In this paper we introduce the Cluster-Based Beacon Dissemination Process (CB-BDP) based on inter vehicle communication in highway scenarios. This process aims to provide vehicles with a local vehicle proximity map of their vicinity. Based on this map, safety applications can be used for accident prevention by informing drivers about evolving hazardous situations. The CB-BDP is designed under the two following objectives. First, since it is used for safety applications, we want the map to be

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... ailed and as accurate as possible. Second, we want the map to be coordinated with nearby vehicles, thereby allowing synchronized and coordinated reactions of nearby vehicles to evolving hazardous situations. In [1] the authors have introduced a clustering scheme design to provide an optimized topology for an efficient and reliable beacon dissemination process. The topology is adaptive and robust in order to meet the challenging VANET conditions. In this paper, we propose a cluster based aggregation-dissemination beaconing process that uses this optimized topology to distribute the vehicle proximity map. An accurate and detailed map results in a heavy load of beacon messages. Our proposed scheme deals with this load by integrating a contention-free medium access control (MAC) strategy for reliable communication.