基于概率计算的车辆碰撞风险模型研究

Modeling of Vehicle Collision Risk Based on Probability Analysis

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。

A vehicle collision risk model is proposed for the vehicle collision avoidance system in this paper. The probabilities of the collision risk and vehicle kinematical parameters are analyzed at first. Then the risk models based on the probability analysis of the angle collision are established. Simulations are carried out for some common scenarios with the micro simulation tool of Vissim. The process of collision for car-following is divided into two stages： the leading vehicle decelerates and the following vehicle can not avoid the collision under this condition. The probability of the rear-end collision used to express the risk of car-following is calculated using the method of the total probability. Then, a deceleration probability density function model is developed. In the analysis of the condition for the collision to occur while the leading vehicle is decelerating, the brake system response time and the sticking coefficient are taken into account and this makes the model robust in reflecting the real traffic situation. To evaluate the performance of the new method, the risk is calculated as a function of the data generated from Vissim. Simulation results indicate that the new approach reflects better the safety situation and is more suitable for the intersection collision avoidance system.