In this paper a study is made of that area of marine traffic engineering which is concerned with collision avoidance, and within that area the sub-section in which human factors are involved.

Collision avoidance at sea is mainly achieved by adherence to the rules for preventing collisions, by routing schemes for separating traffic in high density areas and, within certain port limits, by local rules and advisory services, or occasionally by direct control of ship movements. To these well defined factors may be added the mariner's accumulated experience and instinct for self-preservation which gives rise to such nebulous, but not negligible, entities as the ‘seaman's eye’ and the ‘navigator's sixth sense’.