Improving conflicts detection in maritime traffic: Case studies on the effect of traffic complexity on ship collisions

Abstract

In shipping, collision risk is a serious safety threat. Risk probability estimations used for policymaking are derived from traffic density statistics, largely ignoring the decision-making process on board. Conflict detection and resolution on board is done using rather rudimentary but effective mental-model-based techniques. In this article, the authors analyse traffic using the concept of complexity. The actual geometry of the ships involved in the conflict defines how well the crews on board can resolve the conflict. This geometry is transformed into a complexity value. A reliable detection and resolution of conflicts by human operators decreases in certain situations. A previous study has shown that when complexity reaches a threshold, the risk of a near miss increases significantly. In this study, three actual collisions at open sea are analysed. It will be shown that situations of high complexity, which decreases human reliability, can be predicted well in advance, allowing for a safe resolution. The technique also allows for alerting and a decision support for the crew.