Research on time characteristics of near miss in Bohai Sea

It is an effective method to analyze the maritime traffic risk using near miss model, but there are no works from the temporal perspective. The duration of near miss shows the maritime traffic risk. The longer the duration is, the higher the risk is. The influence of the ship maneuvering capability, speed, size, and Convention on the International Regulations for Preventing Collisions at Sea (COLREGS) on the safety of ship navigation are considered in this article, the navigation safety domain is used to detect near misses, and the duration of a single near miss is defined, which is the time from target ship sailing into the navigation safety domain of own ship to leaving, and then an algorithm for calculating duration of near misses is proposed. To measure the similarity of two ships’ lengths, the similarity coefficient model of ships’ lengths is defined. Based on the $k$ -means algorithm, different parameters $k$ are selected to cluster the duration of near misses. According to the clustering results, the connections between the duration of near misses and the ship type, length, and speed were analyzed to identify a series of time characteristics of near misses, that is high frequencies of short-duration near misses and the strong connections between the long-duration near misses, ship length, and ship speed. The method is first proposed for doing research of near misses in temporal dimension. The findings of this article help researchers and maritime traffic management agencies to better understand the importance of maritime traffic risk from the temporal perspective.