The IMO defines a Vessel Traffic Service (VTS) as a service implemented by a Competent Authority, designed to improve the safety and efficiency of vessel traffic and to protect the environment. The service should have the capability to interact with the traffic and to respond to traffic situations developing in the VTS area. The IALA VTS Manual states that “The realities of modern shipping, with larger and less manoeuvrable ships, traffic congestion in ports and waterways, hazardous cargoes and the potential for environmental damage, demanded that sophisticated measures be taken to reduce risks. Establishing Vessel Traffic Services was and still is a significant response to that demand”.

The IMO identifies three types of service that can be provided by a VTS:

• Information Service (INS)
• Traffic Organisation Service (TOS)
• Navigational Assistance Service (NAS)

The title of each service in each case is largely self-explanatory. In its simplest form, a VTS may provide basic information on which the master of the vessel bases his own decisions without further intervention from ashore.  More usually, however, a VTS is also directly involved in the organisation and management of vessel traffic within its area of responsibility. As part of these services, the VTS should provide an oversight of the navigational safety of vessels and provide navigational assistance and advice if appropriate.

The VTS should be manned by personnel nationally certificated to the internationally recognised IALA V103 course standard. The types of service provided by a VTS will be promulgated in appropriate hydrographic publications.

IALA International Association of Marine Aids to Navigation and Lighthouse Authorities

IALA is a non-profit, international technical association. Established in 1957, it brings together authorities concerned with marine aids to navigation, as well as manufactures and consultants from all parts of the world, and offers them the opportunity to compare their experiences and achievements. IALA’s aim is to harmonize aids to navigation worldwide and to ensure that the movements of vessels are safe, expeditious, cost-effective and harmless to the environment. VTS documentation and standards in the form of standards, recommendations, guidelines, brochures and the VTS Manual are available free of charge for download under the “Publications” tab on the IALA website.

Aids to Navigation (AtoN)

Aids to navigation can take the form of fixed or floating marks that may be lit or unlit, including lighthouses, leading lines, buoys and beacons. A vessel traffic service (VTS) can also be categorised as an AtoN, albeit a very sophisticated and relatively costly one. The mix of AtoN used in a port or waterway is determined by means of a risk assessment, which takes into account the local geography, traffic patterns, vessel size and manoeuvrability, local hydrographic conditions and weather patterns. IALA publications include guidance on maintenance and location of AtoN.