노변 경고 메시지(RSA)는 지원 시스템이 주변 도로 위험 상황을 알리는 메시지로, 차량이 현재 주행 하는 도로상에서 앞으로 발생할 위험 요소 정보를 제공한다. 다른 메시지들이 영향을 받는 영역을 설명하기 위하여 위치 참조 메시지 시스템(LRMS, location referencing message system) 프로필을 사용 하는 것과 달리, 노변 경고 메시지(RSA)는 LRMS를 사용하지 않고 수신된다. V2X를 통해 전송되는 이 메시지는 주행 대상(차량과 휴대용 장치 모두)에 보행자 또는 낙하물 출현과 같은 객체 방해물 속 성 정보, 역주행 또는 저속 주행 차량과 같은 특이 이동 물체 방향과 속도 정보 등에 대해 간단한 알림을 제공한다. 일반적인 메시지의 예는 “전방 다리가 결빙됨”, “기차가 오고 있음” 또는 “해당 지역에서 구급차가 운 행 중임”이다. 모든 범위의 ITIS 문구가 지원되지만, 모바일 위험, 공사 구역, 도로변 이벤트를 다루 는 문구가 가장 자주 사용될 수 있다.

This message is used to send alerts for nearby hazards to travelers. Unlike many other messages which use the LRMS profiles to describe the areas affected, this message likely applies to the receiver by the very fact that it is received. In other words, it does not use LRMS. Typically transmitted via V2X, this message provides simple alerts to travelers (both in vehicle and portable devices). Typical example messages would be “bridge icing ahead” or “train coming” or “ambulances operating in the area.” The full range of ITIS phrases are supported here, but those dealing with mobile hazards, construction zones, and roadside events are expected to be most frequently used. This message is for alerting about roadway hazards, not for vehicle cooperative communications, mayday, or other safety applications. It is generally presumed that each receiving device is aware of its own position and heading; but it is neither a requirement to receive and understand these messages, nor is having a local base map. The position section of the message gives a simple vector for where the hazard is located (fixed or moving) and can be used to filter some messages as being not applicable. Consider a “train approaching” message which indicates the train is in fact traveling away from the receiver. The basic information types themselves are represented in the standard ITIS codes sent only in their integer representation formats. This ITIS list is national in scope, never outdated (items can only be added), and in this use does not allow local additions. Refer to SAE J2540-2 for the complete code list. A priority level for the message is also sent, which may be matched to various other priorities in the cockpit to determine the order and type of message presentation to minimize driver distraction. Message transmission priority is typically handled in the IEEE 1609 standard layer in the application stack and is a function of the application type. A duration field provides a gross level for the range (distance) of applicability for the message over distance. For example, some messages are no longer meaningful to the traveler once the vehicle has moved a distance down the roadway link. In many cases, a complex event is explained in the other supporting ATISmessages, and a linkage value is given when it is available.