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SAE J2735-Draft-Rev28 [issued: 11-10-08]
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261 -
This is an SAE Motor Vehicle Council draft document of the DSRC committee, subject to change.
Annex C-3 Pre-crash Sensing
Application Description
Pre-crash sensing can be used to prepare for imminent, unavoidable collisions. This application could use
DSRC communication in combination with other sensors to mitigate the severity of a crash.
Countermeasures may include pre-tightening of seatbelts, airbag pre-arming, front bumper extension, etc.
Flow of Events
Flow of events
1.
Vehicle “A” sends MSG_BasicSafetyMessageFrame, Part I
2.
Vehicle “B” receives message
3.
Vehicle “B” process the message from Vehicle A and determines 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 imminently.
4.
Vehicle “B” automatically initiates pre-crash countermeasure(s).
Hardware Devices:
DSRC radio
Positional and vehicle sensors
Human-Machine Interface
Occupant
Vehicle
System
Driver
Passenger
Service
Provider
Road
Department
Actors: (What entities play an
active role in use)
X
Support information:
CAMP-VSC Task 3 Report, 2003
Concept of Operations
As in most of the other vehicle safety application scenarios, DSRC communications is used to allow the
host vehicle to detect position, velocity, heading, acceleration, and control parameters for all equipped
vehicles in the immediate vicinity. The in-vehicle unit analyzes these parameters for the other vehicles as
contained in their MSG_BasicSafetyMessageFrame, Part I and MSG_BasicSafetyMessageFrame, Part II
messages and projects expected future vectors for these vehicles. If this analysis determines that a collision
is imminent and unavoidable, the vehicle may deploy countermeasures, such as pre-tightening of seatbelts.
This further information might be used for such potential purposes as determining the need to lower the
bumper on a high-profile vehicle to minimize the damage to a smaller, lower vehicle, or to support a
sensor-based decision to pre-deploy side-impact airbags if the collision vector determination indicates an
imminent side-impact.
Sensors and Other System Needs
On-board sensors, such as airbag accelerometers or radar systems, could be used to confirm the imminent
collision determination derived from the DSRC communications analysis.