Research And Implementation On Ramp Metering And Variable Speed Limit For Highway

In recent years, motor vehicles increase rapidly with economic development. Peak-hourcrowding and frequent traffic accidents become an urgent problem to highway managementdepartment. However, the domestic research on highway control started late, in particular thelack of targeted highway control methods. Therefore, this paper will do research on highwaymanagement control for peak-hour congestion and traffic accidents, in order to provide decisionsupport for highway management department.The main tasks and research results of this paper are as follows:1. Cooperative control methods for ramp. For peak congestion and highway ramp control,establish joint control model of ramps; On this basis, the maximum total flow and minimumaverage waiting time at ramp are considered as the optimization goal, and the ant colonyalgorithm is used to optimize the solving for the target function. First, each ramp metering raterange is divided into multiple sub-intervals with a fixed length, each sub-interval is considered asa vertex which makes of the routes of ants. Eventually we will find the optimal rate of each rampwithin a control period. Experimental results show that it will ensure the smooth operation ofmainline traffic flow during peak hour and avoid traffic congestion caused by the fluctuations oftraffic state in the individual sections.2. Optimal dynamic variable speed-limit control methods on accidents. According to thefrequent highway traffic accidents, we consider speed-limit of each section as the control object,and establish control model of variable speed-limit on sections. Here we present two differentoptimal control objectives, one is the shortest queue length of the accident upstream, the otherone is the maximum service flow at the range influenced by the accident, for traffic accident inhighway, two variable speed-limit control methods UQLS and ATFB are designed to optimizethe regulation of speed-limit in each section. Finally, the experimental results show that twovariable speed limit control method proposed in this paper can effectively resist the downstreamtraffic shock, and relieve traffic congestion. 3. Design and development of ramp-control and variable speed-limit system. Server ofhighway network is built in vissim. Based on COM interface, Ramp-control and variable speedlimit system is developed by using VB.NET language on platform of Windows. The systemprototype can provide technical support to the development of highway management and controlplatform.