## 5 Conclusions and Future Work
In addition, ship control simulation is additionally conducted to review safety in an environment similar to the real one, as well as to examine the feasibility of restricting the fairway width according to the characteristics of the sea area. In a follow-up study, various research methods, such as ship steering simulation, will be used to improve the qualitative completeness of the research. The purpose will be to verify the safety according to the collision risk, grounding risk, and fairway width extension derived from this study, using a ship steering simulation evaluation for operators. 3. The grounding probability was evaluated for the nearest island, obstacle, and low water area, without considering the fairway lines, it is not expected that there will be any serious change in the grounding probability even if the fairway is partially expanded. However, assuming that the ship's trajectories when they navigate along the fairway follow a normal distribution, the grounding probability may increase depending on the deviation in traffic. This study evaluates the grounding probability based on actual data, it was considered too difficult to include the method of calculating the grounding probability by estimating the vessel's track within the scope of the study. Therefore, we present these notes and comments as limitations of this study and suggest that follow-up studies deal with the estimated change in the grounding probability, due to fairway expansion, and perform verifications through actual measurements. Conceptualization, Y.-S.P., W.-S.K. and S.P. ; methodology, W.-S.K. and M.-K.L. ; validation, Y.-S.P. and W.-S.K. ; writing--original draft preparation, W.-S.K. ; writing--review and editing, Y.-S.P. and S.P. ; visualization, W.-S.K. and M.-K.L. ; supervision, Y.-S.P. All authors have read and agreed to the published version of the manuscript. This research received no external funding. Not applicable. The data presented in this study are available on request from the corresponding author. The data are not publicly available due to privacy. The authors declare no conflict of interest. * _Ministry of Oceans and Fisheries. Vessel Fairway Safety Assessment Study--Coastal Fairway Safety Assessment in 2015; Ministry of Oceans and Fisheries: Sejong City, Korea, 2015; Chapter 3; pp. 142-267. * _Ministry of Oceans and Fisheries. Vessel Fairway Safety Assessment Study--A Study on Improvement Measures for Vessel Fairway Assessment in 2021; Ministry of Oceans and Fisheries: Sejong City, Korea, 2021; Chapter 3; pp. 102-160. * _[PERSON] Basic Study on Design Guideline of Traffic Separation Scheme. J. Korean Nav. Port Res._**2007**, _31_, 173-178. * _[PERSON] Recent Trends in Navigation Safety in the Dover Strait. In Proceedings of the of 3 rd International Symposium on Marine Traffic Service, Liverpool, UK, 3-6 April 1978. * _[PERSON]; [PERSON] Safety Assessment of Waterway Network in Bay Area. In Proceedings of the 27 th International Piano Navigation Congress, Osaka, Japan, 19-26 May 1990. * _[PERSON]; [PERSON]; [PERSON] An Assessment of the Quantitative Effect of TSS by Vessel Traffic Flow Simulation. J. Korean Soc. Transp._**2003**, _21_, 41-49. * _PIANC. Harbour Approach Channels Design Guidelines_; PIANC Report N-121; Maritime Navigation Commission: Bruxelles, Begium, 2014. * _[PERSON]; [PERSON] Optimization of fairway design parameters: Systematic approach to manoeuvering safety. Int. J. Naval Arch. Ocean Eng._**2020**, _12_, 129-145. [CrossRef]
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