Dissemination Of an emergency message in a vehicular ad hoc network

Dissemination of emergency messages is one of the most important applications in vehicular ad hoc networks to avoid traffic fatalities. Flooding seems to be the best strategy to achieve the dissemination. But, it causes contentions, collisions and redundancy, well known as the `Broadcast storm problem' [5]. Researches faced this problem by decreasing the number of vehicles called to rebroadcast the emergency message. In this paper, we present a new approach to disseminate emergency messages in a vehicular ad hoc network by using the Unicast and the Broadcast modes alternatively. Simulation results show that performances are good compared to the existing protocols.