Optimization of ship routing and allocation in a container transport network considering port congestion: A variational inequality model

In recent years, the service capacity of coastal ports has failed to keep pace with the increasing demand for ocean transportation, resulting in frequent congestion that adversely affects the fleet deployment of numerous shipping companies. This research introduces a variational inequality model aimed at optimizing ship routing and allocation schemes to address port congestion. The model enhances ship allocation between ports by considering the congestion status of ports and alternative port options. The objective functions incorporate time and transportation costs, with the aim of achieving a balanced shipping cost across different routes. A diagonal algorithm is proposed for solving the model. The case study focuses on several coastal port routes in China and presents modeling and calculation results. The numerical examples demonstrate that as port congestion worsens: (1) the waiting time and shipping schedule losses incurred by shipping companies increase; (2) shipping companies tend to allocate ships to backup ports; (3) small container ships are preferred for shipping companies when choosing ship types. Therefore, in the event of port congestion, shipping companies must devise ship routing and allocation plans based on the severity of congestion and make informed decisions accordingly.

Automated summary

In recent years, the service capacity of coastal ports has not kept up with the increasing demand for ocean transportation, resulting in frequent congestion and negative impacts on the fleet deployment of shipping companies. This research introduces a variational inequality model to optimize ship routing and allocation schemes, taking into account port congestion and alternative port options. The objective is to achieve a balanced shipping cost across different routes.