Studies On The Lanzhou Public Transit Network Accessibility

With the rapid development of the city, expanding the scale of the urbanization, in-creasing of the urban population, more and more serious traffic problems, traffic con-gestion, emissions and other issues have become very serious. Idea of Traffic develop-ment in the past is not consistent with the actual situation under such severe traffic con-dition, which is difficult to solve the travel problems of urban residents. Meanwhile that the government develops public transport, initiates low-carbon living and green travel concept is recognized by people. Therefore, the study of public transport accessibility is becoming more and more important to solve urban traffic problems which will contri-bute a lot for residents to travel.This paper conducted studying reachability of the status quo at home and abroad, factors to accessibility of urban public transport system, and existing accessibility eval-uation models to propose the theory of urban public transport accessibility. This paper presents a mathematical model on evaluation index of urban public transport accessibil-ity, which combines the cumulative opportunity model, accessibility research methods and topological model of temporal constraints measure method to study reachability at macro and micro levels. This model’s accessibility evaluation of urban public transport systems shows a comprehensive and multi-level characteristic that can give the level of the bus system and identify deficiencies of the system.Through TransCAD, bus route system and urban public transport network database are established, whose core is composed of geospatial database and bus route system database. After considering the factors "shortest distance to travel" and "transfer times", the bus travel path generalized cost model was established to determine the design crite-ria of the best path for the bus and calculation methods on the optimal path. Analysis reachability of urban public transport system is based on spatial analysis functions of TransCAD software, developed by GISDK in-depth.From Lanzhou traffic problems currently facing away from the line length, non-linear coefficient, the average concentration of stations and station line Quartet face Lanzhou City Bus spatial characteristics were analyzed, on this basis, up from the space, time accessibility and cost up to terms of the macro, meso and micro-level model analy-sis carried out, the final results of the analysis proposed measures to ease traffic prob-lems.