为研究面向车辆防撞系统的碰撞风险模型,分析了车辆碰撞风险的概率内涵,根据运动学理论并考虑车辆运行特征,建立了基于概率计算的侧向碰撞风险模型,运用Vissim微观交通仿真等方法模拟常见的车辆运行场景,利用输出数据离线计算风险值,并对仿真结果进行评价。将追尾碰撞发生的过程分为前车减速与前车减速条件下的碰撞两起事件,运用条件概率的思想求出追尾事故发生的概率来表征跟车风险。从安全的本质出发提出了跟车风险的表述方法,建立密度函数模型。在分析前车减速条件下追尾碰撞条件时,从汽车地面力学理论的角度补充考虑了制动系统作用时间、附着系数等影响因素,使模型更接近实际状况,并且将判断的标准由停车距离扩展到了制动全过程的位移。通过与其他风险模型产生的计算结果进行比较分析,发现基于概率计算的碰撞风险模型,能够更好地反映实际交通安全状态,更适用于车辆防碰撞系统。

Vehicle collision risk model is proposed for vehicle collision avoidance system in this paper. Probability attributions of collision risk and vehicle kinematical parameters were analyzed at first. Then the risk models based on probability computation for angle collision is established. Simulation evaluation was also implemented at many common scenarios employing micro simulation tool of Vissim. First of all, this paper divided the process of collision for car-following into two stages: leading vehicle decelerates and the following vehicle can not avoid the collision on the condition of it. On the basis of that, the probability of rear-end collision which used to express the risk of car-following was calculated using the method of total probability. What's more, a deceleration probability density function model was developed. In the analysis of the condition on which collision occur while leading vehicle decelerating, brake system response time and sticking coefficient were taken into account and this make the model forceful to reflect the real traffic situation. To evaluate performance of the new method, value of risk was calculated as a function of the data generated from Vissim. Simulation results indicate that the new approach is easer to reflex safety situation and more suitable for intersection collision avoidance system.