Modeling man-guided vehicle trips in a container terminal via simulation

A micro-simulation model aimed at representing the dynamics of container transportation operations back and forth between the quay and yard areas in a pure transshipment container terminal is presented. A fleet of man-guided straddle carriers (SCs) is employed for container transfer during which the path between any couple of origin and destination points are determined by real-time driver decisions. The simulator embodies a multi-step decision process that mirrors the en-route behavior implemented by the SC drivers as a response to the information they receive during their trip. An event-based view, under stochastic conditions, is adopted to reproduce the point-to-point transfer process for each SC along the internal reticular paths within the Manhattan-like layout of the storage blocks in the yard. The problem tackled herein consists in estimating the number of SCs to be assigned to each quay crane involved in discharge/loading operations, while accounting for vehicle traffic, congestion and disruptions encountered by the SCs. Statistical figures are returned for estimating container transfer times and transfer productivity as the congestion increases along both horizontal and vertical corridors of the yard, as well as at intersection points. Measuring these transfer times may be useful to support further quantitative evaluations within the overall discharge-transfer-loading process. Numerical simulation experiments based on real-life data are presented.