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SAE J2735-Draft-Rev29 [issued: 12-11-08]
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244 -
This is an SAE Motor Vehicle Council draft document of the DSRC committee, subject to change.
System
Driver
Passenger
Provider
Department
active role in use)
X
X
Support information:
CAMP-VSC Task 3 Report, 2003
Concept of Operations
This application is similar to the Emergency Electronic Brake Light scenario (Annex C-2). In the
Cooperative Forward Collision Warning scenario, however, the application warns the driver when the
possibility of a collision with a vehicle in front of the host vehicle becomes likely, whereas the brake light
application simply informs the driver of the onset of “hard” braking based on an indication of braking rate.
The concept of operation of the CFCW application can be explained as follows: Every vehicle that is
equipped with DSRC will broadcast the MSG_BasicSafetyMessage, including the optional path history, at
a certain frequency (path history might be included in a subset of all MSG_BasicSafetyMessages). The
CFCW application in the host vehicle receives safety messages and uses the contents to track the state (i.e.,
position, velocity, and acceleration, etc.) of remote vehicles within its communication range. Using such
information, along with its own state and its assessment of the relevance of the target location, the host
vehicle determines the likelihood of a front-end collision with a remote vehicle ahead in its lane and
calculates the threat level. The threat level is used to further determine the appropriate warning through the
vehicle’s driver vehicle interface.
Sensors and Other System Needs
On-board sensors, such as radar or lidar systems, could be used to confirm the [JBK10]collision
determination derived from the DSRC communications analysis.
A map database, where available, may help to provide specific, relevant information related to current road
segments. This could allow, for example, intersection geometry or road curvature to be taken into account.
Annex C-5 Left Turn Assistant
Application Description
The Left Turn Assistant provides information to drivers about gaps and speeds of oncoming cars to help
them make a left turn across traffic safely. This application warns drivers when a collision is probable if
the left turn movement is initiated.
Flow of Events
Flow of events
1.
Oncoming Vehicle “A” sends MSG_BasicSafetyMessage.
2.
Turning Vehicle “B” receives message
3.
Vehicle “B” processes the message from Vehicle A and determines that Vehicle A’s
message is relevant (crossing road segment via map and/or heading and indication of turn)
4.
Vehicle “B” alerts its driver to an oncoming vehicle hazard.