Research On Measurement Of Rational Scale And Optimization Of Grade Structure In Country Highway Network

Country highway network is the main transportation infrastructure services for residents and palys an important part in the whole highway transportation system. Country highway network provides the basic condition for the economic prosperity, urbanization, urban-rural integration and the construction of new rural. Country highway network plays an irreplaceable role in promoting the development of country economy and meeting the travel demand of the residents. With the increasing development of country economy and the travel demand of the residents, the scale and grade structure appear unreasonable phenomenon. According to the actual situation of the country, it is necessary to calculate the reasonable scale and optimize the grade structure of the highway network.Analysis the advantages and disadvantages of analogy method, connectivity method, growth curve method and territory coefficient method which are the common methods of highway network scale measurement. Territory coefficient method has been selected to research the highway network reasonable scale, and the territory coefficient method has been improved according to the actual situation of the country. Analysis the relevance of highway network scale and influencing factors, select the main influencing factors to improve the highway network coefficient. Considering the unbalance development of different sub-region, add the correction factor of sub-region economic development potential, the correction factor of sub-region highway network development potential and the correction factor of sub-region urbanization development level into the territory coefficient method.In the process of grade structure optimization of country highway network, the up and down limits of each class highway are determined according to the traffic flow. With the economic development situation and traffic demand characteristics in different development stages of country, a short-term highway network grade structure optimization model with the goal of minimum construction funds and the highest overall operational efficiency of the highway network, and a long-term highway network grade structure optimization model with the maximum capacity of the road network and the highest technical level of the road network are established. With the appropriate constrains, and the platform of Lingo software, short-term and long-term highway network grade structure optimization model have been solved.Take Y country as an example to research the rational scale measurement and grade structure optimization of highway network. Combining with the actual development of Y country, the reasonable scale of highway network in Y country is calculated by using the improved territory coefficient method. Short-term and long-term highway network highway network grade structure optimization model are established. The models are solved on the platform of Lingo software. The short-term and long-term highway network grade structure optimization results are obtained.