 |
 |
 |
 |
|
 |
 |
SAE J2735-Draft-Rev28 [issued: 11-10-08]
-
41 -
This is an SAE Motor Vehicle Council draft document of the DSRC committee, subject to change.
<xs:element name="lanesCnt" minOccurs="0">
<xs:simpleType>
<xs:restriction base="xs:unsignedByte">
<xs:minInclusive value="1"/>
</xs:restriction>
</xs:simpleType>
</xs:element>
<!-- number of states to follow (not always
one per lane because sign states may be shared) -->
<xs:element name="states" >
<xs:complexType>
<xs:sequence minOccurs="1" maxOccurs="255">
<xs:element name="state" type="MovementState" />
<!-- each active Movement/lane is given in turn and contains its state,
and seconds to the next event etc. -->
</xs:sequence>
</xs:complexType>
</xs:element>
<xs:element name="priority" type="SignalState" minOccurs="0"/>
<!-- the active priority state data, if present -->
<xs:element name="prempt" type="SignalState" minOccurs="0"/>
<!-- the active preemption state data, if present -->
<xs:element name="localSPAT" type="local:SPAT" minOccurs="0"/>
</xs:sequence>
</xs:complexType>
In addition, this item may be used by data structures in other ITS standards.
Remarks: Note: There is no reason this message could not nest multiple intersections worth of data at
once, may ask membership if they want any such nesting (would save a few bytes), Ed.
5.14 Message: MSG_SignalRequestMessage
Use: The Signal Request Message is a message sent by a vehicle to the RSU in a signalized intersection. It
is used for either a priority signal request tr a preemption signal request depending the way the message
flag is set. In either case, the identifies itself (using its VIN or another method supported by the
VehicleIdent data frame), its current speed, heading and location (using the Blob of the BSM), and make a
specific request for service (Vehicle Request) as well as an anticipated time of service (a start time and end
time in seconds from the present). The specific request for service is typically based on previously
decoding and examining the list of supported zones for that intersection (sent in the map messages). The
outcome of the all pending requests to a signal can be found in the Signal Status Message, and may be
reflected in the SPAT message contents if successful.
ASN.1 Representation:
SignalRequestMsg ::= SEQUENCE {
msgID DSRCmsgID,
msgCnt MsgCount,
-- Request Data
request SignalRequest,
-- the specific request to the intersection
-- contains IntersectionID, cancel flags,
-- requested action, optional lanes data
timeOfService DSignalSeconds OPTIONAL,
-- the time in the near future when service is
-- requested to start
endOfService DSignalSeconds OPTIONAL,
-- the time in the near future when service is
-- requested to end
transitStatus TransitStatus OPTIONAL,
-- additional information pertaining
-- to transit events