城市快速路入口匝道控制仿真分析

以深圳春风路高架快速路为例,对不同交通需求水平情况下定时、Alinea、Flow 3种常用入口匝道控制算法的实施效果进行了仿真分析,并详述了各种算法的参数取值.仿真结果表明,入口匝道控制在交通需求高到一定程度的情况下能有效发挥改善主线交通的作用.Alinea和Flow算法总体优于定时控制,但也显著增加了匝道的延误和排队长度.当交通瓶颈与上游2个入口匝道均密切相关时,Flow算法控制效果优于Alinea算法.最后,对在Alinea,Flow算法中引入匝道排队调节的情况进行了仿真分析,结果表明排队检测器离匝道入口的距离是平衡主线拥挤和匝道排队的关键因素.

A Simulation Study on City Expressway on Ramp Metering

As a case study,three well known on ramp metering algorithms,including fixed time,Alinea and Flow,were evaluated via traffic simulation on Shenzhen Chunfeng expressway on various traffic demand levels,the parameters calibrations were also expatiated. Simulation results show that on ramp metering can effectively improve mainline traffic when traffic demand is higher than a certain level.Both Alinea and Flow perform better than fixed time metering,but increase ramp delay and queue obviously. Flow outperforms Alinea in this case study because the traffic bottleneck is closely related to its upstream on ramps traffic.Finally,the scenarios of adding queue adjustment into Alinea and Flow were simulated.Results show that the distance of queue detectors to ramp entrance plays a key role to trade off between the mainline congestion and on ramp queue.