Urban Mixed Traffic Assignment Model Considering Environmental Factors

China has become one of the most potential economic powers in the world which profited from its large-scale construction in a planned way since China founded.Vehicle ownership continues breaking new records due to people’s travel demand and travel times caused by the accelerated process of urbanization,the improved people’s living standard.In this instance,the multi-mode transportation system has emerged,it can meet people’s different travel needs and travel more convenient,fast and safe.However,with the increase of urban vehicle ownership and fuel consumption,it will not only bring energy shortage,but also lead to the environmental problem of air pollution,reducing fuel consumption is the most effective way to reduce vehicle emissions.Therefore,energy and vehicle emissions are the factors that must be considered in the construction of urban transportation system at present and in the future.Under this background,this thesis establishes an urban mixed traffic assignment model which contains environmental factors.This thesis is mainly constructed by the following contents:This thesis,as per the actual situation of urban transportation in China,analyzes the time cost of unit traveler choosing four modes of transportation(private car,taxi,electric car,bus)and the travel cost considering energy consumption,the additive function of time cost and travel cost considering energy consumption(generalized travel cost function)is taken as the objective function,combined with the Logit travel choice model,an urban mixed traffic allocation model considering elastic demand and energy consumption based on time cost was established.The rationality of the model is verified by a numerical example.This thesis also considers the vehicle exhaust emission model,and based on the four traffic modes analyzed which are mentioned above.It is constructed a multi-objective planning model,including urban mixed traffic distribution model considering the time cost and exhaust emissions.Based on the goal of “time cost”considered in Chapter 3,this model takes vehicle exhaust emissions into consideration in the objective function,gives different weights to the two objective functions,and turns them into a single objective programming problem for solving.Finally,a numerical example is given to prove the rationality of the model.