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SAE J2735-Draft-Rev15 [issued: 01-30-07]
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154 -
This is an SAE Motor Vehicle Council draft document of the DSRC committee, subject to change.
ANNEX A-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” 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” automatically initiates pre-crash countermeasure(s).
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
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.