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SAE J2735-Draft-Rev26 [issued: 09-18-08]
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25 -
This is an SAE Motor Vehicle Council draft document of the DSRC committee, subject to change.
local additions, refer to SAE J2540.1 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 will also be explained in the other ATIS messages, and a linkage value is
given in those cases when such data is available. Note that this message is often hard coded in
transmission, that the byte ordering is known and fixed, and therefore no tagging is required to denote
internal elements. The tail element is not used when transmitted over DSRC media and using the Wave
Short Message (WSM) protocol to preserve the fixed and known byte size of the message. The message in
this form is exactly 37 bytes in length.
ASN.1 Representation:
RoadSideAlert ::= SEQUENCE {
typeEvent ITIS.ITIScodes,
-- a category and an item from that category
-- all ITS stds use the same types here
-- to explain the type of the
-- alert / danger / hazard involved
-- two bytes in length
description SEQUENCE (SIZE(8)) OF ITIS.ITIScodes,
-- eight ITIS code entries to further
-- describe the event, give advice, or any
-- other ITIS codes
-- non used positions are set to zero
-- 16 bytes in length
priority Priority,
-- the urgency of this message, a relative
-- degree of merit compared with other
-- similar messages for this type (not other
-- message being sent by the device), nor a
-- priority of display urgency
-- one byte in length
extent Extent,
-- the spatial distance over which this
-- message applies and should be presented
-- to the driver
-- one byte in length
spaceVector SpaceVector,
-- a compact summary of the position,
-- heading, rate of speed, etc of the
-- event in question. Including stationary
-- and wide area events.
-- 15 bytes in length
furtherInfoID FurtherInfoID
-- a link to any other incident
-- information data that may be available
-- in the normal ATIS incident description
-- or other messages
-- two bytes in length
}
-- note that typically the above is encoded as a
-- sequence of 37 known bytes when send over DSRC media
XML Representation:
<xs:element name="roadSideAlert" type="RoadSideAlert"/>
<xs:complexType name="RoadSideAlert" >
<xs:annotation>
<xs:documentation>
note that typically the above is encoded as a
sequence of 37 known bytes when send over DSRC media
</xs:documentation>
</xs:annotation>
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