Review on customized bus route optimization

To comprehensively review the research progress in customized bus route optimization, the relevant literatures were classified and analyzed from three aspects including optimization objective, issue scenario, and solution algorithm. Analysis results show that researches on the single-objective optimization of customized bus routes have mainly focused on the travel time, operating mileage, operating cost, operating revenue, and total system cost formed by the linear weighting of multiple costs. However, research on the multi-objective optimization was mainly achieved by simultaneously considering two or three objectives, including the operating cost, travel cost, and service quality. According to the number of departure and arrival stations, the issue scenarios of customized bus route optimization problems can be divided into three types including one-to-one, many-to-one, and many-to-many. Research on the time impedance scenarios between different stops mainly focuses on the static time impedance, and less on the dynamic time impedance. Research on the scenario of travel demand mainly focuses on the static travel demand, and two-stage optimization strategies are generally used to solve dynamic travel demand scenarios. Since the route optimization problem of customized public transportation is a special vehicle route optimization problem, the precise solution algorithm is suitable for the analysis of small travel demand. For the practical problem of large-scale travel demand, the heuristic intelligent algorithm is generally used. In future studies, the optimization of customized bus routes needs to consider the influence of the parking yard settings, stop selection, and formulate particular time window attributes for different types of travelers. Besides, in the context of a big data environment, how to take into account real-time travel demand and operating cost constraints and provide differentiated customized bus routes will also be a challenging research direction.