The Annexes of IMO Resolution A.857(20) ‘Guidelines for Vessel Traffic Services’ (VTS) describe the skill and
knowledge qualifications required by VTS Operators (VTSO) to provide the required services to improve the safety
of navigation and protection of the environment.
The IMO Guidelines are intended for application in both planned and existing VTS. They provide guidance in
determining how VTS Authorities may recruit, select and train personnel in order to carry out their tasks thereby
providing the required VTS standards.

In planning and establishing a VTS, the Contracting Government(s) or the Competent Authority should:

  • • ensure that the VTS Authority has the equipment and facilities necessary to effectively accomplish the
    objectives of the VTS and;
  • • ensure that the VTS Authority has sufficient staff, appropriately qualified, suitably trained and capable of
    performing the tasks required, taking into consideration, the type and level of services to be provided, as per
    the current IMO Resolution A.857 (20) Guidelines on the Recruitment, Qualifications and Training of VTSO
    (Annex 2).

The role of VTS is to improve the safety and efficiency of navigation, safety of life at sea and the protection of the
marine environment. In performing these functions, VTS Personnel are required to interact with other mariners
with responsibility for safety. It is therefore essential that the VTS operational staff demonstrate a high standard
of professionalism and that they are trained and qualified according to the current international IALA standards.1
VTS personnel should be capable of providing information, traffic organisation and/or navigational assistance
service in the area specified by the relevant VTS Authority. Depending on the characteristics of a VTS Area, such
as traffic patterns and densities, a VTS Centre may comprise VTSO, VTS Supervisors and a VTS Manager. It is for
the VTS Authority to determine the levels of staffing sufficient to meet its obligations and to ensure that trained
personnel are available to undertake these commitments.
Key to all VTS operations is the VTSO. Regardless of the size or complexity of the respective VTS area, all VTS
Centres are likely to require VTSOs who have been trained and authorized to V-103 standards, or similar. In VTS
Centres where more than one VTSO is on watch simultaneously, the VTS Authority may determine a requirement
to establish the position of VTS Supervisor to assist, oversee and/or co-ordinate the activities of the watchkeeping

A VTS Authority may elect, as part of its management infrastructure, to establish the post of VTS manager.

The purpose of this Guideline is to assist authorities in determining an appropriate staffing level for a VTS Centre.
Conferring with existing VTS Authorities will provide a general idea of how VTS Centres are staffed. These
Guidelines apply as far as national law allows.
This Guideline is not intended to be prescriptive, rather it presents factors that should be considered when
determining staffing levels.


The availability of qualified VTS staff is an essential resource without which VTS operations cannot safely be
managed. Determining the adequacy of the number of VTSOs on duty is often difficult to quantify with any
degree of accuracy. Invariably this will be a balance between a number of factors which a VTS Authority will need
to keep under periodic review:

1 IALA Recommendation V-103 on Standards for Training and Certification of VTS Personnel refers.
IALA Guideline G1045 – Staffing Levels at VTS Centres

Edition 1.1 – December 2018 P 5

• periods of duty;
• operational procedures;
• physical working environment;
• human resource requirements;
• types of service offered;
• interaction with Allied Services and adjacent VTS Centres;
• technology, equipment and communications;
• incidents, accidents and other emergencies;
• stress-related workload.


Factors for consideration when determining periods of duty for VTSOs and Supervisors include:
• traffic volumes and densities;
• navigational complexity associated with the VTS Area;
• VHF radio traffic volume;
• back-ground noise levels;
• the number of VTS interventions anticipated, e.g. the extent to which navigational assistance and traffic
organisation is typically required;
• the limits within which operators may develop and maintain situational awareness;
• Health and Safety requirements, particularly when working with visual display units;
• the working environment;
• shift patterns.


Operational procedures have an impact on workload and should be clearly defined.2
Each procedure should set
out the actions to be taken in respect to interaction with ships; interaction with other parties and authorities; and
internal and external contingency situations.
Operational procedures should be developed to eliminate duplication of tasks and to support decision-making.
They should be reviewed and updated at regular intervals in accordance with VTS quality management system
standards to ensure their relevance to VTS aims and objectives.
For example, internal procedures may include the keeping of logbooks whether in manual or electronic format.
VTS Sailing Plans may differ in the way in which they are handled, recorded and broadcast which may affect the
workload and staffing levels with respect to the preparation and execution of the Sailing Plan. Any possible
deviation from the agreed Sailing Plan requires more attention from the VTSO.

The physical working environment includes temperature, ventilation, lighting (including emergency lighting),
room dimensions, suitability of workstations and seating. Facilities should be provided for washing, eating,
resting, as well as toilet facilities.

2 IALA Recommendation V-127 – VTS Operating Procedures – refers
IALA Guideline G1045 – Staffing Levels at VTS Centres
Edition 1.1 – December 2018 P 6
VTS authorities should make arrangements for enforcing health and safety measures derived from the risk
assessment. These measures should cover planning, organisation, control, monitoring and review. VTS
authorities should also consider the working conditions and risks when selecting equipment suitable the
identified tasks and ensure the equipment is properly maintained.
Additional considerations include problems associated with continuous viewing of display screens,
attention/concentration levels; general ergonomics of working environment and noise/distractions within the
work area.

Continuous viewing and manipulation of the VTS display may lead to musculoskeletal problems, visual fatigue and
stress. Health problems can result from poor work organisation, ergonomic design, working environment, job
design, posture and inappropriate work methods. Health problems associated with display screen work can be
prevented by careful design of the workplace as well as by operator training and consultation.

The performance requirements may demand high levels of attention and concentration, for extended periods of
time, where consequences of error may be critical.

The immediate environment within which the VTS personnel work should reflect an ergonomic assessment in
order to facilitate effective delivery of services and to support the health and well-being of VTS personnel. An
analysis should include the optimum ergonomic design of workstations and placement of equipment within the
VTS work area.

Consideration should be given to minimizing noise levels and other possible distractions within the VTS Centre.
Careful management of lighting levels may also improve the overall working environment.
An inadequate working environment will have a negative impact on the performance of the VTS personnel and
may affect their ability to discharge their responsibilities.

Collective agreements, contracts and terms of employment for VTS personnel should be taken into consideration
when determining the staffing levels.
Staffing levels may need to accommodate training and assessment activities.
Careful assessment of the functions required of a VTSO should be considered to ensure that their primary safety
role is not compromised. The requirement for additional or ‘call-in’ personnel should also be considered when
necessary to ensure the primary role is maintained.
Consideration should be given to the rotation of watchkeeping VTSOs and the need for rest breaks, depending on
the intensity of work and the overall working environment. Due to the unique circumstances in each VTS Centre,
it is not appropriate, nor possible, to specify the length or number of breaks necessary to avoid fatigue.

Many variable factors can influence the workload in the VTS Centre, for example peak and lull periods in vessel
traffic, extreme weather and emergency situations. Staffing levels and workload will depend on which types of
services – Information Service; Navigational Assistance Service (NAS) or Traffic Organisation Service (TOS) – are
being provided and the levels at which a particular service is being provided.