Estimating the Number of Tanker Collisions in the Gulf of Finland in 2015

The paper presents a model for estimating the number of ship-ship collisions for future traffic scenarios. The modeling is based on an approach where the number of collisions in an area is estimated as a product of the number collision candidates, i.e. the number of collisions of two ships, if no evasive maneuvers were made, and a causation probability describing the probability of making no evasive maneuvers. However, the number of collisions is presented as a combination of binomially distributed random variables. The model is applied for the assessment of tanker collision frequency in the Gulf of Finland in 2015. 2015 traffic is modeled as three alternative scenarios each having a certain probability of occurrence. The number of collisions can be presented either for each scenario, or as an estimate including the uncertainty in future marine traffic development by taking into account all scenarios and their occurrence probabilities.