基于离散多项Logit模型的多时段控制过渡方案选择

Multinomial Logit Model Based Time-of-day Control Transition Scheme Selection

过渡方案可有效降低多时段控制方案间切换对交通流造成的扰动,对多时段控制策略的效益有显著影响。研究首先对多时段过渡方案选择的流程进行了分析,选取多项Logit模型进行多时段过渡方案选择的判断;其次,通过选择集、特征变量、效用函数选取等步骤,利用经典的3种平滑过渡方案作为选择集,选取车均延误、该时段干道流量、过渡所需时长作为特征变量进行参数标定,以立即过渡、两周期过渡、三周期过渡3种经典的多时段平滑过渡方案为例,建立了多时段控制过渡方案的离散多项Logit选择模型,在效用最大理论的前提下进行概率计算并利用极大似然法对模型的参数进行了估计和检验;最后,选取江苏省苏州市滨河路干道沿线协调范围内交通流状态稳定且呈现较明显的时间规律的4个关键交叉口作为研究对象,以3种平滑过渡方案对控制效益影响最大的晚低峰切换至早高峰的过渡方案对微观交通仿真进行了分析,在早高峰即将到来时,由方案1切换至方案2的过渡过程中,立即过渡方案的车均延误最低,其次为两周期过渡方案,三周期过渡方案车均延误最大。结果表明立即过渡方案的控制效果最佳,进而通过本研究的模型分析,案例交叉口亦分别有50. 77%,56. 72%,46. 88%,47. 00%的概率选择立即过渡方案,与仿真结果一致,表明模型具有很好的适用性。

Transition scheme can effectively reduce disturbance to traffic flow caused by time-of-day（ TOD）control scheme switch,which has significant influence on control efficiency of the TOD strategy. First,the flowchart of TOD transition scheme selection is analyzed,and the multinomial Logit model is selected for judging the choice of TOD transition schemes. Furthermore,through the steps such as selecting choice set,characteristic variables and utility function,using 3 classical smooth transition schemes as a choice set,average vehicle delay,traffic flow of the main road during this period,and time required for the transition as the characteristic variables are selected for parameter calibration. Taking 3 classical TOD smooth transition scheme（ immediate transition scheme, 2-cycle transition scheme and 3-cycle transition scheme） for examples,a discrete multinomial Logit model for TOD transition scheme selection is established. The probability calculation is conducted under the premise of maximum utility theory,and the model parameters are estimated and verified with the maximum likelihood method. Finally,4 key intersections with stabletraffic flow and obvious time patterns in the coordinated area along the main road of Binhe Road in Suzhou City,Jiangsu Province are selected as the research objects. The transition scheme which has the most influence on control benefits in the 3 smooth transition schemes is analyzed in the period from evening valley to morning peak in the micro traffic simulation. The immediate transition scheme shows that when the early peak is approaching,during the transition period from scenario 1 to scenario 2,the average delay of the immediate transition scheme is the lowest,followed by the 2-cycle transition scheme,and the average delay of the 3-cycle transition scheme is the highest. The result of model analysis shows that for 4 typical intersections,there are also the probabilities of 50. 77%,56. 72%,46. 88%,and 47. 00% respectively to select immediate transition scheme as the optimal transition,which is in accordance with the simulation result,and means the proposed model has good applicability.