Spatiotemporal dynamics and driving mechanisms of the coupling coordination between transportation carbon emissions and regional economy: a case study of Sichuan Province

The transportation sector constitutes a significant source of carbon emissions, exhibiting pronounced regional disparities that challenge uniform mitigation strategies. However, existing literature often overlooks the micro-driving mechanisms of these emissions within geologically complex regions. This study investigates Sichuan Province, China—a region characterized by extreme topographic diversity—to scrutinize the evolutionary trajectory of transportation-related carbon emissions using Hurst and Theil indices. Furthermore, a coupling coordination model integrated with geographical detector instruments is employed to rigorously evaluate the coordination level between transportation carbon emissions and the regional economy. This study contributes to the literature by: (1) constructing a multi-level evaluation framework that unveils spatial heterogeneity often obscured in national-level aggregates; (2) identifying a distinct “boundary effect,” wherein high-emission regions are spatially shifting towards the southern and eastern basins, standing in sharp contrast to the western plateau; and (3) revealing that population size functions as the primary micro-driver of coupling coordination, thereby providing a precise scientific basis for differentiated decarbonization strategies. The empirical results indicate a persistent but decelerating upward trend in emissions, suggesting that while coupling quality is improving, targeted policies optimizing the energy structure in the central region and promoting urbanization in the east are urgently required.