中文摘要：

鉴于高速公路上汽车追尾碰撞事故比例日渐增多的状况，汽车防撞系统的研究越来越受到重视。分析得出此类交通事故的主要原因是由于驾驶员未能保持安全的车间距离。以影响行车安全距离主要因素的速度为主要参数，建立了一个简单可行的行车安全距离数学模型，并给出了相关参数的设定和具体的实现过程，实践表明该参数具有很好的实时性和准确性。

英文摘要：

Research on anti-collision system of vehicles becomes more and more significant, because the collision accidents increase on freeways day by day. The analysis of traffic accidents indicates that the major reason of the accidents is the drivers do not keep specific safe distance between vehicles. With the speed that is the main factor affecting the driving distance as primary parameter, a simple and feasible mathematical model of safe driving is established; and relevant parameter settings and concrete implementing procedures are given. The practice shows that this parameter features excellent real-time performance and accuracy.