Optimization Design Of Road Network Traffic Organization Considering Micro-Macro Interaction Effect In CBD

With the rapid development of the social economy,the number of motor vehicles has gradually increased,and the urban traffic situation is becoming more and more severe.As the core area of urban economy,science and technology and culture,the traffic problem of urban CBD area is more prominent.It is urgent to effectively alleviate traffic congestion in the urban CBD area.In the existing way of alleviating urban traffic jams,the effect of new roads and widening existing roads is remarkable,but under limited urban space resources and environment,they cannot be once and for all,and are not economical.The optimization of road traffic organization is another important way to relieve congestion.It can make full use of existing road resources,tap the potential of road network,and effectively improve the efficiency of road network.The optimization of road traffic organization is divided into two levels: micro and macro.However,most of the existing optimization methods of road network traffic only start from a single micro or macro traffic organization level,without considering the joint action of two kinds of organization modes.Based on this,the paper studies the optimal design of road network traffic organization in CBD district by considering the interaction of micro macro traffic organization.According to the definition of CBD District,this paper,discusses CBD district on the road traffic network flow characteristics,analyzes the main contents and measures of micro and macro two levels of traffic organization,studies on interaction effect of micro and macro traffic organization on road network traffic parameters(such as vehicle speed,road capacity etc.),reveals the interaction mechanism of micro macro the traffic organization.And the purpose is to improve the network traffic organization optimization design.Based on the interaction mechanism between micro-macro traffic organizations,a two-layer programming model is established.The upper level planning considers two levels of construction,one is the one-way traffic section,the bus lane and the restricted cargo setting which are belong to the macro traffic organization level,the other is the left intersection at the microscopic traffic organization level,and it is the optimization model both the minimum of the saturation of the main trunk road and total travel time of the road network.The lower level planning adopts an equilibrium distribution model that satisfies the minimum travel impedance of the user.Through the coordination of the upper and lower layers model,the best running condition of road network in CBD area is sought.Comparing the advantages and disadvantages of the existing conventional algorithm,genetic algorithm is selected as a bilevel programming model algorithm to solve the upper and lower flow distribution,user equilibrium model there is no universal solution.During the actual calculation process,the paper,uses the traffic assignment module in transportation planning software to achieve the road traffic distribution in the lower planning,programs by MATLAB software to solve the model,calculates the optimization scheme of CBD district road traffic organization and through the example analysis model is reliable.In the case part,traffic organization optimization design of road network in CBD District of Huangshi is carried out.Through the setting of road network parameters,a corresponding bilevel programming model is built and solved,and the optimization design of traffic organization in Huangshi CBD area is obtained.The optimization scheme and the current traffic conditions is simulated by using VISSIM software,the simulation results show that the optimization scheme of Road intersection,the average queue length and average number of parking vehicles average delay were decreased to some extent.So the paper of considering the micro macro interaction CBD district road network traffic organization optimization design method can effectively alleviate road traffic congestion in the CBD area and can provide reference for the optimization of traffic organization design CBD.