Message management protocol persistent geocast routing

A method for providing a warning message of a hazardous road condition to a group of vehicles, said method comprising:

• detecting the hazardous road condition by a detecting vehicle;
• defining a region of interest along a roadway from a position just in front of the hazardous condition to a predetermined distance behind the hazardous condition;
• defining a critical line behind the hazardous road condition;
• defining a distance from the critical line to a back end of the region of interest;
• broadcasting a warning message from the detecting vehicle to other vehicles in the region of interest using a multi-hop geocast transmission scheme;
• preventing the warning message from being broadcast for a first predetermined period of time after the vehicles in the region of interest have received the message;
• and
• using a contentious timing process to determine which of the vehicles that have received the message in the region of interest will re-broadcast the message to new vehicles entering the region of interest after the first predetermined period of time even if the detecting vehicle has left the region of interest.

A method for providing a warning message to a group of vehicles, said method comprising:

• detecting a hazardous situation by a detecting vehicle;
• broadcasting a warning message from the detecting vehicle to be received by other vehicles even if the detecting vehicle has left the region of interest;
• providing a process by which the message is re-broadcast to a new set of vehicles after a predetermined period of time;
• and
• providing a process by which the message is not further re-broadcast after an event lifetime has expired.