Sequential ship traffic scheduling model for restricted two-way waterway transportation

A good ship traffic scheduling mode can enhance traffic efficiency to a large degree, especially in restricted waterways such as approach channel of ports and straits. A ship scheduling model for restricted two-way waterways is proposed in this article. The assumption is made in the model that two-way transportation is not allowed for cases in which there is at least one large ship. Based on this assumption, a mathematical model is proposed to minimize the weighted average of the mean and the maximum waiting time given several safety restrictions. A sequential scheduling algorithm is proposed to solve such problem, in which the ships are divided into rounds. The ships in each round are scheduled simultaneously to enhance traffic efficiency by the trade-off between the priorities of small and large ships. Experiments are carried out by comparing sequential scheduling method with first-come-first-serve model. The results indicate that the proposed algorithm can reduce ships' waiting time, whereas a lot of ships need to wait for long time with first come first serve. The distinctions are more evident with a higher proportion of large ships, and the proposed algorithm can keep ships' waiting time to an acceptable level.