Spatiotemporal Patterns and Drivers of Population–Transport Coordination in the Pearl River Delta

The demographic–transport nexus is central to regional integration, but remains insufficiently studied in rapidly urbanizing contexts. Taking China’s Pearl River Delta (PRD) as a representative megaregion, this study uses panel data from nine PRD cities spanning 1990 to 2020. We construct an entropy-weighted indicator system and apply a coupling–coordination model in combination with spatial Durbin regressions to trace the co-evolution of population and transport systems and identify their driving forces. Findings reveal that: (1) the regional coupling-coordination index rose from 0.21 to 0.54 but still shows a clear core–periphery gradient—Guangzhou and Shenzhen already display high coordination, whereas ZhaoQing and Jiangmen lag behind; (2) economic growth, a consumption-oriented economic structure and technological progress significantly enhance coordination; (3) the 2009 PRD Master Plan mainly benefits core cities, with limited policy spill-overs; (4) medical-service provision improves coordination, while basic-education supply is not significant, highlighting service-level disparities. We recommend strengthening peripheral inter-city corridors, building 30- to 60-minute commuting rings, and linking transport investment to real-time coupling metrics and coordinated industry relocation to advance the region toward higher-level integration.