Nowadays, vehicles have become an indispensable part of modern life. To ensure road safety and to make possible dynamic route scheduling, emergency message dissemination, traffic monitoring, and so forth, it is desirable to develop a common protocol for Inter-Vehicle Communications (IVC) in order to realize Intelligent Transportation Systems (ITS). Accordingly, this study proposes a protocol, designated as TrafficGather, based on a cluster networking technique. The protocol subdivides a road section into a series of "road blocks", each covered by a network cluster, and permits a vehicle within a road block to transmit its traffic information only in a specific time slot. Simulations performed using the Qualnet simulator confirm the effectiveness and efficiency of the proposed protocol.