一个冰雪条件下可能事故的道路交通流CA模型

史亚雷 庞明宝

摘要 研究冰雪条件下基于CA可能事故的道路交通流微观仿真模型。通过对冰雪下道路附着系数变小造成车辆安全距离加大分析，定义加速、巡航和减速状态下安全距离，建立其可能发生交通事故及其概率统计的CA仿真模型，通过具体道路交通流仿真得到不同冰雪下密度和流量间关系基本相图，以及不同限速和流量控制下的事故概率。结果显示：随着冰雪下道路附着系数的变小，流量在急剧下降;当为冰膜、光滑压实雪时，限速和流量控制效果有限，封路、安装防滑链或特殊轮胎等是必要的措施;当为其它冰雪状态时，适宜的限速和流量控制是保证道路交通安全的重要措施。

关 键 词 冰雪条件;元胞自动机模型;交通事故;道路交通流;附着系数

中图分类号 U491     文献标志码 A

A CA model of road traffic flow with possible accident under ice and snowfall conditions

SHI Yalei， PANG Mingbao

（School of Civil Engineering and Transportation， Hebei University of Technology， Tianjin 300401， China）

Abstract The problem of microscopic simulation model for road traffic flow with possible accident under ice and snowfall conditions was studied based on cellular automata （CA）. By analyzing the wider vehicle safety spacings  due to the the decreas of friction coefficient on ice and snowfall road， safety spacings were defined under acceleration， cruising and deceleration states， respectively. A CA simulation model with possible traffic accident and probability statistics was established. The fundamental phase diagrams of concrete road between traffic density and volume were obtained under different ice snowfall conditions. The accident probabilities were analyzed via the simulation experiments by using speed limits and incoming flow control. The results indicate that the traffic flux will decrease rapidly when the friction coefficient becomes small under ice snowfall conditions. It is necessary to close roads， add antiskid chain or special tires on the vehicles due to the limited effect of speed limits and incoming flow control when the road is covered with ice film， smooth compacted snow. Speed limits and incoming flow control with suitable values are effective measures to guarantee the traffic safety when roads are under the other conditions.

Key words ice and snowfall conditions; cellular automaton（CA） model; traffic accident; traffic flow of road; friction coefficient

0 引言

冰雪条件下道路由于附着系数变小极易发生交通事故，对道路交通的安全运行会产生严重的后果[1-4]，研究冰雪条件下的交通流模型及其特性，并在此基础上提出更加科学合理的量化管控策略，具有重要的理论和工程应用价值。现研究主要集中于3个方面：一是主要研究冰雪条件下事故率和交通流特性的宏观统计分析、评价及其工程措施等方面[1-2]，不涉及具体交通流微观模型的建立和特性分析;二是单一车辆冰雪天气下动力学分析，进行车辆设计研究，也不涉及道路交通流微观模型和道路安全管控[3-5];三是建立在交通流微观仿真模……