管理人员发现频繁需要的区域 向出行的公众传达信息，例如从立交桥上游向公众发出警告 下游的交通堵塞及时让他们改变路线。这使得交通管理人员能够提高效率 旅行者旅行的效率、安全和质量。购买本文件时可获得的所有当前修订均包含在购买本文件中。

Variable message signs (VMSs) are installed in areas where traffic managers identify a frequent need to convey information to the travelling public, such as upstream from interchanges to alert the public to downstream congestion in time for them to alter their routes. This allows traffic managers to improve the efficiency, safety, and quality of traveller journeys.All current amendments available at time of purchase are included with the purchase of this document.