Original scientific paper
https://doi.org/10.31217/p.40.3.10
Cargo-vessel Congestion at Three Major United States Gateways During the 2020–2022 Supply-chain Disruption: A Selected-month, Comparative AIS-based Assessment
Vice Milin
; Faculty of Maritime Studies, University of Split, Split, Croatia
*
* Corresponding author.
Abstract
The 2020–2022 disruption of global supply chains produced severe cargo-ship congestion at United States gateway ports, yet much of the public evidence rests on news reports and proprietary indices rather than open vessel-movement data. This study quantifies and compares cargo-vessel congestion at three major US gateways, Los Angeles/Long Beach, Houston/Galveston, and New York/New Jersey, using open Automatic Identification System (AIS) data from the United States Nationwide AIS archive. To capture within-year variation while controlling for season, two reference months, January and July, were analysed for each of 2020, 2021, and 2022; the analysis therefore rests on selected monthly snapshots rather than a continuous series. Daily indicators of waiting vessels, formally anchored vessels, anchorage dwell time, and throughput were derived, with uncertainty quantified by an autocorrelation-aware moving block bootstrap and robustness confirmed by threshold sensitivity analyses. The congestion signal is strong and spatially uneven. At Los Angeles/Long Beach the mean number of waiting cargo vessels rose from 29 per day in early 2020 to a peak near 69 per day in mid-2021 and remained close to that level into January 2022 before easing to 51 by July 2022; New York/New Jersey stayed comparatively low throughout, and Houston/Galveston surged latest, peaking in mid-2022. All principal contrasts remain significant under the block bootstrap. At Los Angeles/Long Beach waiting grew far faster than throughput (134% versus 23% from January 2020 to 2022), indicating demand exceeding berth capacity rather than merely higher arrivals, and a divergence between formal anchoring and broader waiting is consistent with the offshore queuing system introduced in November 2021. The within-area counts, which the authoritative Marine Exchange of Southern California series tracks, are conservative because part of the queue lay offshore of the study area. Within the limits of its selected-month design, the study is a reproducible comparative assessment rather than a continuous reconstruction of the disruption.
Keywords
Automatic Identification System (AIS); port congestion; supply-chain disruption; COVID-19; anchorage; maritime traffic analysis; Cargo shipping; Vessel waiting time
Hrčak ID:
351169
URI
Publication date:
22.9.2026.
Visits: 0 *