Ships' routeing

Malacca StraitThe practice of following predetermined routes for shipping originated in 1898 and was adopted, for reasons of safety, by shipping companies operating passenger ships across the North Atlantic. Related provisions were subsequently incorporated into the original SOLAS Convention.

Traffic separation schemes and other ship routeing systems have now been established in most of the major congested, shipping areas of the world, and the number of collisions and groundings has often been dramatically reduced.

IMO's responsibility for ships' routeing is enshrined in SOLAS Chapter V, which recognizes the Organization as the only international body for establishing such systems.

Regulation SOLAS V/10 Ships' routeing states:

1 Ships' routeing systems contribute to safety of life at sea, safety and efficiency of navigation and/or protection of the marine environment. Ships' routeing systems are recommended for use by, and may be made mandatory for, all ships, certain categories of ships or ships carrying certain cargoes, when adopted and implemented in accordance with the guidelines and criteria developed by the Organization.*

2 The Organization is recognized as the only international body for developing guidelines, criteria and regulations on an international level for ships' routeing systems. Contracting Governments shall refer proposals for the adoption of ships' routeing systems to the Organization. The Organization will collate and disseminate to Contracting Governments all relevant information with regard to any adopted ships' routeing systems.

3 The initiation of action for establishing a ships' routeing system is the responsibility of the Government or Governments concerned. In developing such systems for adoption by the Organization, the guidelines and criteria developed by the Organization shall be taken into account.

4 Ships' routeing systems should be submitted to the Organization for adoption. However, a Government or Governments implementing ships' routeing systems not intended to be submitted to the Organization for adoption or which have not been adopted by the Organization are encouraged to take into account, wherever possible, the guidelines and criteria developed by the Organization.*

5 Where two or more Governments have a common interest in a particular area, they should formulate joint proposals for the delineation and use of a routeing system therein on the basis of an agreement between them. Upon receipt of such proposal and before proceeding with consideration of it for adoption, the Organization shall ensure details of the proposal are disseminated to the Governments which have a common interest in the area, including countries in the vicinity of the proposed ships' routeing system.

6 Contracting Governments shall adhere to the measures adopted by the Organization concerning ships' routeing. They shall promulgate all information necessary for the safe and effective use of adopted ships' routeing systems. A Government or Governments concerned may monitor traffic in those systems. Contracting Governments shall do everything in their power to secure the appropriate use of ships' routeing systems adopted by the Organization.

7 A ship shall use a mandatory ships' routeing system adopted by the Organization as required for its category or cargo carried and in accordance with the relevant provisions in force unless there are compelling reasons not to use a particular ships' routeing system. Any such reason shall be recorded in the ships' log.

8. Mandatory ships' routeing systems shall be reviewed by the Contracting Government or Governments concerned in accordance with the guidelines and criteria developed by the Organization.

9 All adopted ships' routeing systems and actions taken to enforce compliance with those systems shall be consistent with international law, including the relevant provisions of the 1982 United Nations Convention on the Law of the Sea.

10 Nothing in this regulation nor its associated guidelines and criteria shall prejudice the rights and duties of Governments under international law or the legal regimes of straits used for international navigation and archipelagic sea lanes.

* Refer to the General Provisions on Ships' Routeing adopted by the Organization by resolution A.572(14)), as amended.

Rule 10 of the COLREGs prescribes the conduct of vessels when navigating through traffic separation schemes adopted by IMO. IMO's responsibilities are also determined under the United Nations Convention on Law of The Sea (UNCLOS), which designates IMO as "the competent international organization" in matters of navigational safety, safety of shipping traffic and marine environmental protection.

Governments intending to establish a new routeing system, or amend an existing one, must submit proposed routeing measures to IMO's Sub-Committee on Safety of Navigation (NAV), which will then evaluate the proposal and make a recommendation regarding its adoption. The recommendation is then passed to the MSC for adoption.

As well as traffic separation schemes, other routeing measures adopted by IMO to improve safety at sea include two-way routes, recommended tracks, deep water routes (for the benefit primarily of ships whose ability to manoeuvre is constrained by their draught), precautionary areas (where ships must navigate with particular caution), and areas to be avoided (for reasons of exceptional danger or especially sensitive ecological and environmental factors).

Ships' routeing systems and traffic separation schemes that have been approved by IMO, are contained in the IMO Publication, Ships Routeing - 7th Edition, 1999 plus 2002 amendnents or on CD, which is updated when schemes are amended or new ones added.

The publication includes General provisions on ships' routeing, first adopted by IMO in 1973, and subsequently amended over the years, which are aimed at standardizing the design, development, charted presentation and use of routeing measures adopted by IMO. The provisions state that the objective of ships' routeing is to "improve the safety of navigation in converging areas and in areas where the density of traffic is great or where freedom of movement of shipping is inhibited by restricted searoom, the existence of obstructions to navigation, limited depths or unfavourable meteorological conditions".


Elements used in traffic routeing systems include:

  • traffic separation scheme: a routeing measure aimed at the separation of opposing streams of traffic by appropriate means and by the establishment of traffic lanes
  • traffic lane: an areas within defined limits in which one-way traffic is established. natural obstacles, including those forming separation zones, may constitute a boundary
  • separation zone or line: a zone or line separating traffic lanes in which ships are proceeding in opposite or nearly opposite directions; or separating a traffic lane from the adjacent sea area; or separating traffic lanes designated for particular classes of ship proceeding in the same direction
  • roundabout: a separation point or circular separation zone and a circular traffic lane within defined limits
  • inshore traffic zone: a designated area between the landward boundary of a traffic separation scheme and the adjacent coast
  • recommended route: a route of undefined width, for the convenience of ships in transit, which is often marked by centreline buoys
  • deep-water route: a route within defined limits which has been accurately surveyed for clearance of sea bottom and submerged articles
  • precautionary area: an area within defined limits where ships must navigate with particular caution and within which the direction of flow of traffic may be recommended
  • area to be avoided: an area within defined limits in which either navigation is particularly hazardous or it is exceptionally important to avoid casualties and which should be avoided by all ships, or by certain classes of ships

See also: MSC/Circ.1060 Guidance Note on the Preparation of Proposals on Ships' Routeing Systems and Ship Reporting Systems.


Weather routeing

Weather conditions can also affect a ship's navigation, and in 1983 IMO adopted resolution A.528(13), Recommendation on Weather Routeing, which recognizes that weather routeing - by which ships are provided with "optimum routes" to avoid bad weather - can aid safety. It recommends Governments to advise ships flying their flags of the availability of weather routeing information, particularly that provided by services listed by the World Meteorological Organization.


Historical background on ships' routeing

The 1960 SOLAS Convention referred to ships' routeing measures in busy areas on both sides of the North Atlantic and Contracting Governments undertook the responsibility of using their influence to induce the owners of all ships crossing the Atlantic to follow the recognized routes and to ensure adherence to such routes in converging areas by all ships, so far as circumstances permitted.

Meanwhile, analysis of casualty statistics was showing that collisions between ships were becoming a worrying cause of accidents, especially in congested waterways.

In 1963, the Liverpool Underwriters Association reported 21 collisions responsible for total losses of ships - compared with a five-year average of 13.8. A report on tanker hazards presented to the United States Treasury presented late in 1963 concluded that most accidents were due to human error, with speed in congested waters a principal cause. The report said there too many diverse "rules of the road", the width of navigable channels had generally not kept pace with the increase in sizes of ships, and not enough was being done to use modern communications.

At the same time, the institutes of Navigation of the Federal Republic of Germany, France and the United Kingdom had begun a study on improving safety measures in congested areas, such as the English Channel. The group came up with a series of proposals, including the idea that ships using congested areas should follow a system of one-way traffic schemes, like those being used on land. Traffic lanes of this type were already in use on the Great Lakes of North America.

The proposals were favourably received by the Maritime Safety Committee of IMO (then IMCO) in 1964 and governments were urged to advise their ships to follow the routes suggested by the group.


1967 - Dover Straits TSS established

The Institutes in 1966 published a report proposing traffic separation schemes in a number of areas, and in June 1967 a traffic separation scheme was established in the Dover Straits - the world's first - and a significant fall was seen in the number of collisions between ships on opposing courses.

At the time, observance of the schemes was voluntary, but in 1971 a series of accidents in the English Channel led to calls for immediate action - in the most serious incidents, the tanker Texaco Caribbean was in collision with a freighter off the Varne shoals and the following night the wreck was struck by the freighter Brandenburg, which also sank. Some six weeks later, the freighter Niki struck the wreckage and sank with the loss of all 21 people on board.

As a result, IMO's Maritime Safety Committee meeting in March 1971 recommended that observance of all traffic separation schemes be made mandatory and this recommendation was adopted by the IMO Assembly later the same year. The Dover Stratis scheme was therefore the first mandatory traffic scheme, from 1971.

The Conference which adopted the Collision Regulations (COLREGs), in 1972 also made observance of traffic separation schemes mandatory.

Since then, numerous ships routeing systems have been adopted and they can be found in the publication, Ships Routeing.