Measuring port congestion and lockdown impact using AIS data

This study measures congestion in major container ports and investigates how port characteristics and regional factors influence congestion during the COVID-19 period. Using Automatic Identification System (AIS) data from 19 major global ports between 2019 and 2022, we develop port congestion indicators, including vessel arrivals, vessels staying in port, waiting time, and service time. First, descriptive analysis reveals significantly higher service and waiting times in 2021 due to global supply chain disruptions. Import/export-focused ports were more affected than transshipment hubs, with gateway ports experiencing more severe bottlenecks. Short-term events such as labor strikes also substantially impacted port congestion. Next, using econometric analyses, estimated impulse response functions indicate a decrease in the number of ship calls following stricter mobility restrictions, with average waiting time at anchorage promptly increasing, while average service time at berth was comparatively less affected. Additionally, we find significant spillover effects from neighboring ports, comparable in magnitude to those from the respective ports, highlighting the interconnected nature of maritime supply chains.