The effect of ship operator-based empty container imbalance on container circulation

The purpose of this study is to demonstrate that ship operator-based container imbalance (SOBCI) leads to empty container movement (ECM) beyond trade imbalance, which is described as additional ECM (AECM). This demonstration is supported by a feasible suggestion to overcome additional empty container circulation, critiquing the suggestion of a common container pool and initiating a further discussion to reduce AECM. Two hypotheses examining SOBCI, trade imbalance, and empty container circulation were tested for the container throughputs of Turkish ports using the Mann-Whitney U test and regression analysis. A thought experiment about how to calculate the potential amount of ECM beyond trade imbalance was conducted. Recently, a substantial amount of container accumulation beyond the trade imbalance in the terminals located in IstanbulKocaeli and Mersin for 20-foot containers and in Istanbul-Kocaeli and Gemlik for 40-foot containers has occurred due to SOBCI. In Turkish container terminals between 2013 and 2016, SOBCI explains 32.78% of AECM originating from the market effect. For 20-foot containers, the percentages of avoidable AECM are 30% for Istanbul-Kocaeli and 20% for Mersin. For 40-foot containers, the AECM is 50% for Mersin, 20%–25% for Istanbul-Kocaeli and Gemlik, and 5% for Izmir-Aliaga. The concept of the market effect, its elements, SOBCI, and the magnitude of AECM arising from only the market effect (AECM-OME) were used for the empirical study. This study demonstrates the relationship between SOBCI and AECMOME. Additionally, a unique thought experiment and its mathematical notation are presented to calculate the magnitude of AECM that has been released.