WHAT ARE TSS?
Traffic Separation Schemes
Traffic Separation Schemes (TSS) are IMO-approved routing measures that separate opposing streams of vessel traffic using designated lanes divided by separation zones. They dramatically reduce collision risk in congested waterways by organizing traffic flow in a predictable manner.
TSS are governed by COLREG Rule 10, which sets out the obligations of all vessels using or crossing separation schemes. IMO adopts TSS under SOLAS Chapter V, and they are shown on official Admiralty and nautical charts.
COLREG Rule 10 â Key Requirements
- 1
Vessels using a TSS must proceed in the appropriate traffic lane in the general direction of traffic flow for that lane.
- 2
Vessels must not cross a separation zone or line except when joining or leaving an adjacent lane, or in an emergency.
- 3
Vessels must join or leave a traffic lane at the terminations of the scheme, or as far as practicable, at a small angle to the general direction of traffic flow.
- 4
Vessels must avoid anchoring in a TSS or in areas near its terminations.
- 5
Vessels not using a TSS must avoid it by as wide a margin as is practicable.
- 6
Vessels engaged in fishing within a TSS must not impede the passage of vessels following a traffic lane.
MAJOR SCHEMES
World's Busiest TSS
Traffic lane details, vessel restrictions, and COLREG requirements for the world's most trafficked separation schemes.
Strait of Dover
English Channel
Traffic Lanes
Two lanes (Eastbound / Westbound)
Length
~55 nm
Width
3â7 nm
Vessels must not impede cross-channel ferries
Singapore Strait
Southeast Asia
Traffic Lanes
Three-way (E/W + Phillip Channel)
Length
75 nm
Width
1â3 nm
VLCC requires specific deep-draught routes
Strait of Gibraltar
Mediterranean entrance
Traffic Lanes
Two lanes (Eastbound / Westbound)
Length
~40 nm
Width
3â5 nm
Submarines required to surface and show flag
Strait of Malacca
SE Asia
Traffic Lanes
Westbound / Eastbound lanes
Length
~500 nm
Width
Variable (narrows to 2.8 km)
Vessels >25m draft restricted; STRAITREP mandatory
Off Cape Finisterre
NW Spain / Portugal
Traffic Lanes
NE / SW lanes
Length
~30 nm
Width
5â8 nm
Separation zone: fishing vessels must not impede through traffic
195+ More TSS Schemes
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