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SAE J2735-Draft-Rev18 [issued: 06-26-07]
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187 -
This is an SAE Motor Vehicle Council draft document of the DSRC committee, subject to change.
Annex A-4 Cooperative Forward Collision Warning
Application Description
The cooperative forward collision warning system application may be designed to aid the driver in avoiding
or mitigating collisions with the rear-end of vehicles in the forward path of travel through driver
notification or warning of the impending collision. The system does not attempt to control the host vehicle
in order to avoid an impending collision.
Flow of Events
Flow of events
1.
Vehicle “A” sends MSG_BasicSafetyMessageFrame, Part I
2.
Vehicle “B” receives message
3.
Vehicle “B” recognizes that Vehicle A’s message is relevant and, per the
message information (e.g. location, speed, heading, deceleration, brake
pressure, etc.), that trajectories of Vehicles “A” and “B” will likely intersect.
4.
Vehicle “B” warns its driver of the potential forward crash.
Hardware Devices:
DSRC radio
Positional Sensors
Human-Machine Interface
Occupant
Vehicle
System
Driver
Passenger
Service
Provider
Road
Department
Actors: (What entities
play an 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 A-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 braking, along with an indication of braking rate.
DSRC communications are used to allow the host vehicle to detect position, velocity, acceleration, and
turning status information for all equipped vehicles in the vicinity. The in-vehicle unit analyzes these
parameters for forward vehicles as contained in their MSG_BasicSafetyMessageFrame, Part I and
MSG_BasicSafetyMessageFrame, Part II messages. The unit then projects expected future vectors for
these vehicles. If this analysis determines that a collision is likely, an appropriate warning is issued to the
driver.
Sensors and Other System Needs
On-board sensors, such as radar systems, could be used to confirm the imminent collision determination
derived from the DSRC communications analysis.