了解即時交通路況，避開壅塞道路，一直都是駕駛人最關心的議題。在車載網路（Vehicular Ad-Hoc Network, VANET）環境中，當車輛經過一段道路後。可以將車輛在此路段所耗費的行駛時間，散佈給其他車輛知道。其他車輛在接收到行駛時間資訊後，可依據各路段的行駛時間資訊，規劃出最快的行駛路徑。本研究提出一個有效率散佈車輛行駛時間資訊的新方法，本研究所提的資料散佈方法是由三個子方法所構成，分別是合作尋找最佳行駛路徑、優先散佈較長行駛時間資訊、過濾逾時的行駛時間資訊等。透過以上三個子方法的協同運作，在有限的車載網路頻寬與車載單元系統儲存容量下，讓車輛有效率地散佈路段行駛時間資訊。
本研究使用NS2進行車載網路模擬，將所提的路段行駛時間資訊散佈方法與Traffic Rep、Traffic Info方法作比較，在不同的廣播交通報告數量與道路車輛數目情況下，比較三個方法對於車輛行駛時間的縮短程度。實驗結果顯示，本研究所提的散佈方法能使車輛取得最新的路段行駛時間資訊，進而縮短車輛行駛至目的地所需時間。

To know the real-time traffic conditions so as to avoid travelling on a congested road segment is always the most concerned issue of drivers. In a Vehicular Ad-Hoc Network (VANET), a vehicle can disseminate and share its collected real-time traffic information to its nearby vehicles. In this thesis, we propose a method to disseminate the traveling time reports among the vehicles on the road. After travelling through a road segment, a vehicle sends its traveling time of the road segment to its nearby vehicles. Base on the received travelling time reports, each vehicle on the road is able to maintain a road map with most up-to-date travelling time for each road segment. Given the limited bandwidth of the VANET and limited storage space of the vehicle's On-Board-Unit (OBU), the proposed method facilitates the dissemination of travelling time reports for each vehicle on the road. The proposed data dissemination method includes three parts, namely, cooperation in finding the fastest traveling route, giving priorities to the travelling time reports with larger traveling times and discarding the outdated traveling time reports.
To compare the performance of the proposed method with Traffic Rep and Traffic Info, we performed several experiments using NS2. Given different numbers of travelling time reports in each broadcast and different numbers of vehicles on the road, we compare the time required for each vehicle to reach its destination using different methods. The experimental results show that the proposed method outperforms the existing methods in keeping the travelling time reports of the road segments of each vehicle's local road map most up-to-date and therefore offers the shortest travelling time for each vehicle to reach its destination.

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