Estimation of vessel collision frequency in the Yangtze River estuary considering dynamic ship domains

With the Automatic Identification System (AIS) data collected from Donghai Navigation Safety Administration, this study aims to estimate vessel collision frequency in the Yangtze River estuary water areas considering dynamic ship domain sizes. To take into account the possible impacts of ship type, time of the day, and ship relative speed, ship domain size is further modeled as linear functions of these influencing factors based on our questionnaire survey data. Ship results reveal that the calculated vessel collision frequency in the Yangtze River estuary water areas is about 4.29 x 10(-3)per ship-year, in which cargo ships have the highest vessel collision frequency, while fishing ships have the lowest frequency. Moreover, head-on collision is the collision type that has the largest collision frequency, followed by overtaking collision and crossing collision in the Yangtze River estuary. Big-sized vessels (e.g., Container ship and Cargo ship) are more likely to encounter head-on collisions, while the majority of small vessels (e.g., Fishing ship and Passenger ship) involved in overtaking collisions. Because of higher vessel traffic flow and density, the daytime period is associated with a larger vessel collision frequency, as compared with the nighttime period.