As the transportation paradigm shifts from vehicle-oriented to pedestrian-oriented, active research has been conducted on road designs that consider the safety of pedestrians, cyclists, and personal mobility users. This study aims to respond to this change by developing installation warrant factors and improving the minimum size design standards for triangular islands. This study involved reviewing domestic and international laws and guidelines, analyzing the current installation status of triangular islands, examining case studies of improvements, and assessing policy changes. Based on the findings, important insights were derived, and improvement plans to enhance the safety of pedestrians, vulnerable users, and other road users were proposed. This study identified several issues and confirmed that policies in both domestic and international contexts are shifting towards minimizing or removing the triangular islands. Based on these findings, this study developed 24 factors for installation warrants to determine the installation of triangular islands, such as the design speed and peak-hour volume for pedestrians. In addition, the proposed improvements suggest increasing the minimum size design standards from 9m2 to 22m2 to ensure the safety of users. The factors of installation warrants and improved minimum size design standards proposed in this study are expected to help shift the operation of triangular islands from a vehicle-oriented to a pedestrian-oriented approach.