The US Coast Guard (the Coast Guard) vessel traffic service (VTS) is a shore-based surveillance and communications system with the authority to ensure the safe and efficient movement of vessel traffic in particularly hazardous or congested waterways in the United States. The system’s primary mission is to reduce the risk of collisions, allisions, and groundings. To do this effectively, the system must be able to detect and resolve unsafe traffic situations in a timely manner. There are 12 Coast Guard VTS centers that make up the VTS system, and each center is responsible for managing the traffic that operates inside its designated VTS area. Since 1994, participation in this system has been mandatory for most types of power-driven commercial vessels, towing vessels, and dredge platforms while operating inside a Coast Guard VTS area.
During the years 2010 through 2014, an average of 18% of all reportable collisions, allisions, and groundings involving vessels meeting the requirements of a VTS user occurred while they were operating inside a VTS area. The most common causal factor assigned to these accidents by the Coast Guard was inattention errors by the mariners involved, which suggests that an opportunity exists for the VTS system to further reduce the risk of these types of accidents by taking a more proactive role in traffic management. In this study, the National Transportation Safety Board (NTSB) examined the Coast Guard VTS system’s ability to (1) detect and recognize traffic conflicts and other unsafe situations, (2) provide mariners with timely warning of such traffic conflicts and unsafe situations, and (3) control vessel traffic movements in the interest of safety.
What the NTSB Found
The Coast Guard has not developed a standard method for measuring the collective safety performance of all 12 VTS centers as a VTS system. As a result, there were no standardized public data or statistics available for assessing the system’s overall effectiveness. The Coast Guard VTS NSOP manual provides general requirements and guidance in key areas involving personnel, operations, and equipment; however, VTS directors largely interpret how to implement these requirements based on local conditions at the 12 VTS centers. There were inconsistencies in the collection and use of traffic, incident, and near miss event data by the centers, and few best practices or minimum standards of effectiveness that were being shared and consistently applied across the Coast Guard VTS system. Although the VTS system has sufficient authority to manage vessel traffic, many watch supervisors and operators expressed reluctance to exercise their full authority and direct a vessel. This study found widespread variation in the understanding of Coast Guard VTS authority within the 12 VTS centers and across the VTS system, which has resulted in the inconsistent application of that authority over time. Decisions regarding how and when to exercise VTS authority have been influenced by local stakeholders, economic considerations, and varying management practices at the 12 VTS centers. Moreover, the Coast Guard’s training and qualification process for its watch supervisors and operators has not ensured a consistent understanding and application of VTS authority, and this problem has been exacerbated by the regular turnover of active duty personnel, which creates ongoing staffing and experience deficits in the VTS system’s workforce.
The Coast Guard has long recognized the importance of safety risk management, but it has not been applying continuous risk assessment processes to its 12 VTS areas. Current procedures for the collection and quality control of activity and incident data do not support effective quantitative assessments of risk and safety performance within each VTS area or across the VTS system. Subsequently, these data are not regularly analyzed to identify and mitigate adverse safety trends, which has made it difficult (and in some cases impossible) to make statistically valid assessments of how well VTS centers are achieving their goal of reducing collisions, allisions, and groundings within their respective VTS areas.
As a result of this safety study, the NTSB makes recommendations to the Coast Guard, the American Pilots’ Association, the American Waterways Operators, and the Radio Technical Commission for Maritime Services.