現今，汽車已然成為人類生活中不可缺少的交通工具，為了增進車輛行駛的安全、動態路徑規劃與排程、緊急警示訊息的散播與交通監控等不同車輛網路應用的需求，必須設計一個可供車輛之間交換訊息的傳輸協定來實現智慧型傳輸系統。因此，本論文提出了一個以叢集式網路架構為基礎的車輛通訊協定，稱為交通資訊收集者。該協定的主要目是收集交通的相關資訊進而增進行車的安全。此協定分為叢集網路建立、叢集資料收集與資料回傳三個階段：在叢集網路建立階段中，使用叢集網路技術將道路上的車輛切割成多個連續的叢集區域。叢集資料收集階段以分時多重存取技術為基礎，使得車輛在各叢集區域中可達到分時多重存取且避免無線訊息在傳輸時所發生的碰撞。最後，資料回傳階段將各叢集網路所收集完成的交通資訊，傳送至請求收集資料的車輛。再者，利用交通資訊收集者協定所蒐集到的交通資訊，各叢集區域中的首領可透過本論文所提出之交通安全係數與交通擁塞係數，得知各叢集區域所在之交通狀況，判斷是否發送警示訊息，藉以調整車輛行駛之順暢性與安全度。在評估通訊協定效能方面，本論文使用QualNet軟體來模擬交通資訊收集者通訊協定，藉以驗證該演算法具有高度延展與高效率傳輸的特性。

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 thesis proposes a protocol, designated as TrafficGather, based on a cluster networking technique to collect traffic information and enhance the safety during the movement of vehicles. The protocol comprises three separate phases, namely (i) network configuration, (ii) data collection and (iii) data retrieval. The goal of the network configuration phase is to search for appropriate cluster-head candidates among the vehicles within the vehicular ad hoc networks (VANet) and then to subdivide the network into a series of contiguous clusters on the road. The data collection phase employs a TDMA based scheme to collect traffic information without occurrences of data collisions in each cluster. In data retrieval phase, each cluster-head vehicle returns the collected information to the vehicle which wishes to acquire traffic information. Armed with this information, each cluster-head calculates the traffic estimation index to determine whether or not to issue the message to admonish the abnormal vehicles. Simulations performed using the QualNet simulator confirm the scalable and efficiency properties of the proposed protocol.

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