Developing a Composite Street Livability Index for Commercial Streets in Indian Cities: A Case Study of T. Nagar (Thyagaraya Nagar), Chennai

Commercial streets are the most vibrant public spaces in rapidly urbanizing cities, and their livability has studied limited in the context of Indian urban environments. Existing national and international street assessment frameworks largely emphasize technical design compliance and walkability indicators while giving limited attention to the sociability and vibrancy that characterize commercial streets. This study develops a Composite Street Livability Index (SLI) to evaluate commercial street environments by in-tegrating physical, functional, and experiential dimensions. The methodology adopts a mixed-methods approach combining physical street audits, perception surveys, and behavioural observations. Five key dimensions of livability are identified from national and international frameworks: safety and security; accessibility and connectivity; comfort and amenities; sociability and vibrancy; management and aesthetics. The framework is applied to the commercial street of Thyagaraya Road, T.Nagar, located in Chennai, one of the most active retail districts in India. The results reveal an overall Street Livability Index score of 80.2 out of 100, indicating relatively high livability despite notable spatial variations across the six street nodes. Safety and security (27.8%) and accessibility and connectivity (24.2%) contribute the largest shares to the overall index, reflecting the dominance of pedestrian infrastructure and mobility conditions in shaping street performance. Safety and security recorded the highest qualitative rating (4.07/5), highlighting the corridor’s strong commercial activity and social interaction. However, lower scores in comfort, amenities, and management dimensions indicate the need for improved environmental quality and street maintenance. The proposed index demonstrates the value of integrating infrastructure and social activity indicators to assess commercial streets comprehensively and provides a context-sensitive evaluation tool for planners and policymakers to support people-oriented street transformation in Indian cities.