Calculation Of Accessibility Based On Taxi Trajectory Data

Accessibility can reflect the relationship between urban transportation system and land use,it has been an important indicator of urban planning and one of the effective means to solve traffic problems.In the evaluation of accessibility,the traffic factor is always the main factor.The taxi trajectory data provided by GPS contains a lot of real travel and road condition information.This paper used these information in to the study of accessibility,completing the city level regional accessibility calculation,which provides reference for the accessibility calculation and analysis under the background of big data.This paper calculated and analyzed the regional accessibility based on the mining of taxi trajectory data.Firstly,through literature retrieval,the research status of taxi trajectory data and accessibility was summarized.And through the overview of taxi trajectory data,laid the foundation for the later taxi trajectory data processing methods and steps;Through the overview of accessibility,laid the foundation for the model selection and construction of accessibility measurement in the following paper.In the process of taxi trajectory data processing and index calculation,through data preprocessing and pick-up and drop off point extraction,passenger travel time,travel time,travel frequency and single vehicle travel speed were obtained.In the construction of the accessibility measurement model,the probability method was selected as the accessibility measurement model,which makes up for the defects of the commonly used potential model in the explanatory aspect.The POI data was used to construct the attraction intensity model,and the impedance model was constructed and calibrated by using the relationship between residents’ travel time and frequency.Finally,the results of taxi trajectory data processing and Xi’an road network data were used to verify.In order to make the estimation result more accurate,based on the different taxi sample size of each road section,this paper used the road travel speed estimation method which combines the mean value method and the median value method to estimate the road travel speed,so as to prepare for the calculation of traffic impedance in the accessibility calculation model.Based on the climbing POI data and road speed,the regional attraction intensity and impedance are calculated,and then the regional accessibility level is calculated.The accessibility level of Xi’an city is analyzed and evaluated in different space and time,combined with the regional attraction intensity and road operation status.Finally,according to the attraction intensity and traffic impedance of the surrounding area,the accessibility of each area was classified.The results show that:(1)the frequency of taxi passengers reduces rapidly with the increase of travel time,and the relationship fits well with the improved logarithmic function in the impedance model.(2)Road impedance has a great impact on the accessibility of the study area,but when the area is close to the area with high attraction intensity,it can often reduce part of the impact of excessive road impedance and improve the accessibility of the area.(3)In the comparative analysis of the accessibility of morning and evening peak and normal peak,it is found that due to the road operation conditions,the accessibility level of different periods is quite different.The accessibility of the whole region during normal peak is maintained at a high level,while the accessibility level during morning and evening peak is basically the same,and the level is relatively low.(4)Due to the high attraction intensity in the area within Xi’an Ring Expressway,the accessibility classification is mainly high location-low access-high accessibility,and high location-low access-low accessibility.The areas with high access basically only appear outside the ring expressway.In this paper,through the processing and mining of taxi trajectory data,we get the information of residents’ travel time and space characteristics and road operation status,and use these information to the accessibility calculation model,and get the accessibility level under the actual travel conditions.Combined with the road traffic and land use,explore the accessibility distribution law.