Modeling and controlling congestion caused by a bottleneck in an overcrowded aquarium

Abstract

In this study, we modeled a crowded aquarium using a modified totally asymmetric simple exclusion process and propose a new ticketing system with optimized input rates. We performed a case study for Kaiyukan, a large-scale aquarium in Japan, which encounters heavy congestion primarily caused by a bottleneck in the visitor traffic flow. Kaiyukan has a simple structure and is distinct in that visitors walk through a fixed one-way aisle, as opposed to a typical museum or aquarium layout where visitors can move freely through open areas. We investigated basic congestion features caused by the bottleneck using theoretical analysis and numerical simulations, and developed a new indicator to estimate congestion. Using the model and indicator, we developed a novel ticketing system designed to reduce congestion while preserving the maximum flow. The proposed system includes a 30 min break and indicated a better performance than the conventional method of aiming to maintain a constant input rate. The results indicate that Kaiyukan can reduce the number of visitors waiting and maintain its current daily attendance by introducing our ticketing system.