高速公路主线相互合流至出口最小间距的研究

Minimum spacing between the mainline of highway mutual confluence and the mainline exit

针对高速公路主线相互合流紧接主线的出口路段间距过小,可能导致驾驶员错过出口或发生交通安全事故的现象,以高速公路主线相互合流至主线出口最小间距为研究对象,确定满足其需求的最小长度.基于驾驶员不熟悉路况的最不利情况下,研究主线相互合流至主线出口之间的间距需考虑6个部分,分别是主线相互合流构造距离、车流重新分布距离、认读标志距离、车辆换道距离、安全确认距离及出口减速段.从安全角度出发,建立主线相互合流构造距离计算模型;结合主线相互合流后的交通流特性,根据不同的主线相互合流方式及车道数,确定换道类型和换道次数,并以此计算出车流重新分布所需距离.根据车辆进行换道时的特征和轨迹,建立五阶多项式换道模型,计算车辆换道距离;提出最小间距建议值,并对建议值进行仿真验证.结果表明,当且仅当间距大于等于建议值时,冲突率满足模糊隶属度评价,安全水平为安全.最小间距计算模型合理可靠,据此计算的最小间距建议值可保证行车安全.

For expressway section between the mainline mutual confluence and the mainline exit,which might be too short to cause traffic safety accidents or the driver to miss the exit,we study the reasonable minimum space between the mainline of expressway mutual confluence and the mainline exit based on six main influence factors.Considering the worst circumstance of a driver who is not familiar with the road condition,the six main influence factors are the mainline mutual confluence construction distance,traffic redistribution distance,sign reading distance,vehicle lane changing distance,safety confirmation distance,and exit deceleration section.From a security point of view,we establish a model for the mainline confluence structural distance.Combing with the traffic flow characteristics of mainline mutual confluence,we analyze the effects of different main line mutual confluence and lane number in order to identify lane changing type,the number of changing lane,and the distance required for the redistribution of traffic due to lane changing.According to the characteristics and trajectories of vehicles in lane changing,and by using the five stage lane changing model,we calculate the vehicle lane changing distance and give suggestions on the minimum spacing distance.Finally,the recommended value is simulated and verified by VISSIM simulation.The results show that when the space is greater than or equal to the recommended value,the requirements for conflict rate and safety level are met.The calculation model is a reasonable and reliable model,and the recommended value can ensure traffic safety.