US Patent 6985089 Vehicle-to-vehicle communication protocol

A method is provided for vehicle to vehicle communication among vehicles having wireless communication links. Upon receiving notification of a sudden change in vehicle behavior, a vehicle broadcasts a priority message to surrounding vehicles within a transmission range. If an emergency event has occurred, a repeat cycle is defined for re-broadcasting the message, and a maximum number of initial repetitions for the message is specified. The message is transmitted repeatedly by a leader vehicle, with a pause between each transmission, until the maximum number of repetitions has been reached.