Comprehensive Evaluation And Structure Optimization Of Urban Traffic Mode During The Period Of Ice And Snow In The Cold Region

The season of ice and snow starting from November of this year to next February is long and cold in cold reagion in China; because of the extremely cold weather and the frequent snow, it is extraordinarily diffcult to clean and maintain urban pavement, thus, the mixed pavement that composed of dry pavement and rough ice pavement always exists during this period. The change of weather and road conditions has an impact on the choice of residents’ travel modes and the urban transport structure. The studies on the evaluation of travel modes and the optimization of urban transport structure in the cold area during the ice and snow season can help people to understand the development status of the travel modes and urban transport structure.Meanwhile, providing a method for calculating the reasonable transport structure.The trip environment and the residents’ trip characteristics during the period of ice and snow in the cold reagion are analysised based on the investigated data and resources. Through studing the relationship among the traffic conflicts, pavement attachment coefficient and vehicle’s velocity, the thresholds without traffic conflicts are provided; according to the relationshiop between the traffic accidents and traffic conflicts, the calculation function of accident cost for different travel modes during the period of ice and snow in cold reagion is established. In order to quantify the transportation efficiency, economy and comfort, this article establish the calculation functions of the trip time costing, economic costing and the comfortable benefit based on the Disaggregate Model Theory.From the perspective of the travelers, the evaluation indexes system is established from four aspects: traveling safety, efficiency, economy and comfort. Then the evaluation models of travel modes and transport structure during the period of ice and snow in cold reagion are built; combining with calculation data and considering the region’s trip preferences, the model parameters are calibrated on the basis of the principal component analysis method. Under the precondition of investment without increase in transportation facilities, treating the minimum costing of comprehensive trip as the goal function, the constraint conditions are built from six aspects: travel accessibility, efficiency, the peak hour capacity of rail transportation, limition of urban road resources, traffic environment bearing force, energy supply capacity and urban transport development policy. Thus, the optimization model of transport structure during the period of ice and snow in the cold region could be estabished; at last the development proposals and measures to guarantee are given.This study provides the guidance for the travlers to choose the travling way of minimum comprehensive costing, to provide the approach to evaluate travel modes and optimize transport structure during special period for the transportation planning and management department, to provide reference for the relevant researchers, and to lay the foundation for the realization of sustainable development of urban transportation.