本論文簡要敘述高速公路上的撞擊預防警示系統(Cooperative Collision Avoidance, CCA)在車用安全系統所扮演的角色：當車輛在高速行駛時，若發生緊急事故，往往造成後方車輛閃避不及而追撞。撞擊預防警示系統將獲得前方路況的方法，從過去直接觀察前車行為改為透過無線網路散佈警示訊息，使得駕駛人能夠快速得到視野外的緊急路況，以減低追撞的機會。為了得知警示系統的使用與連環車禍控制的關係，我們提出了對於車禍規模的分析方式，並以一簡易模擬進行驗證，最後加入NS-2模擬真實網路運作的狀況，藉由實驗與分析的方式逐一討論各項變因對於車禍規模的影響。

This thesis presents an overview of highway Cooperative Collision Avoidance (CCA), which is an emerging vehicular safety application. If a vehicle has broken suddenly in a highway, following vehicles would be too hard to take avoidance in a short time, and there would cause chain collisions. Instead of observing accidents passively, CCA makes drivers take notice of road conditions proactively by generating a warning message and distributing it to the following vehicles. CCA truly reduces the probability of the chain collisions by letting drivers get notification for “Out of Sight” as soon as possible. In order to verify the efficiency of CCA, we state an analysis method and consider several traffic factors that affect the scale of chain collisions by a series of simulations in a network simulator, NS-2.

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