Metaheuristic approaches for the Manhattan metric straddle carrier routing problem with buffer areas

This study investigates an optimization problem in container terminals, where straddle carriers (SCs) transport containers between seaside and stacking areas. Container transportation sequences respect both the predetermined loading sequence at quay cranes (QCs) and the capacity restrictions of buffer areas located below QCs for container exchange between SCs and QCs. We propose two sets of strategies. The first prioritizes runtime efficiency, employing methods such as a local search procedure and two variants of Variable Neighborhood Descent. For the second strategy, we use two different metaheuristics, namely Variable Neighborhood Search and a Greedy Randomized Adaptive Search Procedure, to provide solutions with superior objective function values. The performance of these methods is assessed in an extensive computational study and compared with benchmarks from the literature, showing that the proposed methods effectively allocate containers to SCs, resulting in minimized idle times of QCs and, consequently, shorter turnaround times for vessels.