Evaluation And Analysis Of Public Transport Accessibility Of The Elderly In Mountainous Cities ——A Case Study Of The Central Urban Area Of Guiyang

Under the background of increasing aging,the contradiction between the lagging development of public transport system in mountainous cities and the rapid increase of the elderly has intensified.The development speed of urban public transport is too slow,which is not conducive to promoting the public transport travel of the elderly and the construction of urban public transport.Analyzing the impact mechanism of public transport on the public transport travel of the elderly in mountainous cities and improving the utilization rate of public transport system is one of the important measures to promote the construction of urban public transport.Taking the central urban area of Guiyang as the research area,with the help of Arc GIS software,through the improved two-step mobile search method,this paper analyzes the spatial differentiation law of the elderly’s bus accessibility in downhill cities affected by topographic factors,discusses the current problems and puts forward targeted optimization suggestions.The conclusions of this paper are as follows:（1）By combing the characteristics of public transport network and road network in mountainous cities,combined with the traditional two-step mobile search method,this paper analyzes the impact of road slope and bus detour on the bus travel of the elderly.The study found that for mountainous cities,the impact of terrain factors on the accessibility of public transport for the elderly can not be ignored.The improved model is more suitable for analyzing the temporal and spatial differentiation characteristics of public transport accessibility in mountainous cities,while avoiding the distortion of research results.（2）In the "conventional bus + BRT + rail transit" public transport supply mode,rail line 1 and rail line 2 can improve the common traffic accessibility value of the elderly in the core area and along the rail transit,but the public transport supply for the elderly in the urban fringe needs to be improved,and there is an imbalance in the spatial allocation of resources in the public transport system;If rail line 3 is completed and put into use,it will significantly improve the convenience of bus travel for the elderly in Huaxi District.The supply of ground conventional bus and BRT in Wudang district is insufficient,and rail transit has little impact on it.The elderly in street communities in some marginal areas are still in a state of very low accessibility or low accessibility of public transport,and the elderly in suburban areas are marginalized.（3）The central urban area of Guiyang has not yet formed an efficient bus connection system,and the urban fringe enjoying the supply of rail transit is significantly affected by the terrain.In this area,there is a "conventional bus + rail transit" travel mode for the elderly in bus travel activities.In areas with insufficient supply of ground conventional bus,seamless transfer or short-distance transfer cannot be achieved.Some ground conventional bus operation lines should be adjusted or added appropriately to improve the utilization of public transport and promote the convenience of bus travel for the elderly.（4）Rail transit can significantly reduce the adverse impact of excessive bus detour distance on the bus travel of the elderly.Under the three types of public transport service modes,the distance coefficient ratio decreases with the reduction of rail line operation,the range within the high distance coefficient range decreases,and the area with low distance coefficient ratio expands.If rail line 3 is put into operation,it can save the bus travel time of the elderly in Huaxi District,and the impact on Wudang district is not significant.（5）In the three types of life circle classification,the spatial distribution of bus acquisition grade with / without terrain factors presents the characteristics of "small points with large areas".The acquisition stations of most residential communities are in a very low and low state.With the increase of travel time and the operation of rail stations,the number of residential communities in a high and extremely high range increases.Topographic factors have little impact on the old urban area and the areas with sufficient public transport supply and without public transport supply,and have a significant impact on the periphery of the old urban area in a low and general state.（6）According to the analysis results of the improved two-step mobile search method,combined with the current situation of Guiyang public transport system,elderly population density,road slope around residential areas and station line layout,avoid the negative impact of topographic conditions on the public transport travel of the elderly from the aspects of bus stop optimization layout and rail transit construction,and build people-oriented urban transportation and public service facilities in many aspects.