센터시스템과 자율주행시스템이 원격자율주행 관련 메시지를 수신한 뒤 송신 측에 확인 응답을 제공하는 메시지이다.

The signal request message (SRM) is a message sent by a V2X-equipped entity (such as a vehicle) to the RSU in a signalized intersection. It is used for either a priority signal request or a preemption signal request depending on the way each request is set. Each request defines a path through the intersection which is desired in terms of lanes and approaches to be used. Each request can also contain the time of arrival and the expected duration of the service. Multiple requests to multiple intersections are supported. The requestor identifies itself in various ways (using methods supported by the RequestorDescription data frame), and its current speed, heading, and location can be placed in this structure as well. The specific request for service is typically based on previously decoding and examining the list of lanes and approaches for that intersection (sent in MAP messages). The outcome of all of the pending requests to a signal can be found in the signal status message (SSM) and may be reflected in the SPAT message contents if successful.