The Influence Of The Choice Of Accessibility Time Scale On The Equity Of Public Transportation

Based on the time aggregation effect and time boundary effect in MTUP,explore the difference in accessibility and equity caused by changes in travel time threshold and time resolution.On the one hand,under the given travel threshold,the space range that passengers can reach from a bus station with the help of the bus system is taken as the accessibility index.The cumulative opportunity model is used to calculate the bus station accessibility of the stations,and the TAZ accessibility is obtained by summarizing the bus station accessibility.Then at 10 min intervals,change the travel time threshold to get the accessibility index of 10,20,30,40,50,60,70,80 and 90 min respectively,and use the Gini coefficient to calculate the equity.The accessibility under 9 different time thresholds is weighted to calculate the weighted Gini coefficient.By comparing the difference between the weighted Gini coefficient and the calculated Gini coefficient of 9 time thresholds,the optimal travel time threshold is selected.On the other hand,the continuous periods with bus service in a day are divided into time segments with equal spacing,and the buffer method is used to calculate the bus accessibility index of each time segment.The number of travels in different time segments was used as the weight to obtain the accessibility of buses per unit time,and the accessibility index of a day was obtained according to the number of time segments.Changing the length of the time segment to calculate the accessibility index with resolutions of 0.5h,1h,2h,3h,4h,5h,6h,7h,8h,and 9h respectively,and using the Gini coefficient to calculate the equity.Using the 0.5h resolution to calculate the accessibility and equity index results as a benchmark value,calculating the error of the bus accessibility and equity calculation results at different time resolutions.Comprehensively consider the error of bus accessibility and Gini coefficient as well as the calculation difficulty,and select the best travel time resolution.The results show that with the increase of the travel time threshold,the calculation results of the accessibility index and the Gini coefficient gradually increase.As the time resolution increases,the calculation result of the accessibility index gradually decreases.When the time resolution is reduced from 0.5h to 3h,the Gini coefficient gradually increases,and when the time resolution is reduced from 3h to 9h,the Gini coefficient graduallydecreases.The main reason for the change of the Gini coefficient result is the change of the accessibility value and the distribution range of accessibility.Considering the travel time and characteristics of residents in HN city,as well as the calculation accuracy and difficulty of the accessibility index,in order to make the equity evaluation results more credible,choosing40 min as the travel time threshold and 1h as the travel time resolution.