COLLISION AVOIDANCE BEHAVIOUR AND UNCERTAINTY

A review of world-wide collision statistics of the past 20 years indicates that, in spite of the expanded use of radar, the over-all collision rate remains alarmingly high. Because of radar's less than perfect record for preventing ship collisions, development of various types of collision avoidance systems has taken place. The implied promise in this development is that the computer-aided radar will provide a lasting answer to the collision avoidance problem. Motivated by such considerations, an experiment was conducted to the United States Maritime Administration's newly completed Computer Aided Operations Research Facility (CAORF). The purpose was to study the human dynamics involved in collision avoidance behaviour on the bridge of a modern merchant ship, and to evaluate the advantages of a collision avoidance system (C.A.S). During the course of the experiment it was observed that test subjects made a large number of left turns when operating with radar and C.A.S. This paper presents preliminary results of an investigation into the potential confusion caused by such non-standard maneuveres when operating under the following conditions: (i) Visual only--no electronic aids,(ii) Radar, (iii) Collision avoidance system.