The International Maritime Organisation (IMO) defines Vessel Traffic Service (VTS) as the service implemented by a competent authority, designed to improve the safety and efficiency of vessel traffic and to protect the environment. Therefore the efficiency of vessel traffic is one of the main tasks in VTS operations. But from a practical point of view, how can VTS affect the efficiency of port operations in addition to increasing the safety of navigation? The International Association of Lighthouse Authorities (IALA) – the main organisation responsible for developing international recommendations for VTS – divides regular VTS duties in three different categories.
The first and most simple service is the Informational Service (INS). This serves to ensure that essential information becomes available in time for on-board navigational decision-making. Generally under this service, VTS operators provide vessels with all information related to a port’s operations or to navigational safety. Even such a simple service allows an increase in port efficiency as such information can consist of position, identity, intention and destination of vessels, and amendments; also included are changes in information concerning the VTS area, such as boundaries, procedures, radio frequencies, reporting points, meteorological and hydrological conditions, maneuverability limitations of vessels and much else. Using this information, the team on the bridge can optimise its own passage in order to improve passage time, avoid dangerous situations and thereby improve port performance.
Another and more advanced service provided by VTS is the Traffic Organisation Service (TOS). TOS is a service to prevent the development of dangerous maritime traffic situations and to provide for the safe and efficient movement of vessel traffic within the declared VTS area. Examples of this service could be planning or prioritising vessel movements, establishing a system of traffic clearances, organising the allocation of space, following special routes or time slots, observing speed limits, etc.