Traffic Separation Scheme (TSS)

A traffic separation scheme is a routeing measure adopted by the IMO under the Ships’ Routeing publication to organize traffic into lanes of opposing flow separated by a zone or line. COLREG Rule 10 governs conduct in and near IMO-adopted schemes: vessels proceed in the appropriate lane in the general direction of flow, keep clear of the separation zone, and join or leave at the termination or at as small an angle as practicable. Crossing traffic must cross on a heading as nearly as practicable at right angles to the direction of flow.