Enhancing Safety of Navigation: Redesigning Precautionary Areas into Roundabouts in Marine Traffic Separation Schemes

Roundabouts are widely used in road transport to improve traffic flow and reduce congestion by enabling continuous movement in a circular pattern, minimizing stops, enhancing safety, and reducing delays compared to that of signaled intersections. However, roundabouts are rarely used in marine traffic. This study investigates the feasibility of redesigning existing rectangular precautionary areas within traffic separation schemes (TSSs) into circular roundabouts using marine traffic data incorporating both the number of ships passing and crossing, as well as microscopic movement data to further analyze the follow-up times and gaps based on ship domains. This study further assesses the overall performance of the proposed design, drawing on notable formulas and best practices in road transport. The Lombok Strait TSS, in Indonesia, is used as the study area, which is a particularly sensitive sea area and one of the critical “chokepoints” in the maritime supply chain. The results indicate that replacing rectangular areas with circular roundabouts in a TSS can significantly improve traffic management and navigation safety. This study offers a practical approach for redesigning rectangular precautionary areas into circular roundabouts and provides valuable insights for maritime authorities and policymakers aiming to develop more efficient TSS designs in the future.