Published online by Cambridge University Press: 01 September 1978
An area of sea in which there are several traffic streams may be characterized by the number of potential encounters between two ships that would be expected to take place. The traffic flow in an area of 300 sq. n.m. of the Dover Strait over a nine-year period has been analysed to give the numbers of such potential encounters of head-on, crossing, and overtaking ships in three conditions of visibility. The number of collisions occurring has been similarly broken down and hence the risk of each different type of encounter leading to a collision has been determined. It is shown that decreasing visibility makes collision very much more likely, whereas the direction of encounter makes a comparatively minor difference to the probability.