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SAE J2735-Draft-Rev29 [issued: 12-11-08]
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29 -
This is an SAE Motor Vehicle Council draft document of the DSRC committee, subject to change.
</xs:complexType>
Remarks: This message is divided into two primary parts and uses the same BER-DER encoding system
in each. In the first part (those data elements which are always sent at all time) some data element have
been encoded as a well defined octet blob to enable concise encoding and conserve channel bandwidth. In
the second part, DER tags and lengths precede each possible defined element in the normal way. Any
Locally defined content can be added to the part two content in the normal way.. Developers of such local
content should take steps to avoid creating content with tags which could conflict with future revisions of
the standard (such tags should be in the local range of 128~255 to avoid conflict with the national
standard).
5.4 Message: MSG_EmergencyVehicleAlert
Use: The Emergency Vehicle Alert message is used to broadcast warning messages to surrounding
vehicles that an emergency vehicle (typically an incident responder of some type) is operating in the
vicinity and that additional caution is required. The message itself is built on the ATIS roadside alert
message which in turn uses the common ITIS phrase list to both describe the event and provide advice and
recommendation for travelers. The Emergency Vehicle Alert message appends to the message some
additional data elements regarding the overall type of vehicle involved and other useful data. Note that this
message can be used by both private and public response vehicles, and that the relative priority of each (as
well as security certificates) is determined in the application layer.
ASN.1 Representation:
EmergencyVehicleAlert ::= SEQUENCE {
msgID DSRCmsgID,
id TemporaryID OPTIONAL,
rsaMsg RoadSideAlert,
-- the DSRCmsgID inside this
-- data frame is set as per the
-- RoadSideAlert. The CRC is
-- set to a value of zero.
responseType ResponseType OPTIONAL,
details EmergencyDetails OPTIONAL,
-- Combines these 3 items:
-- SirenInUse,
-- LightbarInUse,
-- MultiVehicleReponse,
-- combine above three into one byte!
mass VehicleMass OPTIONAL,
basicType VehicleType OPTIONAL,
-- gross size and axle cnt
-- type of vehicle and agency when known
vehicleType ITIS.VehicleGroupAffected OPTIONAL,
responseEquip ITIS.IncidentResponseEquipment OPTIONAL,
responderType ITIS.ResponderGroupAffected OPTIONAL,
crc MsgCRC,
... -- # LOCAL_CONTENT
}
XML Representation:
<xs:element name="emergencyVehicleAlert" type="EmergencyVehicleAlert"/>
<xs:complexType name="EmergencyVehicleAlert" >
<xs:sequence>
<xs:element name="msgID" type="DSRCmsgID" />
<xs:element name="rsaMsg" type="RoadSideAlert" />
<!-- the DSRCmsgID inside this
data frame is set as per the
RoadSideAlert. The CRC is
set to a value of zero. -->
<xs:element name="responseType" type="ResponseType" minOccurs="0"/>
<xs:element name="details" type="EmergencyDetails" minOccurs="0"/>