| The urban transportation network transports goods and passengers,and has become the lifeline of modern societies.With rapid growth of sharing economy,sharing transportation modes such as customized bus services play an important role in the multi-modal transportation network.However,the development of transportation network brings increasing uncertainties,which exert significant impacts on performance of transportation network and activity-travel behavior of individuals.Activity-based models investigate individuals' travel behavior based on activity demands,and are able to analyze the spatial and temporal distribution pattern of traffic flow in multi-modal transportation networks.Considering the impact of uncertainties in the activity-based model can effectively model individuals' activity-travel patterns in transportation network,thus provides theoretical basis and technical support for the design,adjustment,management,and evaluation of multi-modal transportation networks.This paper first provides an overview of recent researches on the reliability,vulnerability,and resilience of urban transportation networks.With a comprehensive review of definitions,metrics,and evaluation methods of the three measures,this paper analyzes and compares the similarities and differences between reliability,vulnerability,and resilience.To clearly reflect the differences of the three measures,this paper conducts a case study to show that different measures are applicable to evaluate transportation network performance under different perturbations.The analysis results provide a theoretical basis for selecting suitable measures of uncertainty in the subsequent study.Based on the smart card data collected from Nanjing metro system,this paper analyzes the impact of uncertainties on network performance and spatial and temporal travel patterns from the prospective of network and individuals using indices of travel time reliability.The results of analysis considering uncertainties in network differ from those of analysis measuring network performance with no perturbation.By evaluating the travel time reliability and travel patterns of different groups of commuters,this study provides preconditions for analyzing activity-travel behaviors with consideration of uncertainties.This paper constructs the super-network considering customized bus services based on the structure of activity-time-space state-augmented multi-modal(ATS-SAM)super-network,then presents the approach to model daily activity-travel patterns.Through the connectivity evaluation of case network,this paper compares the activity-based model and the traditional transportation analysis.The results indicate that the activity-based model can reflect the interactions between activity and travel behaviors,thus is more applicable to modeling innovative transportation modes such as customized bus services.On the basis of activity-based model,this paper further takes into account the travel time variability caused by uncertainty of transportation network,as well as the day-to-day dynamics of activity-travel pattern caused by uncertainty of travelers' perceptions.The daily activity-travel pattern of travelers can thus be modeled in multi-modal transportation network.A numerical example is conducted to validate the proposed model.It is shown that the activity-based model considering uncertainty is able to model activity and travel choices and depict the learning and adjustment of activity and travel behaviors.The model contributes to analyzing spatial and temporal distribution of individuals in uncertain multi-modal transportation network,which has important theoretical and practical significance for the planning and evaluation of urban transportation system. |
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