| Currently, the national economy is increasing annually, and people’s living condition is improving gradually, but the surrounding environment is deteriorating. The living environment problem, such as "Greenhouse effect" and "fog and haze", has replaced food and clothing problem, and the living environment problem has become one of the primary concerns. Research shows that urban transport carbon dioxide emissions are not only the major components of environmental pollution, but also the culprit leading to the heat island effect of urban. How to safeguard residents under the premise of traffic demand, reduce carbon emissions, protect the environment, that is the problem to be solved. Therefore, for the above-mentioned problems, to carry out the research of urban road network optimization to cut road transport emissions can let urban residents enjoy more convenient, more efficient, more environmentally friendly and low-carbon way to travel and transportation environment, it is particularly necessary.Firstly, the connotation of low-carbon concept were analyzed and the meaning of low-carbon travel were clearly defined in this paper. Secondly, based on comprehensive analysed of the concept of low-carbon and urban road network on two aspects. Research show that the structure of the urban road network optimization is an effective and necessary means of reducing carbon emissions from urban traffic. Then, the road network of carbon emissions basic model and the urban road network structure optimization model based on the concept of low-carbon were established and the case study on the model were conducted.The model in this paper is mainly manifested in two aspects: First, the road network of carbon emissions basic model were established. Most existing models were based on different modes of transportation, and they had little effect on urban road network structural optimization. the idea of the original vehicle pollutant emissions model were referred, the microscopic processing were carried on, and the road network of carbon emissions basic model were established.It could get the carbon emissions of every section by different road, and then quantified the carbon emissions index and estimate the carbon emissions of the road. Second, the urban road network structure optimization model based on the concept of low-carbon were established. This is the whole thesis of the important and difficult. Most of the existing urban road network structure optimization model were based on the maximum of road network capacity or road network security, etc., and carbon emissions index were seldom considered.In this paper, carbon emissions from road network were introduced as the important index of urban road network structure optimization model, and the minimum traffic carbon emissions as one of the optimization objectives, combined with the maximum of road network capacity, and established the objective function. Then, we calculated and verified the applicability of the model with the examples.In this paper, the urban road network were took as research object, and optimized the structure of urban road network from the angle of reducing the carbon dioxide emissions of the road network, and established the urban road network structure optimization model based on the concept of low-carbon. It makes a new exploration on the implementation of urban traffic low-carbon travel. The research results provided a reference for the research and decision of the government agency and research institution in the new period of urban transportation planning and network planning. |
