Traffic Stream Characteristics Analysis for Roadway Linking to Pick-up Zone of Passenger Transportation Hub: A Fundamental Diagram Derived from Threshold Queueing Theory

A pick-up zone links a hub of inter-city transportation (e.g., airplane and rail, etc.) with a connected roadway belonging to the city road network. Passengers depart through the pick-up zone and the interactions between passengers and vehicles lead to delays and queues of vehicles on the connected roadway. A better understanding of the unique traffic characteristics of the connected roadway can help to reveal the collecting or dispersing capacity of the hub. This paper treats passenger boarding in a pick-up zone as a service process in a queue system and uses a fundamental diagram model derived from M/M/1 threshold queueing theory with two service phases to investigate the supply–demand relationship of the system. A calibration method is proposed to determine the parameters of the model. Numerical experiments showed that the model can capture a unique capacity drop in the pick-up zone. Moreover, analyses on the impacts of designed parameters on the model features, such as capacity and degree of capacity drop, were performed, and the comparisons showed that the model used performs better than other classical methods with a 0.69 mean squared error and a 0.90 sum of squares due to error). The results will be important supports for hub capacity management.