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SAE J2735-Draft-Rev18 [issued: 06-26-07]
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199 -
This is an SAE Motor Vehicle Council draft document of the DSRC committee, subject to change.
Annex C Emergency Vehicle Approaching Warning
1.
Application Description
The purpose of this message is to provide warning to a driver when a PSOBE equipped vehicle such as
police, fire or ambulance is in the vicinity and a potential interference with the emergency vehicle's path is
eminent.
Two problems are being addressed by this message. First, the notification to the driver that an emergency
vehicle with its siren/lights flashing is in the area. This can occur if the emergency lights are hidden behind
an obstruction and the sirens cannot be heard above the surrounding audio (noise, radio, etc). The second is
identification of where the vehicle is and what to do to avoid interference with its path.
When an emergency vehicle and other surrounding vehicles are equipped with PSOBE’s and OBE's, the
vehicles can establish communication when they are within range of each other and share information
relative to their location and direction. A PSOBE is required in emergency vehicles as this is a special
application that is not available to standard OBE's. This application should be implemented as a high
powered application to extend range. From calculations resulting from this information, the private vehicle
can first notify its driver of the situation then may offer suggestions to avoid path interference. While
difficult to make this function robust and precise, enough information can be made available to the driver
that improvements over a non-equipped system can be significant.
2.
Preconditions for operation:
1.
The private vehicles are equipped with active OBE.
2.
The emergency vehicles are equipped with active PSOBE.
3.
Both systems are active and functional.
4.
Emergency vehicles can provide location, speed, and direction of travel.
5.
Private vehicles have available it's location, speed, direction of travel.
3.
Flow of Events
Flow of events
8.
Vehicle “A”, a PSOBE equipped vehicle is operating in a non-emergency condition.
It is acting similarly to any OBE equipped vehicle and it sends typical Vehicle Safety
data frames.
9.
Vehicle "A" determines that activation of an Emergency Vehicle Approaching
Warning is needed. This could occur through various determinants such as activation
of its siren and emergency lights, or other inputs to be determined by application
developers.
10. This activates a PSOBE broadcast of emergency notification warning, current
location information, speed, and direction of travel.