## 5 Conclusions and Future Work  
The maritime traffic safety assessment system includes the \"Harbour Approach Channels Design Guidelines\" provided by the International Association of Water Transportation Facilities (PIANC) as a standard for fairway design and Korea's port and fishing port design standards. The PIANC Guide and the Port and Fishing Port Design Standards recommend designing an appropriate fairway width based on the maximum length or width of ships passing through the target sea area in the same direction. The PIANC Guide recommends setting the fairway width 3.8-18.6 times the width of the largest ship, and the port and  
Figure 11: (**a**) Analysis of the ES value before and after expansion of the Yeosu fairway, (**b**) the Masan fairway, and (**c**) the Gadeok fairway. fishing port design standards recommend setting the fairway width at least 1-2 times the length of the largest vessel. As a result of reviewing according to this standard, it was found that the width of the target fairway was appropriate. However, as a result of performing a congestion assessment, which is an evaluation technique in the safety diagnosis system, we found that the congestion level was very high in the Yeosu fairway and the Gadeok fairway at a specific time; with the number of vessels exceeding the carrying capacity of the fairway. This presents a problem when designing a fairway based on the largest ship; and to design an appropriate fairway, the design must consider both the vessel traffic volume and the characteristics of the sea area. To this end, in this study, a case study on the target fairway was conducted. We proposed a method for setting the appropriate width of the fairway that can solve the risk of collision between ships within a certain fairway and the risk of grounding between ships and islands, obstacles, and low water depths. The risk of collision was evaluated using the ES model, and the risk of grounding was evaluated using the IWRAP Mk II evaluation technique. If the frequency of grounding was higher than the probability of 1 in 10,000, it was judged that there was a risk of grounding. As a result of evaluating the collision risk and grounding risk for the four South Coast TSS fairways, the grounding probability was found to be lower than \(10^{-4}\) for all fairways, indicating that the criteria presented in this study were satisfied. However, the overall environmental stress according to the ES model was over 10% in the Yeosu fairway, Masan fairway, and Gadeok fairway; thus, there was a risk for vessel passage. Based on these results, the width of the three fairways showing a high risk of collision was extended from 100 m to 1 km, and the evaluation was performed again using the ES model. As the stress level became less than 10%, the risk of collision was found to be low. In the existing evaluation method, when establishing a new fairway or examining an existing fairway, the fairway width is designed based on the specifications of the largest ship. Thus, a fairway width design method was proposed that reflects the characteristics of different ships and sea areas and considers the risk of ship collision and grounding. However, in this study, additional research is needed, due to the following limitations. 1. Diversification of evaluation models. Among the various risk assessment models, the ES model and the IWRAP Mk II model were used. The ES model quantifies the psychological risk of the operator, and the IWRAP Mk II model is used in many areas. However, because results can be derived differently, depending on various theories and research methodologies, it is necessary to derive comprehensive results through a diversification of evaluation models. 2. Ship control simulation. In the maritime traffic safety diagnosis, the fairway design and adequacy are primarily reviewed in accordance with the design standards and guidelines.