LANDSCAPE VITALITY ASSESSMENT OF ASSOCIATED SPACE UNDER OVERPASS: A CASE STUDY OF CHONGQING, CHINA

Urbanization has improved traffic flow via overpasses, yet underpass spaces lag in landscape development, falling short of residents' expectations. This leads to reduced aesthetics, potential misuse, and underutilization of urban land. This study analyzed the landscape vitality of 21 underpass spaces in Chongqing’s urban interchanges. Influencing factors were classified into natural, physical, and event environmental factors based on landscape perception theory, Alexander’s pattern language, and environmental behavior theory. Vitality indicators were identified through literature review, behavioral observation, and focus group interviews. An evaluation system with five criteria was constructed using grey relational analysis and analytic hierarchy process: natural vitality (0.0824), locational vitality (0.2139), spatial vitality (0.2805), facility vitality (0.3386), and cultural vitality (0.0846). These criteria involve 19 indicators, with activity facility quantity having the highest weight (0.1489). Five underpass spaces were evaluated—Egongyan, Huanghuayuan, Sujiaba, Yanggongqiao, and Wulidian—and their landscape vitality ranked. Key areas for improvement include plant aesthetics, entrance accessibility, activity space suitability, noise control, facility quantity, space management, and cultural features. This study provides guidance for future urban underpass space optimization.