根據交通部統計，汽車駕駛者在行駛高速公路時，因未保持安全的行車間距或是在遇到緊急狀況時無法及時煞車而導致車禍發生的次數，佔了約所有交通事故發生原因的百分之二十五，是非常大的比例；因此，如何提醒駕駛者保持安全的行車距離並提供一個緊急警告機制來降低前後車碰撞發生率，是非常重要的議題。
本篇論文提出一個以Dedicated Short Range Communication（DSRC）車間通訊為基礎的碰撞避免機制 ── Cooperative Collisions Prediction and Warning Mechanism（CCPWM）來提供駕駛員與乘客非常重要的保護。透過DSRC來交換一些必要的資訊，例如：位置、車速以及加速狀況，CCPWM可以事先計算出車禍發生的可能性，即時提醒駕駛者並督促駕駛者保持適當的行車間距，以減少與前後車發生碰撞的機會，降低車禍的發生率；CCPWM亦可在車輛發生緊急狀況時，例如緊急煞車，以提供「向周圍車輛廣播緊急警告」的方式來降低連環車禍的發生率。
為了驗證CCPWM的可靠性，本篇論文設計了一個名為HiTSim（DSRC based Highway Traffic Simulator）的模擬器，它可以模擬高速公路的交通狀況與以DSRC為基礎的車用無線網路（Vehicular Ad Hoc Networks, VANETs）的通訊狀況。在這個模擬器上，我們可以清楚地比較出CCPWM對碰撞發生率的影響，它將大幅降低車禍率；再者，即使仍有碰撞事故發生，碰撞時的車速與衝撞力都下降了許多，駕駛員與乘客的安全都有較多的保障。

According to the statistics from Ministry of Transportation and Communication, R.O.C [30], tailgating accounts for 25% of all traffic accidents. Tailgating occurs when drivers fail to keep a safe driving distance or when drivers lack the sufficient amount of time to react and stop the vehicle. Therefore, how to remind the drivers to keep safe distance and how to provide an emergency warning mechanism to reduce the collision ratio is a very important issue.
This thesis proposes a Dedicated Short Range Communication (DSRC) inter-vehicle communication based Collision Avoidance Mechanism ─ Cooperative Collisions Prediction and Warning Mechanism (CCPWM) to provide of protection for drivers and passengers on highway. By exchanging necessary information such as position, velocity, and acceleration situation through DSRC, CCPWM can measure the possibility of a collision to remind and monitor the drivers to keep safe distance in order to reduce the ratio of tailgating, and also provide another solution by broadcasting emergency warning to surrounding vehicles, in order to decrease the ratio of multi-vehicle chain accidents.
In order to prove the reliability of CCPWM, a simulator, HiTSim (DSRC based Highway Traffic Simulator), is designed. It can simulate the situation of highway traffic and the situation of DSRC based Vehicular Ad Hoc Networks (VANETs). By HiTSim, we can figure out the influence of CCPWM on traffic crash ratio clearly. It reduces a large percentage of traffic crash. Furthermore, even if the traffic crash still occurs, CCPWM can effectively lower the collision speed and impulsive force. The safety of drivers and passengers are ensured by CCPWM very much.

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