Abstract
Abstract Infrastructure investment mobilized under China’s Belt and Road Initiative (BRI) has emerged as a prominent force shaping urban transformation in Southeast Asia. This study develops an Economic Sustainable Development Index (ESDI) grounded in the Growth-Poverty-Inequality (GPI) triangle and examines its spatiotemporal evolution from 2000 to 2022 using multi-source spatial data. To assess the association between infrastructure investment and ESDI, we implement a dual-track empirical framework combining Continuous Staggered Difference-in-Differences (DiD) and Panel Vector Autoregression (PVAR), while accounting for trade-related dynamics. The results indicate that accumulated infrastructure stock is positively and robustly associated with improvements in ESDI after controlling for trade fluctuations. Notably, the effects exhibit a lag structure with sustainability gains emerging approximately 4 years after investment onset, consistent with a post-construction gestation period. Spatial patterns suggest a closer alignment between infrastructure investment and economic sustainability under constrained urban expansion. Together, these findings highlight the potential role of state-led infrastructure investment as a structural driver of higher-quality urbanization under rapid economic development in Southeast Asia.