Flex-Route Transit Service with Different Degree of Dynamism

Flex-route transit, which combines the characteristics of both traditional fixed-route transit and demand-responsive transit, is the most promising form of flexible transit services for shaping new travel patterns in low-demand areas. In this paper, we explore the operational efficiency of a partially dynamic flex-route transit system, in which the operator accepts both static (advanced booking) requests and dynamic (real-time) requests. A mixed integer programming (MIP) is employed to solve the static vehicle routing problem. And an insertion heuristic is proposed to tackle the dynamic requests arrive in real-time. Simulation experiments based on a real-life flex-route transit service are conducted to assess the system cost with different degrees of dynamism. The results demonstrate that although allowing real-time requests can improve the reservation flexibility of the system, a better system performance can be achieved when more people choose to make reservations in advance.