Research On Quantitative Evaluation Method Of Urban Transportation System Resilience Under Extreme Weather Events

The frequent occurrence of Extreme weather events(EWEs)in recent years has posed major hazards to the operation of urban transportation systems,resulting in long-term socio-economic impacts.As the lifeline of the urban network,the urban transportation system can provide access to the impacted areas when EWEs occur to support emergency response and long-term recovery operations after a disaster.Thus,quantitative evaluation the urban transportation system resilience to minimize the impact caused by EWEs becomes critical to the stable operation of urban transportation systems throughout the disaster life cycle.However,there is generally a lack of reliable data to monitor the urban transportation system performance under EWEs in real time.At the same time,methods for evaluating the urban transportation system resilience under EWEs are also lacking in the existing literature.Based on this,this paper proposes a method to quantitatively evaluate the urban transportation system resilience under EWEs using bus GPS trajectory dataset.The main contents and results of the study are as follows:First of all,the definition of urban transportation system resilience under EWEs is summarized by combining the previous understanding of transportation system resilience.Second,the selection principles of resilience evaluation indicators based on the transportation system performance,this paper selects displacement as a key indicator for evaluating the urban transportation system performance,and measures transportation system performance by using the baseline method to calculate the deviation of the total displacement of all buses under rainstorm events.By plotting the transportation system performance curves,this paper also proposes a new destructive indicator for evaluating the destructiveness of EWEs on the urban transportation system.Then,according to the principles and steps of transportation zones division,the urban road network within the third ring road of Fuzhou center is divided into 89 transportation zones,and the destructiveness and resilience of the transportation system in 89 transportation zones are quantitatively evaluated in both temporal and spatial dimensions during the rainstorm.The results of the empirical study show that the transportation system resilience of 89 transportation zones are at a high level during the yellow rainstorm warning,while 12 transportation zones are at a medium level of the transportation system resilience and 77 transportation zones are at a high level of the transportation system resilience during the red rainstorm warning.In addition,89 transportation zones have a degree of resistance to rainstorm event and are able to absorb their initial impact within the first few hours.Through the development of contingency plans and mitigation measures,the performance of the transportation system in transportation zone 11 during the red rainstorm warning improved by 26% compared to that during the yellow rainstorm warning.Finally,17 influencing factors are selected from three perspectives: land use and development,population and economic characteristics,and transportation service level to investigate the influence mechanism of transportation system resilience of 89 transportation zones during the red rainstorm warning.Through the correlation analysis,it is verified that there is a significant negative strong correlation between the resilience and destructiveness of the transportation system in 89 transportation zones.Regression analysis is used to obtain the significant variables affecting transportation system resilience values of 89 transportation zones during the red rainstorm warning,and suggestions are given to improve the transportation system resilience in transportation zones under EWEs based on actual investigations.The resilience evaluation method proposed in this paper provides valuable information for urban transportation systems when faced with EWEs.The results of the empirical study will help policymaker prioritize the resource distribution and develop effective policies or measures to further improve the transportation system resilience in the city.