RT Journal Article SR Electronic A1 Mohanty, Malaya A1 Ranjan Samal, Satya A1 Samal, Kundan T1 Developing a Speed-Based Congestion Severity Index Using the Clustering Technique for Developing Countries JF Communications - Scientific Letters of the University of Zilina YR 2025 VO 27 IS 2 SP D67 OP D75 DO 10.26552/com.C.2025.020 UL https://komunikacie.uniza.sk/artkey/csl-202502-0005.php AB A novel approach for traffic congestion assessment has been presented using percentile speeds as key indicators, focusing on urban roads. By evaluating the 98th, 85th, and 15th percentile speeds, authors of the research developed a congestion severity index, offering a more precise and intuitive method for analyzing traffic flow compared to traditional travel time-based indices. Key congestion indices, such as the Planning Time Index (PTI) and Travel Time Index (TTI) were compared to percentile speeds, revealing a significant association with the 15th and 85th percentile speeds. The K-means clustering technique was applied to classify congestion severity into three levels, validated by a high silhouette value indicating the robust clustering. The study's speed-based congestion severity index provides a practical and efficient framework for real-time congestion management, particularly in heterogeneous traffic environments.