A basic concept for estimating the reliability of collision avoidance maneuver can be derived by applying reliability theory to the relation between collision avoidance maneuver and traffic environment. A Markov reliability model was analytically constructed by making an encounter of two ships on collision course correspond to a failure, an evasive action to a repair and an occurance of collision accident to an absorbing state in terms of reliarbility engineering, respectively. The model was numerically expressed under assumptions based on the traffic survey, the statistical analysis of collision avoidance maneuver at sea and simulated maneuvers by a ship handling simulator. Then the reliability of collision avoidance maneuvers by the model was compared with that based on collision statistics at the Seto Inland Sea over the last five years. They were found to correspond well by the appropriate estimations of parameters in the model. Based on the model it would be capable for us to evaluate how much the components related to collision avoidance maneuver would have an effect on its reliability.
