Studies On Bus Network Optimization In Taiyuan City

Optimization of urban bus networks is the main part of transport planning in a city. It is one of the effective solutions to improve the difficult transportation in the case of limited investment. Based on analyzing present bus network of Taiyuan city, consulting national and international theories and experience of transit network planning, using geographic information system (GIS) software, the author optimized the current bus network of Taiyuan.This paper consists of five parts: 1) preface; 2) analysis of current transit; 3) forecast of transit demand and assignment of transit volume; 4) the network planning; and 5) evaluation for optimized Taiyuan public transit network.In the preface, the author elaborated the bus network optimization purpose, concept, content and significance, and analyzed the research situation of bus network optimization in domestic and abroad, and then the research content and the research technique were carried out.In the second part, the study took some indexes, such as: bus line length, bus network density, repetition coefficient, non-linear coefficient, bus stop density, average distance between stops and stop coverage, to make the evaluation of bus network in Taiyuan by the support of GIS technology. We found that there are still some problems in the bus network, although public bus network in Taiyuan has been greatly developed. These problems revealed in the study are that the bus line length is too long on the whole and the network density is low relatively; both the repetition coefficient and its difference in spatial distribution are large; and the indexes of non-linear coefficient, stop density and stop coverage are not consistent with the values from "Urban road Transportation Plan Design Criterion ".In the third part, by investigating the Taiyuan resident's travel characteristic, the public transportation passenger flow demand forecast model and the allocation forecast model was proposed. In the part of the demand forecast model, under the forecast frame of "four terrace works", the article mainly researched the methods of travel production forecast, compared the characteristics of the methods, and then, chose the increment method demand forecast model and gave the related parameters to demarcate this method. In the part of the allocation forecast model, by comparing the advantages and disadvantages of various forecasting methods, an optimization model of the passenger flow based on the GIS had been chosen and the allocative scheme of the passenger flow was given.In the fourth part, from the angle of raising the service level to passengers and the enterprise's interests, the GIS-based optimization scheme had been put forward on the basis of analyzing the bus network optimization objectives and its impact, and then, the author used this scheme to optimize present bus network of Taiyuan.Finally, the results of optimized bus network showed that, the bus stop coverage and density were increased; average distance between the stops decreased; Less than or equal to 15 kilometers average length and density of the bus lines increased slightly; and the bus line repetition coefficient and non-linear coefficient reduced slightly. Compared with those from the values of "Urban Road Transportation Plan Design Criterion", all of the indexes were nearly approached their criterion. Therefore, the optimized bus network was more convenient for the residents than before.