In this paper Commandant Oudet, who might well be called the architect of routing in the Dover Strait, discusses certain aspects of what has come to be known as the Sandettie problem, namely the emergence of a potential accident black spot at the north-eastern extremity of the one-way routes in the Strait. Various solutions are discussed, including the reversal of the direction of traffic flow in the Strait recently proposed by the Honourable Company of Master Mariners and supported by Trinity House. Commandant Oudet shows that this proposal, unless the direction of flow were reversed in adjoining traffic separation schemes, would have the effect of greatly increasing the number of crossings and encounters outside the Strait. ‘The remedy would be worse than the disease’, he concludes. ‘It would be better to abandon traffic separation altogether’.

Places where road traffic is particularly dangerous and congested are often referred to as accident black spots; and the term is beginning to be used in the same sense in a navigational context. At sea an excessive density traffic always involves danger, because it is impossible to build fly-overs, as on land, and so avoid crossings; all encounters and all crossings take place on the same plane.