## 4 Results
### Risks Related to Vessel Traffic in the Area Covered by the VTS Systems  
To address the issue of risks associated with vessel traffic in areas covered by the VTS systems, the IWRAP MK II software [57] was used to calculate the probability of collision. The aim of IWRAP MK II is to provide the user with a standardized quantitative method for calculating the probability of a collision in analyzed waterway [58]. The need to use this type of software follows directly from recommendations in the literature [3]. The IWRAP MK II software uses historical data extracted from each AIS, which are statistically processed to achieve the intended results. An AIS is mandatory for seagoing \begin{table}
\begin{tabular}{c c l} \hline \hline
**VTS System** & & **Selected Features of Traffic Management** \\ \hline \multirow{6}{*}{VTS Zatoka Gdanska} & \(\bullet\) & Indicating and selecting appropriate sea routes for the serviced vessels; \\  & \(\bullet\) & Managing vessels entering to the ports of Gdynia, Gdansk, and Port Polnocny, which are located radially around the Gulf of Gdansk; \\  & \(\bullet\) & Utilizing the arrangement of navigation routes and the TSS, which practically eliminates the issue of two-way traffic; \\  & \(\bullet\) & Assigning directional entry and exit lanes for vessels, allowing them to pass each other safely; \\  & VTS Zatoka Gdanska & \(\bullet\) & Monitoring of vessel traffic regardless of weather conditions such as wind speed, visibility and water levels; \\  & \(\bullet\) & Not involved in planning vessel queuing; such decisions are made by another decision-making center (the Harbor Master Duty Service); \\  & \(\bullet\) & Not responsible for the most sensitive stage of a vessel’s entry into the port (the section from the Pilot Station to the quay), where additional services such as pilotage and tug assistance are planned. \\ \hline \multirow{6}{*}{VTS Lawica Slupska} & \(\bullet\) & A lack of direct management of vessel traffic using the TSS system; \\  & \(\bullet\) & The width of the directional traffic lanes ensures the free flow of vessels through the zone; \\  & \(\bullet\) & The directional traffic lanes are wide enough, allowing for safe and unobstructed movement of vessels without operator assistance. \\ \hline \multirow{6}{*}{VTS Swinoujsce-Szczecin} & \(\bullet\) & Traffic management covers the entire process from the moment the vessel is taken over at the boundary of the VTS system’s responsibility until docking, and for departing vessels, from docking to leaving the port; \\  & \(\bullet\) & Vessel traffic planning includes all aspects related to the ship’s visit to the port, requiring coordination of various activities and services; \\  & \(\bullet\) & The decision-making process involves multiple stakeholders, including Port Captain services and Port Authority coordination; \\  & \(\bullet\) & The VTS operator actively participates in the decision-making process at every stage of the vessel’s entry and exit from the port, unlike VTS Gulf of Gdansk, where the operator receives a pre-made decision; \\  & \(\bullet\) & VTS Swinoujsce-Szczecin operators are involved in managing associated services such as pilotage and towing; \\  & \(\bullet\) & The decision-making process is the result of collaboration between two VTS centers, as well as other stakeholders and associated services. \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Comparison of the VTS systems in Poland according to the criterion traffic management (our own elaboration based on [53; 54; 55; 56]). vessels and the data are transmitted by transmitters operating on VHF channels. According to international regulations [59], the transmitted data are divided into three groups: static data, dynamic data and voyage-related data. Among the relevant data used for statistical processing are a vessel's position, course and speed; identification data such as ship's name; draught; longitude; latitude; etc.